硫化剂DCP用量对NBR/EVM并用胶交联密度及力学性能的影响

Effect of Curing Agent DCP Dosage on the Crosslinking Density and Physical-Mechanical Properties of NBR/EVM Blends

研究了硫化剂DCP(过氧化二异丙苯)用量对丁腈橡胶(NBR)/乙烯-醋酸乙烯酯橡胶(EVM)共混胶的硫化特性、两相交联密度、物理力学性能以及热空气老化性能的影响。结果表明,随着硫化剂DCP用量的增大,NBR/EVM共混胶的硫化速度和交联密度逐渐增大。与老化前相比,经热空气老化后硫化胶的交联密度增大,经125℃热空气老化后硫化胶的交联密度增大速率逐渐变大,且在DCP用量为1.5份时老化后的硫化胶交联密度增大一倍多。随着硫化剂DCP用量的增大,NBR/EVM硫化胶中NBR相的交联密度逐渐增大、EVM相的交联密度微降,在DCP用量为1.5份时两相交联密度相差最大。与老化前相比,经过热空气老化后硫化胶中NBR相的交联密度明显增大,EVM相的交联密度则变化不大。随着硫化剂DCP用量的增大,NBR/EVM硫化胶的拉伸强度基本保持不变,硬度和100%定伸应力均逐渐增大,拉断伸长率和压缩永久变形均逐渐减小。与老化前相比,经70℃、100℃热空气老化后硫化胶的硬度、拉伸强度、100%定伸应力均增大,而拉断伸长率基本保持不变。经125℃热空气老化后硫化胶的100%定伸应力明显变大,拉伸强度和拉断伸长率均明显减小。

The effects of curing agent Dicumyl Peroxid（DCP） usage on vulcanization properties,two-phase crosslinking density,physic-mechanical properties and hot air aging properties of Acrylonitrile Butadiene Rubber（NBR）/Ethylene-Vinyl Acetate Rubbers（EVM） blends were investigated. The results showed that,with the increasing of curing agent DCP usage,the curing ratio and crosslinking density of NBR/EVM blend increased gradually, crosslinking density of vulcanizate were higher after aging,the growth rate of crosslinking density increased gradually after 125 ℃ hot air aging and the crosslinking density of vulcanizate were more than twice as high as unaging with 1.5 phr DCR With the increase of curing agent DCP, the crosslinking density of N BR phase increased gradually and EVM phase decreased slightly,the difference of the two phase crosslinking density was largest with 1.5 phr DCP. After hot air aging,the crosslinking density of NBR phase increased significantly and EVM phase changed a little. With the increase of curing agent DCP, tensile strength of NBR/EVM vulcanizate basically remained,hardness and modulus at 100% increased gradually, elongation at break and compression set decreased gradually. After 70 ℃ and 100 ℃ hot air aging,the hardness, tensile strength and modulus at 100% were higher than unaging,elongation at break basically remained. After 125 ℃ hot air aging,modulus at 100% increased significantly, tensile strength and elongation at break decreased significantly.