CA2037458A1 - Process for the production of hybrid mica/cellulose reinfored polystyrene composites - Google Patents

Abstract

ABSTRACT

Under study was the method of preparation of hybrid composites of silane coated mica/cellulose fiber (coated with polymer + isocyanate, silane, and grafted with a polymer) and polystyrene. The resulting hybrid composites can be exposed to various environmental conditions, e.g. exposure to boiling water for 24 hours and to heat at +105°C for 5 days as well as at a subzero temperatures (e.g. -20°C). Treated cellulose fiber/mica-filled composites show superior mechanical properties and dimensional stability even under most extreme conditions in comparison with those of non-treated cellulose fiber/mica-filled composites.

Description

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BACKGROUND OF THE INVENTION

The present invention has to do with the preparation of composite materials with the addition of more than one reinforcement into a thermoplastic resin. More 5 specifically, it deals with the compatibility of at least two normally incompatible fillers, e.g. inorganic and organic, in an incompatible polymer matrix. This question is examined by using surface modified fillers.
The present invention also deals with reinforced thermoplastic composites which exhibit good physical properties, particularly dimensional stability, as well as improved 10 strength or modulus, even after exposure to adverse environments.
Manytypes of composite compositions orthermoplastic orthermoset resins have been proposed and commercialized. Among the reinforcing fillers used here, only organic fillers, such as wood flour, wood pulp, non-wQQdy fibers, and inorganic fillers, such as calcium carbonate, talc, mica, glass are well known. Such materials are 15 described in Woodhams, in U.S. Patent No. 3,764,456, issued October 9, 1973, and in U.S. Patent No. 4,442,243, which describe mica-reinforced thermoplastic composites having improved durability, physical and aesthetic properties which are prepared by mixing the resin and the mica in the presence of propylene polymer wax The mica can be pretreated to provide functional groups for a subsequent chemical 20 reaction with the propylene polymer wax.
Tatsumi, Japan Patent Kokai No. 252,353/87, issued Nov. 4, 1987, prepared high-strength building materials from fiber-cement compositions having mica as one of the constituents.
As described in the 1978 SPI proceedings, mica reinforcement imparts a high 25 degree of stiffness in a polymeric matrix; it also results in improved strength, wrap resistance and thermal stability, lower shrinkage and cost reduction. Unlike asbestos and glass, rnica is non-tQxic and does not irritate the skin. AISQ~ being a soft mineral causes relatively little tool wear.

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Show et al., France Patent No. 7,634,301, issued Nov. 15, 1976, described the preparation of a new material which can be adapted to different applications. It is formed by a copolymer or a lignocellulosic element which is bound to a polymer by grafting in such a manner that the resulting product can play a reinforcement role in 5 the polymer, in the place of highly expensive mineral fibers, such as glass fiber.
Kokta, U.K. Patent No. 2,203,743, found that cellulosic-filled polyethylene composites compared well to either mica composites. The strength of polyethylene grafted aspen fiber composites remained virtually unaffected after boiling in water for 3 hours and the cellulosic-filled composites compared well with that of mica.
10 Moreover, cellulosic composites remained dimensionally as stable as mica composites after 35 days in water at room temperature.
Beshay, U.S. Patent No. 4,717,742, reported that silane grafted cellulose pulp and polyethylene composites, after being boiled in water for 4 hours, remained stronger than polyethylene and mica. In addition, grafted aspen pulp-filled composites 15 do not lose their reinforcing properties even at -40C and keep their reinforcing advantages vis-à-vis mica.
The published literature includes a number of proposals for dispersing and compatibilising discontinuous cellulose fibers in a thermoplastic matrix.
Hamed, U.S. Patent No. 3,943,079, described the pretreatment of cellulose fibers 20 with a plastic polymer and a lubricant.
Kokta, U.K. Patent No. 2, 192,397, 2,192,398 and 2,203,743, detailed the precoating of cellulose fibers with a compatible polymer in the presence of silane or isocyanate coupling agents and prepared the composites of polyvinyl chloride or polyethylene and coated fibers.
Beshay, U.S. Patent No. 4,717,742, reported on silane grafted cellulose pulp and polyethylene composites.
Lund, U.S. Patent No. 4,241,133, mixed elongated wood flakes with a binder (e~g. a polyisocyanate), which were then shaped into a mat and hot-pressed to form elongated structures such as building beams, posts, etc.
Fujimura, Japan Patent Kokai No. 137,243/78, found that a cellulosic material, e.g. straw, acetylated with gaseous acetic anhydride, is a good reinforcing filler for 5 polyethylene.
Gaylord, U.S. Patent No.3,485,777, showed the compatibility of grafted cellulose fibers with polyvinyl chloride or polymethylmethacrylate matrices. In his U.S. Patent No. 3,645,939, he also reported the good compatibility of plastics, e.g. polyethylene, polyvinyl chloride or acrylic rubber, with cellulose by precoating the fibers with a 10 thermoplastic, ethylenically unsaturated carboxylic acid or anhydride and a free radical initiator.
Dainippon Ink and Chemical Inc., Japan Patent Kokai No. 79,064/85, described the use of a copolymer of maleic anhydride, phthalic anhydride, and the like, and benzoyl peroxide, as a good prepreg with good blocking resistance on decorative 15 laminated sheets.
Pleska, France Patent No. 2,456,133, showed that a mixture of polyolefin fibril and polyolefin grafted with a polar monomer (e.g. maleic anhydride) exhibited good compatibility with cellulose fibers.
Eldin, Canadian Patent No. 1,192,102, described organic and inorganic fiber 20 composites prepreg coated with two different resins, e.g. maleic acid (derivatives)/hydrantoin vinylether copolymers.
Kansai Kogyo Co. Ltd., Japan Patent Kokai No. 217,552/83, prepared extruded composites containing pp, wood flour and citric acid ester to produce a composite sheet with high flexural strength and high heat distortion temperature.
Lachowicz et al., U.S. Patent No. 4,107,110, described that ~c-cellulose fibers, coated with graft copolymer comprising 1,2-polybutadine to which an acylate, such as butylmethacrylate, is grafted, could be used in reinforcing PE and other plastic 7 ~

compositions~

SUMMARY OF THE INVENTION

Mica or cellulose fibers, grafted with a compatible polymer or a small amount of certain bonding agents, such as isocyanate or silane, provide better adhesion when added to the polystyrene matrix.
Such hybrid composites improved their physical and mechanical properties, as well as durability, even at sub-zero conditions or at high temperatures.
In the present invention, composites are made of mica surface modified with silane bonding agents and discontinuous cellulose fibers modified by grafting with polystyrene, or pre-reacted with silane bonding agen~s such as A-,100, or with PMPPIC, dispersed in a polystyrene matrix.
Composites containing from 1 to 50% of mica + cellulose fibers by weight, based 15 on the total weight of composites, and 1 to 100 weight ratio of mica and cellulose fibers are within the scope of the invention.

