抄録
The tensile strength of polystyrene decreases with increasing temperature and with decreasing molecular weight, showing a S mark curve with the change of temperature or molecular weight.
As amorphous polymers such as polystyrene maintain their strength with the entangled bonds of molecular chains, the following experimental equation representing the relation between the temperature T and the tensile strength Ts has been introduced from the change of density of effective molecular chain with the temperature based on the entangled bonding of molecular chains.
Ts=Sb[1-3/(Tm-Tb)√2∫TTbexp{-9(T-Tm)2/2(Tm-Tb)2}dT]
where Sb is the tensile strength at the temperature of brittle fracture point, Tm is the maximum temperature of dispersion of the distribution of density of effective molecular chain and Tb is the temperature of brittle fracture point.
The experimental data of polystyrenes of various molecular weights indicate a sufficient agreement with the experimental Ts curves.
