Polycarbonate of bisphenol A

The shatterproof glass used in impact-resistant windows is actually not a glass material derived from silicon dioxide. Instead, shatterproof glass is a thermoset plastic or thermoplastic, i.e., a pliable material that is even easier to mold when hot. Shatterproof windows are made using a specific thermoset material known as polycarbonate of bisphenol A (or bisphenol A polycarbonate). This clear,... 

General Electric markets the polycarbonate of bisphenol A as Lexan.W Similar bisphenol A polycarbonate sheets are marketed by Rohm and Haas as the product TuffakJ2]... 

The synthesis of polycarbonate of bisphenol A begins with the reaction of bisphenol A and sodium hydroxide to obtain the sodium salt of bisphenol A, as in Fig. 14.4.3. The sodium salt of bisphenol A is then reacted with phosgene to... 

The properties of the polycarbonate of bisphenol A are directly related to the structure of the polymer. The molecular stiffness associated with this polycarbonate arises from the presence of the rigid phenyl groups on the molecular chain or backbone of the polymer and the additional presence of two methyl side groups. The transparency of the material arises from the amorphous (noncrystalline) nature of the polymer. A significant crystalline structure is not observed in the polycarbonate of bisphenol A because intermolecular attractions between phenyl groups of neighboring polymer chains in the melt lead to a lack of flexibility of the chains that deters the development of a crystalline structure. 

Morphology, Viscoelastic Properties, and Stress-Strain Behavior of Blends of Polycarbonate of Bisphenol-A (PC) and Atactic Polystyrene (PST)... 

Materials. Polycarbonate of Bisphenol-A(PC) was a commercial product (Lexan, General Electric Co., U.S.A.), with a viscosimetric average molecular weight Mv = 40,000. High molecular-weight atactic polystyrene (Mv == 280,000) was obtained from Schuchardt, Miinchen. 

The elimination of a cyclic intermediate can serve to drive polycondensation forward in special cases. Thus heating the polycarbonate copolymer prepared from ethylene glycol bis(chlorocarbonic acid) and bisphenol A at 280° C in a vacuum leads to elimination of cyclic ethylene carbonate and the formation of the polycarbonate of bisphenol A [46]. 

When the polycarbonate of bisphenol A was made interfacially in a non-solvent for the polymer the distribution of molecular weights showed two clear maxima and was unusually broad [40]. This was probably a consequence of the two-step process often employed in the preparation of polycarbonates here, the first step yields low-molecular-weight polymer from phosgene and the aqueous alkaline solution of the aromatic diol, then an accelerator salt and more alkali and phosgene are added in the second step. Polycarbonates prepared in the melt and in solution show the expected essentially statistical distribution of molecular weights [40]. Polycarbonates have also been prepared from bisphenols and bisphenol bischloroformates studies of this reaction in nitrobenzene solution have shown it to be second order [79]. 

In the literature there are reports of radial distribution function analyses performed with polystyrene,6 7 polycarbonate of bisphenol-A,7 8 and a number of other amorphous polymers.9 As an illustration, we present results obtained with atactic polystyrene. Figure 4.2 shows the x-ray scattering intensity data obtained with CuKa radiation. The strong peak at 26 around 20° represents the so-called amorphous halo, whereas the smaller peak at around 10° is called the polymerization peak by some and has attracted interest with regard to its structural origin. The experimentally measured intensity is first corrected for background, polarization, absorption, etc.,... 

PS is miscible with several polymers, viz. polyphenyleneether (PPE), polyvinylmethylether (PVME), poly-2-chlorostyrene (PCS), polymethylstyrene (PMS), polycarbonate of tetramethyl bisphenol-A (TMPC), co-polycarbonate of bisphenol-A and tetramethyl bisphenol-A, polycyclohexyl acrylate (PCHA), polyethylmethacrylate (PEMA), poly-n-propyl methacrylate (PPMA), polycyclohexyl methacrylate (PCHMA), copolymers of cyclohexyl methacrylate and methyl methacrylate, bromobenzylated- or sulfonated-PPE, etc. Other miscible blends are listed in Appendix 2. 