DETAILLED DESCRIPTION OF THE INVENTION

The mica used in the present invention includes both phlogopite and muscovite of untreated and surface treated mica in the form of powder, flake, delaminated, highly delaminated or super-delaminated grades of NP-, FM-, (;~X-, S-, HK-series. Treated mica, especially silane treated mica, of NP grades offers the best results.

Cellulosic material includes fibers from softwood or/and hardwood pulps, e.g.
25 chemical or mechanical or chemi-mechanical or refiner or stone groundwood or thermo-mechanical or chemi-thermomechanical or explosion or low-yield or high-yield or ultra high-yield pulp, nutsheels, corn cobs, rice hulls, vegetable fibers, certain bamboo type reeds, grasses, bagasse, cotton, rayon (regenerated cellulose), sawdust, wood flour, wood shavings and the like.
Cellulose fibers from wood sawdust, wood flour, wood pulps, e.g. mechanical pulps or chemi-thermomechanical aspen pulps, revealed themselves to be the best.
5 Many types of wood pulp are available. They can be classified according to their treatment (chemical, mechanical, thermal) in the pulp and paper industry. Waste pulp and /or recycled pulp can also be used. The fibers have an aspect ratio (length divided by diameter) ranging from 2 to 5 for sawdust, wood flour as well as for mechanical pulps, from 15 to 50 for chemi-mechanical and chemi-thermomechanical 10 pulps, and from 50 to 150 for low-yield chemical pulps (e.g. kraft, soda or bisulfite).
In some instances, it is preferable to use fiber mixtures with widely different aspect ratios.
The polymer contained in the matrix is described as being "polystyrene". In fact, it includes both polystyrene polymer and copolymer (a major proportion of polystyrene 15 with a minor proportion of other vinyl polymer). The polymer "polystyrene" includes polystyrene of different densities as well as different proportions of crystalline and amorphous fractions.
It is normal practice to treat the surface of the filler which is used in the composition to improve its compatibility, dispersibility and adhesion in relation to resin.
20 Thus, the following processes for such treatment were taken into account.
(1 ) Coating process, i.e. a process according to which the surface of the filler is coated with a coupling agent and, consequently, forms a strong bonding with the filler and polymer, e.g. polymeric diisocyanate type or the like, and with a substance compatible with the resin, e.g. rubber-type or vinyl-type of low molecular-weight 25 materials or the like. In preparing the coated cellulose fibers, one of the preferred techniques is to mix the bonding agent with 5% to 15% by weight of polymer based on totai polymer weight, and then mix the resulting mixture with cellulosic fibers in a ,J l ~

roll mill. Further details appear in Goettler, U.S. Patent No. 4,376,144, issued Mar.
8, 1983. The latter reported the technique which consists of combining the bonding agent, e.g. isocyanate, with the cellulose fibers in a pre-treatment stage for cellulose-PVC composites. Kokta, U.K. Patent No. 2,193,503, issued Feb. 10, 1988, and 5 2,191,398, issued Jan. 13, 1988, reported the post-coating procedure for cellulose fiber with polystyrene or polyvinyl chloride and isocyanate bonding agent before mixing the cellulose fibers with polystyrene or polyvinyl chloride composites.

(2) Surface treatment with a coupling agent, e.g. a process according to which the surface of a filler is treated with a coupling agent, e.g. of a silane type or the like, 10 and a substance compatible with the resin, e.g. rubber-type or vinyl-type of low molecular weight-materials or the like. This process also consists of adding an organic peroxide while the filler is heated. Further details appear in Hishida, U.K.
Patent No. 2,090,849. The latter described the surface coating of jute fibers with various coupling agents, e.g. stearate, silane, titanate, acrylics, etc., and prepared 15 composites of polypropylene and polystyrene. Beshay, U.S. Patent No. 4,717,742, issued Jan. 5, 1988, reported a technique for grafting a bonding agent, e.g. silane, onto cellulose fibers in a pre-treatment stage for cellulose-polyethylene composites.
Kokta, U.K. Patent No. 2,192,397, issued Jan. 13, 1988, and 2,203,743, issued Oct.
26, 1988, reported a post-treatment procedure for cellulose fibers with a silane 20 bonding agent before mixing the cellulose fibers with polyvinyl chloride or polysthylene composites.

(3) Grafting process, e.g. a process according to which a substance compatible with the resin, e.g. rubber-type or vinyl-type of low molecular-weight materials or the like, is directly attached to the surface of filler. In preparing the graft copolymer, the 25 xanthate method of grafting is a favorite technique in order to initiate branching on the cellulose matrix. Further details of this method are given by R.W. Faessinger and J.S.
Conte, U.S. Patent No. 3,359,224, Dec., 1967; E. Ehrnooth, J. Polvm. Sci., Symp. No.

