網狀高分子の化學

Abstract

Folry's theory on the molecular weight distribution of three dimensional polymers is reviewed and its relationship with vulcanization of rubber is discussed. The elasticity of rubber is recently described by many workers. After Flory's theory, the elasticity is proportional to α-1/α2 where α is elongation ratio, and number of cress-linkages ν, while Kubo states that the elasticity is proportional to ν4/3, but Flory's opinion is more reasonable. The tensile strength of vulcanized rubber decreases linearly with reciprocal molecular weight of original rubbr, because of the network defect due to terminal chain. The vulcanzation lowers the concentration of terminal chain, but on the other hand has negative effect on account of its hindrance of crystallization on stretching. The theoretical equation for the tensile strength is propcsed, by which the maximum tensile strength is explained. The author discussed the reinforcing effect of filler, i.e. filler fixes rubber on its surface and acts as cross-linkage on stretching. The theoretical equation is introduced by author. Finally, the elastic property of plasticized polyvinyl-chloride is discussed. It is explained as visco-elasticity. Logarithm of elasticity decreases with prasticizer.