Bisphenole-A-polycarbonate

Figure C2.1.17. Stress-strain curve measured from plane-strain compression of bisphenol-A polycarbonate at 25 ° C. The sample was loaded to a maximum strain and then rapidly unloaded. After unloading, most of the defonnation remains.

The first HFIP-based polycarbonate was synthesi2ed from bisphenol AF with a nonfluorkiated aromatic diol (bisphenol A) and phosgene (121,122). Incorporation of about 2—6% of bisphenol AF and bisphenol A polycarbonate improved the dimensional stabkity and heat-distortion properties over bisphenol A homopolycarbonate. Later developments in this area concern the flame-retardant properties of these polymers (123,124). 

Polycarbonates. Currently, all audio CDs (CD-AD), all CD-ROM, and the biggest fraction of substrate disks for WORM and EOD worldwide are manufactured from a modified bisphenol A—polycarbonate (BPA-PC) (3). In 1991, some 1.3 x 10 compact disks were produced, equivalent to an annual amount of about 35,000 t BPA-PC. WORM and EOD disks are manufactured mainly from BPA-PC for sizes of 5.25 in. and below, and glass for larger form factors (eg, 12 in.), partially also from BPA-PC, and in some cases from aluminum or from cross-linked polymers (epoxy resins) (190). 

Fig. 26. Qualitative compatison of substrate materials for optical disks (187) An = birefringence IS = impact strength BM = bending modulus HDT = heat distortion temperature Met = metallizability WA = water absorption Proc = processibility. The materials are bisphenol A—polycarbonate (BPA-PC), copolymer (20 80) of BPA-PC and trimethylcyclohexane—polycarbonate (TMC-PC), poly(methyl methacrylate) (PMMA), uv-curable cross-linked polymer (uv-DM), cycHc polyolefins (CPO), and, for comparison, glass.

Fig. 2. Molecular structures of selected photoconductive polymers with pendent groups (1) poly(A/-vinylcarba2ole) [25067-59-8] (PVK), (2) A/-polysiloxane carbazole, (3) bisphenol A polycarbonate [24936-68-3] (4) polystyrene [9003-53-6] (5) polyvin5i(l,2-/n7 j -bis(9H-carba2ol-9-yl)cyclobutane) [80218-52-6]...

Figure 6 shows the field dependence of hole mobiUty for TAPC-doped bisphenol A polycarbonate at various temperatures (37). The mobilities decrease with increasing field at low fields. At high fields, a log oc relationship is observed. The experimental results can be reproduced by Monte Carlo simulation, shown by soHd lines in Figure 6. The model predicts that the high field mobiUty follows the following equation (37) where d = a/kT (p is the width of the Gaussian distribution density of states), Z is a parameter that characterizes the degree of positional disorder, E is the electric field, is a prefactor mobihty, and Cis an empirical constant given as 2.9 X lO " (cm/V). ...

ABS can be blended with bisphenol A polycarbonate resins to make a material having excellent low temperature toughness. The most important apphcation of this blend is for automotive body panels. 

Bisphenol A Polycarbonate Resins. These resins are manufactured by interfacial polymerization (84,85). A small amount of resin is produced by melt-polymerization of bisphenol with diphenyl carbonate in Russia and the People s RepubHc of China. Melt technology continues to be developmental in Japan and the West, but no commercial activities have started-up to date, although some were active in the late 1960s. No reports of solvent-based PC manufacture have been received. 

Bisphenol A Polycarbonate grade, no solvent required 150,000 Undisclosed Falling him USA General Electric... 

A more recent development of interest with this material is that scratch-resistant coatings may be stoved on at temperatures not feasible with conventional bisphenol A polycarbonates to give products with a scratch resistance comparable to glass. 

Alloys of bisphenol A polycarbonates with ABS and MBS resins have been known for many years. Subsequently many other alloys containing polycarbonates have been introduced so that by the mid-1990s they comprised at least 15% of the polycarbonate market. 

Yet another recent development has been the alloying of polycarbonates with liquid crystal polymers such as Vectra (see Section 25.8.1). These alloys are notable for their very good flow properties and higher strength and rigidity than conventional bisphenol A polycarbonates. 

In the 1980s a number of copolymers became established, known as polyester carbonates, which may be considered as being intermediate between bisphenol A polycarbonates and the polyarylates discussed in Chapter 25. 

Aliphatic polycarbonates have few characteristics which make them potentially valuable materials but study of various aromatic polycarbonates is instructive even if not of immediate commercial significance. Although bisphenol A polycarbonates still show the best all-round properties other carbonic ester polymers have been prepared which are outstandingly good in one or two specific properties. For example, some materials have better heat resistance, some have better resistance to hydrolysis, some have greater solvent resistance whilst others are less permeable to gases. 

McNeill and Basan [151] studied the thermal degradation of blends of PVC with bisphenol-A polycarbonate. The structure of bisphenol-A polycarbonate is given in Eq. (42). 

Structure of bisphenol-A polycarbonate copolymerized with 3% by weight of labile groups... 

Birley, A.W. and Chen, X.Y., A preliminary study of blends of bisphenol A polycarbonate and poly (ethylene terephtalate), Brit. Polym. J., 17, 297, 1985. 

Epoxy resins for printed circuits, castings, rocket motor casings, coatings, and adhesives are almost all made from bisphenol A. Polycarbonates based on bisphenol A are used in glazing applications such as aircraft windows, school windows, and other areas where a combination of toughness and high clarity are required. 

We have not mentioned here the crucial inverse mapping of the realistic polymer structure onto the stream line. For polymers without side groups, such as polyethylene or bisphenol-A-polycarbonate, the following strategy has successfully been used [98] an energy minimization of the internal energy contributions was carried out simultaneously with a minimization of the distances of all atoms to the stream line (to this end, the sum of the squared dis-... 

At this point, we will comment on how this procedure generalizes to other polymers. The other case that was considered by us [28,30,32,175,176] was concerned with bisphenol-A-polycarbonate (BPA-PC) (cf. Fig. 5.1). While for PE we had a correspondence that five chemical repeat units correspond to one effective bond of the bond fluctuation model, for BPA-PC the mapping ratio was inverse - one chemical repeat unit was mapped onto three effective bonds One must consider, however, the very different sizes of the chemical repeat units while for PE this is a single CH2 group, in BPA-PC the repeat unit involves 12 C-C or C-0 bonds along the backbone, and the end-to-end distance of the repeat unit is of the order of 10 A. Thus in this case also one effective bond corresponds to a group of four successive covalent bonds along the backbone of the chain, and a lattice unit corresponds to about 2.03 A [175],... 

The photochemical degradation of bisphenol-A polycarbonate (PC) has been the subject of a number of investigations.-3 ... 

Both vibrational spectroscopies are valuable tools in the characterization of crystalline polymers. The degree of crystallinity is calculated from the ratio of isolated vibrational modes, specific to the crystalline regions, and a mode whose intensity is not influenced by degree of crystallinity and serves as internal standard. A significant number of studies have used both types of spectroscopy for quantitative crystallinity determination in the polyethylenes [38,74-82] and other semi-crystalline polymers such as polyfethylene terephthalate) [83-85], isotactic poly(propylene) [86,87], polyfaryl ether ether ketone) [88], polyftetra-fluoroethylene) [89,90] and bisphenol A polycarbonate [91]. 

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