Bisphenol A polycarbonate. See

Figure 12.6. (S/8V )<1 for multiply-bonded backbone atoms. Let R, R and R" denote nonhydrogen structural units. [It makes no difference whether the two C atoms are in a linear chain segment as in polyisoprene, or in a ring structure such as a backbone phenyl ring of bisphenol-A polycarbonate. (See Figure 5.2 for the structures of these two polymers.) The carbon atom on the left has 8=2 and Sv =3, so that (8/8v )=(2/3)=0.66667. The carbon atom on the right has 8=3 and Sv =4, so that (8/8v )=(3/4)=0.75.

Figure 2.11 depicts the increase in d>cc with increasing triphenylamine content in commercial bisphenol A polycarbonate (see Chart 2.6) [52], and Fig. 2.12 shows a plot of log vs. 1/T. It can be seen that the hole mobility may be varied over several orders of magnitude by changing the TPA concentration [53]. Here, irradiations were performed at wavelengths of 2exc=300 and 337 nm, respec-... 

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. 

Fig. 6.3 presents results obtained with a dual-layer system [8, 9]. Here, the CG layer consisted of a dispersion of the triphenylamine triazo pigment AZO-3 (see Chart 6.1) in poly (vinyl butyral) in a 4 10 weight ratio, while the CT layer consisted of a mixture of bisphenol A polycarbonate and the triarylamine derivative MAPS (see Chart 6.1) in a 10 9 weight ratio. 

A high-pressure probe constructed to allow the study of supercritical xenon as it interacts with different polymers (bisphenol-A polycarbonate or polytetrafluoro-ethylene) was reported by Nagasaka et al The probe, which has a zirconia cell with a Be-Cu flange and indium o-ring can be used in a range of pressure up to 20 MPa, and temperatures from 150 to 400 K (see Fig. 6). Experiments performed up to 10 MPa showed xenon inside the polymer experienced a very different state from that of free xenon, which was attributed to the limitation on xenon cluster size. Essentially no exchange between the supercritical and confined xenon phases occurred on the second timescale. 

To date, results have been obtained for minimum-energy type simulations of elastic deformations of a nearest-neighbor face-centered cubic (fee) crystal of argon [20] with different inclusion shapes (cubic, orthorhombic, spherical, and biaxially ellipsoidal). On bisphenol-A-polycarbonate, elastic constant calculations were also performed [20] as finite deformation simulations to plastic unit events (see [21]). The first molecular dynamics results on a nearest-neighbor fee crystal of argon have also become available [42]. The consistency of the method with thermodynamics and statistical mechanics has been tested to a satisfactory extent [20] e.g., the calculations with different inclusion shapes all yield identical results the results are independent of the method employed to calculate the elastic properties of the system and its constituents (constant-strain and constant-stress simulations give practically identical values). 

As far as sub-Tg dynamics (often called p-relaxation) and its relation to ductility is concerned, bisphenol-A polycarbonate (PC) is one of the most studied, yet still controversial systems. For a recent review of the field, see Reference 48. From NMR line shapes, large-angle phenylene rotations described by 180° flips augmented by additional oscillations were identified at room temperature and above. Such 180° flips were subsequently confirmed by NMR line shape studies and 2D... 

The largest outlet for phenol worldwide is phenoHc resins (qv). However, the growth rate of bisphenol A is higher than that of the other significant derivatives and is projected to become the principal use of phenol in the future (see Epoxy resins Polycarbonates). Table 6 shows the portion of world phenol demand by use and the anticipated growth rate of the uses. 

Bisphenol A is a solid material in the form of white flakes, insoluble in water but soluble in alcohols. As a phenolic compound, it reacts with strong alkaline solutions. Bisphenol A is an important monomer for producing epoxy resins, polycarbonates, and polysulfones. It is produced by the condensation reaction of acetone and phenol in the presence of HCI. (See Chapter 10, p. 273)... 

Bisphenols. See also Bisphenol A (BPA) aromatic polycarbonates derived from, 19 806-808t... 

The most-common polycarbonates are based on bisphenol A (see Figure 4.75) but, more recently, heat resistant grades were launched based on other bisphenols, possibly blended with bisphenol A. 

Polycarbonates. The polycarbonates surfaced in the 1950s, so they are middle-aged polymers. They are made in a condensation polymerization process. The reactants are either Bisphenol A and phosgene or Bisphenol A, phosgene, and phenol. Since Bisphenol A is a derivative of phenol, the building block is the same in either case—phenol. The polycarbonate based on Bisphenol A has the best balance of properties. If you look hard, you can see the monomers in Figure 24—7. ... 

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