Polyester chemical behavior

The chemistry of polycarbonates is similar to the chemical behavior of polyesters. We can think of a carbonate as being a diester of carbonic acid, H2CO3, which is unstable itself. Polycarbonate is a strong, clear plastic used in automobiles (25%), glazing and sheet (20%), optical media (15%), appliances (8%), computers (7%), medical industry (7%), and recreation and... 

Polycarbonate (PC). Polycarbonate is similar to the chemical behavior of polyesters. It is produced from a reaction of bisphenol A [2,2-bis (4-hydroxyphenyl)-propane] and phosgene. The price has ranged from 1.29 per pound to 1.36 per pound [6], Demand for polyurethane was 1,440 million lb in 1996 and is expected to grow at a rate of 5.2% annually [7],... 

The doublet structure of the methyl signal at 17 ppm is caused by the stereochemistry. Polylactides, not yet described in any pharmacopoeias, are rather new biodegradable polyesters derived from the chiral lactic acid and used, e. g., in drug delivery systems. The stereochemistry of the polymer is important to the physical and chemical behavior, especially the polymer properties. Pure tactic polymerization can be differentiated from atactic or mixed polymers by simple comparison of the C NMR spectra (Figure 3-10) [4]. 

Pitt et al. [65], and more recently, Albertsson et al. [73], have prepared chemically cross-linked aliphatic polyesters by ROP of the corresponding cyclic ester monomers in the presence of Y,y -bis(e-caprolactone)-type comonomers (Scheme 17). The cross-linked films displayed different swelling behaviors, degradability, and elastomeric properties depending on the nature of the lactone and composition of the comonomers feed. 

In this paper, the effect of temperature and concentration on corrosion behavior and corrosion mechanism of epoxy and unsaturated polyester resins in NaOH solution were studied, and were discussed by considering their chemical structures. Corrosion rate studies were also made by applying the concept of metallic corrosion. 

The conclusion was reached that the mechanical properties of glass-reinforced unsaturated polyester are influenced by the chemical structure of the spacer groups in the methacrylate functional silane. Effective factors include hydro-phobicity, reactivity of the double bond, chain flexibility of the backbone, and adsorption behavior. 

For example, crystallization-induced chemical reorganization has been reported (29-34) to cause such behavior for a variety of materials, including polyesters and various random and block copolymers. It would not be un-... 

Determination of B for a series of blends made it possible to establish empirical rules for the observed miscibilities. Thus, for example, Prud homme [1982] reported systematic variation of miscibility in a series of halogenated polymer/ aliphatic polyester blends. The highest miscibility was observed for the chlorinated polymer, e.g., PVC, and the lowest for the fluorinated, PVF, with the brominated, PVB, having an intermediate behavior. Furthermore, when the chlorinated polymer was mixed with a series of polyesters, the highest miscibility was found when the ratio of the -CH - to -COO- groups reached an optimum value. This optimum value depended on the chemical nature of the halogenated polymer — as shown in Figure 2.7, for PVDC blends with aliphatic polyesters this value is 5 to 6. 

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