Lee Sung-Hun, Park Gun-Woo, Kim Hee-Jun, Chung Kyungho, Jang Keon-Soo
Department of Polymer Engineering, School of Chemical and Materials Engineering, The University of Suwon, Hwaseong 18323, Gyeonggi-do, Korea.
Polymers (Basel). 2022 Aug 26;14(17):3502. doi: 10.3390/polym14173502.
Natural rubber (NR) presents a number of advantages over other types of rubber but has poor resistance to chemicals and aging. The incorporation of ethylene propylene diene monomer (EPDM) into the NR matrix may be able to address this issue. Mineral fillers, such as carbon black (CB) and silica are routinely incorporated into various elastomers owing to their low cost, enhanced processability, good functionality, and high resistance to chemicals and aging. Other fillers have been examined as potential alternatives to CB and silica. In this study, phlogopite was surface-modified using 10 phr of compatibilizers, such as aminopropyltriethoxysilane (A1S), aminoethylaminopropyltrimethoxysilane (A2S), or 3-glycidoxypropyltrimethoxysilane (ES), and mixed with NR/EPDM blends. The effects of untreated and surface-treated phlogopite on the mechanical properties of the rubber blend were then compared with those of common fillers (CB and silica) for rubbers. The incorporation of surface-modified phlogopite into NR/EPDM considerably enhanced various properties. The functionalization of the phlogopite surface using silane-based matters (amino- and epoxide-functionalized) led to excellent compatibility between the rubber matrix and phlogopite, thereby improving diverse properties of the elastomeric composites, with effects analogous to those of CB. The tensile strength and elongation at break of the phlogopite-embedded NR/EPDM composite were lower than those of the CB-incorporated NR/EPDM composite by 30% and 10%, respectively. Among the prepared samples, the ES-functionalized phlogopite showed the best compatibility with the rubber matrix, exhibiting a tensile strength and modulus of composites that were 35% and 18% higher, respectively, compared with those of the untreated phlogopite-incorporated NR/EPDM composite. The ES-functionalized phlogopite/NR/EPDM showed similar strength and higher modulus (by 18%) to the CB/NR/EPDM rubber composite, despite slightly lower elongation at break and toughness. The results of rebound resilience and compression set tests indicated that the elasticity of the surface-modified phlogopite/NR/EPDM rubber composite was higher than that of the silica- and CB-reinforced composites. These improvements could be attributed to enhancements in the physical and chemical interactions among the rubber matrix, stearic acid, and functionalized (compatibilized) phlogopite. Therefore, the functionalized phlogopite can be utilized in a wide range of applications for rubber compounding.
天然橡胶（NR）相较于其他类型的橡胶具有许多优势，但耐化学性和抗老化性能较差。将三元乙丙橡胶（EPDM）加入NR基体中或许能够解决这一问题。矿物填料，如炭黑（CB）和白炭黑，由于成本低、加工性能增强、功能良好以及耐化学性和抗老化性高，常被加入到各种弹性体中。其他填料也已作为CB和白炭黑的潜在替代品进行了研究。在本研究中，使用10份增容剂，如氨丙基三乙氧基硅烷（A1S）、氨乙基氨丙基三甲氧基硅烷（A2S）或3 - 缩水甘油氧基丙基三甲氧基硅烷（ES）对金云母进行表面改性，并与NR/EPDM共混物混合。然后将未处理和表面处理的金云母对橡胶共混物力学性能的影响与橡胶常用填料（CB和白炭黑）的影响进行比较。将表面改性的金云母加入到NR/EPDM中显著提高了各种性能。使用硅烷类物质（氨基和环氧官能化）对金云母表面进行功能化处理，使得橡胶基体与金云母之间具有优异的相容性，从而改善了弹性体复合材料的各种性能，其效果与CB类似。嵌入金云母的NR/EPDM复合材料的拉伸强度和断裂伸长率分别比加入CB的NR/EPDM复合材料低30%和10%。在所制备的样品中，ES官能化的金云母与橡胶基体表现出最佳的相容性，其复合材料的拉伸强度和模量分别比未处理的加入金云母的NR/EPDM复合材料高35%和18%。ES官能化的金云母/NR/EPDM尽管断裂伸长率和韧性略低，但与CB/NR/EPDM橡胶复合材料具有相似的强度和更高的模量（高18%）。回弹性和压缩永久变形测试结果表明，表面改性的金云母/NR/EPDM橡胶复合材料的弹性高于白炭黑和CB增强的复合材料。这些改进可归因于橡胶基体、硬脂酸和功能化（增容）金云母之间物理和化学相互作用的增强。因此，功能化的金云母可广泛用于橡胶配方的各种应用中。
