生物质硅炭增强改性氢化丁腈橡胶的性能及老化规律

以生物质硅炭(Si/CB)取代部分N550炭黑为补强剂、HNBR为基体制备了生物质硅炭改性的HNBR复合材料。研究了硅炭对HNBR的补强行为,高温真空介质中橡胶的热老化行为及主链老化结构的演变。与传统炭黑的增强效果相比,生物质硅炭增强的HNBR表现出更好的韧性、撕裂强度、较低的永久变形及高温力学性能。160℃下老化20 d,材料的拉伸强度保持率大于100%,生物质硅炭表现出较好的耐老化能力。链接-CN官能团的α-碳原子高温下易均裂氢原子生成自由基,连续加氢还原使-C■N转化为-C■NH,直至形成化学交联结构,导致橡胶的玻璃化转变温度升高。氢化丁腈的CN含量越低,耐老化能力越突出。依据分子主链老化的结构演变信息,提出了HNBR的可能老化机理。

Properties and ageing law of hydrogenated nitrile rubber reinforced with biomass silica

Novel HNBR Rubber composites were fabricated employing biomass silicon carbon(SiCB),carbon black N550 and unsaturated carboxylate as reinforcing agents, hydrogenated nitrile butadiene rubber with high saturation as the matrix.The reinforcement effect of SiCB on HNBR composites, the ageing behavior of rubber composites and the structure evolution for the macromolecule chain were investigated.Compared with HNBR composites reinforced by carbon black N550,the HNBR/SiCB composites showed the super flexibility, tear strength, permanent set and high-temperature mechanical properties.After aging in dilute oxygen medium for 20 days at 160 ℃,the fabricated HNBR composites showed the super anti-ageing ability with tensile strength retention above 100%.The α-H atoms connected to C atom adjacent to CN groups were easy to generate free radicals by hemolysis at high temperature, and the - C■N groups were continuous hydrogenation reduced into - C■NH till the formation of chemical crosslinking structure, which resulted in an increase of glass transition temperature for rubber.The less content of - CN group, the stronger anti-ageing ability for rubber composites was observed.According to the structure information evolution from FTIR,the possible ageing mechanism for HNBR at elevated temperature was given.