摘要:
PBZ polymers are synthesized by the reaction of AA- and BB-monomers. The BB-monomer is conveniently synthesized and isolated as a phosphate salt having a uniform number of phosphate ions associated with each BB-monomer ion. Such high purity monophosphate and diphosphate salts can be obtained by precipitating the monomer from an aqueous acid solution by adjusting the pH balance or from a mixture of phosphoric acid and a volatile, polar, saturated organic liquid at a relatively low temperature.
摘要:
AB-polybenzoxazole monomer, such as 3-amino-4-hydroxybenzoic acid, can be synthesized in high yields from a hydroxy-benzoic acid or related compound in a three-step process of (1) nitration, (2) hydrolysis of the ester, and (3) reduction of the nitro moiety. The monomer is conveniently recovered as a phosphate salt in high purity by precipitating and recrystallizing from a phosphoric acid solution. The monomer may be polymerized in high concentrations in polyphosphoric acid containing high levels of P.sub.2 O.sub.5 to yield a high molecular weight polymer without dehydrohalogenation.
摘要翻译:可以在(1)硝化的三步法中,从羟基 - 苯甲酸或相关化合物以高产率合成AB-聚苯并恶唑单体,例如3-氨基-4-羟基苯甲酸,(2)酯的水解 ,和(3)还原硝基部分。 通过从磷酸溶液中沉淀和重结晶,可以方便地将单体作为高纯度的磷酸盐回收。 单体可以在含有高含量的P 2 O 5的多磷酸中以高浓度聚合,得到高分子量聚合物,而无需脱卤化氢。
摘要:
AB-polybenzoxazole monomer, such as 3-amino-4-hydroxybenzoic acid, can be synthesized in high yields from a hydroxy-benzoic acid or related compound in a three-step process of (1) nitration, (2) hydrolysis of the ester, and (3) reduction of the nitro moiety. The monomer is conveniently recovered as a phosphate salt in high purity by precipitating and recrystallizing from a phosphoric acid solution.
摘要:
Polybenzoxazole polymers can be synthesized from BB-monomer having pendant methyl groups. The resulting polymer has pendant methyl groups, which can be used to cross-link the polymers.
摘要:
AB-polybenzoxazole monomer, such as 3-amino-4-hydroxybenzoic acid, can be synthesized in high yields from a hydroxy-benzoic acid or related compound in a three-step process of (1) nitration, (2) hydrolysis of the ester, and (3) reduction of the nitro moiety. The monomer is conveniently recovered as a phosphate salt in high purity by precipitating and recrystallizing from a phosphoric acid solution.
摘要:
The present invention encompasses non-phase-separated thermoplastic block copolymers containing rigid rod PBZ blocks and thermoplastic PBZ blocks; dopes and compositions containing those block copolymers; a process for making shaped articles from thermoplastic block copolymers containing rigid rod PBZ blocks and thermoplastic PBZ blocks; and shaped articles made by that process.
摘要:
A prepolymer or elastomer is the reaction product of reactants (a) at least one polyester polyol or fatty acid derived polyol which is the reaction product of at least one initiator and a mixture of fatty acids or derivatives of fatty acids comprising at least about 45 weight percent monounsaturated fatty acids or derivatives thereof, (b) optionally, at least one polyol which is different from the polyol of (a); and (c) at least one isocyanate compound (herein after isocyanate) having an average of at least about 1.8 isocyanate groups per molecule. A process comprises admixing reactants (a) at least one polyol composition comprising the fatty acid derived polyol which is the reaction product of at least one initiator and a mixture of fatty acids or derivatives of fatty acids comprising at least about any of 45 weight percent monounsaturated fatty acids or derivatives thereof; and (b) at least one isocyanate having an average functionality of at least about 1.8 under reaction conditions to form a reaction product which is an elastomer or prepolymer is formed therefrom. An article, coating or thermoplastic polyurethane comprises the elastomer is formed from the prepolymer of or using the process of the invention.