SE470597B - Process for preparing thermoelasts having varied crystalline structure such as polyoxetane ABA or star segment copolymers by means of a segment-binding process - Google Patents

Abstract

A process for preparing a thermoelast having segments A and at least one segment B, with the A segments being crystalline at temperatures of less than approx. 60 degree C and the segment B being amorphous at temperatures of greater than approx. -20 degree C, which segments A are polyethers which are derived from monomers of oxetane and derivatives thereof and/or tetrahydrofuran and derivatives thereof, which process comprises: starting with monofunctional, hydroxylterminated segments A which are crystalline at temperatures of less than approx. 60 degree C and separately starting with bi-, tri- or tetrafunctional, hydroxyl-terminated segments B which are amorphous at temperatures of more than approx. 20 degree C, end-blocking the segments A by separately reacting the segments A with a bifunctional diisocyanate, in which one isocyanate group is at least approx. five times as reactive with the terminal hydroxyl group in the segment A as is the other isocyanate group, as a result of which the more reactive isocyanate group tends to react with the terminal hydroxyl group in the segments A, leaving the less reactive isocyanate group free and unreacted, and adding bi-, trior tetrafunctional segments B to the end-blocked segments A in approximately the stoichiometric proportions in which they are intended to be included in the thermoelast, such that the free and unreacted isocyanate group on the endblocked segment A reacts with a functional group in the segment B with the formation of the thermoelasts ABA or AnB.

Description

4 20 25 30 35 470 597 2 to develop thermoelastics suitable as binders for solid high energy compositions. However, many thermoelastics are unable to meet various requirements imposed on propellant formulations, in particular the requirement to be able to be processed at temperatures below about 120 ° C, whereby it is desirable that a thermoplastic polymer to be used as a binder in a high energy system has a melting temperature between about 60 and about 120 ° C. The lower value in this range relates to the fact that the fuel composition may be exposed to certain elevated temperatures during storage and use and it is not desirable that there be appreciable softening of the fuel composition. The upper value in this range is determined by the instability at elevated temperatures of many components normally included in propellant compositions, especially particulate oxidizing agents and energetic plasticizers. Many thermoelastics exhibit high melt viscosity, which precludes admixture of large amounts of solids, and many exhibit high creep tendency and / or shrinkage after processing. Thermoelastics (TPBs) usually acquire their thermoplastic properties from segments, which form glassy areas that can contribute to physical properties that adversely affect their use as binders. Thermoelastics are block copolymers with the property of forming physical crosslinks at predetermined temperatures. A classic TPE, such as Kraton, acquires its property by having the glass transition temperature of a segment component above room temperature. At temperatures below 109 ° C, the glassy segments of Kraton form glassy areas and thus physically crosslink the amorphous segments. The strength of these elastomers depends on the degree of phase separation. It thus remains desirable to have regulated but significant immiscibility between the two types of segments, which is a function of their chemical structure and molecular weight. On the other hand, as the segments become increasingly immiscible, the melt viscosity will increase and this has a detrimental effect on the machinability of the material. The aforementioned US-A-4 361 526 proposes a thermoplastic adhesive which is a block copolymer of a diene and styrene, the styrene blocks forming a fusible crystal structure and the diene blocks imparting rubbery or elastomeric properties to the copolymer. This polymer requires machining with a solvent and solvent handling is undesirable because the propellant cannot be cast in a conventional manner, for example into a rocket engine housing. Furthermore, solvent-based handling offers problems in terms of removal and expansion of solvents.

It has been proposed to produce thermoelastics having both segments A and B, both of which are derived from cyclic ethers, such as oxetane and oxetane derivatives and tetrahydrofuran (THF) and tetrahydrofuran derivatives. The monomer or combination of monomers in segments A is selected to give a crystalline structure at normal room temperatures, while the monomer or combination of monomers in segments B is selected to ensure an amorphous structure at normal room temperatures. Such proposed thermoelastics (TPE) include ABA three-block polymers, (AB) n polymers in which segments A and B alternate, and AnB star polymers in which a plurality of segments A are bonded to a central multifunctional segment B. Such TPEs are believed to be extremely suitable for use. in binder systems for high-energy compositions, such as fuels, explosives, carburetors or the like. Segments A and B of such polymers are miscible in a melt of the polymer. The melt viscosities of such TPE decrease rapidly as the temperature rises above the melting point of the crystalline segments A and contribute to its processability. Furthermore, a thermoplastic based on crystalline areas exhibits advantageous solvent resistance and minimal shrinkage after curing. Such TPE can be formulated to exhibit a melting temperature falling within a desired range of 60-120 ° C, to be chemically stable up to 120 ° C and above, to have low melt viscosity, to be compatible with existing components in high energy compositions, to maintain it mechanical integrity when filling with solids up to 90% by weight and having a glass transition temperature below -20 ° C and even below -40 ° C.

Two methods have previously been proposed for producing such TPEs. According to a proposed method, ABA trisegment or (AB) n polymers can be joined by a segment bonding technique, wherein a bonding group, such as phosgene or an isocyanate, is allowed to react with both ends of the middle segment (B ) and the end segments (A) may consequently react with the bonding group (x). In general, the following reaction occurs: B + 2x- + xBxêê »AxBxA or B + 2x- + xBx-êa (AB) n.

According to another preferred method, an ABA polymer is formed by systematic monomer addition. For example, monomer A may be reacted with an initiating adduct to form a segment A by cation polymerization and the reaction may be continued until monomer A is substantially depleted. Then monomer or monomers of segment B are added and the polymerization is allowed to proceed from the active end of segment A. When the monomers of segment B are substantially depleted, additional monomers of segment A are added and the polymerization is allowed to proceed from that of segment B. The reaction can be represented of the equation: A (monomer) - + A (active polymer) .E_ÅÉ2É2ÉÉfÅ AB (active polymer) .è_ÅE2E2ÉÉEš, ABA trisegment polymer.

