Strength properties of solvent vapour-treated pre-tensioned polypropylene films Part Ⅰ Halohydrocarbon solvents

摘要

The strength properties of solvent vapour-treated pre-tensioned polypropylene(PP) films have beeninvestigated. The results showed that the variation ofproperties (yield stress, draw stress, initial modulus, tensilestrength and breaking factor) were determined by the net-balance of two opposing effects:orientation crystallizationfrom pre-tensioning and solvent presence one the hand, andplasticization by residual solvent defined by the interactionparameter, x, or non-specific cohesion force, D, of the halo-solvents, on the other. The greater influence of crystallizatonwas shown in the draw stress initial modulus and yield stressfor chlorolform- and carbon-tetrachloride-treated PP films.The tensile strength and breaking factor seemed invariantwith solvent-vapour treatment but still showed a greaterinfluence of stretching orientation brought about by the greater pre-tensioning.