Glass transition temperature ketone

Mathias et al. synthesized poly(ether sulfone)s and poly(ether ether ketone)s with pendent adamantane groups.192 Incorporating adamantane into a polymer as a pendent group has been demonstrated to significantly increase the glass transition temperature. 

Due to the side chains this poiymer is amorphous with a glass transition temperature of 185 °C. In contrast, unsubstituted poly(arylene ether ketone)s are crystalline and high melting (T > 300 °C).The iR spectrum shows absorption bands at 3300 cm" and 1710-1730 cm" for the acid group in the side chain and at 1650 cm" for the keto group. 

Estimate the glass transition temperature of poly(ether-ether-ketone) or PEEK. Its repeating unit is ... 

The polymerization takes place with coupling at the C4 position of the 1-naphthoxy group. The restricted rotation about the C4—C4 binaphthyl bond of the poly(ether sulfone)s and poly(ether ketone)s resulted in higher glass transition temperatures than the analogous biphenyl poly-... 

Early fundamental studies of gas transport in polymers were almost entirely confined to hydrocarbon materials above their glass transition temperatures. The essentially nonpolar structures of the elastomers led to a number of reasonably successful attempts to correlate gas transport parameters with various physical characteristics of the gases and the polymers. These have been summarized and discussed in a number of papers In addition to studies with hydrocarbon elastomers a few studies of other amorphous polymers above their glass transition temperatures have dealt with polyvinyl acetate silicones and fluorocarbon polymers Recent studies have also dealt with poly(methyl aciylate) poly-(vinyl methyl ether) and poly(vinyl methyl ketone) With these more... 

More tractable and potentially useful polyether ketones, incorporating phenylene-carborane-phenylene units, and with properties suitable for high temperature applications, have been prepared by acylation reactions (using trifluoromethanesulfonic acid as both medium and catalyst) between appropriate dicarboxylic acids and phenoxyphenylcarboranes. For example, the polyetherketone 20 (Scheme 3.6), derived from bis(4-phenoxyphenyl)-para-carborane and biphenyl-4,4 -dicarboxylic acid, is essentially amorphous on isolation from trifluoromethanesulfonic acid, but crystallizes when heated above its glass transition temperature (267°C) before hnally melting at about 390 0... 

As a starting point for this computational approach to the photooxida-tive process in polymeric materials, we have examined the simplest prototype neat, amorphous, linear polyethylene above its glass transition temperature. In practice, polyethylene is partially crystalline, and contains truly linear olefins, vinylidene groups, ketones and hydroperoxides in addition to the short side chains. Much insight has already been gained into the photooxidation process by conventional experimentation on such polymers (12,13), yet several important questions still remain. Several good reviews have appeared recently (14-16). 

It is important to point out that the quantum yield for the Norrish II chain scission reaction ( Cs) is highly affected by the mobility of polymer chains. For example, the photolysis CS for a film of the copolymer poly(styrene-co-phenyl vinyl ketone) irradiated at 313 nm in the solid state was shown to be low (0.04—0.09) at temperatures below the copolymer Tg (glass transition temperature) but increased dramatically at,... 

The photo-Fries reaction occurs readily in solid polymers and is observable in phenyl esters, particularly in poly(phenyl acrylate) and poly (phenyl methacrylate) and their derivatives. The course of the reaction can be followed very easily by ultraviolet spectroscopy, since the product hydroxy ketones have strong absorbance at 260 and 320 nm (Fig. 10). Reaction occurs with equal efficiency in small model compounds in solution and in the polymers in the solid phase (44). An Arrhenius plot of the quantum yield for the para product (Fig. 11) shows a linear increase up to 294 K, above which no further change in quantum efficiency is observed, either above or below the glass transition temperature. 

FIGURE 1. Quantum yield of chain scission, 5, due to Norrish Type II reaction in styrene-phenyl vinyl ketone co-polymer as function of temperature. Xex=313 nm. Tg= glass transition temperature. [After Fig. 1, Macromolecules, 230 (1973)]. 

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