WO2012098378A1

WO2012098378A1 - Polymeric materials

Info

Publication number: WO2012098378A1
Application number: PCT/GB2012/050063
Authority: WO
Inventors: Marcus Jarman-Smith; Nuno Sereno; Joanne Wilson; Mark Brady
Original assignee: Invibio Limited
Priority date: 2011-01-18
Filing date: 2012-01-13
Publication date: 2012-07-26
Also published as: GB2487467A; GB201200515D0; GB201100815D0

Abstract

A method of making a material, for example a porous material for a medical implant or part thereof comprises: (a) providing a mixture of polymeric material and filler material in a mould; (b) heating the mixture in order to melt the polymeric material; and wherein the material in the mould is subjected to a pressure of less than 2MPa during step (b). The filler material may be removed so that a porous material, defined by the polymeric material remains.

Description

POLYMERIC MATERIALS

This invention relates to polymeric materials and particularly, although not exclusively, relates to porous polymeric materials for use, for example, in making medical implants or parts thereof and to methods of manufacturing porous materials and components.

It is well known to make porous medical implants and there are a number of prior art proposals. For example, methods of creating porous osseoconductive PEEK, allegedly suitable for medical use, have been described and include heat sintering of particles (see WO2009/09959). In heat sintering, particles of polymer are held in a mould in contact with each other and the polymer heated to just allow thermal bonding of the adjacent polymer particles at their contact points. However, disadvantageously, the pore diameter is dictated by the particle sizes of the selected polymer and this may not be optimal for bone ingrowth. Also, the final porous shape is dictated by the mould used since machining post-sintering is generally difficult. Furthermore, since the sintered particles are only bonded at their contact points, the bond between the particles may be relatively weak leading to potential friability of the porous material.

US2010/0255053 relates to a method of manufacturing a medical device having a porous scaffold in combination with a bioactive material. This however uses a method of manufacture which does not lend itself to allowing subsequent machining or finishing of a near net shape and again relies on sintering of polymer particles which places limitations on pore diameter.

Other porous materials such as porous HA (Hydroxyapatite) fillers or mineral based analogues or bioglasses have optimal porosity but no structural integrity (HA) or may be excessively brittle alone (bioglasses).

It is an object of embodiments of the present invention to address problems associated with porous polymeric materials and/or the manufacture of such materials.

According to a first aspect of the present invention, there is provided a method of making a material, said method comprising:

(a) providing a mixture of polymeric material and filler material in a mould;

(b) heating the mixture in order to melt the polymeric material; and

wherein the material in the mould is subjected to a pressure of less than 2MPa during step (b).

Suitably, the method comprises a method of making a material having pores defined by the polymeric material. Suitably, the method comprises a method of making a porous material. The method may comprise a method of making a porous polymeric material with filler material located within the pores of the polymeric material. The method may comprise removing the filler material from the pores. Alternatively, the method may comprise leaving the filler material in the pores. The method may comprise a method of making an interconnected compound material.

Suitably, there is provided a method of making a porous material, said method comprising:

(a) providing a mixture of polymeric material and filler material in a mould;

(b) heating the mixture in order to melt the polymeric material; and

Suitably, the material in the mould is subjected to a pressure of less than 2MPa during step (b).

Suitably, the material in the mould is subjected to a pressure of less than 1 MPa during step (b).

Preferably, the material in the mould is subjected to a pressure of less than 500kPa, suitably to less than 200kPa, for example to less than 1 10kPa of compressive load during step (b). Preferably, the material in the mould is subjected to atmospheric pressure during step (b).

Suitably, the material in the mould is subjected to a pressure of less than 2MPa during step (a).

Suitably, the material in the mould is subjected to a pressure of less than 1 MPa during step (a).

Preferably, the material in the mould is subjected to a pressure of less than 500kPa, suitably to less than 200kPs, for example to less than 1 10kPa of compressive load during step (a). Preferably, the material in the mould is subjected to atmospheric pressure during step (a).

Suitably, the material in the mould is subjected to a pressure of less than 2MPa between step

(a) and step (b). Suitably, the material in the mould is subjected to a pressure of less than 1 MPa between step (a) and step (b). Preferably, the material in the mould is subjected to a pressure of less than 500kPa, suitably to less than 200kPa, for example to less than 1 10kPa between step (a) and step (b). Preferably, the material in the mould is subjected to atmospheric pressure between step (a) and step (b).

Suitably, the material in the mould is subjected to a pressure of less than 2MPa following step

(b) at least until the material has cooled. Suitably, the material in the mould is subjected to a pressure of less than 1 MPa following step (b) at least until the material has cooled. Preferably, the material in the mould is subjected to a pressure of less than 500kPa, suitably to less than 200kPa, for example to less than 1 10kPa following step (b) at least until the material has cooled.

Suitably, the method comprises subjecting the material in the mould to atmospheric pressure between step (a) and step (b). Suitably, the method comprises subjecting the material in the mould to atmospheric pressure following step (b) at least until the material has cooled. Suitably, the method comprises subjecting the material in the mould to a pressure of less than 1 MPa.

Preferably, the material in the mould is subjected to a pressure of less than 500kPa, suitably to less than 200kPa, for example to less than 1 10kPa.

Preferably, step (b) of the method comprises:

(b)(i) subjecting the mixture to a temperature below the melting point of the polymeric material to pre-heat the mixture; and then

(b)(ii) subjecting the mixture to a temperature above the melting temperature of the polymeric material in order to melt the polymeric material.

Suitably, the material in the mould is subjected to a pressure of less than 2MPa during step (b)(i). Suitably, the material in the mould is subjected to a pressure of less than 2MPa during step (b)(ii).

Suitably, the method comprises subjecting the material in the mould to a pressure of less than 1 MPa during step (b)(ii). Suitably, the method comprises subjecting the material in the mould to a pressure of less than 1 MPa during step (b)(i) or step (b)(ii). Preferably, the material in the mould is subjected to a pressure of less than 500kPa, suitably to less than 200kPa, for example to less than 1 10kPa during step (b)(i). Preferably, the material in the mould is subjected to atmospheric pressure during step (b)(i). Preferably, the material in the mould is subjected to a pressure of less than 500kPa, suitably to less than 200kPa, for example to less than 1 10kPa during step (b)(ii). Preferably, the material in the mould is subjected to atmospheric pressure during step (b)(ii).

Suitably, the method comprises subjecting the material in the mould to atmospheric pressure between step (a) and step (b)(i). Suitably, the method comprises subjecting the material in the mould to atmospheric pressure between step (b)(i) and step (b)(ii). Suitably, the method comprises subjecting the material in the mould to atmospheric pressure following step (b)(ii) at least until the material has cooled.

Suitably, the material in the mould is subjected to less than 30kg of compressive load during step (b).

Suitably, the material in the mould is subjected to less than 20kg of compressive load during step (b). Suitably, the material in the mould is subjected to less than 10kg of compressive load during step (b).

Preferably, the material in the mould is subjected to less than 5kg of compressive load, suitably to less than 2kg of compressive load, for example to less than 1 kg of compressive load during step (b). Preferably, the material in the mould is subjected to no compression force during step (b).

Suitably, the material in the mould is subjected to less than 30kg of compressive load during step (a). Suitably, the material in the mould is subjected to less than 20kg of compressive load during step (a).

Suitably, the material in the mould is subjected to less than 10kg of compressive load during step (a). Preferably, the material in the mould is subjected to less than 5kg of compressive load, suitably to less than 2kg of compressive load, for example to less than 1 kg of compressive load during step (a). Preferably, the material in the mould is subjected to no compression force during step (a). Suitably, the material in the mould is subjected to less than 30kg of compressive load between step (a) and step (b). Suitably, the material in the mould is subjected to less than 20kg of compressive load between step (a) and step (b). Suitably, the material in the mould is subjected to less than 10kg of compressive load between step (a) and step (b). Preferably, the material in the mould is subjected to less than 5kg of compressive load, suitably to less than 2kg of compressive load, for example to less than 1 kg of compressive load between step (a) and step (b). Preferably, the material in the mould is subjected to no compression force between step (a) and step (b). Suitably, the material in the mould is subjected to less than 30kg of compressive load following step (b) at least until the material has cooled. Suitably, the material in the mould is subjected to less than 20kg of compressive load following step (b) at least until the material has cooled. Suitably, the material in the mould is subjected to less than 10kg of compressive load following step (b) at least until the material has cooled. Preferably, the material in the mould is subjected to less than 5kg of compressive load, suitably to less than 2kg of compressive load, for example to less than 1 kg of compressive load following step (b) at least until the material has cooled. Suitably, the method comprises subjecting the material in the mould to no compression between step (a) and step (b). Suitably, the method comprises subjecting the material in the mould to no compression following step (b) at least until the material has cooled.

