Study on degrees of mesomorphic zone of polymer.â .Determination of degrees of crystallinity of Eucommia ulmoides gum and natural rubber by dynamic mechanical thermal analysis

The number of free chain segments of the amorphous zone in NR and EU gum, tested with DMTA, can be used to calculate their degrees of crystallinity. The results indicate that the degree of crystallinity of NR is 86% after crystallizing at −25 °C for 12 h, which is very similar to the degree of crystallinity of EU gum, which is 87%. By increasing the crosslink density, unlike NR, which only shows the critical crystallization point, EU gum will firstly show the percolation threshold, and after that show the critical crystallization point.223