Alternatively, a difunctional initiator could be used to initiate the polymerization of segment B. When segment A is added, the polymerization could proceed from both active ends of segment B. The reaction can be represented by the equation: ßuuønomer) -> Bmunfunctionally active polymer (ABA trisegment polymer). By selecting appropriate segment functionality or repeating steps, these methods are also proposed as suitable for producing (AB) n polymers and AnB star polymers.

Both of these methods of making TPE polyethers have proved less satisfactory. Combining segments A and B has been found to be minimal with either of the two methods described above, and consequently, an improved process for producing TPE with both crystalline polyether segments A and amorphous polyether segments B is desirable.

According to US-A-4 806 613 issued in the name of Robert Wardle, a three step process for forming thermoelastics with crystalline polyether segments A and amorphous polyether segments B is proposed.

Both of these polyether segments A and B are synthesized separately.

Segments A and segments B are end-blocked separately with a diisocyanate, one isocyanate group being significantly more reactive with active groups on the segments than the other isocyanate group. Finally, end-blocked segments are mixed and reacted with a difunctional binding chemical, each function of the binding chemical being isocyanate-reactive and sufficiently unobstructed to react with a free isocyanate group on a blocked segment. However, it is statistically unrealistic to link functional segments A and B and form exclusively ABA elastomers by regulating the stoichiometry of the segments.

It is highly desirable that an even more efficient and simpler process be provided for the preparation of such ABA and ANS thermoelastics having crystalline polyether segments A and amorphous polyether segments B, which process does not require three steps, does not require the use of the difunctional bonding compound of U.S. Pat. A-4 806 613 and can give mainly exclusively ABA or AnB elastomers.

According to the present invention, there is provided a novel one-step process for forming thermoelastics with crystalline polyether segments A and amorphous polyether segments B. After individual synthesis of monofunctional segments A and di-, tri- or tetrafunctional segments B, the monofunctional crystalline segment A is end-blocked with a difunctional isocyanate, wherein a of the isocyanate groups is substantially more reactive with the functional group on the segments than the other diisocyanate group, whereby the more reactive isocyanate groups tend to react with the functional group in segment A leaving the less reactive isocyanate group free and unreacted and then di-, tri- or tetra-functional segments B to the end-blocked segments A at approximately stoichiometric conditions, wherein they are intended to be included in the thermoelastomer so that the free and unreacted isocyanate group on the end-blocked monofunctional segments A 10 15 20 25 _30 35 470 597 6 react r with a functional group in segments B during the formation of thermo-loads ABA and AnB.

The process according to the invention is directed to the production of thermoelastic polymers, in which at least one segment B is flanked by at least a pair of segments A. Segments A are crystalline at temperatures below about 60 ° C and preferably at temperatures below about 75 ° C and segments B are amorphous at temperatures down to about -20 ° C and preferably down to about -40 ° C. Each of segments A and B are polyethers derived from cyclic ethers including oxetane and oxetane derivatives and THF and THF derivatives. The polymers melt at temperatures between about 60 and about 120 ° C and preferably between about 75 and about 100 ° C. Segments A and B are mutually miscible in the melt and consequently the melt viscosity of the block polymer drops rapidly as the temperature rises above the melting point, whereby high energy formulations may contain high levels of solids, eg up to about 90% by weight solids, and are easily processed. The invention includes block polymers TPE, such as ABA three block polymers and Anβ star polymers. Contributing to the miscibility between segments A and B is their similar chemical structure. Oxetane and tetrahydrofuran (THF) monomer units used in the formation of the segments according to the invention have the general formula: R // // R-- f. R _ <: ______ RR wherein the groups R are the same or different and selected from groups of the general formula: - (CH 2) n X, where n is 0-10 and X is selected from the group consisting of -H, -NO 2, -CN, -Cl, -F, -O-alkyl, -OH, -I , -ONO 2, -N (NO 2) -alkyl, -CECH, -Br, -CH = CH (H or alkyl), -O-CO- (H or alkyl), -CO 2 - (H or alkyl), -N (H or alkyl) 2, -O- (CH 2) 1-5 -O- (CH 2) 0_8-CH 3 and -N 3.

Examples of oxetane used to form block polymers of the invention include, but are not limited to: BEMO 3,3-bis (ethoxymethyl) oxetane, BCHO 3,3-bis (chloromethyl) oxetane, BMMO 3,3-bis (methoxymethyl) oxetane , BFMO 3,3-bis (fluoromethyl) oxetane, HMMO 3-hydroxymethyl-3-methyloxetane, BAOMO 3,3-bis (acetoxymethyl) oxetane, BHMO 3,3-bis (hydroxymethyl) oxetane, OMMO 3-octoxymethyl-3- methyloxetane, BMEMO 3,3-bis (methoxyethoxymethyl) oxetane, CMMO 3-chloromethyl-3-methyloxetane, AMO 3-azidomethyl-3-methyloxetane, BIMO 3-3-bis (iodomethyl) oxetane, IMO 3-iodomethyl-3-methyloethane , PMO 3-propynomethylmethyloxetane, BNMO 3,3-bis (nitratomethyl) oxetane, NMO 3-nitratomethyl-3-methyloxetane, BMNAMO 3,3-bis (methylnitraminomethyl) oxetane, MNAMMO 3-methylnitraminomethyl-3-methyloxetane, and B 3-bis (azidomethyl) oxetane.

The production of TPE according to the invention requires (1) formation of a polymer, which is to function as segments A, which is crystalline in nature with a relatively elevated melting point, i.e. between about 60 and about 120 ° C, preferably close to 80 ° C and (2 ) formation of a polymer, which is to function as segment B, which is amorphous in structure and has a glass transition temperature (Tg) below about -20 ° C and preferably below about -40 ° C.