Suitably, the method comprises subjecting the material in the mould to less than 10kg of compressive load.

Preferably, the material in the mould is subjected to less than 5kg of compressive load, suitably to less than 2kg of compressive load, for example to less than 1 kg of compressive load.

Preferably, step (b) of the method comprises:

Suitably, the material in the mould is subjected to less than 30kg of compressive load during step (b)(i). Suitably, the material in the mould is subjected to less than 20kg of compressive load during step (b)(i). Suitably, the material in the mould is subjected to less than 30kg of compressive load during step (b)(ii). Suitably, the material in the mould is subjected to less than 20kg of compressive load during step (b)(ii).

Suitably, the method comprises subjecting the material in the mould to less than 10kg of compressive load during step (b)(ii). Suitably, the method comprises subjecting the material in the mould to less than 10kg of compressive load during step (b)(i) or step (b)(ii).

Preferably, the material in the mould is subjected to less than 5kg of compressive load, suitably to less than 2kg of compressive load, for example to less than 1 kg of compressive load during step (b)(i). Preferably, the material in the mould is subjected to no compression force during step (b)(i). Preferably, the material in the mould is subjected to less than 5kg of compressive load, suitably to less than 2kg of compressive load, for example to less than 1 kg of compressive load during step (b)(ii). Preferably, the material in the mould is subjected to no compression force during step (b)(ii).

Suitably, the method comprises subjecting the material in the mould to no compression between step (a) and step (b)(i). Suitably, the method comprises subjecting the material in the mould to no compression between step (b)(i) and step (b)(ii). Suitably, the method comprises subjecting the material in the mould to no compression following step (b)(ii) at least until the material has cooled.

Suitably, the method comprises subjecting the mixture to minimal compression during moulding which may allow the production of a porous material having interconnected pores. The material may thus have an open structure.

Generally when materials are blended and molten they are also compressed to aid bonding and consolidation. During compression moulding for example the material may be subjected to compressive loads of 1 ton. Surprisingly it has been found that according to the method of the present invention suitable bonding and consolidation may be achieved without placing significant compressive force on the blend and melt.

Surprisingly, it has been found that the use of minimal compression may allow the manufacture of a porous material which has the requisite bonding and consolidation and which may have a more open structure. Surprisingly it has been found that the use of minimal compression during moulding may allow the manufacture of a porous material having desirable porosity without compromising strength. The method may surprisingly allow the manufacture of a porous material having open interconnectivity of pores and which may be suitable for use in medical applications. Suitably, the method comprises pre-heating the mixture in order to build up "heat stock". This may mean that when the temperature is raised the polymeric material throughout the mould may melt more evenly.

Surprisingly it has been found that the method of the present invention may allow the manufacture of a porous material without the need to apply large pressures to the material in the mould and whilst avoiding problems associated with exposing material in different areas of the mould to uneven temperatures. Suitably, the method comprises heating the mould in an oven. The method may comprise heating in an inert environment, for example a nitrogen environment, which may restrict polymer degradation. The use of an inert environment may allow the temperature of the polymeric material to be maintained above the melting temperature for a longer time period without degrading and may thus reduce difficulties associated with exposing material in different areas of the mould to uneven temperatures. Suitably, step (b)(i) is performed in an inert atmosphere. Step (b)(i) may be performed in an inert atmosphere. Step (b) may be performed in an inert atmosphere. Preferably, step (b) of the method comprises heating the mould in an oven and comprises:

(b)(i) maintaining the oven at a first temperature below the melting point of the polymeric material to pre-heat the mixture; and then

(b)(ii) increasing the temperature of the oven to a second temperature which is above the melting temperature of the polymeric material and maintaining the oven at said second temperature in order to melt the polymeric material.

The method may comprise placing a mould in an oven which has been pre-heated to a temperature below the melting temperature of the polymeric material. Alternatively, the mould may be placed in an oven which has not been pre-heated but which is set to go directly to a temperature below the melting temperature of the polymeric material.

Suitably, the method comprises heating the mixture until all the polymeric material is molten. Suitably, the method comprises heating the mixture such that all the polymeric material is fully molten. Suitably, the method comprises heating the mixture until the polymeric material is flowable. Suitably, the method comprises heating the mixture until all the polymeric material is flowable.

Suitably, the method comprises holding the mixture at a temperature above the melting temperature of the polymeric material for a sufficiently long period of time to permit full melting of the polymeric material and merging together of adjacent polymeric material.

Suitably, the mixture comprises heating the polymeric material so as to cause full bonding of polymeric material throughout the porous material. Suitably, the mixture comprises heating the polymeric material so as to cause full bonding and flow of polymeric material around any structures in the mould. The porous material may thus have good structural integrity and low friability.

The method may comprise blending a filler material and a polymeric material such that the presence of the filler material within the mixture may allow the holding of the mixture at a molten state for sufficiently long periods of time to ensure full melt and flow together of the polymeric material.

Suitably, the method comprises retaining the filler material within the porous material until it has been processed downstream of the moulding stage. The filler material may for example give added structural integrity to the porous material which may be beneficial in a machining stage. Suitably, the method comprises removing the filler material subsequent to the moulding stage. Suitably, the method comprises removing the filler material in the final stage. Suitably, the filler is removed by solubilising it. Retaining the filler material until the final stage may help prevent contamination of the pores during processing downstream of the moulding stage.

The mould may have an internal volume of at least 10,000mm³. Suitably, the mould has an internal volume of at least 20,000mm³. Suitably, the mould has an internal volume of around 50,000mm³. Suitably, the mould has an internal volume of less than 125,000 mm³.

The mould may have an internal height of at least 5mm, for example at least 10mm. Suitably, the mould has an internal height of around 20mm. Suitably, the mould has an internal height of less than 50mm. The mould may have an internal width of at least 20mm, for example at least 40mm. Suitably, the mould has an internal width of around 50mm. Suitably, the mould has an internal width of less than 100mm. The mould may have an internal length of at least 20mm, for example at least 40mm. Suitably, the mould has an internal length of around 50mm. Suitably, the mould has an internal length of less than 100mm.

Suitably, step (b)(i) comprises subjecting the mixture to a temperature within 200°C of the melting point of the polymeric material. Preferably, step (b)(i) comprises subjecting the mixture to a temperature within 150°C of the melting point of the polymeric material. Suitably, step (b)(i) comprises subjecting the mixture to a temperature within 100°C of the melting point of the polymeric material. Suitably, step (b)(i) comprises subjecting the mixture to a temperature within 50°C of the melting point of the polymeric material.

Suitably, step (b)(i) comprises subjecting the mixture to a temperature of at least 150°C. Preferably, step (b)(i) comprises subjecting the mixture to a temperature of at least 200°C. Suitably, step (b)(i) comprises subjecting the mixture to a temperature of at least 250°C. Suitably, step (b)(i) comprises subjecting the mixture to a temperature of at least 300°C.

Suitably, step (b)(i) comprises subjecting the mixture to a temperature below the melting point of the polymeric material to pre-heat the mixture for a period of at least 10 minutes. Preferably, step (b)(i) comprises subjecting the mixture to a temperature below the melting point of the polymeric material to pre-heat the mixture for a period of at least 20minut.es. Suitably, step (b)(i) comprises subjecting the mixture to a temperature below the melting point of the polymeric material to pre-heat the mixture for a period of at least 30 minutes. Step (b)(i) may comprise subjecting the mixture to a temperature below the melting point of the polymeric material to pre-heat the mixture for a period of around 40 minutes.

Suitably, step (b)(i) comprises subjecting the mixture to a temperature of at least 150°C for at least 20 minutes. Suitably, step (b)(i) comprises subjecting the mixture to a temperature within 50°C of the melting temperature of the polymer for at least 20 minutes. Suitably, step (b)(ii) comprises subjecting the mixture to a temperature above the melting temperature of the polymeric material for a period of at least 10 minutes. Suitably, step (b)(ii) comprises subjecting the mixture to a temperature above the melting temperature of the polymeric material for a period of at least 20 minutes. Suitably, step (b)(ii) comprises subjecting the mixture to a temperature above the melting temperature of the polymeric material for a period of at least 30 minutes. Suitably, step (b)(ii) comprises subjecting the mixture to a temperature above the melting temperature of the polymeric material for a period of around 40 minutes.

