环氧树脂对天然橡胶硫化进程和力学性能的影响

Effects of Epoxy on Vulcanization and Properties of Natural Rubber

将液态环氧树脂(EP)在密炼阶段混合到天然橡胶(NR),制备了NR/EP复合材料。对NR加入EP进行DSC测试热分析表明,天然橡胶助剂中硬脂酸可促进环氧树脂固化;橡胶加工分析和交联度测试发现,较多环氧树脂可减缓天然橡胶的硫化反应并减小交联度,降低最大混炼扭矩和平衡扭矩,减弱甚至抑制其返原;升高混炼温度可加速NR硫化进程但降低其交联度,抑制NR返原的最小EP含量增大。NR硫化剂被EP吸收固化包裹则降低了NR交联度;EP和NR黏度差异大,EP固化后容易造成NR内结构分布不均匀;这两方面降低了复合材料的拉伸强度和撕裂强度。

NR/EP composites were prepared by mixing liquid epoxy resin {EP） with natural rubber （NR） during mixing stage. DSC testing of EP added with rubber additives shows that stearic acid promotes the curing of epoxy resin. Analyses of rubber processing and crosslinking degree tbund that more epoxy reduce the curing reaction of natural rubber and its crosslinking degree corresponding to the maximuna ）nixing torque and the balance torque, weakening or even inhibiting the rubber reversion. Curing process of NR was accelerated when increased mixing temperature while decreasing the crosslinking degree, where the critical minimum EP content capable of inhibiting NR reversion. Curing agent is absorbed by EP hereafter being curing packaged resulting in the reduced crosslinking degree of NR. The great viscosity difference between EP and NR easily leads to uneven distribution of NR structure. These two aspects reduce the tensile strength and tear strength of composites.