~fti~-! f 42,1569, 1982; V. Hornof, C. Daneault, B.V. Kokta and J. Valade, Modified Cellulosic, R.M. Rowell and R.A. Young (eds.), Academic Press, New York, 227, 1978; M. H. El-afie, E.M. Khalil, S.A. Abdez-Hafiz and A. Hebeish, Acta Polvmerica, 36, 668, 1985;
and B.V. Kokta, P.D. Kamdem, A.D. Beshay and C. Daneault, Polvmer Com~osites, 5 B. Sedlacek (ed.), Water de Gruyter and Co., Berlin, 251 (1986). These references disclose, for example, the grafting of different vinyl monomers onto wood pulps or cotton fabric.
When selecting the surface-treating agent, it is necessary to take into consideration the type of resin and the reason for improving the properties of the 10 composition. Since it is only natural to use a surface-treated agent or a compatible vinyl monomer suitable for this purpose, it is difficult to limit oneself to special materials.
The use of a combination of fillers with known fillers or additives (taking into consideration costs and properties of the composites) is of course possible, and such 15 a combination is also within the technical scope of the present invention.
The polymer is added to a mixture of coated mica and uncoated (or coated) cellulose fibers to form a composite, usually in an internal mixer, in an extruder or in a roll mill. Other ingredients, such as fillers, plasticizers, stabilizers, colorants, etc., an also be added at this point. Apart from mica, inorganic filler materials may be 20 selected: calcium carbonate, talc, glass fibers, etc.
The following specific examples illustrate the use of mixtures of coated mica and cellulose fibers in polystyrene composites.

High impact polystyrene (PS 525) was supplied by Polysar Limited, Sarnia, Ontario, Canada.
Mica-200-NP-Suzorite (200 mesh, silane treated) was supplied by Mariella Co., ~ U ~ ~ L,~ S

Montréal, Canada.
Hardwood species of aspen (Populus tremuloides Michx) was used in the form of chemithermomechanical pulp (CTMP), CTMP was prepared in a Sund Defibrator.
Its properties are described in Kokta, U.K. Patent No. 2,193,503.
CTMP aspen pulp was dried in an air circulating oven at 55C for 48 hours, and then ground to a mesh size 60 mixtures; 60.5%, mesh 60; 20.2%, mesh 80; 15.5%, mesh 100; and 3.5%, mesh 200, with a Granu Grinder, C.W. Brabender Instruments Inc., U.S.A.
The wood fibers were precoated with 10% PS 525 ~ 8% PMPPIC or 4% silane A-1100 or grafted with polystyrene (89.1 % add-on).

Preparation of the com~osites A 25 gram mixture of cellulosic fiber + mica (15-35% by weight of composite) and polymer were mixed in a roll mill at 175C. After mixing 5 to 10 times, the resulting 15 mixtures were reground once again to mesh size 20 and then molded into shoulder-shaped test specimens (ASTM D-638, Type V). Standard molding conditions were temperature, 175C; pressure during heating and cooling, 3.8 MPa; heating time, 20 min; cooling time,15 min. Width and thickness of each specimen were measured with the help of a micrometer.

Mechanical tests The mechanical properties (e.g. tensile strength at yield point and the corresponding elongation and energy as well tensile modulus at 0.1 % strain) of all the samples were measured with an Instron Tester (Model 4201) following ASTM D-638.
25 The mechanical properties were au~omatically calculated by a HP-86B computer. The strain rate was 1.5 mm/min. The samples were tested after conditioning at 23+0.5C
and 50% R.H. for at least 18 hours in a controlled atmosphere. Mechanical properties 2 ~ ~ ji L,~
were reported after taking the statistical average of six measurements. The coefficients of variation 2.5-8.5% were taken into amount for each set of tests.
Table I shows the mechanical properties of both treated and untreated CTMP/treated mica-filled PS 525 composites. The properties of the composites were 5 compared to those of virgin polystyrene. it is obvious that the mechanical properties of treated CTMP/treated mica-filled composites improved compared to those of both the original polymer and non-treated CTMP/treated mica-filled composites. In general, properties are enhanced when compositions of isocyanate-coated CTMP and mica are taken as 3:1 or 1:3 wt. ratio and up to a 25 wt. % fiber addition. As for 1:1 wt. ratio 10 of silane-coated or grafted CTMP and mica, the tensile strength values ranked best at a 25 wt. % filler level, whereas modulus improved up to a 35 wt. % filler level. The best improvements in elongation and energy for the same composites occured at a 3:1 wt. ratio of coated CTMP and mica and at a 25 wt. % filler level. According to Table 1, properties improved even more when polystyrene-grafted CTMP was used as 15 a hybrid-fiber component.

EXAMPLE ll The composites were prepared and evaluated as described in Example 1, except that polystyrene used in this case was high-heat crystal polystyrene (PS 201 ) provided 20 by Polysar Limited of Canada. The mechanical properties are presented in Table ll.
I~ appears from this table that the mechanical properties of treated CTMP and mica-filled composites increased in many cases compared to those of virgin polystyrene and those of non-treated CTMP and mica-filled composites. In addition, tensile strength, elongation and energy for isocyanate-coated CTMP/mica-filled composites 25 ranked best. Silane-coated CTMP/mica, however, provided the best results with regard to modulus.

EXAMPLE lll The composites were prepared and evaluated as described in Examples I and Il, except that the impact strength (Izod, un-notched) of the composites was tested with an Impact Tester (Model TMI, No. 43-01 of Testing Machines Inc., U.S.A.), 5 following ASTM D-256. The properties appearing in Table lll reveal that impact strength of PS 201 based composites exceeds that of the original thermoplastic when silane-coated or grafted CTMP is used as a hybrid filler component. On the contrary, impact strength of PS 525 based composites is generally inferior to that of the original polymer.

EXAMPLE IV
The composites of both treated and untreated cellulose fiber/mica were prepared and evaluated as described in Examples I and ll, except that CTMP aspen was replaced by sawdust aspen. The tensile properties are presented in Table IV. This 15 table reveals that the properties of the composite materials comprising treated sawdust and mica improved in many cases, up to 25% of fiber level compared to those of virgin polymer and those of non-treated sawdust/mica-filled composites.
Moreover, compared with the mechanical properties of treated sawdust/mica-filled composites, isocyanate-coated wood fibers provided results better than those of 20 silane-coated ones.

EXAMPLE V
The composites of both treated and untreated cellulose fiber/mica fiber and PS
525 were prepared and evaluated as described in Example 1, except that CTMP aspen 25 was replaced by sawdust spruce. The tensile properties are presented in Table V, wherein the coated sawdust spruce fibers follow nearly similar trends to those of sawdust aspen fibers (as discussed in Example IV).

