摘要:
A method of making a polyether polymer comprises reacting a salt of a dihydroxy-substituted aromatic hydrocarbon with a substituted aromatic compound of formula (I) Z(A1-X1)2 (I) in the presence of a catalyst to form an intermediate polymer having endgroups, wherein the molar ratio of the salt of a dihydroxy-substituted aromatic hydrocarbon to the substituted aromatic compound is less than 1, Z is an activating radical, A1 is an aromatic radical and X1 is fluoro, chloro, bromo or nitro; determining the additional amount of the salt of a dihydroxy-substituted aromatic hydrocarbon needed to form a final polyether polymer with a predetermined molecular weight and adding the additional amount of the salt of a dihydroxy-substituted aromatic hydrocarbon to the intermediate polymer.
摘要:
A method of making a polyether polymer comprises reacting a salt of a dihydroxy-substituted aromatic hydrocarbon with a substituted aromatic compound of formula (I) Z(A1—X1)2 (I) in the presence of a catalyst to form an intermediate polymer having endgroups, wherein the molar ratio of the salt of a dihydroxy-substituted aromatic hydrocarbon to the substituted aromatic compound is less than 1, Z is an activating radical, A1 is an aromatic radical and X1 is fluoro, chloro, bromo or nitro; determining the additional amount of the salt of a dihydroxy-substituted aromatic hydrocarbon needed to form a final polyether polymer with a predetermined molecular weight and adding the additional amount of the salt of a dihydroxy-substituted aromatic hydrocarbon to the intermediate polymer.
摘要:
Embodiments of the invention provide for methods of producing a composition comprising a crosslinkable silane-terminated polymer having at least one crosslinkable silyl group in each molecule. The method comprises providing a polymer having at least one unsaturated group and at least one alcoholic hydroxyl group in each molecule, adding to the polymer a compound having a hydrogen-silicon bond and a crosslinkable silyl group in each molecule and a hydrosilylation catalyst to thereby carry out a hydrosilylation reaction to form a composition comprising hydrosilylated polyoxyalkylene polymers, reacting the hydrosilylated polyoxyalkylene polymers with at least one isocyanate in the presence of a first tin-free catalyst to form an isocyanate reacted hydrosilylated polymer, and optionally reacting the isocyanate reacted hydrosilylated polymer with a polyol having a nominal functionality of at least 2 to form a polyol reacted crosslinkable silane-terminated polymer.
摘要:
Embodiments of the invention provide for methods of producing a composition comprising a crosslinkable silane-terminated polymer having at least one crosslinkable silyl group in each molecule. The method comprises providing a polymer having at least one unsaturated group and at least one alcoholic hydroxyl group in each molecule, adding to the polymer a compound having a hydrogen-silicon bond and a crosslinkable silyl group in each molecule and a hydrosilylation catalyst to thereby carry out a hydrosilylation reaction to form a composition comprising hydrosilylated polyoxyalkylene polymers, reacting the hydrosilylated polyoxyalkylene polymers with at least one isocyanate in the presence of a first tin-free catalyst to form an isocyanate reacted hydrosilylated polymer, and optionally reacting the isocyanate reacted hydrosilylated polymer with a polyol having a nominal functionality of at least 2 to form a polyol reacted crosslinkable silane-terminated polymer.
摘要:
Compositions comprise phase separated polyetherimide/polyphenylene ether sulfone blends. The dispersed phase has an average cross sectional size of 0.1 to 10 micrometers. The composition retains has good hydrolytic stability and is capable of withstanding steam autoclaving at temperatures of 130 to 138° C.
摘要:
Compositions comprise phase separated polyetherimide/polyphenylene ether sulfone blends. The dispersed phase has an average cross sectional size of 0.1 to 10 micrometers. The composition retains has good hydrolytic stability and is capable of withstanding steam autoclaving at temperatures of 130 to 138° C.
摘要:
Unexpected corrosion of downstream sections of a dialkyl carbonate manufacturing apparatus has been traced to alkyl chloroformate impurities, which slowly decompose to yield hydrochloric acid. An improved process and apparatus for dialkyl carbonate synthesis reduce corrosion by physically removing or chemically decomposing the alkyl chloroformate impurities within the corrosion-resistant upstream sections of the apparatus.
摘要:
Blends of polysulfones, polyethersulfones and polyphenylene ether sulfones with resorcinol based polyesters, or resorcinol based polyester carbonate polymers, and silicone copolymers have improved flame resistance. Peak heat release energy is reduced and the time to reach peak heat release is increased.
摘要:
The present invention provides a method of making polycarbonate oligomers, polycarbonate, molded articles formed from polycarbonate, and an apparatus for making polycarbonate. An oligomer mixture is first prepared by the steps of providing an equilibration system comprising a vessel, a reaction mixture contained within the vessel, and means for mixing the reaction mixture contained within the vessel wherein the reaction mixture comprises a melted activated diaryl carbonate composition, and a catalyst present in sufficient amount to initiate an oligomerization reaction between a dihydroxy composition and the activated diaryl carbonate to form polycarbonate oligomers. The method further includes the steps of introducing a melted dihydroxy composition to the reaction mixture contained within the equilibration system, maintaining the reaction mixture contained within the vessel at an oligomerization temperature, said oligomerization temperature being below the melting point the dihydroxy composition, and sufficiently high to allow formation of a homogeneous melt within the vessel, and continuously drawing off a product stream from the equilibration system, wherein the product stream comprises a polycarbonate oligomer mixture. This polycarbonate oligomer mixture is suitably used as a feed stock for producing polycarbonate in a polycondensation system. The polycarbonate is suitably used for the preparation of molded articles.