Abstract

A study is performed of mixtures of ultra-high-molecular-weight high-density polyethylene (UHMWHDPE; T_m = 141°C; enthalpy of fusion, 180 J g⁻¹) with 90 wt % low molecular weight component (copper complex of phthalocyanine, anthracene, succinic acid, and spiropyran) in the presence of acid–base indicators (anthraquinone, phenolphthalein, phenol red, bromocresol purple, Congo red, methyl orange, and thymol blue), organic acids (succinic, fumaric, and aspartic), melamine, and cyanuric acid. The mixtures are subjected to plastic deformation at 1 GPa on an anvil-type high pressure apparatus and are analyzed with a DSC. Enthalpies of melting are determined for the polymer in the deformed mixtures (from 135 to 763 J g⁻¹). It is found that the enthalpy of fusion of UHMWHDPE in mixtures with organic acids grows along with the strength of the acid. The enthalpy of melting of the polymer is no more than 210 J g⁻¹ in mixtures with alkaline indicators, and is 664–763 J g⁻¹ in mixtures with acids. Endothermic peaks of small crystallite melting and the exothermic peaks of cold crystallization are observed on the thermograms of the deformed mixtures at temperatures T_m below those of the polymer. It is shown that the enthalpies of crystallization of the polymer in the deformed mixtures from melts are almost identical to those of the initial UHMWHDPE.

中文翻译：

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高密度聚乙烯混合有机酸和酸碱指示剂在高压下发生塑性变形后的熔融结晶

摘要

对超高分子量高密度聚乙烯（UHMWHDPE；T _m = 141°C；熔化焓，180 J g ^-1）与 90 wt% 低分子量组分（铜络合物）的混合物进行了研究。酞菁、蒽、琥珀酸和螺吡喃），存在酸碱指示剂（蒽醌、酚酞、酚红、溴甲酚紫、刚果红、甲基橙和百里酚蓝）、有机酸（琥珀酸、富马酸和天冬氨酸） 、三聚氰胺和氰尿酸。混合物在砧型高压设备上在 1 GPa 下进行塑性变形，并用 DSC 进行分析。确定变形混合物中聚合物的熔化焓（从 135 到 763 J g ^-1）。发现 UHMWHDPE 在与有机酸的混合物中的熔化焓随着酸的强度而增加。聚合物的熔融焓在与碱性指示剂的混合物中不超过 210 J g ^-1，在与酸的混合物中为 664-763 J g ^-1。在低于聚合物温度的温度T _m下，在变形混合物的热分析图上观察到小微晶熔化的吸热峰和冷结晶的放热峰。结果表明，聚合物在变形混合物中的结晶焓几乎与初始 UHMWHDPE 的结晶焓相同。