Suitably, step (b)(i) comprises pre-heating the mixture for a period of time lasting for at least 50% of the period of time for which the mixture is heated in step (b)(ii). Preferably, step (b)(i) comprises pre-heating the mixture for a period of time lasting for at least 100% of the period of time for which the mixture is heated in step (b)(ii). Step (b)(i) may comprise pre-heating the mixture for a period of time lasting for at least 200% of the period of time for which the mixture is heated in step (b)(ii).

Suitably, step (b)(ii) is commenced within 12 hours of commencing step (b)(i). Suitably, step (b)(ii) is commenced within 6 hours of commencing step (b)(i). Step (b)(i) may be commenced within 4 hours, for example within 1 or 2 hours of commencing step (b)(i). Suitably, step (b)(ii) is terminated within 1 hour of terminating step (b)(i). Suitably, step (b)(ii) is terminated within 40 minutes of terminating step (b)(i). Step (b)(i) may be terminated within 30 minutes of terminating step (b)(i).

Suitably, step (b)(ii) is performed immediately following step (b)(i). Suitably, the mixture is not allowed to cool between step b(i) and step b(ii).

Suitably, the method comprises combining polymeric material and filler material prior to step (a). Suitably, the method comprises mixing un-molten polymeric material with filler material. The method may comprise using timed conveyors arranged to meet and combine polymeric material and filler material. The method may employ mechanical devices that facilitate even blending and homogeneous particle mixing to produce the polymeric material and filler material mixture. Alternatively, the filler material and polymeric material may be combined in the mould by careful laying up of alternative materials in the mould.

Suitably, the method comprises allowing the porous material to cool and then further processing it.

Suitably, the method comprises a method of making a near net shape of porous material in a mould which can then be machined and/or finished to produce an end shape of porous material.

Suitably, the method comprises manufacturing a material using a soluble filler and the method comprises making a porous material in a mould and then machining the material to a desired shape and then removing the soluble material following the machining step.

Suitably, the method comprises removing filler material from the porous material as the last stage of the method. Removal of the filler material at the last stage may allow sterility to be better maintained. There may be less risk of contaminants entering into the body of the porous material during manufacturing stages, such as machining, if the pores remain blocked by filler material until after that stage.

Suitably, the method comprises leaching the polymeric material to remove the filler material. Alternatively, the method may comprise manufacturing the porous material using a filler that is semi-permanent or permanent and which may thus be left in the porous material. The method may thus comprise manufacturing a porous material comprising a pores defined by a polymeric material and which pores may be open and/or which pores may contain filler material. Suitably, the filler material comprises a "space filler", for example salts or soluble glasses, adapted to maintain spaces between the polymeric material during the moulding stage such that the method produces a porous material. Suitably, the space filler is soluble, suitably water soluble. The filler material may comprise a permanent or semi-permanent filler, for example BaS0₄, Carbon fibres, glass fibres, HA, TCP, antimicrobial compounds, bioactive compounds, bioactive ceramics or CFR. The filler material may comprise a bioglass, for example a reactive bioglass. The filler may comprise 45S5 bioglass. The filler may comprise a a glass with 45 wt.% of Si0₂ and 5: 1 ratio of CaO to P₂0₅. The method may allow the combination of a polymeric material such as PEEK with a reactive bioglass such as 45S5 whilst substantially avoiding reaction between the polymeric material and the reactive bioglass.

The method may comprise manufacturing a porous material which comprises a "space filler", for example a salt (suitably a water-soluble salt e.g. sodium chloride) or soluble glass, and additional permanent or semi-permanent fillers, for example BaS0₄, Carbon fibres, glass fibres, HA, TCP, antimicrobial compounds, bioactive compounds, bioactive ceramics or CFR.

The method may comprise manufacturing a porous material which comprises polymeric material powder, granules, microgranules and/or particles, for example PEEK powder, granules, microgranules and/or particles. The method may comprise manufacturing a porous material which comprises polymeric material powder, granules, microgranules and/or particles, for example PEEK powder, granules, microgranules and/or particles mixed with permanent or semi-permanent fillers, for example BaS0₄, Carbon fibres, glass fibres, HA, TCP, antimicrobial compounds, bioactive compounds, bioactive ceramics or CFR in addition to a soluble space filler, for example salts or soluble glasses.

The method may comprise creating areas of solid polymeric material, for example PEEK, by adding only polymeric material to regions of the mould and/or by placing the mixture onto solid polymeric inserts and/or by subsequently moulding polymeric material over regions of the porous material.

The method may comprise placing the mixture onto other materials such as cobalt chrome to create surfaces with a polymer and/or porosity. It will be appreciated that other biomaterial combinations are possible. For example the porous material could be placed with elastomers or other materials with a lower melting temperature to allow these materials to interbond.

Suitably, the method comprises providing a mixture of polymeric material and filler material in a mould wherein the ratio by weight of polymeric material to filler material in the mould is between 0.5 to 1 and 2 to 1 , for example around 1 to 1.

Suitably, the method comprises providing a mixture of polymeric material and filler material in a mould wherein the ratio of the average particle size of polymeric material to filler material is between 0.5 to 1 and 2 to 1 , for example around 1 to 1. Suitably, the polymeric material has an average particle size of less than 0.5mm diameter, for example of around 300μιη. Suitably, the filler material has an average particle size of less than 0.5mm diameter, for example of around 300μιη. Suitably, the method comprises making a porous material having pores between 200μιη and 700μιη. The porous material may thus be suitable to allow bone ingrowth. The material may have an average pore size of between 350μιη and 450μιη. The material may for example have an average pore size of around 400μιη The material may have a porosity of at least 40%, for example around 50%. The material may for example have an average pore size of around 400μιη and may have a porosity of around 50%.

Suitably, the method comprises a method of making a radiolucent porous material.

Suitably, the method comprises making a porous material which has macro porosity. Suitably, the method comprises making a porous material which has an osseoconductive range of pore size. Suitably, the method comprises a method of making a porous material having a pseudo- randomised structure which may be more representative of in vivo bone. Suitably, the method comprises a method of making a porous material having a pseudo-randomised porous structure. Suitably, the method comprises a method of making a porous material having a compressive strength of at least 5MPa. Suitably, the method comprises a method of making a porous material having a compressive strength of at least 7MPa. The method may comprise a method of making a porous material having a compressive strength of up to 50MPa. The method may comprise a method of making a porous material having a compressive strength of up to 40MPa.

Suitably, the method comprises a method of making a porous material, wherein the method uses filler material in an amount of at least 40% by weight, for example around 50% by weight of the mixture of filler material and polymeric material. Suitably, the method provides for the manufacture of a porous material in which there is interconnectivity of pores.

Suitably, the method provides a means of combining reactive filler material with polymeric material. The method may for example provide a method of combining 45S5 bioglass and PEEK and they may suitably be combined in an interconnected manner. Said method preferably comprises selecting first particles which comprise said polymeric material and selecting second particles which comprise said filler material. Said composition may be formed by blending, preferably dry-blending, said first particles and said second particles. A substantially homogenous blend is preferably formed. Blending is preferably undertaken in the absence of any solvent. It is preferably carried out at a temperature in the range 5 to 50°C, more preferably 10 to 35°C, especially at ambient temperature.

Said first particles may include particles having a volume in the range 0.001 to 3mm³, preferably in the range 0.01 to 2.5mm³, more preferably in the range 0.05 to 1.0 mm³, especially 0.1 to 0.5mm³. Preferably substantially all of said first particles have a volume as aforesaid.

The average volume of said first particles (total volume of first particles divided by the total number of said first particles) may be at least 0.001 mm³, preferably at least 0.01 mm³, more preferably at least 0.1 mm³. The average volume (as described) may be less than 1 mm³.

Said first particles may include particles having a maximum dimension in one direction of at least 0.1 mm, preferably at least 0.2mm, more preferably at least 0.3mm. The maximum dimension may be less than 2mm, preferably less than 1 mm, more preferably less than 0.8mm. Preferably, substantially all particles in the mass have maximum dimensions as aforesaid.

The average of the maximum dimensions (sum of maximum dimensions of all particles divided by the total number of said particles) may be at least 0.1 mm, preferably at least 0.3mm. The average may be less than 2mm, preferably less than 1 mm, more preferably less than 0.8mm.

The ratio of the average volume of the first particles to the average volume of the second particles may be in the range 0.2 to 5, preferably in the range 0.3 to 3, more preferably in the range 0.5 to 2.