Examples of suitable crystalline segments A include poly-BEMO, polyBMMO and polyBFMO. Both polyBEMO and polyBMO melt at between 80 and 90 ° C and polyBFMO has a melting point of about 105 ° C. These crystalline homopolymers can be selected as block A according to the specific binder requirements. For example, polyBMMO has a higher ether oxygen content than polyBEMO, which may be advantageous in some contexts. Although the melting point 80-90 ° C for polyBMMO and polyBEMO is generally preferred, the higher melting temperature for polyBFMO may be preferred in specific binder contexts. PolyBFMO also has a higher density than either of polyBEMO or polyBMMO, which may be suitable for some binder contexts.

The advantage of crystalline hard segments is shown by the dynamic mechanical properties in the following table.

B_D_§ ___ DAIA Iš! E_l§l _____ §L ____ gl 1 25 303400000 52500000 2 30 310000000 41900000 3 35 277200000 43300000 4 40 233000000 30000000 5 45 101100000 31300000 0 50 133000000 124300000 7 S4 101500000 2040011 10000 9000 10000000 15200000 11 02 00500000 13400000 12 04 51300000 11000000 13 00 40100000 9000000 14 00 30500000 1000000 15 10 20400000 5100000 10 12 10000000 3500000 11 14 0200000 1440000 10 10 400000 100000 0 '= Lmningamiml GI = loss index This table shows that a TPE containing a crystal segments maintain good mechanical properties to within a very few degrees of melting point. At the melting point, the material softens and flows with a relatively low viscosity.

The soft or amorphous segment B is selected from homopolymers and copolymers (or higher number of blended polymers) which are found to have a low glass transition temperature. An important class of amorphous segments of the invention are copolymers of THF and mono-oxetane monomers including those monomers which form the crystalline homopolymers described above. For example, THF / BEMO, THF / BMO and THF / BFMO copolymers have been found to be amorphous at room temperature and have low glass transition temperatures.

The physical properties of these block copolymers depend on the relative proportions of THF and the oxetane monomer, with molar ratios ranging from between 20% and about 80% of THF monomers.

Oxetanes with long or bulky side chains can be copolymerized with THF to give segment B which is "internally softened". This means that the side chains (R) sterically prevent tight packing of polymer chains and this contributes to low viscosity and low value of Tg provides internal softening in a THF / oxetane copolymer, are OMMO and BMEMO. Here, too, the molar ratio of THF: oxetane is between about 80:20 and about 20:80. of the copolymer. The oxetane monomers, which In addition, homopolymers and copolymers of different energetic oxetanes exhibit amorphous properties. Segment B formed with energetic polymers are useful in the formation of energetic thermoelastomers. High energy polymers and copolymers include but are not limited to polyNMMO, polyBAMO / AMO, polyBAMO / NMMO and polyAMMO, the monomers used to form the copolymers being used throughout the molar ratio spectrum depending on the desired physical and energetic properties of segment B. the energetic homopolymer or copolymer segments B to form (AB) segment polymers, it may be appropriate to use non-energetic segments A, such as polyBEMO, polyBMMO and polyBFMO segments described above to achieve low vulnerability of high energy compositions formed therefrom. However, when high energy binders are desired or required, it is considered within the scope of the invention to have segment A similarly formed with high energy monomers. An example would be polyBAMO.

The properties of the block polymer depend on the molecular weights of the individual segments and the total molecular weights.

Typically, segments A have molecular weights from about 3000 to about 15,500, while segments B have molecular weights from about 5,000 to about 50,000. Preferably, segments A are shorter than segments B and the total molecular weights of segments A typically ranges from about 1/5 to 1 time the molecular weight of segment B of the ABA trisegment polymer or the molecular weight of segments B of an AnB star polymer. Usually the segments A are the same size. The preferred sizes of segments A and B for each specific binder application must be determined empirically.

Thermoelastics produced according to the invention are mixed with other components in a high-energy formulation, such as a propellant formulation. The binder system, in addition to TPE, may optionally contain a plasticizer at a plasticizer to TPE ratio of up to about 2.5: 1, with suitable high energy plasticizers including nitroglycerin, butanetriol trinitrate (BTTN) and trimethylolethane trinitrate (TMETN). If the TPE segment is internally softened, eg with OMMO or BEMO as above, there is less need for external plasticizers, although high-energy nitroester-type plasticizers can be used to enhance the energy content of the binder system as a whole.

The binder system may also contain a minor amount of wetting agent or lubricant which allows the addition of higher solids contents.

The dry content of the high energy composition generally ranged from about 50% to about 90% by weight and higher levels are generally preferred as long as this is consistent with the integrity of the structure. The solids include particulate fuel materials such as ammonium perchlorate, cyclotetramethylenetetranitramine (HMX) and cyclotrimethylenetrinitramine (RDX). Furthermore, the high energy composition may contain minor amounts of other components known in the art, such as binders, combustion rate modifiers, etc.

The thermoelastomer can be mixed with the solids and other components of the high energy formulation at temperatures above its melting temperature. The mixing is performed in conventional mixers. Due to the low viscosity of the molten polymer, no solvents are required to stir or otherwise perform processing, such as extrusion. An advantage of the use of thermoelastics for binders is mixing, although this is generally desirable from an energy utilization point of view.

An important advantage of having a fuel that is digestible is that the fuel from a discarded missile can be melted down and used again. At times of such remelting, the propellant can be reformulated, for example by adding additional fuel or oxidizing agent in particulate form. Thus, the thermoplastic in the propellant composition allows any recirculation as opposed to the combustion required to handle crosslinked propellant compositions. Since the thermoplastic fuel does not have a "service life", there is no limit to the time for casting and if any problems arise during the casting process, the process can be postponed as needed by simply retaining the fuel formulation in molten form.

For the process of the invention it is necessary to obtain monofunctional monomer segments A. Such monofunctional monomer segments A can be formed by the cationic polymerization process described in co-pending patent application Serial Number 07/323 588 filed March 14, 1989 to Thiokol Corporation, whose content here was incorporated by reference. The di-, tri- or tetrafunctional monomer segments B can also be prepared according to the process described in said application 07/323 588 as well as with any other suitable polymerization technique, such as with the technique described by Manser et al in US-A-4 393 199 and in the aforementioned U.S. Patent 4,483,978.

