Copolycarbonates

Thermotropic polycarbonates have been prepared from mixtures of 4,4 -dihydroxybiphenyl and various diphenols (10). Nematic melts were found for copolycarbonates prepared from methyfliydroquiaone, chlorohydroquiaone, 4,4 -dihydroxydiphenyl ether, and 4,4 -dihydroxybenzophenone. Slightly crystalline polycarbonates have been prepared from mixtures of hydroquinone and BPA (T = 154°C, =313°C, AH = 11.0 J/g (2.63 cal/g)), and... 

The synthesis of copolycarbonates from 2,5-dimethyl-2,5-hexanediol and bis(hy-droxymethyl)benzene was also achieved by this method.[264]... 

Copolycarbonates, (I), consisting of isosorbide, bisphenol A, and diphenyl carbonate were prepared by Dhara et al. (4) and used as optical waveguides. 

J.M. Silva, D.M. Dardaris, and G.C. Davis, Method of preparing transparent silicone-containing copolycarbonates, US Patent 6833422, assigned to General Electric Company (Niskayuna, NY), December 21, 2004. 

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. 

Di, J, Davis, G, and Jackson, J et al. 2007. New transparent copolycarbonate compositions with low OSU heat release values, Society of Plastics Engineers Annual Technical Conference, ANTEC 2007, Cincinnati, OH. 

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... 

Figure 8.12. Tensile Young s modulus of a copolycarbonate composite as a function of carbon fiber concentration. [Adapted, by permission, from Zihlif A M, Di Liello V, Martuscelli E, Ragosta G, Int. J. Polym. Mat., 29, Nos.3-4, 1995, 211-20.]...

Table 3.28 Comparision of bisphenol-TMC polycarbonate, bisphenol-TMC copolycarbonates and other amorphous thermoplastics [94]...

At the same time the polycarbonates 54a-f (all of them with m=3,4,5,6) were prepared and characterized by Sato and coworkers [66,67]. All syntheses were conducted by transesterification of the corresponding diols with the biscar-bonates 55 in bulk. None of the four homo PEIs (54a, m=3-6) proved to be thermotropic. In the case of the copolycarbonates only those containing more than 50 mol% of the biphenylester unit (e.g. 54d-f, m=3) were apparently thermotropic. This thermotropic property was attributed to the mesogenic character of... 

Mahabadi and Alexandru [74] have published data on thermotropic copolycarbonates of biphenol (BP) and diethylene glycol (DEG) with hydroquinone (HQ), methyl hydroquinone (MHQ), f-butyl HQ, oxydiphenol (ODP) or bis(4-hydroxyphenyl)methane (DPM) or bisphenol A. The tabulated compositions and calculated MI values are recorded with the published data on mesophase transitions in Table 4. Mesophases appear only to be present when the MI score >10.1. However, the gap in values between mesogenic materials and non-mes-ogenic materials in the three series reported is about +1 and therefore it cannot be claimed on this evidence alone that polycarbonates have a similar critical value to polyesters and polyamides. 

Further evidence to support the case for polycarbonates comes from the work of Kricheldorf and Lubbers [75]. They prepared several series of copolycarbonates of 4,4 -dihydroxybiphenyl and various other aromatic diols (Table 5). It is noteworthy that all their series of copolymers cease to exhibit a nematic phase when the MI 10.5. Hence by combining both sets of results it can be said that the critical value for polycarbonates lies between 10.1 and 10.5. 

Table 4. Application of mesogenic index to copolycarbonates of biphenol and Deg... 

Reference Code Copolycarbonate Composition (moles) Melting Transition Mesogenic Index... 

The blends of PC with PET, PBT and PETG were opaque whereas the blends with PCT and PCTG were transparent. The blends of an unidentified copolycarbonate, (coPC) with PET, PBT, PETG and PCTG were transparent. The opacity of the blends was attributed to their crystallinity. Mason [1995] found the irradiated (30 kGy, gamma irradiation) DB to show more acceptable yellowness index than irradiated PC (3 for DB as compared to 15 for PC), good injection molding characteristics (spiral flow similar to that of PC), similar part ejection force for PC and DB, and reasonable chemical resistance. 

Frechet, F.M. Houlihan, F. Bouchard, B. Kryczka, and C.G. Willson, Design, synthesis and study of novel thermally depolymerizable polycarbonates, J. Chem. Soc. Commun., p. 1514 (1985) F.M. Houhhan, F. Bouchard, J.M.J. Frechet, and C.G. Willson, Thermally depolynner polycarbo nates. II. Synthesis of novel linear tertiary copolycarbonates by phase transfer catalysis, Macromol ecules, 19, 13 (1986). 

Uchiyama, A, Ono, Y, Ikeda, Y, Shuto, H., and Yahata, K. (2012). Copolycarbonate optical films developed using birefringence dispersion control, Pol m., 44,995-1008. 

The partial degradation method has given good results in the case of the MS analysis of aromatic copolyesters, copolycarbonates, aliphatic copolyesters of microbial origin, copolyesters containing a photolabile unit in the... 

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