Said second particles may be a D₅₀ in the range 1 to 20000μιη. Preferably, the D₅₀ is in the range 10 to 2000μιη. In some embodiments wherein, for example, the second particles are arranged to produce a material to be used in an osseoconductive capacity, the D₅₀ may be in the range 10 to 1200μιη to allow pores to be produced which are suitable for bone ingrowth. In other embodiments, lower porosity may be required in which case the D₅₀ may be in the range 10 to100 μιτι. Said filler material could comprise filaments, which may be cylindrical. Such filaments may have an average diameter of 0.2 to 1 mm, suitably 0.4 to 0.8mm and an average length of at least 1.0mm, for example at least 1 .4mm. The average length may be less than 5mm or less than 3mm or less than 2mm. Non-filamentous filler is preferred.

Said composition may include at least 30 wt%, preferably at least 40wt%, more preferably at least 45 wt% of said polymeric material. Said composition may include less that 65 wt% or less than 60 wt% of said polymeric material. Said composition may include at least 30 wt%, preferably at least 40 wt%, more preferably at least 45 wt% of said filler material. Said composition may include less than 65 wt% or less than 60 wt% of said filler material. Said composition preferably includes 40 to 60 wt%, more preferably 45 to 55 wt%, of said polymeric material and 40 to 60 wt%, more preferably 45 to 55 wt% of said filler material. The ratio of the wt% of said polymeric material to said filler material is preferably in the range 0.6 to 1.3. Preferably at least 90 wt%, preferably at least 95 wt%, more preferably about 100 wt% of said composition is made up of said polymeric material and filler material.

Said polymeric material preferably comprises a bio-compatible polymeric material. Said polymeric material preferably comprises a thermoplastic polymer.

Suitably, the polymeric material is of a type which includes:

(a) phenyl moieties;

(b) ketone moieties; and

(c) ether moieties.

Said polymeric material may have a Notched Izod Impact Strength (specimen 80mm x 10mm x 4mm with a cut 0.25mm notch (Type A), tested at 23°C, in accordance with ISO180) of at least 4KJm^"2, preferably at least 5KJm^"2, more preferably at least 6KJm^"2. Said Notched Izod Impact Strength, measured as aforesaid, may be less than 10KJm^"2, suitably less than 8KJm^"2.

The Notched Izod Impact Strength, measured as aforesaid, may be at least 3KJm^"2, suitably at least 4KJm^"2, preferably at least 5KJm^"2. Said impact strength may be less than 50 KJm^"2, suitably less than 30KJm^"2. Said polymeric material suitably has a melt viscosity (MV) of at least 0.06 kNsm^"2, preferably has a MV of at least 0.09 kNsm^"2, more preferably at least 0.12 kNsm^"2, especially at least 0.15 kNsm^"2.

MV is suitably measured using capillary rheometry operating at 400°C at a shear rate of 1000s^"1 using a tungsten carbide die, 0.5x3.175mm. Said polymeric material may have a MV of less than 1.00 kNsm^"2, preferably less than 0.5 kNsm^"2. Said polymeric material may have a MV in the range 0.09 to 0.5 kNsm^"2, preferably in the range 0.14 to 0.5 kNsm^"2, more preferably in the range 0.3 to 0.5 kNsm^"2.

Said polymeric material may have a tensile strength, measured in accordance with IS0527 (specimen type 1 b) tested at 23°C at a rate of 50mm/minute of at least 20 MPa, preferably at least 60 MPa, more preferably at least 80 MPa. The tensile strength is preferably in the range 80-1 10 MPa, more preferably in the range 80-100 MPa.

Said polymeric material may have a flexural strength, measured in accordance with IS0178 (80mm x 10mm x 4mm specimen, tested in three-point-bend at 23°C at a rate of 2mm/minute) of at least 50 MPa, preferably at least 100 MPa, more preferably at least 145 MPa. The flexural strength is preferably in the range 145-180MPa, more preferably in the range 145-164 MPa.

Said polymeric material may have a flexural modulus, measured in accordance with IS0178 (80mm x 10mm x 4mm specimen, tested in three-point-bend at 23°C at a rate of 2mm/minute) of at least 1 GPa, suitably at least 2 GPa, preferably at least 3 GPa, more preferably at least 3.5 GPa. The flexural modulus is preferably in the range 3.5-4.5 GPa, more preferably in the range 3.5-4.1 GPa. Said polymeric material may be amorphous or semi-crystalline. It is preferably semi-crystalline.

The level and extent of crystallinity in a polymer is preferably measured by wide angle X-ray diffraction (also referred to as Wide Angle X-ray Scattering or WAXS), for example as described by Blundell and Osborn (Polymer 24, 953, 1983). Alternatively, crystallinity may be assessed by Differential Scanning Calorimetry (DSC).

The level of crystallinity of said polymeric material may be at least 1 %, suitably at least 3%, preferably at least 5% and more preferably at least 10%. In especially preferred embodiments, the crystallinity may be greater than 25%.

The main peak of the melting endotherm (Tm) of said polymeric material (if crystalline) may be at least 300°C.

Said polymeric material may include a repeat unit of general formula

or a repeat unit of general formula

wherein A, B, C and D independently represent 0 or 1 , provided at least one of A or B represents 1 and at least one of C or D represents 1 , E and E' independently represent an oxygen or a sulphur atom or a direct link, G represents an oxygen or sulphur atom, a direct link or a -O-Ph-0- moiety where Ph represents a phenyl group, m, r, s, t, v, w, and z represent zero or 1 and Ar is selected from one of the following moieties (i) to (v) which is bonded via one or more of its phenyl moieties to adjacent moieties

Unless otherwise stated in this specification, a phenyl moiety has 1 ,4-, linkages to moieties to which it is bonded.

Said polymeric material may be a homopolymer which includes a repeat unit of IV or V or may be a random or block copolymer of at least two different units of IV and/or V. As an alternative to a polymeric material comprising units IV and/or V discussed above, said polymeric material may include a repeat unit of general formula

or a homopolymer having a repeat unit of general formula

wherein A, B, C, and D independently represent 0 or 1 provided at least one of A or B represents 1 and at least one of C or D represents 1 , and E, E', G, Ar, m, r, s, t, v, w and z are as described in any statement herein.

A and B preferably represent 1 ; and C and D preferably represent 1.

Said polymeric material may be a homopolymer which includes a repeat unit of IV* or V* or a random or block copolymer of at least two different units of IV* and/or V*.

Preferably, said polymeric material is a homopolymer having a repeat unit of general formula IV. Preferably Ar is selected from the following moieties (vi) to (x)

In (vii), the middle phenyl may be 1 ,4- or 1 ,3-substituted. It is preferably 1 ,4-substituted.

Suitable moieties Ar are moieties (ii), (iii), (iv) and (v) and, of these, moieties, (ii), (iii) and (v) are preferred. Other preferred moieties Ar are moieties (vii), (viii), (ix) and (x) and, of these, moieties (vii), (viii) and (x) are especially preferred.

An especially preferred class of polymeric materials are polymers (or copolymers) which consist essentially of phenyl moieties in conjunction with ketone and/or ether moieties. That is, in the preferred class, the polymer material does not include repeat units which include -S-, -S0₂- or aromatic groups other than phenyl. Preferred bio-compatible polymeric materials of the type described include: (a) a polymer consisting essentially of units of formula IV wherein Ar represents moiety (v), E and E' represent oxygen atoms, m represents 0, w represents 1 , G represents a direct link, s represents 0, and A and B represent 1 (i.e. polyetheretherketone).

(b) a polymer consisting essentially of units of formula IV wherein E represents an oxygen atom, E' represents a direct link, Ar represents a moiety of structure (ii), m represents 0, A represents 1 , B represents 0 (i.e. polyetherketone); a polymer consisting essentially of units of formula IV wherein E represents an oxygen atom, Ar represents moiety (ii), m represents 0, E' represents a direct link, A represents 1 , B represents 0, (i.e. polyetherketoneketone). a polymer consisting essentially of units of formula IV wherein Ar represents moiety (ii), E and E' represent oxygen atoms, G represents a direct link, m represents 0, w represents 1 , r represents 0, s represents 1 and A and B represent 1. (i.e. polyetherketoneetherketoneketone). a polymer consisting essentially of units of formula IV, wherein Ar represents moiety (v), E and E' represents oxygen atoms, G represents a direct link, m represents 0, w represents 0, s, r, A and B represent 1 (i.e. polyetheretherketoneketone). a polymer comprising units of formula IV, wherein Ar represents moiety (v), E and E' represent oxygen atoms, m represents 1 , w represents 1 , A represents 1 , B represents 1 , r and s represent 0 and G represents a direct link (i.e. polyether- diphenyl-ether-phenyl-ketone-phenyl-).

