Sezemský Jan, Špatenka Petr
Department of Materials Engineering, Faculty of Mechanical Engineering Czech Technical University in Prague, Karlovo Náměstí 13, 121 35 Prague 2, Czech Republic.
Polymers (Basel). 2021 Jan 21;13(3):331. doi: 10.3390/polym13030331.
The aim of this study is to investigate a multilayer structure made of polyethylene and polyamide by rotational molding. Due to the different polarity of these polymers, it is difficult to ensure enough adhesion between created layers. Two methods leading to improve adhesion are introduced. Plasma modification of polyethylene powder, after which new functional groups are bound to the treated surface, may enhance specific adhesion by forming hydrogen bonds with-CONH groups of polyamide. Different strategies of adding material to the mold give rise to complicated interlayer which increases joint strength by mechanism of the mechanical adhesion. Mechanical tests show a significant improvement of joint strength, where treated samples reached two-fold values of peel strength (7.657 ± 1.024 N∙mm) against the untreated sample (3.662 ± 0.430 N∙mm). During bending test, delamination occurred only in samples that were made of the untreated polyethylene. Adding polyamide during the melting stage of polyethylene powder in rotomolding resulted in the formation of entanglements which improve the peel strength almost eight times in comparison with the sample where the polyethylene was left to completely melt and create smooth interlayer surface.
本研究的目的是通过滚塑成型研究一种由聚乙烯和聚酰胺制成的多层结构。由于这些聚合物的极性不同，难以确保所形成层之间有足够的附着力。介绍了两种提高附着力的方法。对聚乙烯粉末进行等离子体改性，之后新的官能团会结合到处理过的表面，通过与聚酰胺的-CONH基团形成氢键可增强特定附着力。向模具中添加材料的不同策略会产生复杂的中间层，通过机械附着力机制提高结合强度。力学测试表明结合强度有显著提高，经处理的样品的剥离强度（7.657±1.024 N∙mm）是未处理样品（3.662±0.430 N∙mm）的两倍。在弯曲试验中，分层仅发生在由未处理聚乙烯制成的样品中。在滚塑成型中聚乙烯粉末的熔化阶段添加聚酰胺会导致缠结的形成，与让聚乙烯完全熔化并形成光滑中间层表面的样品相比，其剥离强度提高了近八倍。