EXAMPLE Vl The composites of both treated and untreated sawdust aspen and sawdust spruce fibers/mica, and PS 201 and PS 525 were prepared as described in Example 1~ The Izod impact strength of the composites was evaluated as described in Example 5 Ill, while the properties appear in Tables Vl and Vll. In general, the mechanical properties of treated sawdust/mica-filled composites provided inferior results compared to those of the virgin polymers. But, in many cases, the impact strength of treated sawdusVmica-filled composites was better in comparison with that of non-treated wood fiber/mica-filled composites.

EXAMPLE Vll The composites of both treated and untreated CTMP aspen as well as sawdust aspen/mica, and PS 525 were prepared as described in Example 1. However, mica-200-NP-Suzorite was replaced by mica 60-NP-Suzorite (60 mesh, silane coated). The 15 resulting hybrid composites were exposed to various environmental conditions, e.g.
exposure to boiling water for 24 hours and to heat at +1 05C for 5 days as well as at a subzero temperature (e.g. -20C). The mechanical properties were tested at room temperature or at subzero temperature as described in Example 1. A part of the unexposed samples as well as a part of those which underwent boiling water and heat 20 exposure, were tested at room temperature. The remaining unexposed samples and boiling water exposed samples were kept at -20C in the Thermostatic Instron Chamber (Model 311) for 2 hours, and the mechanical properties were evàluated at that temperature. Tables VIII-XI summarize the percentage change in the mechanical properties, e.g. tensile strength, elongation, energy and modulus (based on the 25 properties of the original polymer under an identical treatment), of composites containing a filler content of only 25%, under various extreme conditions. Tables Vlll and X reveal that the strength of non-treated wood fibers/mica-filled composites deteriorates, but that the strength of PMPPIC coated wood fiber-filled and/or mica-filled (e.g. 3:1 weight ratio of wood fibers and mica) composites improved. Under all extreme conditions, except boiling water exposure, strength improved compared to that of the original polymer. Again, compared to room temperature, strength improved 5 even more when samples were exposed to high temperatures. At subzero temperatures, the strength of non-treated wood fibers/mica-filled composites deteriorated. On the other hand, some properties improved under identical conditions when treated wood fiber/mica-filled composites were considered. Although only the strength of wood fiber-filled composites deteriorated due to testing at subzero 10 temperatures after exposure to boiling water, strength improved marginally for wood fiber/mica-filled composites under identical conditions. Again from Tables Vlll and X, where modulus of composites under various extreme conditions is compared, it is observed that modulus follows a similar trend to that of strength. Moreover, in many cases, modulus of treated wood fiber/mica-filled composites revealed itself to be 15 superior compared to that of non-treated wood fiber/mica-filled composites.
Tables IX and Xl indicate that both elongation and energy of treated wood fiber/mica-filled composites are superior to those of non-treated wood fiber/mica composites under all extreme conditions. Due to exposure in boiling water, both elongation and energy deteriorate for non-treated wood fiber/mica-filled composites.
20 However, these properties improved when treated wood fibers alone, or mixtures of wood fibers and mica, were used. In most cases, both elongation and energy of non-teated wood fibers or silane-treated wood fiber/mica-filled composites decreased due to heat exposure. A contrary result occurred for PMPPIC trea~ed wood fiber/mica-filled composites. Elongation of treated wood fiber/mica-filled composites improved in many 25 cases, even at subzero temperatures, whereas energy for composites under identical conditions revealed itself inferior to the original polymer. Once again, elongation and energy of the composites deteriorated at subzero temperatures after being exposed to boiling water.

EXAMPLE Vlll The composites of both treated and untreated CTMP aspen as well as sawdust 5 aspen/mica, and PS 525 were prepared as described in Example 1. The resulting hybrid composites were exposed to various environmental conditions, e.g. exposure to boiling water for 24 hours and to heat at +105C for 5 days as described in Example Vll. Dimensional stability (i.e. change in weight as well as cross section area) of the composites filled with 25 wt. % of CTMP/mica are presented in Tables Xll and 10 Xlll. It is obvious that both weight and area increased along with a rise in the proportion of wood fibers in the composites. Non-treated wood fiber/mica-filled composites showed a greater development in both weight and area, whereas isocyanate or silane-coated wood fiber/mica-filled composites exhibited a lesser increase. As a result, treated wood fiber/mica-filled composites provided better 15 dimensional stability, even after being boiled in water for 24 hours. When heated in an oven at +1 05C for 5 days, the order of stability followed almost exactly the same trend as that of exposure to boiling water.
Although the present invention has been described in some detail above with the help of illustrations and examples, it is obvious that certain changes may be practiced 20 within the scope of the appended claims.