The polymers grow from an alcohol. The number of hydroxyl functional groups on the alcohol generally determines the functionality of the polymer chain growing therefrom and thus a diol gives rise to a difunctional polymer, a triol to a trifunctional polymer, etc. Preferably the hydroxyl groups in the polyol are generally unblocked. Suitable diols include, but are not limited to, ethylene glycol, propylene glycol, 1,3-propanediol, and 1,4-butanediol. Suitable triols include but are not limited to glycerol, trimethylolpropane and 1,2,4-butanetriol. Suitable tetraols include, but are not limited to, pentaerythritol and 2,2 '(oxidimethylene) bis (2-ethyl-1,3-propanediol), with the latter being preferred.

A monofunctional polymer can be bonded using a monofunctional alcohol as an initiator. Although a simple alkyl alcohol, such as methanol or ethanol, gives rise to some monofunctional polymer, it has been found that by far the best results are obtained if the initiator alcohol is a primary alcohol having the hydroxyl group on a vicinal carbon to an unsaturated bond. Examples of preferred monofunctional alcohol initiators are benzyl alcohol and allyl alcohol. Good yields of low polydispersity monofunctional polymer are achieved with such initiators.

According to the new process according to the invention, thermoelastics are produced which contain both crystalline polyether segments A and amorphous polyether segments B with at least a pair of segments A fusing at least one segment B. The monofunctional segments A and the polyfunctional segments B are synthesized separately. The monofunctional crystalline segment A is then end-blocked with a difunctional isocyanate. The diisocyanate has an isocyanate group that is significantly more reactive with the terminal functional groups on the segments than the other isocyanate group, whereby the more reactive isocyanate group tends to react with the functional group in segment A leaving the less reactive isocyanate group free and unreacted and then adding di-, tri- or tetrafunctional segments B to the end-blocked segments A at approximately stoichiometric ratio, being intended to be included in the thermoelastomer so that the free and unreacted isocyanate group on the end-blocked monofunctional segment A reacts with a functional group in segments B during the formation of ABA and AnB thermoelastics. Oxetane and THF / oxetane polymer segments prepared synthetically in the manner described above exhibit terminal hydroxyl functions which are reacted with the diisocyanates of the invention. An important aspect of the invention is that the endblocked diisocyanate compound has two isocyanate groups and that one of the isocyanate groups is significantly more reactive with the terminal hydroxyl groups in the polymer segments than the other isocyanate group. One of the problems with bonding of these types of polymer segments is that oxetane-derived hydroxyl end moieties have neopentyl structure, whereby the terminal hydroxyl moieties are substantially blocked. The diisocyanate is selected so that one of the isocyanate groups reacts with a terminal hydroxyl group in a monofunctional polymer segment while the other isocyanate group remains free and unreacted. Diisocyanate was used because isocyanate with higher functionality could result in unwanted crosslinking. The different reactivities of the isocyanate groups are necessary to ensure that no significant chain elongation occurs by binding of similar segments. Thus, for the purpose of the invention, one isocyanate group in the diisocyanate should be about 5 times more reactive with terminal hydroxyl groups in oxetane and THF / oxetane segments than the other group. Preferably, one isocyanate group is at least about 10 times more reactive than the other.

A diisocyanate which is particularly useful for the purposes of the invention is 2,4-toluene diisocyanate (TDI), wherein the isocyanate group in position 4 is significantly more reactive with blocked terminal hydroxyl groups than the isocyanate group in position 2. Isophorone diisocyanate (IPDI) is in some contexts suitable although less suitable than TDI. Examples of diisocyanate that did not work well include diphenylmethylene diisocyanate (MDI) and hexamethylene diisocyanate (HDI).

In the end-blocking reaction, the diisocyanate is used in approximately stoichiometric molar amount, preferably a slightly molar excess, relative to terminal hydroxyl groups on the monofunctional polymer chain. Thus, cal molar equivalents are used, eg 0.9-1.1 molar equivalents of diisocyanate. In the ideal reaction, all the more reactive isocyanate groups react with terminal hydroxyl groups in segments A and leave the less reactive isocyanate groups free.

Thus, end-blocking reaction can be maximized for specific polymer chains A by regulating the relative molar ratio of polymer block to diisocyanate.

Since segment A is first allowed to react with the diisocyanate, there is no competition for segment B for diisocyanate molecules, and end-blocking reaction of segment A can be performed in full. The diisocyanate can react faster with one segment A than the other, but this difference can be compensated with a longer reaction time with the slower reacting segment. The reactivity of the terminal hydroxyl groups varies with steric factors and also with side chain groups. Energetic oxetanes, for example, have in particular side chain groups which are electron repellent and make their terminal hydroxyl groups less reactive. The reactivity of the block polymers A for bonding purposes, once end-blocked with diisocyanate, is mainly due to the reactivity of the free isocyanate only and not to the chemical balance of the polymer chain itself A. The end-blocking reaction can be carried out and is preferably carried out in a suitable solvent, i.e. one which dissolves the block polymer A and does not react with the free isocyanate groups. The reaction is promoted by suitable urethane catalyst.

Lewis acids and protic acids are generally suitable catalysts. A preferred class of catalysts are organic tin compounds having at least one and preferably two labile groups, such as chloride or acetate, attached directly to the tin.

A suitable tin catalyst is diphenyltin dichloride.

Di-, tri- or tetrafunctional block polymers B are then added and reacted with the resulting isocyanate-terminated segments A to form the desired thermoelastics ABA or AnB. The di-, tri- or tetrafunctional block polymer B is added to the isocyanate-terminated block polymers A in such an amount that the total number of polymer-functional groups B is approximately equal to the number of free isocyanate groups on the end-blocked segments.

