抄録
The second order transition phenomena in polyethylene are discussed based on our dilatometric measurement. Calculating the value (V1−V0)/(V2−V0) from the result of measurement on three samples, each having different crystallinity, it is found that the crystallinity of polyethylene changes with temperature above −30°C. Also the transition at −55°C is found, below which the expansion coefficient of crystalline phase becomes equal to that of amorphous phase, and this phenomenon is thought to be the true second order transition. The crystallinity of each sample is calculated by using the method of Hoffmann and Weeks as the first approximation and applying some further calculation. The application of the least-mean-square method to the decision of transition by means of the electronic computor is attempted.
