等规度和分子量及其分布对聚丙烯结晶行为及力学性能的影响

Effect of isotacticity,molecular weight and its distribution on crystallization and mechanical properties of polypropylene

选取了3种具有不同等规度和不同分子量及其分布的均聚聚丙烯试样,利用DSC,GPC,SAXS,WAXD等方法研究了等规度、分子量及其分布对均聚聚丙烯结晶行为及力学性能的影响。实验结果表明,结晶行为主要受试样等规度的影响,对于等规度相近的试样,结晶温度和结晶度还受试样分子量及其分布的影响;力学性能与结晶度呈正相关,高等规度、宽分子量分布的试样具有更高的结晶度,以及较高的屈服应力、弯曲模量和热变形温度。

The effects of isotacticity,molecular weight and its distribution on the crystallization and mechanical properties of homo-polypropylene were studied using methods such as DSC,GPC,SAXS,and WAXD.Results indicate that crystallization behavior is primarily influenced by isotacticity.For samples with similar isotacticity,the crystallization temperature and crystallinity are also influenced by the molecular weight and its distribution.Mechanical properties show a positive correlation with crystallinity.Samples with high isotacticity and a broad molecular weight distribution exhibit increased crystallinity,which contributes to higher yield stress,flexural modulus,and thermal deformation temperature.