For example, a monofunctional hard segment, usually BAMO, is reacted with a slight molar excess of 2,4-toluene diisocyanate (2,4-TDI) in the presence of a catalytic amount of diphenyltin dichloride. The large reactivity difference between the two functional isocyanates, estimated by a factor of 26.6 when reacted with an unblocked alcohol, excludes any measurable dimerization reaction.

The resulting isocyanate-terminated polymer is then reacted with a difunctional or higher functionally soft segment such as AMMO or 3-methyl-3- (nitratomethyl) oxetane (NMMO). These soft segments are particularly advantageous because the relatively high reactivity of the hydroxyl end groups allows the condensation reaction with the less reactive isocyanate of 2,4-TDI to proceed at a significant rate.

The progress of the reaction can be monitored by both 300 M fl z 1 H NMR and FTIR. These two analytical methods complement and interact with each other in this case. The progress of the reaction between isocyanate and alcohol to urethane can be easily 1H NHR spectra, the methylene group closest to it can be followed. In the terminal alcohol a signal which clearly deviates from the signal from the same methylene adjacent to a urethane bond. These two absorptions can be quantified and compared. During the reaction, the conversion of alcohol end groups to urethane bonds can be monitored. The carbon absorption of the isocyanate groups in 2,4-TDI and in urethane resulting from the condensation of these functional groups with terminal oxetane alcohols is well defined and strong in an FTIR spectrum even at the low concentration present in this reaction.

This allows parallel monitoring of the reaction of alcohol to urethane by 1 H NMR and observation with FTIR of the conversion of the isocyanate to urethane based on carbonyl absorptions.

Together, these methods provide strong evidence that the intended segment binding reaction proceeds as intended. Table I contains data from the analysis of the product from a representative binding reaction.

Table I Representative results from the production of ABA materials by segment coupling a end-for groups (Anno / GPc etc. (nmo / segment-aydr. Arena. .LL _m fl__ nn__m._p_'s _nl ._. Mn9.l_ w _-_ v.ikf A 1oo / o 12,4 6,0 2, o6 1,3 1oo / oo ioø 3546 ao / 1oo 5,1 1.1 1,85 3,2 o / 1oo so 1oo 3521 c 60/40 15,5 6,1 1, 92 12.6 6/94 20 1oo - te ° ri 60/40 - - - 14.1 o / 1oo zo 1oo - aMw, Mn and NHR MW are given in number of thousands The segment factor is the difference between the reaction of the triad resulting from BAMO-BAMO-BAMO and BAMO-BAMO-AMMO measured with fully relaxed 13C NHR at the quaternary carbon atoms in the polymer, divided by 2. Segment index is the sum of the integration of the absorbances of all BAMO-BAMO-BAMO triads and AMHO-AMMO -AMHO triads divided by the total number of triads The BAMO "end groups" in the final product are the initiating alcohol used to produce the monofunctional hard segment BAHO These data show that the reaction proceeds without a significant increase in polydispersite t. Determining the hydroxyl equivalent weight of the product by a titration method was not possible due to interference with the test method of the -NH groups in the urethane bonds.

The GPC molecular weight increased significantly while the polydispersity of the product is midway between the two starting materials. 10 15 20 25 30 35 470 597 17 This shows that the coupling reaction was largely successful and that side reactions were not significant. The IH NHR molecular weight and end group type are both based on the observation that almost all terminal alcohol groups were transferred to urethanes leaving the side chain in the alcohol to initiate the monofunctional polymerization of BAHO as the main end group. In the case of a segment coupling reaction, 13 C NM segment data is somewhat trivial because the polymerizations were performed separately, so the existence of a perfect segment structure can be expected.

The invention is now described in more detail with the following specific examples.

