Dziemidkiewicz Anna, Maciejewska Magdalena
Institute of Polymer and Dye Technology, Lodz University of Technology, Stefanowskiego Street 12/16, 90-924 Lodz, Poland.
Materials (Basel). 2021 Feb 8;14(4):807. doi: 10.3390/ma14040807.
The commonly used curing system for chloroprene rubber (CR) is a combination of two metal oxides, such as magnesium oxide (MgO) and zinc oxide (ZnO). Application of MgO and ZnO enables to obtain a good balance between processability of rubber compounds and mechanical properties of the vulcanizates. Despite high activity in crosslinking reactions, ZnO is classified as ecotoxic to aquatic organisms, thus environmental legislation requires its quantity in technology to be limited. In our studies more environmentally friendly curing systems were applied, which enabled eliminating ZnO from CR compounds. These curing systems consisted of manganese acetylacetonate (Mn(acac)) or nickel acetylacetonate (Ni(acac)) and triethanolamine (TEOA) used as a base necessary to perform Heck's reaction. Both metal acetylacetonates exhibited high activity in crosslinking reactions, which was confirmed by a great torque increment during rheometric measurements and high degree of elastomer crosslinking. The type of metal acetylacetonate and the amount of TEOA seemed to have less influence on the efficiency of the curing system than the filler used. Rubber compounds filled with carbon black (CB) were characterized by definitely shorter optimal vulcanization times and higher degree of crosslinking compared to CR composites filled with nanosized SiO. Moreover, application of the proposed curing systems allowed to obtain CR vulcanizates with mechanical properties comparable with the benchmarks cured with metal oxides.
氯丁橡胶（CR）常用的硫化体系是两种金属氧化物的组合，如氧化镁（MgO）和氧化锌（ZnO）。氧化镁和氧化锌的应用能够在橡胶混合物的加工性能和硫化胶的机械性能之间取得良好的平衡。尽管氧化锌在交联反应中活性很高，但它被归类为对水生生物具有生态毒性，因此环境法规要求在技术中限制其用量。在我们的研究中，应用了更环保的硫化体系，从而能够从CR化合物中消除氧化锌。这些硫化体系由乙酰丙酮锰（Mn(acac)）或乙酰丙酮镍（Ni(acac)）和用作进行赫克反应所需碱的三乙醇胺（TEOA）组成。两种金属乙酰丙酮化物在交联反应中均表现出高活性，这在流变测量过程中的大幅扭矩增加和高程度的弹性体交联中得到了证实。与使用的填料相比，金属乙酰丙酮化物的类型和三乙醇胺的用量对硫化体系效率的影响似乎较小。与填充纳米二氧化硅的CR复合材料相比，填充炭黑（CB）的橡胶混合物的特点是最佳硫化时间明显更短，交联程度更高。此外，应用所提出的硫化体系能够获得机械性能与用金属氧化物硫化的基准材料相当的CR硫化胶。