Polycarbonate of bisphenol-A (PC) is recognized as an engineering, amorphous polymer. However, there are many reports that PC does crystallize in blends with, e.g., PCL [Jonza and Porter, 1986], and other polymers [Utracki, 1998]. 

Blend families, i.e., blends of polyphenylene ether (PPE), blends of polyesters (PEST), blends of polycarbonate of bisphenol-A (PC), tend to be appropriate for certain types of apphcations which require the special attributes of the major blend component. For this reason, it is possible to group blend families together under the major resin component and to list the types of applications that have been commercialized. 

Fig. 2.3 Polyethylene terephthalate (PET) polyamide-6 (Nylon-6) polycarbonate of bisphenol-A (PC).

Among the large variety of hetero-chain polymers we are also interested in polycarbonates, one of which, the polycarbonate of bisphenol-A (PC), is also depicted in Fig. 2.3, even though it is not exactly a condensation polymer. 

For the simple chain cmisidered in the examples presented in Eqs. (3.7)-(3.9), all of the U, are square and identical [14]. In polyoxymethylene, all of the U, are square, but there are two square U, with distinctly different numerical values of the elements [15]. Half of the statistical weight matrices for polyoxymethylene incorporate second-order interactions between pairs of oxygen atoms, and the other half incorporate second-order interactions between pairs of methylene groups. For other polymers, such as the polycarbonate of bisphenol A [16], some of the U, may be rectangular but not square, because there is a different number of rotational isomeric states at bonds / — 1 and i. The RIS model does not require that all bonds adopt the same value for V. 

The behavior of the two-phase systems is complex and responses on aging can be affected by the thermal history and aging temperature. This is well illustrated by a series of investigations, the two-phase blend of acrylonitrile-butadiene-styrene copolymer (ABS, Tg = 110 °C) and polycarbonate of bisphenol-A (BPAPC, Tg = 151 °C). Due to the phase-separated structure of the blend, two enthalpy recovery peaks are detected by enthalpy relaxation and attributed to the two components (Tang and Lee-SuUivan 2008). However, aging appears to have little effect on the ABS component even at temperatures close to the ABS glass transition. 

PBT Polybutylene terephthalate PC Polycarbonate of bisphenol-A PCL Poly-E-caprolactone PCW Postconsumer waste PD Polydispersity, MJM ... 

Today, very few unmodified resins are being used. Some polymers require less modification than others. For example, the semicrystalline polymers that aheady have a two-phase structure may need modification less urgently. By contrast, the amorphous resins, such as PVC, PS, PPE, or polycarbonate of bisphenol A (PC), are brittle and require blending more frequently. The advantages of blending fall into two categories. 

As an example of regularity in the diffraction patterns, the waxs spectra for different polycarbonates of bisphenol A (54) are shown in Figure 12. The figure shows different diffraction patterns starting from the monomer (x = 1, which is crystalline), the pentamer (x = 5), and other oligomers up to the bulk. It is interesting to note that there is a correlation of the most intense reflection in the crystalline monomer with the amorphous halo in the BPA polymers and that the first sharp diffraction peak gets broader as one moves from the pentamer to the polymer. 

Fig. 12. Waxs spectra of different polycarbonates of bisphenol A starting from the monomer x = 1), to the pentamer x = 5), to the pol)maer. Notice the sharp diffraction maxima in the monomer (crystalline) and the broader patterns on the pol3rmeric substances.

The serial product in equation (6) imphes that the Uj need not all be identical. The only restriction on their relationship is that all pairs must be conformable for matrix multiplication. Conformabihty is ensured by the requirements expressed in the first two points before equation (4). Equation (6) can be used with chains in which different types of bonds are present, as in polyoxyethylene (14). It can also be used for chains in which not all bonds have the same number of rotational isomeric states, as in the polycarbonate of bisphenol A (15). 

The photochemical and photophysical processes taking place on irradiation of the polycarbonate of bisphenol A have been thoroughly investigated. Xenotester treatment of the polycarbonate Makrofol resulted in a combination of scission and rearrangement reactions primarily on the surface of the sample. ... 

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