Safandowska Marta, Makarewicz Cezary, Rozanski Artur
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland.
Molecules. 2024 Oct 19;29(20):4950. doi: 10.3390/molecules29204950.
This work focused on determining the factors that are of key importance in the oxygen barrier properties of low-density polyethylene (LDPE). It has been shown that, depending on the type and amount of the low-molecular-weight compound (tetracosane, paraffin wax, paraffin oil) introduced into the LDPE matrix, it can contribute to the improvement or deterioration of barrier properties. Tetracosane and paraffin wax incorporated into the LDPE matrix caused a reduction in oxygen permeability parameters compared to neat polyethylene. As their content increased, the barrier properties of the samples towards oxygen also increased. A completely opposite effect was achieved with paraffin oil. The results of comprehensive studies provide evidence that in the case of LDPE blends, two mechanisms are responsible for changing/controlling their transport properties. The first mechanism is associated with changes in the molecular packing in the interlamellar amorphous regions, while the second is related to the crystallinity of the samples. In cases where there are no changes in crystallinity, the density of the amorphous phase becomes the decisive factor in barrier properties, as clearly shown by results assessing chain dynamics.
这项工作聚焦于确定对低密度聚乙烯（LDPE）的氧气阻隔性能至关重要的因素。结果表明，根据引入LDPE基体中的低分子量化合物（二十四烷、石蜡、石蜡油）的类型和数量，其可能有助于改善或恶化阻隔性能。与纯聚乙烯相比，掺入LDPE基体中的二十四烷和石蜡使氧气渗透参数降低。随着它们含量的增加，样品对氧气的阻隔性能也增强。而石蜡油则产生了完全相反的效果。综合研究结果表明，对于LDPE共混物，有两种机制负责改变/控制其传输性能。第一种机制与层间无定形区域中分子堆积的变化有关，而第二种机制与样品的结晶度有关。在结晶度没有变化的情况下，无定形相的密度成为阻隔性能的决定性因素，评估链动力学的结果清楚地表明了这一点。