Said polymeric material may consist essentially of one of units (a) to (f) defined above. Alternatively, said polymeric material may comprise a copolymer comprising at least two units selected from (a) to (f) defined above. Preferred copolymers include units (a). For example, a copolymer may comprise units (a) and (f); or may comprise units (a) and (e).

Said polymeric material preferably comprises, more preferably consists essentially of, a repeat unit of formula (XX)

where t1 , and w1 independently represent 0 or 1 and v1 represents 0, 1 or 2. Preferred polymeric materials have a said repeat unit wherein t1 =1 , v1 =0 and w1 =0; t1 =0, v1 =0 and w1 =0; t1 =0, w1 = 1 , v1 =2; or t1 =0, v1 = 1 and w1 =0. More preferred have t1 = 1 , v1 =0 and w1 =0; or t1 =0, v1 =0 and w1 =0. The most preferred has t1 =1 , v1 =0 and w1 =0.

In preferred embodiments, said polymeric material is selected from polyetheretherketone, polyetherketone, polyetherketoneetherketoneketone and polyetherketoneketone. In a more preferred embodiment, said polymeric material is selected from polyetherketone and polyetheretherketone. In an especially preferred embodiment, said polymeric material is polyetheretherketone.

Said filler material suitably has a melting point which is greater than the Tm of the polymeric material, suitably by at least 50°C, preferably by at least 100°C, more preferably by at least 250°C, especially by at least 400°C

Suitably, the filler material comprises a glass. The filler material may consist of a glass. Suitably, the filler material comprises a glass having a melting temperature higher than that of the polymeric material.

Suitably, the filler material comprises a ceramic material. The filler material may consist of a ceramic material. Suitably, the filler material comprises a ceramic material having a melting temperature higher than that of the polymeric material. The ceramic material may be a bioactive glass and/or a controlled release glass, wherein said ceramic material includes less than 20mole% sodium oxide and/or is water soluble. The ceramic material may include greater than 20mole% sodium oxide. The ceramic material may be a bioactive glass and/or a controlled release glass, wherein said ceramic material includes greater than 20mole% sodium oxide and/or is water soluble.

Surprisingly it has been found that when a polymeric material such as PEEK and a reactive filler material such as 45S5 (or analogues) are combined and moulded without compression it may be possible to make a porous material having interconnected bioactive compound without reactivity between the polymeric material and the filler material presenting an issue. Suitably, the method comprises making a porous material in which the the glass obtains interconnectivity. Accordingly, the porous material may be such that, in use as a medical implant, any resorption over time can create a pathway for tissue into the polymer construct. A said bioactive glass may include less than 20mole% sodium oxide as described; a said controlled release glass is suitably water soluble. A said bioactive glass comprising less than 20mole% sodium oxide may be water soluble. Water soluble glasses may be prone to softening at the melt temperature of the polymeric material, for example PEEK (340°C). Therefore shear or compression may squash the glass and prevent the glass from becoming interconnected, indeed if the pressure is too excessive the glass may mix with the PEEK to the point where it becomes useless as a space filler. Suitably, the method comprises moulding the mixture of polymeric material and filler material under conditions which do not cause the filler material to be squashed. The method may comprise moulding without the use of compression. The method may be such that it provides a means to combine a glass filler material and polymeric material whilst still allowing retention of glass shape and interconnectivity. The method may employ soluble phosphate based glass as the filler material and the moulding conditions may be such that they provide for retention of glass shape and interconnectivity during the moulding process,

Said ceramic material suitably includes a glass former and a glass modifier.

A glass former may be selected from silicon dioxide, phosphorous pentoxide or boron trioxide. Said glass former preferably comprises silicon dioxide or phosphorous pentoxide.

Said ceramic material suitably includes 85mole% or less, preferably 75mole% or less of a said glass former. A glass modifier may be an oxide or carbonate, for example a metal oxide or carbonate or a lanthanide oxide or carbonate. A metal of said oxide or carbonate may be an alkali or alkaline earth metal. Said ceramic material preferably includes a glass modifier selected from Li₂0, Na₂0, K₂0, MgO, ZnO and CaO. The sum of the amount of glass formers and glass modifiers in said ceramic material may be at least 80mole%, preferably at least 90mole%, more preferably at least 95mole%.

Said ceramic material may include other compounds in addition to said glass former and glass modifier. Less than 20mole%, preferably less than 10mole%, more preferably less than 5mole% of other compounds may be included.

A bioactive glass as described is suitably able to elicit a reaction when implanted in a human body. For example, being "bioactive" may imply chemical formation of a calcium phosphate layer (amorphous, partially crystalline or crystalline) via ion exchange between surrounding fluid in vitro and the ceramic material. In vitro assessment of whether a said ceramic material is bioactive may be undertaken as described by Kokubo at Biomaterials (2006) 27:2907-2915

Said ceramic material, for example bioactive glass, suitably includes less than 15mole% sodium oxide, preferably less than 10mole% sodium oxide, more preferably less than 7mole% sodium oxide, especially less than 3mole% sodium oxide. In some cases, said ceramic material may include less than 1 mole% sodium oxide, preferably 0mole% of sodium oxide.

The total amount of alkali metal oxide in said ceramic material, for example bioactive glass, is suitably less than 15mole%, preferably less than 10mole%, more preferably less than 7mole%, especially less than 3mole%. In some cases, the total amount may be less than 1 mole% and is preferably 0mole%.

A bioactive glass as described may include silicon dioxide as a glass former. It may include at least 10mole%, suitably at least 20mole%, preferably at least 30mole%, more preferably at least 40mole% of silicon dioxide. The amount of silicon dioxide may be less than 70mole%, suitably less than 60mole%.

A said bioactive glass which includes a high level of silicon dioxide may be insoluble in water or have low solubility.

Properties of bio-active glasses may be dependent on the network connectivity, see Journal of Materials Science: Material in Medicine 10 (1999) 697-701 (Wallace) and Journal of Materials Science Letters 15 (1996) 1 122-1 125 (Hill). Said bio-active glass may have a network connectivity of 2 or greater, preferably greater than 2.1. The network connectivity may be less than 3.2, preferably less than 2.5. The cross-link density as discussed in the aforementioned Hill paper may be greater than -0.10, preferably greater than 0. The cross-link density may be less than 0.8. Controlled release glasses could also be bioactive but need not be. Controlled release glasses are preferably biocompatible and/or biologically inert.

A said controlled release glass suitably includes less than 20mole%, preferably less than 10mole%, more preferably less than 5mole%, especially less than 1 mole% of silicon dioxide.

A said controlled release glass may include phosphorous pentoxide as a glass former. It may include at least 10mole%, preferably at least 20mole%, more preferably at least 25mole%, especially at least 30mole% of phosphorous pentoxide. The amount of phosphorous pentoxide may be less than 85mole% or less than 60mole%. A said controlled release glass suitably includes less than 15mole%, preferably less than 10mole%, more preferably less than 7mole%, especially less than 5mole% of sodium oxide. The total amount of alkali metal oxide in said controlled release glass is suitably less than 15mole%, preferably less than 10mole%, more preferably less than 7mole%, especially less than 5mole% of alkali metal oxide.

Said controlled release glass may include an alkali earth metal oxide or carbonate or oxide or carbonate of a lanthanide. The total amount of such oxides or carbonates in said glass may be less than 80mole%, preferably less than 75mole%, more preferably less than 70mole%, especially less than 60mole%. The total amount of such oxides or carbonates in said glass may be at least 5mole%, preferably at least 15mole%, more preferably at least 25mole%. The total amount of such oxides or carbonates in said glass may be up to 40mole%.

Said controlled release glass is preferably completely soluble in water at 38°C.

On dissolution (in isolation, i.e. not when as part of said mass of material), said controlled release glass suitably has a pH of less than 7, suitably less than 6.8, preferably less than 6.5, more preferably less than 6.

The filler may comprise bioactive glass 45S5. The filler may comprise a bioactive glass comprising Si0₂ (46mol%), Na₂0 (24mol%), CaO (27mol%), P₂0₅ (3mol%). The filler may comprise bioactive glass 13-93 glass powder. The filler may comprise a bioactive glass comprising Si0₂ (53wt%), Na₂0 (6wt%), K₂0 (12wt%), CaO (20wt%), P₂0₅ (4wt%), MgO (5wt%).