Preparation 1 Preparation of a monofunctional BAMO polymer To a stirred solution of 0.51 ml (4.93 mmol) of benzyl alcohol in 23.5 ml of CH 2 Cl 2 was added 0.18 ml (1.488 mmol) of boron trifluoride etherate and 20 g (119.0 mmol ) BAMO was added. After 268 hours, a small aliquot was removed and diluted with CDCL3. NMR analysis showed that the reaction was substantially complete. The bulk solution was diluted with 50 mL of CH 2 Cl 2 and 25 mL of saturated aqueous NaHCO 3. The phases were separated and the aqueous phase was extracted with 50 ml of CH 2 Cl 2. The combined organic phases were dried (MgSO 4) and the solvent was removed under reduced pressure to leave a white crystalline solid. The BAMO polymer product exhibited the following physical properties: Property value hydroxyl equivalent weight 3521 NM molecular weight 3200 GPC MW 5700 GPC Mn 3100 GPC MW / Mn 1.85 10 15 20 25 30 35 470 597 18 Preparation 2 Preparation of polyfunctional AMO polymer To a stirred solution of 0 60 g (6.66 mmol) of butanediol and 0.473 g (3.33 mmol) of boron trifluoride etherate in 113.56 ml of CH 2 Cl 2 were added 60 g (472.4 mmol) of AMMO. After 30 minutes, the reaction mixture began to boil under reflux and was cooled with an ice bath to stop the reflux. The ice bath was removed after 10 minutes and the reaction was allowed to proceed. The reaction was stopped after 75 hours and the AMO product was isolated. The product had the following properties: Properties yëggg hydroxyl equivalent weight 3546 GPC MW 12400 GPC Mp 9670 GPC Mn 6010 GPC Mw / Mn 2.06 Preparation 3 Preparation of a polyfunctional NMMO polyger To a stirred solution of 0.09016 g (1.0 mmol) of butanediol and 0.50 mL (0.5 mmol) of Et 3 BF 4 in 43 mL of CH 2 Cl 2 was added 30 g (204.1 mmol) of NMMO and heated to reflux under nitrogen until the reaction was about 95.3% complete. Work-up of the reaction product gave an NMMO polymer having the following properties: Property XSggg GPC Mp 17600 GPC Mw 21400 GPC Mn 8850 GPC Mw / Mn 0 2.42 10 15 20 25 30 35 470 597 19 Preparation 4 Preparation of monofunctional BAMO polymer To a solution 0.556 g (5.142 mmol) of benzyl alcohol and 0.213 g (0.8570 mmol / l) of Et 3 OPF 6 in 35.23 ml of CH 2 Cl 2 were added 30 g (17.84 mmol) of BAMO. After a few minutes, the reaction mixture was subjected to vigorous reflux. The reaction solution was cooled to room temperature and stirred. After 21/2 hours, an NMR sample was taken which showed that the reaction was 96% complete. Workup of the reaction product gave a monofunctional BAMO polymer having the following properties: Properties yggg GPC Mp 7530 GPC Mw 9640 GPC Mn 4800 GPc Mw / Mn 2, 01 Preparation 5 Preparation of a monofunctional BAMO golyger To a stirred solution of 1.11 ml ( 10.7 mmol) of benzyl alcohol and 0.250 g (5.35 mL) of boron trifluoride etherate in 97.59 mL of CH 2 Cl 2 were added 36.36 g (267.9 mL) of BAMO. After about 21 3/4 hours, the reaction was stopped and the reaction solution was worked up by adding 200 ml of CHCl 2 2 NaHCO 3. The phases were separated and the NaHCO 3 phase was extracted with and 100 ml of saturated aqueous solution of 150 ml of CH 2 Cl 2. The combined organic phases were dried (MgSO 4) and the solvent was removed on a rotary evaporator. The product was washed with hexanes and the product was re-isolated under rotary evaporation to give a polymeric BAMO product having the following properties: 10 15 20 25 30 35 470 597 20 Properties ygggg hydroxyl equivalent weight 3355 GPC MW 4890 GPC Mp 4230 GPC Mn 2770 GPC Mw / Mn 1.77 Preparation 6 Preparation of a polyfunctional AMMO polymer To a stirred solution of 0.85 g (9.449 mmol) of butanediol and 0.67 g (4.745 mmol) of boron trifluoride etherate in 95.17 ml of CH 2 Cl 2 was added 60 g (472.4 mmol) of AMMO under nitrogen. . After 29 hours, NMR analysis showed that the reaction was essentially complete.

To the reaction solution were added 100 ml of CH 2 Cl 2 and 50 ml of saturated aqueous solution of NaHCO 3. The phases were separated and the aqueous phase was diluted with 100 ml of CH 2 Cl 2. The combined organic phases were dried over MgSO 4 and the solvent was stripped off with the rotary evaporator leaving the AMMO polymer. The product had the following properties: Characteristic value Hydroxyl equivalent weight 3125 GPC MW 10860 GPC Mp 7150 GPC Mn 5040 GPC MW / Mn 2.14 Preparation 7 Preparation of a monofunctional BAMO golyger To a stirred solution of 0.95 ml (9.0 mmol) of butanediol in 35 mL of CH 2 Cl 2 was added 0.37 g (1.5 mmol) of Et 3 OPF 6 followed by 30.0 g (179 mmol) of BAHO. After 20 minutes, the reaction mixture was diluted with CH 2 Cl 2 and saturated aqueous NaHCO 3.

The phases were separated and the aqueous phase was washed with 50 ml of CH 2 Cl 2. The combined organic phases were dried over MQSO 4 and the solvent was removed under reduced pressure leaving crystalline BAMO polymer. The product had the following properties: Properties value NHR MW 4423 GPC Mn 3950 GPC Mw 6635 GPC MW / Mn 1.68 Preparation 8 Preparation of a trifunctional NMO polymer To a stirred solution of 1.15 g (8.3 mmol) of trimethylolpropane in 140 ml CH 2 Cl 2 was added 0.77 mL (6.25 mmol) of BF 3 -OEt 2 followed by 100 g (680 mmol) of NMMO. After 72 h, the reaction mixture was diluted with 100 mL of CH 2 Cl 2 and 25 mL of saturated aqueous NaHCO 3. The phases were separated and the aqueous phase was washed with 100 ml of CH 2 Cl 2. The combined organic phases were dried over MgSO 4 and the solvent was removed under reduced pressure leaving amorphous NMO polymer as a clear viscous liquid.

The product had the following properties: Properties value hydroxyl equivalent weight 3759 GPC Mn 8660 GPC MW 13530 GPC Mw / nn 1, see Preparation 9 Preparation of a tetrafunctional NMMO polymer To a stirred solution of 1.56 g (8.3 mmol) 2.2 '( oxidimethylene) bis (2-ethyl-1,3-propanediol) in 140 mL of CH 2 Cl 2 was added 0.77 mL (6.25 mmol) of BF 3 -OEt 2 followed by 100 g (680 mmol) of NMMO. After 24 h, the reaction mixture was diluted with 100 mL of CH 2 Cl 2 and 25 mL of saturated aqueous NaHCO 3. The phases were separated and the aqueous phase was washed with 100 mL of CH 2 Cl 2. The combined organic phases were dried over MgSO 4 and the solvent was removed under reduced pressure to give the amorphous NMMO polymer as a clear viscous liquid. The product had the following properties: Properties yëggg hydroxyl equivalent weight 3497 GPC Mn 8630 GPC MW 13100 GPC Mw / Mn 1, 52 Example 1 Preparation of an ABA three-block polymer (BAMO-AMMO-BAMO) To a stirred solution of 4.0 g (1.24 mmol ) of a monofunctional BAMO polymer (Preparation 1) in 8 ml of CH 2 Cl 2 was added 0.193 ml (1.36 mmol) of 2,4-toluene diisocyanate and 0.004 g (0.012 mmol) of diphenyltin dichloride. After 18 hours, IH NHR analysis showed that a high percentage of alcohol end groups were converted to urethanes. FTIR showed strong isocyanate and urethane absorbances. To the solution was added 4.52 g (0.62 mmol) of a difunctional AMO polymer (Preparation 2) in 10 mL of CH 2 Cl 2. After an additional 45 hours, FTIR indicated that no isocyanate absorbance was present. 1 H NMR showed that a high percentage of AMMO end groups had reacted. The product was isolated by removing all volatile components under reduced pressure. The product exhibited the following properties: Properties yärdg NM molecular weight 12600 GPC MW 15500 GPC Mn 8100 GPc Mw / mn 1, 92 10 15 20 25 30 35 470 597 23 Example 2 Preparation of an ABA three-block polymer (BAMO-NMMO-BAMO) To a stirred solution of 10.94 g (1.53 mmol) of a monofunctional BAMO polymer (Preparation 4) dissolved in 25 ml of CH 2 Cl 2 under nitrogen were added 0.272 ml (1.91 mmol) of 2,4-toluene diisocyanate and 0.020 g of diphenyltin dichloride. After hours, an NM analysis showed that a high percentage of alcohol end groups were converted to urethanes. FTIR showed a urethane / isocyanate ratio of 0.67. To this solution was added 13.0 g (0.76 mmol) of a difunctional NMMO polymer (Preparation 3) in 35 mL of CH 2 Cl 2. After an additional 360 hours, the FTIR showed that no isocyanate groups remained. The product was isolated by precipitation in methanol to remove the catalyst.

