Tetramethyl polycarbonate

Fig. 8.12. Sorption isotherms (a) and the permeability coefficients (b) for C02 sorption by (1) bisphenol A polycarbonate, (2) tetramethyl polycarbonate, (3) tetrachloropolycarbonate, and (4) tetrabromopolycarbonate at 35°C [189].

Blends of tetramethyl polycarbonate, TMPC, with PS were reported miscible [Wisniewsky et al., 1984]. Couchman [1996] demonstrated that the concentration dependence of r at 230°C can be predicted from the characteristic parameters of the two components, assuming absence of specific interactions. 

In Figure 2.7, we report the case of two glassy polymer blends the solubility of CH4 in PS-TMPC (tetramethyl polycarbonate) blends of different compositions (0-20-40-60-100% of PS) is shown in Figure 2.7a at 35° while the solubility isotherms of COj in five different blends of (bisphenol-chloral) polycarbonate (BCPC) and PMMA (0-25-50-75% of PMMA)[" 1 at 35° C are shown in Figure 2.7b. The NELF estimation of the solubility is also reported, based only on the pure component characteristic parameters... 

Tetramethyl polycarbonate CO2 195 6.6 5.62 160 [120] High pressure scanning calorimetry... 

Werumeus Buning, G.H. and Gijsen, R.M.R., Stress-optical study of the tetramethyl-polycarbonate / polystyrene blend. Polymer Preprints, 1988, 29, 2 (Fall), in print. 

A number of technologists have attempted to obtain miscible systems with polycarbonate (PC) as one of the blend constituents. Given the high performance and cost associated with PC polymers, blends of PC and multicomponent copolymers may get the job done for less cost. PC/ABS blends have been reported in the product literature. Although they were not compatibilized, they exhibit good balance of properties. In this section a terpolymer made of three comonomers, (1) a-methlystyrene (AMS), (2) acrylonitrile (AN), and (3) methyl methacrylate (MMA) can be evaluated for miscible regions in the copolymer compositional space and blend composition with (4) tetramethyl polycarbonate (TMPC) homopolymer. The binary interaction parameter for the terpolymer/homopolymer system can be written as follows ... 

Shabana HM, Guo W, Olley RH, Bassett DC (1993) Electron-microscopic observation of spinodal decomposition in blends of tetramethyl polycarbonate and polystyrene. Polymer 34 1313-1315... 

The Sanchez-Lacombe EOS has been applied to PMMA/SAN [29], polycarbonate (PC), tetramethyl polycarbonate (TMPC) andpoly(e-caprolactone) binary and ternary blends [30],... 

Hydrolysis studies compared a polycarbonate urethane with a poly(tetramethyl-ene adipate) urethane and a polyether urethane based on PTMEG. After 2 weeks in 80°C water, the polycarbonate urethane had the best retention of tensile properties [92], Polycarbonates can hydrolyze, although the mechanism of hydrolysis is not acid-catalyzed, as in the case of the polyesters. Polycarbonate polyurethanes have better hydrolysis resistance than do standard adipate polyurethanes, by virtue of the highest retention of tensile properties. It is interesting to note in the study that the PTMEG-based urethanes, renowned for excellent hydrolysis resistance, had lower retention of physical properties than did the polycarbonate urethanes. 

PS-PMMA Poly(styrene-co- acrylonitrile), PS, PMMA, poly(cyclohexyI methacrylate), polycarbonate or poly(tetramethyl carbonate) (Lowenhaupt er al. 1994)... 

Rotational-echo double resonance NMR Tetramethyl bisphenol A polycarbonate Tetrachlorophthalic dimethyl ester Wiliams, Landel, Ferry... 

In order to investigate the molecular motions involved in this transition and, in particular, the nature of the associated cooperativity, it is interesting to consider not only BPA-PC, but also tetramethyl bisphenol A polycarbonate, TMBPA-PC, (Fig. 25) as well as copolymers of BPA and TMBPA carbonates, and compatible blends of BPA-PC and TMBPA-PC. 

Methyl methacrylate-co-N-methyl glutarimide copolymer Bisphenol A polycarbonate Tetramethyl bisphenol A polycarbonate Aryl-aliphatic copolyamides... 

In order to investigate the effect of a methyl substitution of the phenyl hydrogen in ortho position to the carbonate group, tetramethyl bisphenol A polycarbonate (TMBPA-PC), whose the chemical structure is shown in Fig. 66b, has also been considered. In the case of TMBPA-PC, the secondary fi transition happens at 50 °C, at 1 Hz (Fig. 67), in such a way that it allows one to examine the consequences of such a large shift of the fi transition on the mechanical properties. 

Investigation of the mechanical properties of bisphenol A polycarbonate (BPA-PC) and tetramethyl bisphenol A polycarbonate (TMBPA-PC) has led to... 

The observation that Bib is more exothermic than Bz3 is not surprising when one considers the fact that blends of tetramethyl bisphenol-A polycarbonate with polystyrene are miscible while blends of bisphenol-A polycarbonate with polystyrene are immiscible (43 ). Apparently, substitution of methyl groups on the aromatic rings in the backbones of these materials enhances miscibility with the styrene repeat unit. The observation that Biz is also exothermic is quite surprising, considering the similarity of the trimethyl and dimethyl ether units. Using regular solution approximations, one could... 

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