The filler may comprise bioactive glass 13-92. The filler may comprise a glass powder having 0wt% Na₂0.

The filler may comprise a contolled release glass having nominal composition Ag₂0 (1- 30wt%), Li₂0, Na₂0, K₂0 (0-12wt%), Al₂0₃ (0-5wt%), P₂0₅ (0-70wt%) and B₂0₃ (40-80wt%) . The filler may be a combeite. The filler may be a mineral with formula Na₂Ca₂Si₃0₉.

The method may produce a mass of material which can be subsequently processed. The mass of material may be used in subsequent process steps to manufacture parts, for example medical implants or parts thereof or parts having non-medical applications. The parts may be arranged to be bioactive and/or encourage formation of bone or other tissues in, on or around a medical implant or part incorporating the mass of material. In some embodiments, the ceramic material may be arranged to act as a fugitive material. In this case, the ceramic material may be removed in a dissolution process (using a non-aqueous or, preferably, an aqueous solvent) either before use of the part or subsequently. A part wherein the ceramic material acts as a fugitive material may be used in medical or non-medical applications. When the ceramic material is arranged to be removed during use of the part, dissolution of the ceramic material may be arranged to release an active material which had been incorporated in the part. In this case, the part may have a functional effect and/or act as a delivery vehicle for the active material. In medical applications, the ceramic material may be arranged to be removed in vivo, (or it may be leached prior to implantation) thereby to allow pore formation in a medical implant or part thereof.

Said ceramic material suitably has a melting point which is greater than the melting point of said polymeric material. The melting point of the ceramic material may be at least 100°C, suitably at least 200°C, preferably at least 300°C, more preferably at least 350°C greater than the melting point of said polymeric material. The melting point of the ceramic material may be at least 450°C, preferably at least 500°C, more preferably at least 600°C, especially at least 700°C.

Said mass of material may include discrete particles of ceramic material which are suitably dispersed in the polymeric material. Said ceramic material dispersed in particles in said mass of material may have a D₅₀ in the range 1 to 20000μιη. Preferably, the D₅₀ is in the range 10 to 2000μιη. In some embodiments wherein, for example, the mass of material is to be used to produce a porous member to be used in an osseoconductive capacity, the D₅₀ may be in the range 10 to 1200μιη to allow pores to be produced which are suitable for bone ingrowth. In other embodiments, lower porosity may be required in which case the D₅₀ may be in the range 10 to 100μηη.

In some embodiments, said ceramic material or part of said ceramic material may be arranged to be leached from a part in which it is incorporated, for example an implant when the implant is in situ in a human body. Said mass of material may include a further active material which may be arranged to have a beneficial effect when liberated. For example, said active material which may be dissolved from a part, for example an implant, made from a said mass of material may comprise an active material, for example an anti-bacterial agent (e.g. silver or anti-biotic containing), a radioactive compound (e.g. which emits alpha, beta or gamma radiation for therapy, research, tracing, imaging, synovectomy or microdosimetry) or an active agent which may facilitate bone integration or other processes associated with bone (e.g. the active agent may be calcium phosphate).

Said first particles may comprise said polymeric material and other optional additives, suitably so that said first particles are homogenous particles. Said first particles may comprise 40 to 100 wt% (preferably 60 to 100 wt%) of said polymeric material and 0 to 60 wt% of other additives.

Other additives may comprise reinforcing agents and may comprise additives which are arranged to improve mechanical properties of components made from the mixture. Preferred reinforcing agents comprise fibres.

80 wt%, 90 wt% , 95 wt% or about 100 wt% of said first particles are suitably made up of said polymeric material, especially a polymeric material having a repeat unit of formula (XX), especially of polyetheretherketones.

Said mixture may include other additives, for example, reinforcing agents which may comprise additives which are arranged to improve mechanical properties of components made from the material. Preferred reinforcing agents comprise fibres.

Said fibres may comprise a fibrous filler or a non-fibrous filler. Said fibres may include both a fibrous filler and a non-fibrous filler.

A said fibrous filler may be continuous or discontinuous. In preferred embodiments a said fibrous filler is discontinuous.

Preferably, fibres which are discontinuous have an average length of less than 10mm, preferably less than 7mm. A said fibrous filler may be selected from inorganic fibrous materials, high-melting organic fibrous materials and carbon fibre.

A said fibrous filler may be selected from inorganic fibrous materials, non-melting and high- melting organic fibrous materials, such as aramid fibres, and carbon fibre.

A said fibrous filler may be selected from glass fiber, carbon fibre, asbestos fiber, silica fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, fluorocarbon resin fibre and potassium titanate fiber. Preferred fibrous fillers are glass fibre and carbon fibre. A fibrous filler may comprise nanofibres.

A said non-fibrous filler may be selected from mica, silica, talc, alumina, kaolin, calcium sulfate, calcium carbonate, titanium oxide, ferrite, clay, glass powder, zinc oxide, nickel carbonate, iron oxide, quartz powder, magnesium carbonate, fluorocarbon resin and barium sulfate. The list of non-fibrous fillers may further include graphite, carbon powder and nanotubes. The non- fibrous fillers may be introduced in the form of powder or flaky particles. Preferred reinforcing agents are glass fibre and/or carbon fibre.

Other additives may comprise radiopacifiers, for example barium sulphate and any other radiopacifiers described in co-pending application PCT/GB2006/003947. Up to 20wt%, or up to 5wt% of radiopacifiers may be included. Preferably, less than 1wt%, more preferably no radiopacifier is included.

Other additives may include colourants, for example titanium dioxide. Up to 3wt% of colourant may be included but preferably less than 1wt%, more preferably no, colourant is included. Said mixture may include up to 15wt%, for example up to 10wt% of other materials -that is, in addition to said polymeric material and filler.

Preferably, said mixture consists essentially of polymeric material and filler and more preferably consists essentially of a single type of polymeric material and a single type of filler.

The method may include a step of altering the shape of the material. The material may be machined to alter its shape and/or to form the shape of at least part of a desired medical implant. The method may include forming the material into a medical implant or a part thereof.

The method may include the step of treating the material to remove at least some of said filler material. Suitably, such treatment is undertaken after altering the shape of the material as described. The treatment may be arranged to define porosity in the material.

Means for removing filler material may be arranged to solubilise said filler material. Said means suitably comprises a solvent. Said solvent preferably comprises water and more preferably includes at least 80wt%, preferably at least 95wt%, especially at least 99wt% water. The solvent preferably consists essentially of water. Means for removing the filler material may comprise contacting the material with a solvent formulation (preferably comprising water as aforesaid) which is at a temperature of 100^°C or greater and a pressure at or above ambient pressure thereby to charge the solvent formulation with filler material and separating the charged solvent from the product.

In the method, said solvent formulation may be at a temperature of greater than 150^°C, suitably greater than 200^°C when contacted with said material. Said solvent formulation may be at a temperature of less than 500^°C, suitably less than 450^°C, preferably less than 400^°C, more preferably less than 350^°C when contacted with said material.

The solvent formulation may be under a pressure of at least 4 bar, suitably at least 8 bar, preferably at least 10 bar when contacted with said material. The pressure may be less than 300 bar, preferably less than 200 bar, more preferably less than 100 bar, especially less than 50 bar. The pressure is preferably selected to maintain the solvent formulation in the liquid state when in contact with said material.

Preferably, in the method, the solvent formulation is arranged to flow from a first region to a third region via a second region in which said material is arranged.

The filler (especially when sodium chloride is used) may comprise substantially spherical particles which are used with particles of polymeric material (e.g. of polyetheretherketone). The spherical filler (e.g. of sodium chloride) may be made as described in Journal of Alloys and Compounds 499 (2010) 43-47 or as described in Biomaterials 25 (2004) 4955-4962.

In one embodiment, a mould used in the method may be modified by inclusion of a grid (or the like) associated with a lower internal wall of the mould. The grid is intended to provide a means whereby grains (e.g. spherical grains) of filler material can be spaced from other grains in the same row, so that filler material is less tightly packed in the mould. The filler material may be sintered to set the shape of the filler material and subsequently polymeric material may be introduced into the sintered filler material to define a mixture. After heating to melt the polymeric material, the filler may be dissolved to leave a structure defined by the polymeric material which is more open. According to a second aspect of the present invention, there is provided a method of making a material, said method comprising:

(a) providing a mixture of polymeric material and filler material in a mould;

(b) heating the mixture in order to melt the polymeric material by: (i) subjecting the mixture to a temperature below the melting point of the polymeric material to pre-heat the mixture; and then

(ii) subjecting the mixture to a temperature above the melting temperature of the polymeric material in order to melt the polymeric material.