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TABLE I

Composition Tensile Elongation Energy Modulus of fibersstrength (MPa) (%) (mJ) (GPa) Weight % of fiber15 25 35 15 25 35 15 25 35 15 25 35 CTMP Mica 16.8~ 1.5~ 17.2~ 1.4 Non-treated CTMP (aspen) 100 0 18.9 22.3 21.5 1.6 1.7 2.2 22.9 25.1 39.7 1.8 2.0 2.3 18.8 17.6 17.0 1.5 1.51.2 21.5 22.2 17.5 1.7 1.9 2.0 18.7 18.2 16.1 1.5 1.5 1.0 22.9 21.4 13.4 1.7 2.1 2.2 17.2 17.0 15.2 1.5 1.5 1.3 22.2 18.8 16.4 1.6 1.7 1.9 0 100 16.3 15.9 15.0 1.3 1.1 1.0 14.7 12.6 11.8 1.8 2.0 2.4 CTMP (aspen) coated wnh PMPPIC (8%~
100 0 17.9 23.3 20.0 2.9 3.7 3.5 46.9 76.8 58.7 1.5 1.7 1.8 19.3 18.6 17.5 1.8 1.7 1.4 26.6 27.7 19.8 1.6 1.7 1.9 18.9 18.2 15.6 1.7 1.4 1.0 25.2 20.4 14.3 1.9 1.9 2.2 18.9 18.9 20.3 1.6 1.6 1.4 23.1 25.8 24.2 1.6 1.9 2.1 CTMP (aspen) coated wnh silane A-1100 (4%~*~
100 0 17.5 20.6 17.9 1.4 1.7 1.5 19.3 29.3 21.2 1.6 1.8 2.0 17.2 18.5 16.0 1.6 1.8 1.2 24.7 28.5 14.3 1.5 1.8 2.0 16.2 19.0 16.6 1.5 1.7 1.2 20.4 28.4 15.0 1.6 2.0 2.2 17.2 17.5 17.4 1.5 1.3 1.3 20.8 18.5 17.7 1.7 2.0 2.2 CTMP (aspen) arafted with polvstyrene (89.1%)~
100 0 18.1 21.1 24.3 4.5 3.6 3.0 79.0 63.4 60.7 1.4 1.5 1.6 17.4 19.9 21.3 1.6 3.0 2.4 23.0 56.4 47.5 1.5 1.7 1.8 17.5 21.8 18.3 1.5 1.9 1.4 20.7 38.3 22.0 1.6 1.8 2.2 16.5 17.2 16.3 1.4 1.6 1.2 19.3 23.6 15.7 1.6 1.9 2.3 PS 525 (virgin) By weight of CTMP (aspen) TABLE ll Composition Tensile Elongation Energy Modulus of fibersstrength (MPa) (%) (mJ) (GPa) Weight % of fiber 15 25 35 15 25 35 1525 35 15 25 35 CTMP Mica 41.5* 3.3* 80.5* 1.9*
Non-treated CTMP (aspen) 100 0 36.0 35.8 33.8 2.7 2.6 2.2 63.7 57.9 44.1 1.9 2.0 2.2 3Z.2 28.4 26.1 2.6 1.7 1.6 61.9 37.0 35.0 2.0 2.1 2.3 31.8 27.9 23.2 2.3 1.6 1.3 51.9 30.5 23.2 2.1 2.3 2.4 30.7 26.4 24.7 2.6 1.5 1.3 50.4 26.7 23.2 2.0 2.3 2.6 0 100 29.9 26.8 24.8 1.7 1.5 1.2 35.9 30.0 23.1 2.2 2.6 2.7 CTMP (aspen) coated with PMPPIC (8%)**
100 0 42.7 48.7 46.4 3.5 3.7 3.1 98.0 117.4 90.3 1.9 2.1 2.2 43.0 46.1 33.0 2.7 2.6 1.9 76.2 84.0 38.3 2.2 2.2 2.4 41.2 37.4 33.1 2.8 2.2 1.6 89.0 63.7 33.5 2.1 2.2 2.7 32.6 33.6 30.7 2.1 1.9 1.8 46.1 42.0 35.5 1.9 2.2 2.4 CTMP (aspen) coated with silane A-1100 (4%)**
100 0 35.4 37.2 31.2 2.2 2.3 1.6 51.3 61.6 33.4 2.0 2.2 2.4 39.6 36.6 30.0 2.8 2.5 1.6 88.1 71.1 31.5 2.2 2.4 2.7 41.4 37.9 34.9 2.5 2.4 2.0 70.6 74.3 55.8 2.3 2.3 2.6 30.3 26.7 22.1 2.2 1.6 1.3 55.3 33.1 23.1 2.0 2.4 2.5 CTMP (aspen) grafted with polystyrene (89.1%)**
100 0 43.1 44.8 42.8 3.1 3.1 2.8 77.0 77.4 71.1 2.0 2.0 2.1 39.3 38.5 28.3 2.8 2.3 1.7 76.0 64.3 38.5 2.1 2.2 2.4 34.4 31.9 23.2 2.3 2.2 1.3 59.1 46.1 26.5 2.1 2.2 2.3 * PS 201 (virgin) ** By weight of CTMP (aspen) 203745&
TABLE lll Izod Impact Strength (J/m) Composition (Weight %) Polystyrene 201 Polystyrene 525 Weight % of fiber1 5 2 5 3 5 1 5 2 5 3 5 CTMP Mica 7.8~ 25.2 Non-treated CTMP (aspen) 100 0 6.3 6.1 4.9 12.0 11.3 7.0 6.46.0 4.7 12.312.0 10.2 6.06.2 6.5 12.613.0 10.4 7.57.9 5.2 12.610.5 8.7 0 100 5.75.7 6.4 11.310.2 8.2 CTMP (aspen) coated wnh PMPPIC (8%)~
100 0 5.8 6.3 6.6 11.5 12.2 9.0 6.3 6.6 6.4 10.7 12.4 9.4 6.7 7.6 6.2 11.6 10.6 9.9 6.0 6.2 5.7 11.3 10.9 9.8 CTMP (aspen! coated with siiane A-110Q (8%)~*
100 0 7.4 6.2 5.1 21.5 12.6 8.0 6.3 7.0 4.6 13.0 9.5 9.5 7.7 8.1 7.6 11.8 9.9 8.8 8.1 7.8 7.6 10.6 10.1 7.1 CIMP (aspen) grafted with polystyrene (89.1%)~
- - - 10.9 10.6 7.3 7.06.3 5.7 12.310.8 9.5 8.57.2 5.3 13.811.2 11.1 :
Only polymer By weight of CTMP (aspen) 203~ 8 TABLE IV

