QUANTITATIVE ANALYSIS OF POLYMER FRACTURESURFACE ROUGHNESS BY VERTICAL SECTIONPROFILE METHOD
垂直轮廓剖面迹线法测定聚合物材料断面粗糙度的研究

The fracture surface roughness of several polymers are measured by means of vertical sectionfracture profile method in present paper. The experimental results show that the measuring value of fracturesurface profile roughness parameter RL are effected by the shape of specimen, the displaying of fracturedsurface morphology and fracture modles etc. On the conditions of notch speCimen fractured surfacemorphology is harmonius distribution, the measuring values on two different surfaces of the specimen areequal, and the measuring results on speimen surface is equal to that on interior section for brittle fracturebut larger than that of specimen interior section for ductile fracture. The symbol of whole specimen fracturedsurface roughness is more reasonable with the average value RL of the measuring values on specimen surfaceand interior.The fracture surface morphology is radiation patterns for unnotch impact specimens ofpolyvinyl chloride. The measuring values on specimen surfaces are closely related with the location of fractureorigins and the measuring results of specimen interior section are usually higher than the average value ontwo specimen surfaces. The linear relation between impact strength and the measuring results of specimen interior section is better. The impact strength of polymers increases linearly with fracture surface roughnessparameter Rs increasing in the case of brittle fracture. The variation of impact strength depends on thechange of total fractured surface area for brittle fracture but depends on both real fractured surface area andthe plastic deformation energy consumed in the subsurface or crack initiating energy in the case of tough fracture. It is not enough to describe impact energy consuming procedure only by two-dimension parameterRs for tough fracture.