Wręczycki Jakub, Bieliński Dariusz M, Anyszka Rafał
Institute of Polymer and Dye Technology, Faculty of Chemistry, Lodz University of Technology, 90-924 Lodz, Poland.
Department of Mechanics of Solids, Surfaces & Systems (MS3), Faculty of Engineering Technology, University of Twente, 7500 AE, Enschede, The Netherlands.
Polymers (Basel). 2018 Aug 5;10(8):870. doi: 10.3390/polym10080870.
It is widely acknowledged that waste sulfur generated from the petroleum industry creates huge storage and ecological problems. Therefore, the various methods of utilization are becoming increasingly attractive research topics worldwide. The thermal ability of elemental sulfur to homolytic cleavage of S₈ rings enables its free radical copolymerization with unsaturated organic species and the obtaining of chemically stable polymeric materials. Here we report a novel possibility to use sulfur/organic copolymers obtained via "inverse vulcanization" as curatives for rubber. For this purpose, several various sulfur/organic copolymers were synthesized and analyzed from the point of view of their performance as rubber crosslinking agents. Solvent extraction was used to purify sulfur/organic copolymers from unreacted (elemental) sulfur. Thermal properties of the prepared copolymers were characterized by thermogravimetric analysis and differential scanning calorimetry (TGA⁻DSC). Crosslink density and structure of cured elastomers was studied by equilibrium swelling, thiol-amine analysis and freezing point depression. Mechanical properties of the vulcanizates were determined under static and dynamic conditions (DMA-dynamic mechanical analysis). It is proved that the utilization of sulfur/organic copolymers as curatives enables an effective crosslinking process of rubbers. Taking into account the results of a crosslink density analysis and mechanical properties of the vulcanizates cured with purified copolymers, it is evident that relatively long copolymer macromolecules are also involved in the formation of chemical bonds between unsaturated rubber macromolecules.
人们普遍认为，石油工业产生的废硫会造成巨大的储存和生态问题。因此，各种利用方法正成为全球越来越有吸引力的研究课题。元素硫对S₈环的均裂裂解的热能力使其能够与不饱和有机物种进行自由基共聚，并获得化学稳定的聚合物材料。在此，我们报告了一种新的可能性，即使用通过“反向硫化”获得的硫/有机共聚物作为橡胶的硫化剂。为此，合成了几种不同的硫/有机共聚物，并从它们作为橡胶交联剂的性能角度进行了分析。采用溶剂萃取法从未反应的（元素）硫中纯化硫/有机共聚物。通过热重分析和差示扫描量热法（TGA⁻DSC）对制备的共聚物的热性能进行了表征。通过平衡溶胀、硫醇-胺分析和凝固点降低研究了硫化弹性体的交联密度和结构。在静态和动态条件下（DMA-动态力学分析）测定了硫化胶的力学性能。结果表明，使用硫/有机共聚物作为硫化剂能够实现橡胶的有效交联过程。考虑到用纯化的共聚物硫化的硫化胶的交联密度分析结果和力学性能，很明显，相对较长的共聚物大分子也参与了不饱和橡胶大分子之间化学键的形成。