The product exhibited the following properties: Property value E1'0 3484 psi t Em 8% Tm 202 psi Shore A hardness 53 GPC MW 28000 GPC Mn 11400 GPC Mw / Mn 246 Example 3 Preparation of an ABA three-block polymer (BAMO-AMMO-BAMO) To a Stirred solution of 2.0 g (0.596 mmol) of a monofunctional BAMO polymer (Preparation 5) dissolved in 8 ml of CH 2 Cl 2 under argon was added 0.093 ml (0.654 mmol) of 2,4-toluene diisocyanate and a trace amount of diphenyltin dichloride. After 24 hours, 1 H NMR analysis showed that> 95% of the hydrolysis groups reacted. FTIR showed a urethane / isocyanate ratio of 0.96.

To the solution was added 1.8 g (0.297 mmol) of AMMO polymer (Preparation 6) in 8 ml of CH 2 Cl 2. After an additional 144 hours, the FTIR ratio was about 7.5. After an additional 24 hours, the CH 2 Cl 2 was completely gone. The product was redissolved and FTIR showed that essentially no isocyanate groups remained. The product was isolated on a rotary evaporator under high vacuum. The product exhibited the following physical properties: Property Value GPC MW 11200 GPC Mn 5970 GPC Mp 9510 GPC Mw / Mn 1.88 Example 4 Preparation of a three-armed star polymer - (A gl To a stirred solution of 2.2 g (0.50 mmol) of a monofunctional BAMO polymer (Preparation 1) in 10 ml of CH 2 Cl 2 was added 0.085 ml (0.60 mmol) of 2,4-toluene diisocyanate and about 0.004 g (0.012 mmol) of diphenyltin dichloride.The reaction was allowed to proceed until 1 H NMR analysis showed that more than 90% of the BAMO hydroxyl end groups were converted to urethanes, then 1.88 g (0.17 mmol) of trifunctional NMMO (Preparation 8) dissolved in 10 ml of CH 2 Cl 2 were added.The reaction was allowed to proceed until FTIR analysis confirmed that all isocyanate was converted to urethane .

The reaction mixture was poured into 50 ml of methanol and the product was isolated by filtration. The product had the following properties: Properties Value GPC Mn 7930 GPC Mw 18670 GPC Mw / Mn 2.35 Example 5 Preparation of a four-armed star polymer - (A451 To a stirred solution of 2.2 g (0.50 mmol) of a mono functional BAMO polymer (Preparation 7) in 10 ml of CH 2 Cl 2 was added 0.085 ml (0.60 mmol) of 2,4-toluene diisocyanate and about 0.004 g (0.012 mmol) of diphenyltin dichloride. NHR analysis showed that more than 90% of the BAMO hydroxyl end groups were converted to urethanes, whereupon 1.75 g (0.12 mmol) of tetrafunctional NMMO (Preparation 9) dissolved in 10 ml of CH 2 Cl 2 were added, the reaction was continued until FTIR analysis confirmed that all isocyanate converted to urethane.

The reaction mixture was poured into 50 ml of methanol and the product was isolated by filtration. The product had the following properties: Properties Value GPC Mn 9025 GPC Mw 21400 GPC Mw / Mn 2, 37 In the above-mentioned representations and experiments, 1 H NMR spectra were recorded with a Varian XL-300 spectrometer operating at 300 MHz. 130 NMR spectra were recorded with the same instrument operating at 75 MHz. Spectra was taken up on CDCl 3 solutions using the remaining CHCl 3 as the internal standard. FTIR spectra were recorded with a Nicolet 20DX on dilute CH 2 Cl 2 solutions. GPC trace amounts were obtained with a Waters LC for GPC using THF as the mobile phase and a differential refractometer detector. A series of four microcontroller gel columns were used varying in porosity from 105 to 102 Å. Polyethylene glycol adipate was used as the broad molecular weight calibration standard. Hydroxyl equivalent weight was determined by reaction with tosyl isocyanate in THF followed by titration of urethane with t-butylammonium hydroxide.

Based on the above description of the invention, those skilled in the art will appreciate that modifications may be made without departing from the spirit thereof. It is therefore intended that the scope of the invention not be limited to the specific embodiments illustrated and set forth.

