Random copolycarbonates

At our 1958 symposium, polycarbonate was introduced. Since then this polymer has reached a domestic production of 50 million pounds per year. J. T. Gregory, J. A. Cook, and A. B. Robertson report on the synthesis of polycarbonate oligomers useful in making random and block copolycarbonates. 

D isphenol-A carbonate oligomers have been used in the syntheses of random and block copolycarbonates (J, 2). The physical properties of these polymers can be altered by tailoring sequence distribution and block size in the copolymer. To tailor sequence distribution and block size, it is necessary to know the molecular weight and molecular-weight distribution of bisphenol-A prepolymers present during synthesis. 

Chemoenzymatic synthesis of a water-soluble polycarbonate having pendent carboxyl groups on the polymer main chain was achieved by lipase-catalyzed polymerization of 5-methyl-5-benzyloxycarbonyl-l,3-dioxan-2-one (MBC), followed by debenzylation.186 The copolymerization of MBC with TMC using lipase PF catalyst produced the random copolycarbonate.187... 

Vitalini, D., Mineo, R, Di Bella, S., Fragala L, Maravigm, R, and Scamporrino, E., Synthesis and Matrix-Assisted Laser Desorption Ionization-Time of Flight Characterization of an Exactly Alternating Copolycarbonate and Two Random Copolyefhers Containing Schiff Base Copper(It) Complex Nonlinear Optical Units in the Main Chain, Macromolecules, 29, 4478, 1996. 

Random Copolycarbonates Characterization and Comparative Properties of Polymers Containing Tetrachlorinated Bisphenols... 

Yokoe M., Aoi K., Okada M., Biodegradable polymers based on renewable resources. Vll. Novel random and alternating copolycarbonates from l,4 3,6-dianhydrohexitols and aliphatic diols, J. Polym. ScL Part A Polym. Chem., 41,2003,2312-2321. Yokoe M., Aoi K., Okada M., Biodegradable polymers based on renewable resources. Vlll. Environmental and enzymatic degradabihty of copolycarbonates containing l,4 3,6-dianhydrohexitols, J. App. Polym. ScL, 98, 2005,1679-1687. 

Block copolymers comprising carbonate and arylene ether blocks have been prepared by the catalytic decarboxylation of random or alternating copolycarbonates. This novel route to block copolymers is catalyzed by a number of catalysts and requires only that one of the bisphenols in the starting copolycarbonates be activated by electron-withdrawing substituents, e.g. 4,4 -dihydroxydiphenyl sulfone (bisphenol S), or 4,4 -dihydroxybenzophenone (bisphcnol K). 

The random copolycarbonates were prepared by the standard phosgenation procedure in dichloromethane with pyridine as the acid acceptor. Because of the slight difference in reactivity, these polymers may have a very small degree of blockiness which should not affect the results of this work. The alternating copolycarbonates were prepared in a similar fashion except that bisphenol A was first converted to the bis-chloroformate before the addition of bisphenol S or bisphenol K. All polymers were capped with tert-butylphenol. This work was conducted on 1 1 copolycarbonates of bisphenol A with either bisphenol S or bisphenol K. The chemistry of this novel procedure is illustrated in Scheme 1. 

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