摘要:
A copolymer with recurring constituent units derived by polymerizing tetrahydrofuran, ethylene oxide and at least one additional cyclic ether that can be substituted or unsubstituted that decreases the hydrophilicity imparted to the copolymer by the ethylene oxide.
摘要:
Copolyether glycols are prepared by copolymerizing alkylene oxides or cyclic acetals and tetrahydrofuran, using(1) a polymeric catalyst which contains sulfonic acid groups; and(2) a chain terminator which is water or an alkanediol.
摘要:
Ester end-capped copolyether glycol is prepared by copolymerizing tetrahydrofuran and an alkylene oxide or cyclic acetal in a reaction mixture which contains, in addition to the tetrahydrofuran and alkylene oxide or cyclic acetal,(1) a polymeric catalyst which contains .alpha.-fluoro sulfonic acid groups,And(2) an acylium ion precursor such as acetic anhydride.
摘要:
A copolymer with recurring constituent units derived by polymerizing tetrahydrofuran, ethylene oxide and at least one additional cyclic ether that can be substituted or unsubstituted that decreases the hydrophilicity imparted to the copolymer by the ethylene oxide.
摘要:
Treatment of poly(tetramethylene ether) glycols with acid catalysts at elevated temperatures leads to a chain coupling with rapid increase in molecular weight. Various alcohols including diols and triols can be incorporated into poly(tetramethylene ether) glycol backbone with modified properties and performance.
摘要:
Poly(tetramethylene ether) glycol is prepared by polymerizing tetrahydrofuran, using(1) a polymeric catalyst which contains sulfonic acid groups, and(2) a chain terminator which is water or 1,4-butanediol.
摘要:
In the preparation of poly(tetramethylene ether) glycol by the polymerization of tetrahydrofuran (THF) using a cationic initiator, molecular weight distribution (MWD) can be held within narrow limits by bringing the THF and the initiator together in a mol ratio such that the degree of polymerization will be at about a minimum and at a temperature which will promote about a maximum number of tertiary oxonium ions, then quickly cooling the reaction mass to -25.degree. C. to +25.degree. C., and then adding enough THF to complete the polymerization. When the desired molecular weight and MWD have been reached, the polymerization is quenched and the polymer isolated.
摘要:
Poly(tetramethylene ether) ester is converted to poly(tetramethylene ether) glycol by alcoholysis using as a catalyst an oxide, hydroxide or alkoxide of calcium, strontium, barium or magnesium.
摘要:
Esters of poly(tetramethylene ether) glycol are prepared by polymerizing tetrahydrofuran in a reaction mixture which contains, in addition to the tetrahydrofuran, and acylium ion precursor such as acetic anhydride, a polymeric catalyst which contains sulfonic acid groups and, optionally, a carboxylic acid such as acetic acid.
摘要:
A catalyst and process for preparing it and its use in polymerizing tetrahydrofuran to produce polytetramethylene ether glycol ether are disclosed. The catalyst is a blend of a fluorinated resin containing sulfonic acid groups and a fluorinated resin containing carboxylic acid groups. The catalyst is partially dried to contain from 1,000 to 2,000 ppm water, so that when it is used to polymerize tetrahydrofuran, the product polytetramethylene ether glycol will have a number average molecular weight of from 250 to 4,000.