Composition Tensile Elongation Energy Modulus of fibersstrength (MPa) (%) (mJ) (GPa) Wei~t % of fiber 15 25 35 15 25 35 1525 35 15 25 35 Sawdust Mica 41.5~ 3.3~ 80.5~ 1.9 Non-treated sawdust (aspen) 100 0 35.6 32.5 30.6 2.5 2.2 2.1 54.7 49.1 40.1 2.2 2.3 2.4 32.1 26.8 25.4 2.1 1.9 1.5 49.5 46.9 25.2 2.0 2.2 2.5 33.7 26.6 25.3 2.1 1.7 1.4 48.6 31.9 25.9 1.8 2.1 2.3 33.4 28.6 23.4 2.5 1.8 1.5 60.9 35.3 28.3 2.0 2.5 2.9 0 100 29.9 26.8 24.8 1.7 1.5 1.2 35.9 30.0 23.1 2.2 2.5 2.6 Sawdust (aspen) coated with PMPPIC (8%)~
100 0 42.6 44.7 38.5 3.4 3.3 2.7 85.5 91.8 68.7 1.9 2.0 2.0 36.7 41.0 31.1 2.2 2.4 1.7 55.4 75.1 40.1 2.1 2.1 2.3 36.1 36.6 31.4 2.1 2.1 1.9 50.6 53.6 39.9 2.1 2.3 2.4 35.2 34.3 31.4 2.1 1.8 1.7 48.0 44.2 36.7 2.2 2.4 2.8 Sawdust (aspen) coated with silane A-1100 (4%)~*
100 0 33.3 36.6 31.6 2.1 2.2 1.8 46.8 57.7 37.2 2.0 2.2 2.2 36.6 37.3 28.7 2.5 2.7 1.8 63.5 86.1 42.8 2.1 2.3 2.3 37.5 35.3 30.6 2.5 2.2 1.5 70.2 60.1 30.7 2.1 2.3 2.7 31.8 31.6 25.1 2.2 1.9 1.4 51.6 45.7 26.0 2.3 2.5 2.6 -PS 201 (virgin) By weight of sawdust (aspen) ~7''~3~

TABLE V

Composition Tensile Elongation Energy Modulus of fibersstrength (MPa) (%) (mJ) (GPa) Weight % of fiber 15 25 35 15 25 35 15 25 35 15 25 35 Sawdust Mica 16.8* 1.5* 17.2* 1.4*
Non-treated sawdust (aspen) 100 0 17.2 18.2 1,.8 1.8 1.8 1.6 22.7 25.0 21.3 1.7 1.9 2.0 17.5 16.6 16.3 1.5 1.3 1.2 22.6 17.5 16.4 1.7 1.8 2.1 17.2 16.6 15.5 1.5 1.4 1.2 22.2 18.2 14.7 1.7 1.9 2.0 16.1 14.9 14.7 1.3 1.2 1.0 16.5 14.5 12.2 1.8 1.9 2.1 0 100 16.3 15.9 15.0 1.3 1.1 1.0 14.7 12.6 11.8 1.8 2.0 2.4 Sawdust (spruce) coated with PMPPIC (8%)**
100 0 20.0 20.7 18.0 3.1 3.0 2.2 48.7 47.2 32.1 1.4 1.6 1.8 18.4 24.5 19.1 2.0 3.3 1.6 30.8 75.1 25.2 1.5 1.8 1.8 19.2 22.0 18.6 1.8 2.8 1.5 28.3 59.1 23.6 1.7 1.9 1.9 18.0 19.8 - 2.0 2.0 - 33.7 38.8 - 1.6 1.9 Sawdust (spruce) coated with silane A-1100 (4%)**
100 0 18.9 18.5 18.3 4.2 2.1 1.8 77.2 36.1 26.3 1.6 1.7 1.9 17.4 18.7 18.7 1.7 2.4 1.9 23.9 39.4 30.2 1.3 1.6 1.6 16.9 17.2 16.3 1.6 2.0 1.8 23.2 30.9 27.5 1.5 1.7 1.7 17.1 16.5 16.4 1.5 1.4 1.3 21.4 17.9 17.1 1.5 1.8 2.0 * PS 525 (virgin) ** By weight of sawdust (spruce) r.7 iJ

TABLE Vl Izod Impact Strength (J/m) Composition (Weight) Sawdust (aspen) Sawdust (spruce~
Weight % of fiber 1 5 2 5 3 5 1 5 2 5 3 5 Sawdust Mica 7.8~ 7.8 Non-treated sawdust 100 0 6.9 6.6 6.2 6.5 6.3 5.8 5.9 6.5 5.4 6.36.9 5.2 6.2 6.3 6.3 5.75.8 6.3 9.1 8.3 6.S 7.28.4 5.4 0 100 5.7 5.7 6.4 5.75.7 6.4 Sawdust coated with PMPPIC (8%)**
100 0 6.6 8.5 7.6 6.9 8.3 6.1 6.3 6.9 7.0 6.46.5 6.6 5.4 6.6 7.7 6.47.0 6.7 5.1 6.3 6.5 6.37.1 6.5 Sawdust coated with sLane A-1100 (8%!
100 0 7.7 6.3 5.6 7.3 6.8 6.0 7.5 6.8 ~.4 6.76.5 6.5 6.9 6.5 6.2 6.75.8 5.2 6.8 6.0 5.9 6.55.8 5.4 -* PS 201 ~virgin) ** By weight of sawdust ^,3 C~

TABLE Vll Izod Impact Strength (J/m) Composition Weight % Sawdust (aspen) Sawdust (spruce~
Weight % of fiber 15 25 35 15 25 35 Sawdust MiGa - e_ 25~2* 252*
Non-treated sawdust 100 0 17.3 11.2 9~8 11 ~8 11 ~4 6~7 14~6 12~6 9~6 11 ~411 ~4 7~7 12~0 12~3 9~8 10~ 4 8~9 11 ~6 10.3 9~2 11 ~210~5 8~2 0 100 113 10~2 8~2 11 310~2 8~2 Sawdust coated with PMPPIC (û%)**
100 0 17~9 12~2 11~4 12~2 14~9 91 14~7 13~4 9~ 1l44 10~9 15~2 123 11~ 8167 103 11~7 11~3 11~0 10~6120 9~6 Sawdust coated with silane A-1100 (8%)**
100 0 169 15~8 11~0 14~7 13~9 12~5 13~2 11 ~6 74 10.0 7~7 7~2 13~3 11~4 7~5 14~7 12~4 10~3 12~1 9~4 9~4 16~0 13~8 13~8 Sawdust grafted with polystyrene (11.8)**
50 10.9 9~2 8~0 .

