EFFECT OF MECHANICAL PRE-CONDITIONING ON FRACTURE RESISTANCE OF POLYPROPYLENE

• Published in: Chinese journal of polymer science Vol. 29; no. 3; pp. 318 - 324
• Main Authors: Han, Liang, Xiang, Fang-ming, Li, Yan-li, Huang, Ting, Wang, Yong, Zhang, Ji-hong
• Format: Journal Article
• Language: English
• Published: Heidelberg Chinese Chemical Society and Institute of Chemistry, CAS 01.05.2011
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Industrial Chemistry/Chemical Engineering; Polymer Sciences; 冲击强度; 大肠杆菌; 抗断裂; 线性关系; 缺口试样; 聚丙烯; PP; Mechanical pre-conditioning; Microvoid; Fracture resistance
• ISSN: 0256-7679; 1439-6203
• DOI: 10.1007/s10118-011-1038-6

The effect of externally applied mechanical pre-conditioning, i.e. pre-impact treatment, on the fracture resistance was investigated for polypropylene （PP）. Impact strength was obtained via notched and/or unnotched samples. It has been shown that the pre-impact treatment is favorable to the improvement of the fracture resistance. The impact strength increases linearly with the applied pre-impact energy. Both optical and SEM results show that there are at least two possible mechanisms for the improvement of the fracture resistance. One is the crack blunting effect which is introduced to notched sample by pre-impact treatment, reducing the sensitivity of PP to the applied notch. The other is the formation of large amount of microvoids induced by pre-impact treatment, which changes the stress distribution and induces intensive plastic deformation of PP at the second impact measurement, leading to the improvement of the fracture resistance.