Mihelčič Mohor, Oseli Alen, Huskić Miroslav, Slemenik Perše Lidija
Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva Ulica 6, 1000 Ljubljana, Slovenia.
Faculty of Polymer Technology, Ozare 19, 2380 Slovenj Gradec, Slovenia.
Polymers (Basel). 2022 Dec 12;14(24):5438. doi: 10.3390/polym14245438.
To decrease the amount of plastic waste, the use of recycling techniques become a necessity. However, numerous recycling cycles result in the mechanical, thermal, and chemical degradation of the polymer, which leads to an inefficient use of recycled polymers for the production of plastic products. In this study, the effects of recycling and the improvement of polymer performance with the incorporation of an additive into recycled polypropylene was studied by spectroscopic, rheological, optical, and mechanical characterization techniques. The results showed that after 20 recycling steps of mechanical processing of polypropylene, the main degradation processes of polypropylene are chain scission of polymer chains and oxidation, which can be improved by the addition of a stabilizing additive. It was shown that a small amount of an additive significantly improves the properties of the recycled polypropylene up to the 20th reprocessing cycle. The use of an additive improves the rheological properties of the recycled melt, surface properties, and time-dependent mechanical properties of solid polypropylene since it was shown that the additive acts as a hardener and additionally crosslinks the recycled polymer chains.
为了减少塑料废弃物的数量，采用回收技术成为必要之举。然而，大量的回收循环会导致聚合物的机械、热和化学降解，从而致使回收聚合物在塑料制品生产中的利用效率低下。在本研究中，通过光谱、流变、光学和机械表征技术，研究了回收的影响以及在回收聚丙烯中添加添加剂对聚合物性能的改善情况。结果表明，聚丙烯经过20次机械加工回收步骤后，聚丙烯的主要降解过程是聚合物链的断链和氧化，而添加稳定添加剂可对此加以改善。结果显示，少量添加剂能显著改善回收聚丙烯直至第20次再加工循环时的性能。由于添加剂起到硬化剂的作用并额外交联回收的聚合物链，因此使用添加剂可改善回收熔体的流变性能、表面性能以及固态聚丙烯随时间变化的机械性能。