Suitably, there is provided a method of making a porous material, said method comprising: (a) providing a mixture of polymeric material and filler material in a mould;

(b) heating the mixture in order to melt the polymeric material by:

(i) subjecting the mixture to a temperature below the melting point of the polymeric material to pre-heat the mixture; and then

Suitably, the method comprises subjecting the material in the mould to a pressure of less than 2MPa. Suitably, the method comprises subjecting the material in the mould to a pressure of less than 2MPa during step (b)(ii). Suitably, the method comprises subjecting the material in the mould to a pressure of less than 2MPa during step (b)(i) or step (b)(ii).

Suitably, the method comprises subjecting the material in the mould to pressures as defined in relation to the first aspect.

Suitably, the method comprises subjecting the material in the mould to less than 10kg of compressive load. Suitably, the method comprises subjecting the material in the mould to less than 10kg of compressive load during step (b)(ii). Suitably, the method comprises subjecting the material in the mould to less than 10kg of compressive load during step (b)(i) or step (b)(ii). Suitably, the method comprises subjecting the material in the mould to no compression during step (b)(i). Suitably, the method comprises subjecting the material in the mould to no compression during step (b)(ii). Suitably, the method comprises subjecting the material in the mould to no compression during step (a).

The method may comprise any feature as described in relation to the first aspect.

According to a third aspect of the invention, there is provided a method of making a component, the method comprising:

(i) making a material according to the method of the first and/or second aspect;

(ii) optionally removing the filler material; and

(iii) optionally shaping the mass of material.

Suitably, there is provided a method of making a component, the method comprising:

(i) making a porous material according to the method of the first and/or second aspect;

(ii) optionally removing the filler material; and

(iii) optionally shaping the mass of porous material.

The method may comprise making a porous material according to the method of the first aspect. The method may comprise making a porous material according to the method of the second aspect.

The method may be used in non-medical or medical applications. Non-medical applications include manufacture of filters, meshes, light-weight parts and parts arranged to elute active materials, for example lubricants. The component may comprise a part or the whole of a device which may be incorporated into or associated with a human body. Thus, the component may suitably be a part of or the whole of a medical implant. The medical implant may be arranged to replace or supplement soft or hard tissue. It may replace or supplement bone. It may be used in addressing trauma injury or craniomaxillofacial injury. It may be used in joint replacement, for example as part of a hip or finger joint replacement; or in spinal surgery.

Suitably, any desired shape may be produced. Near net-shaped ingots may be produced for further processing, for example machining; or a component which does not require any significant machining prior to use may be produced.

When said method includes removing said ceramic material in step (b), the method suitably involves contacting a product formed after processing in step (a) with a means for removing the ceramic material or salt or other suitable porogen or filler, suitably so as to define porosity. Contact may take place at any time. However, contact suitably takes place after any machining or physical manipulation of said product that may be involved in making a component (or part thereof) for use, for example as part of or the whole of a device which may be incorporated into or associated with a human body. This is because a product may have more strength to withstand, for example machining, whilst ceramic material is in situ. Step (b) may thus be performed subsequent to step (c).

Said means for removing the ceramic material may be arranged to solubilise said ceramic material.

According to a fourth aspect of the present invention there is provided a material manufactured according to the method of the first and/or second aspect.

Suitably, there is provided a porous material manufactured according to the method of the first and/or second aspect.

According to a fifth aspect of the present invention there is provided a component manufactured according to the method of the third aspect. According to a sixth aspect of the present invention there is provided a medical implant comprising a polymeric material and a filler material comprising a reactive bioactive compound and which filler material is located within pores defined by the polymeric material.

Suitably, the filler material is interconnected. Suitably, the filler material is interconnected such that, in use, resorption of the filler over time can create a pathway for tissue into the porous structure of the polymeric material. Suitably, the filler is a bioactive glass. Suitably, the filler material is a bioactive glass and/or a controlled release glass, wherein said filler material includes greater than 20mole% sodium oxide and/or is water soluble. Suitably, the polymeric material comprises PEEK. Suitably, the polymeric material is PEEK. Suitably, the filler material comprises 45S5 (or analogues). Suitably, the filler material comprises 45S5. Suitably, the filler material is 45S5 (or analogues). Suitably, the filler material is 45S5. The filler material may be a combeite. The medical implant may comprise a porous material having any feature as described in relation to any aspect of the invention. The medical implant may comprise a porous material manufactured according to the method of the first and/or second aspect.

Any feature of any aspect of any invention or embodiment described herein may be combined with any feature of any aspect of any invention or embodiment described herein mutatis mutandis.

Specific embodiments of the invention will now be described, by way of example. Example 1

A porous material was produced by combining a polymeric material and filler material and heating the mixture to melt the polymeric material. A structure mould was filled with a 50:50 blend of a filler material and a polymeric material. The filler material was a soluble phosphate based glass consisting of sodium phosphate glass and the polymeric material was PEEK in the form of micropellets. Both the polymeric material and filler material comprised particles having an average size of around 0.5mm diameter. The filler material and polymeric material were combined and blended before being introduced to the mould and were distributed evenly and as homogeneously as possible within the mould.

The mould had internal dimensions of 20mm high by 50mm wide by 50mm long. Once the mould was filled with the polymeric material and filler material mixture it was placed in an oven. During the moulding process the material in the mould was subjected to no compression.

The oven was pre-heated to 320°C and the mould was maintained in the oven at that temperature for 40 minutes so as to subject the mixture to a temperature below the melting temperature of the polymeric material to pre-heat the mixture. The temperature of the oven was then raised to 370°C and the mould was maintained in the oven at that temperature for 40 minutes so as to subject the mixture to a temperature above the melting temperature of the polymeric material in order to melt the polymeric material.

This manufacturing method was observed to allow even melting throughout the polymeric material.

In order to provide the material with open pores it was exposed to a hot (90°C) distilled water to remove the filler which left a porous polymeric material.

It will be appreciated that the method may be varied though it may be desirable to retain a step of holding the mixture at temperatures below the melting temperature of the polymeric material to gradually build up heat in the material. Pre-heating may allow the heat to transfer evenly throughout the shape.

One problem with melting or sintering over a certain thin small size is that the heat conduction will take time to reach the core. Therefore heating directly at above melt temperature may first heat (and melt) the exterior and then progressively work inwards to heat the core. The time taken for sufficient heat to reach the core and sinter or melt the core, may be prolonged so that the exterior may be held at melt temperature for a longer period of time. This may effectively expose the shape to uneven temperature. It will be appreciated that preferred embodiments of the present invention may avoid this problem by using a prolonged period of heating below the melting temperature of the polymeric material then the temperature may be raised to melt the entire structure more evenly.

It will be appreciated that the step of pre-heating the mixture may be modified. For example, in an alternative embodiment (not described in detail) the oven was be held for 2 hours at 200°C then held for 30 minutes at 320°C before increasing the temperature above the melting temperature of the polymeric material.

Example 2:

A porous material was produced by combining a polymeric material and filler material and heating the mixture to melt the polymeric material. The method was generally the same as that of Example 1 but the step of pre-heating the mixture was omitted.

A structure mould was filled with a 50:50 blend of a filler material and a polymeric material. The filler material was a soluble phosphate based glass consisting of sodium phosphate and the polymeric material was PEEK in the form of micropellets. Both the polymeric material and filler material comprised particles having an average size of around 0.5mm diameter.

The filler material and polymeric material were combined and blended before being introduced to the mould and were distributed evenly and as homogeneously as possible within the mould.

The mould had internal dimensions of 20mm high by 50mm wide by 50mm long. Once the mould was filled with the polymeric material and filler material mixture it was placed in an oven. During the moulding process the material in the mould was subjected to no compressive force.

The oven was pre-heated to 370°C and the mould was maintained in the oven at that temperature so as to subject the mixture to a temperature above the melting temperature of the polymeric material in order to melt the polymeric material. It was observed that after 30 minutes the polymeric material melts on the surface. At first this "sinters" and does not flow. If the material were removed from the mould at this point then material not at the surface or directly in contact with the parameter would remain as a dry blend and un-fused. This would fall away as particles. Leaving the mould in the oven for further time (40 minutes total) to allow heat to enter the core was observed to allow the centre to sinter and be weakly bonded whilst the parameters had gone beyond sintering and had fully melted and flowed.