* PS525 (virgin) ** By weight of sawdust ~7~

TABLE Vlll -Composition Improvement~ % of Improvement~ % of modulus tansile strength Weight % A B C D E A B C D E
CTMP Mica Non-treated CTMP (aspen) 100 0 +32.7 28.4 +40.8 +18.6 +14.2 +42.9 15.4 +30.8 +69.2 +30.0 +9.8 27.8 +79.6 +5.0 +14.4 +28.6 7.7 +61.5 +61.5 0 +14.9-19.8 +92.8 +4.2 +24.8 +35.7 +23.1 +92.3 +76.9 +100.0 +5.4 -10.7 - +6.2 +23.1 +35.7 +30.8 - +82.3 +90.0 0 100 +6.0 -4.1 +38.8 +15.6 +15.1 +57.1 +53.8 +99.9 +76.9 +80.0 CTMP (aspen) coated wRh PMPPIC (8%)~
100 0 +38.7 +11.8 +55.1 +18.6 +23.7 +21.4 +15.4 +30.8 +38.5 +50.0 +25.0 +22.0 +65.1 +40.8 +28.9 +28.6 +7.7 +38.5 +70.0 +20.0 +26.2 -12.4 +72.2 +25.0 +23.7 +50.0 +7.7 +71.5 +46.2 +100.0 +32.7 +11.2 +11.0 +16.4 +20.4 +42.9 +38.5 +30.8 +92.3 +101.0 CTMP (aspen) coated with silane A-1100 (4%)*~
100 0 +22.6-6.5 +61.2 +25.9 +17.8 +28.6 0 +69.2 +76.9 +50.0 +11.3-4.1 +39.5 +33.1+26.0 +28.6-15.4 +69.2 +76.9 +70.0 +4.0-10.7 +44.6 +25.8+8.3 +35.7+30.8 +53.9 +106.7 +70.0 +6.2-3.6 +75.8 +14.3+35.9 +28.6+46.2 +69.2+115.4 +123.0 Based on PS 525 (virgin~ after similar treatment *~ By weight of CTMP (aspen) A: Testing at room temperature B: Testing at room temperature after boiling in water for 24 hours C: Testing at room temperature after heating in an oven at 105C for 5 days D: Testing at 20C
E: Testing at 20C afler boiling in water for 24 hours TABLE IX

,.
Composition Improvement~ % of Improvement~ % of energy elongation Weight %A B C D E A B C D E
CTMP Mica Non-treated CTMP (aspen) 100 0+13.3 +47.1 +27.8 +28.6 -41.2 +45.9 +1.0 +84.3 -25.5 -52.7 -6.0 -~6.5 -16.7 -23.8 -51.0+9.3 -11.6+15.3 -67.5 -63.5 +6.7 -4.1 -11.7 +1.0 -53.1+102.3 -16.7+37.9 -45.0 -60.2 -14.7 -15.9 0 -8.1 -58.0-6.4 -24.2 - -56.1 -67.9 0 100 -13.3 -29.4 -49.4 0 -62.8-11.1 -36.4-44.2 -48.1 -71.1 CTMP (aspen) coated with PMPPIC (8%~
100 0 +146.7 +94.1 +177.8 +38.1 -47.7 +346.5 +206.6+343.7 -17.0 -52.6 25 +33.3+142.4 +7.8 +29.1 +43.1 +89.0 +273.7+56.4 +17.0 -51.2 50 +26.7+47.1 +2.2 -22.4 -50.0 +77.9 +54.6 +67.3 -60.4 -56.1 +2.0 -11.8 -22.2 0 -54.5 +34.7-16.2 -25.9 -42.7 -59.1 CTMP (aspen) coated with silane A-1100 (4%~
100 0+13.3+111.8 -22.2 +7.6 -47.1 +70.4 +163.1 -1.0 -40.0 -56.2 25 +20.0+82.4 -32.2 +22.9 -51.0 +37.2 +131.7 -22.5 -21.6 -57.7 50 +20.7-17.7 -34.4 -3.3 -58.0 +48.1 -26.8 +23.4 -45.9 -70.2 -13.3-23.5 -23.3 -14.8 -57.3 -12.2-26.8 +3.5 -54.8 -59.7 Based on PS 525 (virgin) after similar study ~ By weight of CTMP (aspen) A: Testing at room temperature B: Testing at room temperature after boiling in water for 24 hours C: Testing at room temperature after heating in an oven at 105C for 5 days D: Testing at 20C
E: Testing at 20C after boiling in water for 24 hours TABLE X

Composition Improvement~ % of Improvement~ % of modulus tensile strength Weight % A B C D E A B C D E
Sawdust Mica Non-treated sawdust (aspen) 100 0 +8.930.2 +37.4 7.6+0.1 +35.7 7.7 +46.2 +46.2 +40.0 25+10.1 24.8 +48.65.4 +6.6 +35.7 o +61.5 +100.0 +10.0 50 +3.7 20.1 +63.3+2.0+8.3 +42.9 +15.4 +84.6 +70.8 +70.0 75 +3.6 -16.0 -12.6+3.1 +6.7 +28.6 +30.8 +7.7+97.7 +102.0 0 100+6.0 -4.1 +38.8+15.6+15.1 +57.1 +53.8 +99.9 +76.9 +80.0 Sawdust (aspen) coated with PMPPIC (8%)**
100 0 +36.9 +13.0 +63.3 +15.1 +18.3 0 0 -15.4 +38.5 +60.0 25+22.6 +0.5 +29.9 +20.0 +28.5 +28.6 +23.1 +15.4 +53.9 +70.0 50+14.5 11.2 +30.5 +0.4 +14.3 +42.9 0 +46.2 +53.9 +90.0 75+17.6 2.9 +25.0 9.6 +26.0 +50.0 +61.5 +76.9 +100.0 +140.0 Sawdust (aspen) coated with silane A-1100 (4%)~*
100 0 +16.117.8 22.7 +4.8+11.0 +14.3 0 30.8 +54.6 +40.0 5.2 11.54.8 +10.2+5.3 +21.4 0 +30.8 +69.2 +40.0 50 +0.6 16.5+26.3+5.114.1 +35.7+23.1+53.9 +84.6 +50.0 3.0 20.1+23.1+6.9 5.8 +35.7+15.4+38.5 +97.7 +90.0 -* Based on PS 525 (virgin) after similar treatment *~ By weight of sawdust (aspen) A: Testing at room temperature B: Testing at room temperature af~er boiling in water for 24 hours C: Testing at room temperature afler heating in an oven at 105C for 5 days D: Testing at 20C
E: Testing at 20C after boiling in water for 24 hours ~7~