Claims (16)

10 15 20 25 30 35 470 597 26 Patent claims A process for producing a thermoplastic having segment A and at least one segment B, wherein segment A is crystalline at temperatures below about 60 ° C and segment B is amorphous at temperatures above about -20 ° C, wherein segment A is polyethers derived from monomers of oxetane and derivatives thereof and / or tetrahydrofuran and derivatives thereof, which process comprises: starting from monofunctional hydroxyl-terminated segments A which are crystalline at temperatures below about 60 ° C and separately starting from di-, tri- or tetrafunctional hydroxyl-terminated segments B which are amorphous at temperatures above about -20 ° C, end blocks block A by separately reacting these segments A with a difunctional diisocyanate, wherein an isocyanate group is at least about five times as reactive with the terminal hydroxyl group in segments A as the second isocyanate group, whereby the more reactive isocyanate group tends to react with the terminal hydroxyl group in segments A leaving the less reactive isocyanate group is free and unreacted, and adds di-, tri- or tetrafunctional segment B to the end-blocked segments A at approximately stoichiometric ratios as they are intended to be included in the thermoelastic, so that the free and unreacted isocyanate group on the end-blocked segment A reacted with a functional group in segment B to form thermoelastics ABA or Anß. A process according to claim 1, wherein the oxetane monomers have the general formula: wherein the groups R are the same or different and selected from groups of the general formula: - (CH 2) n X , where n is 0-10 and X is selected from the group consisting of -H, -NO 2, -CN, -Cl, -F, -O-alkyl, -OH, -I, -ONO 2, -N (HO 2) - alkyl, -CECH, -Br, -CH = CH (H or alkyl), -O-CO- (H or alkyl), -CO 2 - (H or alkyl), -N (H or alkyl) 2, -O- (CH2) 1-5-0- (CH2) o_8-CH3 and -N3. The process of claim 1, wherein the THF monomers have the general formula: wherein the groups R are the same or different and selected from groups of the general formula: - (CH 2) n X, where n is 0-10 and X is selected from the group consisting of -H, -NO 2, -CN, -Cl, -F, -O-alkyl, -OH, -I, -NO 2, -N (NO 2) -alkyl,--CH, - Br, -CH = CH (H or alkyl), -O-CO- (H or alkyl), -CO 2 - (H or alkyl), -N (H or alkyl) 2, -O- (CH 2) 1-5 -O - (CH2) O_8-CH3 and -N3. The method of claim 1, wherein segment B is di-, tri- or tetrafunctional and has a molecular weight of between 5,000 and about 50,000 and each of the monofunctional segments A has a molecular weight of between 3,000 and about 12,500. The method of claim 1, wherein the monofunctional segments A together have a molecular weight between about 1/3 and about 1 times the molecular weight of segment B or the total weight of segments B. The method of claim 1, wherein segment A is selected from the group consisting of poly (3,3-bis (ethoxymethyl) oxetane), poly (3,3-bis (methoxymethyl) oxetane), poly (3,3-bis ( fluoromethyl) oxetane) and poly (3,3-bis (azidomethyl) oxetane). 10 15 20 25 30 35 470 597 28 A process according to claim 1, wherein segment B is selected from poly (3-azidomethyl) -3-methyloxetane), (3-azidomethyl-3-methyloxetane) / 3,3-bis (azidomethyl) oxetane copolymer, tetrahydrofuran [3,3-bis (azidomethyl) oxetane copolymer, tetrahydrofuran] -3-azidomethyl-3-methyloxetane copolymer, tetrahydrofuran / 3-octoxymethyl-3-methyloxetane copolymer, tetrahydrofuran / 3,3-bis (methoxyethoxymethyl) oxethydrofuran copolymer; , 3-bis (ethoxymethyl) oxetane copolymer, tetrahydrofuran / 3,3-bis (methoxymethyl) oxetane copolymer, tetrahydrofuran / 3,3-bis (fluoromethyl) oxetane copolymer, poly (3-nitratomethyl-3-methyloxetane) and 3.3 -bis (azidomethyloxetane / 3-nitratomethyl--3-methyloxetane) copolymer. The process of claim 1, wherein the oxetane monomers are selected from the group consisting of: 3,3-bis (ethoxymethyl) oxetane, 3,3-bis (chloromethyl) oxetane, 3,3-bis (methoxymethyl) oxetane, 3,3- bis (fluoromethyl) oxetane, 3-hydroxymethyl-3-methyloxetane, 3,3-bis (acetoxymethyl) oxetane, 3,3-bis (hydroxymethyl) oxetane, 2-octoxymethyl-3-methyloxetane, 3,3-bis (methoxyethoxymethyl) oxetane, 3-chloromethyl-3-methyl-oxetane, 3-azidomethyl-3-methyloxetane, 3,3-bis (iodomethyl) -oxetane, 3-iodomethyl-3-methyloxetane, 3-propynomethylmethyl-oxetane, 3,3- bis (nitratomethyl) oxetane, 3-nitratomethyl-3-methyloxetane, 3,3-bis (methylnitraminomethyl) oxetane, 3-methylnitraminomethyl-3-methyloxetane and 3,3-bis (azidomethyl) oxetane. The method of claim 1, wherein the diisocyanate is toluene diisocyanate. The process of claim 1, wherein the reactions are carried out in the presence of a urethane catalyst. The method of claim 1, wherein the segment B is dysfunctional, thereby producing an ABA polymer. The method of claim 1, wherein in said end-blocking reaction, the diisocyanate is present in a molar ratio of between about 0.9 and about 1.1 relative to the number of moles of hydroxyl groups in the monofunctional segment A. 470 597 29 The method of claim 1, wherein the segment B is tri- or tetrafunctional, thereby producing an AnB star segment polymer. Product produced by the process according to claim 1. 3,3-bis (azidomethyl) oxetane / 3-azidomethyl-3-methyloxetane / 3,3-bis (azidomethyl) oxetane ABA three-block polymer prepared according to the process of claim 1. 3,3-bis (azidomethyl) oxetane / 3-nitratomethyl-3-methyloxetane / 3,3-bis (azidomethyl) oxetane ABA three-block polymer prepared according to the process of claim 1.