Maciejewska Magdalena, Sowińska Anna
Institute of Polymer and Dye Technology, Lodz University of Technology, Stefanowskiego Street 12/16, 90-924 Lodz, Poland.
Polymers (Basel). 2021 May 19;13(10):1656. doi: 10.3390/polym13101656.
This work concerns the effect of fillers and ionic liquids on the cure characteristics of natural rubber (NR) compounds, as well as the mechanical and thermal properties of the vulcanizates. Three types of white filler were applied, such as cellulose, nanosized silica and hydrotalcite, to modify the performance of NR composites. Additionally, ionic liquids (ILs) with bromide anion and different cations, i.e., 1-butyl-3-methylimidazolium (Bmi) and 1-butyl-3-methylpyrrolidinium (Bmpyr), were used to improve the cure characteristics of NR compounds and functional properties of the vulcanizates. The type of filler and the structure of ILs were proved to affect the rheometric properties and cure characteristics of NR compounds as well as the performance of the NR vulcanizates. Owing to the adsorption of curatives onto the surface, silica reduced the activity of the crosslinking system, prolonging the optimal vulcanization time of NR compounds and reducing the crosslinking degree of the elastomer. However, silica-filled NR exhibited the highest thermal stability. Hydrotalcite increased the crosslink density and, consequently, the mechanical properties of the vulcanizates, but deteriorated their thermal stability. ILs beneficially influenced the cure characteristics of NR compounds, as well as the crosslink density and mechanical performance of the vulcanizates, particularly those filled with silica. Cellulose did not significantly affect the vulcanization of NR compounds and crosslink density of the vulcanizates compared to the unfilled elastomer, but deteriorated their tensile strength. On the other hand, cellulose improved the thermal stability and did not considerably alter the damping properties of the vulcanizates.
本研究关注填料和离子液体对天然橡胶（NR）胶料硫化特性的影响，以及硫化胶的力学性能和热性能。使用了三种白色填料，如纤维素、纳米二氧化硅和水滑石，以改善NR复合材料的性能。此外，使用了带有溴离子和不同阳离子（即1-丁基-3-甲基咪唑鎓（Bmi）和1-丁基-3-甲基吡咯烷鎓（Bmpyr））的离子液体（ILs）来改善NR胶料的硫化特性和硫化胶的功能性能。结果证明，填料类型和离子液体结构会影响NR胶料的流变性能和硫化特性，以及NR硫化胶的性能。由于硫化剂吸附在二氧化硅表面，二氧化硅降低了交联体系的活性，延长了NR胶料的最佳硫化时间，并降低了弹性体的交联度。然而，二氧化硅填充的NR表现出最高的热稳定性。水滑石提高了交联密度，从而提高了硫化胶的力学性能，但降低了它们的热稳定性。离子液体对NR胶料的硫化特性以及硫化胶的交联密度和力学性能有有益影响，特别是对填充二氧化硅的硫化胶。与未填充的弹性体相比，纤维素对NR胶料的硫化和硫化胶的交联密度没有显著影响，但降低了它们的拉伸强度。另一方面，纤维素提高了热稳定性，并且没有显著改变硫化胶的阻尼性能。