TABLE Xl Composition Improvement~ % of Improvemant~ % of energy elongation Weight %A B C D E A E~ C D E
Sawdust Mica Non-treated sawdust (aspen) 100 0+13.3 +5.9+5.6 0 62.1 +20.4 6.6 +40.6 54.2 75.3 25 17.3 2.4 33.331.9 62.116.924.022.0 71.4 74.6 6.7 11.8 20.415.2 60.10.1 26.86.6 60.5 69.6 75 -20.0 -17.7 -43.9-15.2 -66.7-20.4-28.8-60.4 -59.3 -76.5 0 100-13.3 -29.4 -49.4 0 -62.8-11.1-36.4-44.2 -48.1 -71.1 Sawdust (aspen) coated with PMPPIC (8%)**
100 0 +106.7 +47.1 +61.1 +33.3 -50.7 +153.5 +89.4+160.9 -24.4 60.1 25+66.7 +62.4 +22.2 +20.5 45.7 +136.6 +101.0 +47.7 34.0 53.3 50+13.3 +41.8 22.8 13.8 57.5 +40.8 +40.9 16.8 61.5 66.9 0 25.9 47.2 13.8 68.8 26.8 27.247.0 57.5 70.5 Sawdust (aspen) coated with silane A-1100 (4/O)**
100 0+106.7 +2.4 26.1 +9.6 54.1 +212.2 6.1 52.3 43.4 65.8 25-13.3 +8.8 -38.3 -1.9 -58.1-16.9 +0.5 48.1 51.8 72.4 50-13.3 -5.3 -38.9 -6.7 -65.5-15.1 -13.1 -37.1 -54.9 -79.8 75-13.0 0 -22.2 -11.7 -69.9-25.0 -17.7 +15.6 -56.9 -81.9 * Based on PS 525 (virgin) after similar study ** 8y weight of sawdust (aspen) A: Testing at room temperature B: Testing at room temperature after boiling in water for 24 hours C: Testing at room temperature after heating in an oven at 105C for 5 days D: Testing at 20C
E: Testing at 20C after boiling in water for 24 hours 20~74 i~

TABLE Xll Composition Comparison of dimensional stability (Weight /O) Weight Cross section area Weight % B C B C
CTMP Mica -+0.7* 0.2* +3.0* +2.3*
Non-treated CTMP (aspen) 100 0 +12.9 0.8 +12.6 0.6 +7.2 0.6 +11.9 0.6 +4.5 -0.5 +7.3 +1.6 +3.5 -0.4 +4.7 +2.8 0 100 +0.4 -0.2 +0.7 +0.7 CTMP (aspen) coated wnh PMPPIC (8%)**
100 0 +5.2 -0.7 +6.5 -1.0 +4.5 -0.5 +5.9 +2.2 +3.8 -0.4 +4.5 +0.8 +2.4 -0.2 +2.9 +0.5 CTMP (aspen) coated with silane A-1100 (8%)~
100 0 +8.4 -0.6 +10.5 +5.0 +6.7 -0.4 +7.0 +3.7 +3.6 -0.3 +4.1 +2.2 +2.7 -0.2 +3.0 +0.7 * PS 525 (virgin) ** By weight of CTMP
B: After boiling in water 24 hours C: After heating in an oven at 105C for 5 days 2037~a8 TABLE Xlll Composition (Weight %) Comparison of dimensional stability Weight Cross section area Weight % B C B C
Sawdust Mica (aspen) , +0.7~-0.2~ +3.0* +2.3*
Non-treated sawdust (aspen3 100 0 +7.1 -0.8 +7.9 -1.1 +6.0 -0.4 +6.4 -0.9 +3.9 -0.3 ~4.2 -0.7 +2.9 -0.2 +3.7 +2.8 0 100 +0.4 -0.2 +0.7 +0.7 Sawdust (aspen) coated with PMPPIC l8%3~
100 0 +5.1 -0.8 +5.5 -0.7 +4.0 -0.4 +6.6 +3.5 +3.4 -0.3 +4.5 +2.7 +2.4 -0.2 +3.4 +2.0 Sawdust (aspen) coated with silane A-1100 (8%!~
100 0 +5.7 -0.4 +6.4 +4.9 -~5.0 -0.3 +6.1 +3.1 -~3.3 -0.3 +4.4 +2.5 +2.2 -0.2 +2.9 +2.2 * PS 525 (virgin) By weight of sawdust (aspen) B: After boiling in water 24 hours C: After heating in an oven at 105C for 5 days

Claims (7)

1. A composite comprising from 1 to 50% by weight of treated hybrid fillers, such as discontinuous cellulose fibers and inorganic fillers, dispersed in a matrix from 1 to 95% by weight of polystyrene, and hybrid fillers comprising from 1 to 100% by weight of cellulose fibers and from 100 to 1% by weight of inorganic fillers, and comprising from 0 to 50% by weight of plasticizer.

2. The treated fiber as defined in claim 1 wherein the treatment comprises the precoating with a compatible polymer + linear polymethylene polyphenyl isocyanate or pretreatment with a silane coupling agent, particularly gamma-aminopropyl triethoxy silane, or grafting with a vinyl compatible vinyl monomer.

3. The treated fiber as defined in claim 1 wherein the cellulosic fiber is selected from softwood pulp or hardwood pulp or a mixture of hardwood and softwood pulp or sawdust or wood flour.

4. The treated fiber as defined in claim 1 wherein the cellulosic fiber is selected from non-wood plants, e.g. bagasse, nutshells, corn cobs, jute and the like.

5. The treated inorganic filler as defined in claim 1 wherein the inorganic filler material is selected from mica, talc, calcium carbonate, silica, glass fibers, asbestos or wollastone, specifically glass fibers.

6. A compression molding made from a composite according to any of claims 1-5.

7. An injection molding made from a composite according to any of claims 1-5.