Glass Transition with the Chain Length and Nature of Terminal Group

Variation of the Glass Transition with the Chain Length and Nature of Terminal Group (2i) 

Two series of polymem were investigated. In the first, termination was accomplished by insufficient heating these materials are thus terminated by hydroxyl groups, the terminal unit beii  

Termination in the second set was accomplished by the addition of excess NagO accompanied by extensive heating and elimination of water. Since it is impossible to eliminate all the water, some chains are still hydroxyl terminated, the vast majority of the terminal groups, however, are 

While a relatively large number of theories exist which correlate the glass transition with the molecular weight or the chain length of polymers, only five rq)resentative theories were chosen for the investigations. These theories, as well as their application to the polyphosphates, are described below. 

The same was done for the -OH terminated material, line B resulting from 7 gi = 299°C and 7 g2=—115°C. Both cases show satisfactory agreement between theory and experiment, the calculations giving straight lines over the range for which experimental data are available. 

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