Leaving the mould in the oven for further time (50 minutes total) allowed the interior to melt and flow, however the exterior had been held above the melting temperature for a longer time which can result in degradation of the polymer.

In an alternative embodiment (not illustrated) the issue regarding possible degradation of the polymer may be remedied by creating an inert environment for the melt of the polymer which may inhibit polymer degradation.

The method of this example may be appropriate for manufacturing porous material depending on the dimensions of the mould used but it will be appreciated that the method of Example 1 may provide more beneficial results.

Example 3:

A porous material was produced by combining a polymeric material and filler material and heating the mixture to melt the polymeric material. A mixture of 50% by weight of PEEK powder (polymeric material) having 0.1 mm mean diameter and 50% by weight of bioactive ceramic, namely HA, (filler material) having 0.1 mm mean diameter were combined and placed into a mould.

The combination of a homogeneously mixed blend was facilitated by feeding the materials using separate timed conveyors so that they met combining equal amounts. Gravimetric separation/settling of contents was minimised by immobilisation of the mould once filled. The filled mould which had an internal size of 10cm x 10cm x 4cm was heated in an oven at 300°C for 30 minutes. The oven temperature was then raised to 370°C for a further 30 minutes to fully melt the mixture. The shape formed in the mould was allowed to cool and the near net shape produced from the moulding process was then machined to the desired shape. Example 4:

A porous material was produced by combining a polymeric material and filler material and heating the mixture to melt the polymeric material. A mixture of 50% by weight of PEEK micropellets (polymeric material) having 0.6mm mean diameter and 50% by weight of soluble bioglass, namely MOCSI, (filler material) having 0.5mm mean diameter) were combined and placed into a mould .

The combination of a homogeneously mixed blend was facilitated by mixing the polymeric material and filler material and then layering the mixture into a mould by hand. Gravimetric separation/settling of contents was minimised by carefully laying up the mixture into the mould direct.

The filled mould which had an internal size of 10cm x 10cm x 4cm was heated in an oven at 300°C for 30 minutes. The oven temperature was then raised to 370°C for a further 30 minutes to fully melt the mixture. The shape formed in the mould was allowed to cool and the near net shape produced from the moulding process was then machined to the desired shape. The shape was then leached in deionised water at 100°C to remove all of the filler. Example 5:

An interconnected compound material was produced by combining a polymeric material and filler material and heating the mixture to melt the polymeric material. A mixture of 50% by weight of PEEK micropellets (polymeric material) having 0.6mm mean diameter and 50% by weight of bioactive bioglass, 45S5 (filler material) having mean diameter between 300μιη and 700μιη were combined and placed into a mould. The combination of a homogeneously mixed blend was facilitated by mixing the polymeric material and filler material and then layering the mixture into a mould by hand. Gravimetric separation/settling of contents was minimised by blending carefully, laying up the mixture into the mould direct. The filled mould which had an internal size of 10cm x 10cm x 4cm was heated in an oven at 300°C for 30 minutes. The oven temperature was then raised to 370°C for a further 30 minutes to fully melt the mixture. The shape formed in the mould was allowed to cool and the near net shape produced from the moulding process was then machined to the desired shape to result in a shape incorporating a bioactive compound that would degrade in vivo over time to leave interconnected channels to permit bony ingrowth.

Example 6

An interconnected compound material was produced by combining a polymeric material and filler material and heating the mixture to melt the polymeric material.

A mixture of 50% by weight of PEEK micropellets (polymeric material) having 0.6mm mean diameter and 50% by weight of spherical tri calcium phosphate (filler material) having mean diameter between 300mm and 700mm were combined and placed into a mould.

Gravimetric separation/settling of contents was minimised by blending carefully, laying up by hand with equal portions of the two materials and filling the mould direct.

The filled mould which had an internal size of 10cm x 10cm x 4cm was heated in an oven at 300°C for 30 minutes. The oven temperature was then raised to 370°C for a further 30 minutes to fully melt the mixture. The shape formed in the mould was allowed to cool and the near net shape produced from the moulding process was then machined to the desired shape to result in a shape incorporating a bioactive compound that would degrade in vivo over time to leave interconnected channels to permit bony ingrowth.

It will be appreciated that preferred embodiments of the present invention may allow the manufacture of a porous material which may have optimal porosity and better interconnectivity and which may retain structural integrity whilst better replicating the structure required for tissue ingrowth.

Claims

1. A method of making a material, said method comprising: (a) providing a mixture of polymeric material and filler material in a mould;

(b) heating the mixture in order to melt the polymeric material; and

2. A method according to claim 1 , wherein said method is for making a porous material, wherein filler material is removed after step (b).

3. A method according to claim 1 or claim 2, wherein said material defines a medical implant or part thereof.

4. A method according to any preceding claim, wherein the material in the mould is subjected to atmospheric pressure during step (b).

5. A method according to any preceding claim, wherein step (b) of the method comprises: (b)(i) subjecting the mixture to a temperature below the melting point of the polymeric material to pre-heat the mixture; and then

6. A method according to any preceding claim, wherein step (b) of the method comprises heating the mould in an oven and comprises:

7. A method according to any preceding claim, wherein the method comprises holding the mixture at a temperature above the melting temperature of the polymeric material for a sufficiently long period of time to permit full melting of the polymeric material and merging together of adjacent polymeric material.

8. A method according to any preceding claim, the method comprising removing the filler material subsequent to the moulding stage.

9. A method according to claim 5 or claim 6, wherein step (b)(i) comprises subjecting the mixture to a temperature of at least 200°C.

10. A method according to any of claims 5, 6 or 9, wherein step (b)(i) comprises subjecting the mixture to a temperature below the melting point of the polymeric material to preheat the mixture for a period of at least 10 minutes.

1 1. A method according to any of claims 5, 6, 9 or 10, wherein step (b)(ii) comprises subjecting the mixture to a temperature above the melting temperature of the polymeric material for a period of at least 10 minutes.

12. A method according to any of claims 5, 6, or 9 to 1 1 , wherein step (b)(i) comprises preheating the mixture for a period of time lasting for at least 50% of the period of time for which the mixture is heated in step (b)(ii).

13. A method according to any preceding claim, wherein the method comprises a method of making a near net shape of porous material in a mould which can then be machined and/or finished to produce an end shape of porous material.

14. A method according to any preceding claim, wherein the method comprises manufacturing a material using a soluble filler and the method comprises making a porous material in a mould, then machining the material to a desired shape and then removing the soluble material following the machining step.

15. A method according to any preceding claim, wherein the method comprises providing a mixture of polymeric material and filler material in a mould wherein the ratio by weight of polymeric material to filler material in the mould is between 0.5 to 1 and 2 to 1 , for example around 1 to 1.

16. A method according to any preceding claim, wherein said filler is a water soluble salt or water soluble glass.

17. A method according to any preceding claim, wherein the method comprises combining 45S5 bioglass and PEEK.

18. A method according to any preceding claim, wherein said polymeric material includes a repeat unit of general formula

or a repeat unit of general formula

wherein A, B, C and D independently represent 0 or 1 , provided that at least one of A or B represents 1 and at least one of C or D represents 1 , E and E' independently represent an oxygen or a sulphur atom or a direct link, G represents an oxygen or sulphur atom, a direct link or a -O- Ph-O- moiety where Ph represents a phenyl group, m, r, s, t, v, w, and z represent zero or 1 and Ar is selected from one of the following moieties (i) to (v) which is bonded via one or more of its phenyl moieties to adjacent moieties

19. A method according to any preceding claim, wherein said polymeric material comprises a repeat unit of formula (XX)

where t1 , and w1 independently represent 0 or 1 and v1 represents 0, 1 or 2.

20. A method according to any preceding claim, wherein said polymeric material is polyetheretherketone.

21. A method according to any preceding claim, wherein said filler material has a melting point which is greater than the Tm of the polymeric material by at least 400°C.

22. A method according to any preceding claim, wherein said filler material comprises a glass or ceramic material.

23. A method according to any preceding claim, wherein the filler is a combeite.

24. A method of making a component, the method comprising:

(i) making a material according to the method of any of claims 1 to 21 ;

(ii) optionally removing the filler material; and

(iii) optionally shaping the mass of material.

25. A medical implant or part thereof comprising a polymeric material and a filler material comprising a reactive bioactive compound, said filler material being located within pores defined by the polymeric material.