Polycarbonate bisphenol copolycarbonates

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

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. 

Solvent resistance was measured in 22 solvent systems, in 18 of these, the bisphenol A polymer and TCBF copolycarbonates behaved similarly. In 3 of them, viz., carbon tetrachloride, acetic acid, and acetonitrile, the TCBF copolyc urbonates were definitely better. In only one case, namely that of ethyl acetate, was bisphenol A polycarbonate superior. 

The first blends studied on polyesters based on 1,4-CHDM were made of the amorphous copolyester of terepthalic and isophthalic acids and 1,4-CHDM (PCTA) and polycarbonate of bisphenol A (126). The single displayed for the whole range of compositions was taken as demonstrative of full miscibility, which is explained as due to the positive physical interactions between the polyester and the polycarbonate. PCTA is also miscible with a copolycarbonate of bisphenol A and l,l-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclo hexanone (TMC) for all compositions except for those involving a polycarbonate entirely made of TMC (127). 

Liaw and Chang [a.345] reported on brominated fluorine-containing homopolycarbonates and copolycarbonates of varied unit ratio that were synthesised from 3,3, 5,5 -tetrabromobisphenol-AF and bisphenol-A polycondensed with trichloromethyl chloroformate using a phase-transfer catalyst at 25 °C. The homopolycarbonate based on tetrabromobisphenol-AF had the highest Tg at 205 °C. The TG cnrves show that the Tj of polycarbonates was in the range of 445-475 °C. The LOI of homopolycarbonates based on bisphenol-A and tetrabromobisphenol-AF were found to be 26 and 93, respectively. 

The polymers included in this study are bisphenol-A polycarbonate (Bis-A PC), polyesteicarbonates (PEC), whose structures are defined in Figure 1, phenolphthalein bisphenol-A copolycarbonate, and polysulfone. All samples were compression molded and physically aged as described elsewhere, with the exception of those for the Fourier transform infrared (FTIR) measurements and solid state variable temperature nuclear magnetic resonance (VTNMR)... 

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