轧制和退火过程中等规聚丙烯的力学性能

Research of Mechanical Properties in Isotactic Polypropylene During Rolling and Heat Treatment

借助拉伸试验对轧制和退火后的等规聚丙烯进行了轧向及横向上力学性能的研究。结果发现,结晶度和大分子链的取向是影响材料力学性能的主要原因,力学性能的变化主要发生在轧制过程中。轧制后,大分子链沿轧向排列,出现各向异性:轧向上拥有高的拉伸强度和低的延伸率。结晶度的变化主要是影响材料的弹性模量和横向上的屈服强度。退火后,大分子链的取向发生较小的变化。非晶部分的再晶化与无序化共同影响材料的性能,在伸拉强度没有减少的基础上增大了材料轧向上的延伸率。

The mechanical properties of the rolled and subsequently heat treated isotactic polypropylene were measured by the tensile tests. It is found that the crystallinity and the orientation of macromolecule are the main reasons changing the mechanical properties and the great changes are happened during rolling, After rolling, the orientation of macromolecule leads to the strong anisotropy mechanical properties along the rolling and transverse directions. The elastic modulus and the yield strength are affected mainly by the crystallinity. After the subsequent heat treatment, slightly changes of the orientation of macromolecule were found. The co-influence of the recrystallization and the relaxation of amorphous part results in the higher total elongation without decrease of the tensile strength in rolling direction after heat treatment.