聚丁二烯胶乳的辐射硫化

Vulcanization of polybutadiene latex induced by ^(60)Coγ-rays irradiation

用^(60)Co辐射硫化聚丁二烯胶乳(Polybutadiene latex,PBL)制备全硫化粉末橡胶(Fully vulcanized polybu- tadiene rubber particles,FVBR),并研究胶乳的交联行为。用动态激光光散射仪和原子力显微镜(Atomic force microscopy,AFM)观测粒径尺寸、粒径分布与形貌,并用力学和动态力学(Dynamic mechanical analysis,DMA)测试仪分析了交联对宏观力学及其动态力学性能的影响。结果表明,辐射交联使胶乳粒子体积收缩,并随吸收剂量增加胶膜的体积溶胀倍率(Q_v)和交联点间平均分子量(M_c)减小;而交联密度(V_e)和凝胶含量增大。随着交联密度的增加,抗张强度和断裂伸长率降低,杨氏模量(E)和硬度(Shore A)则增大;其弹性模量(E′)增加,而动态损耗峰(Tanδ)变窄。PBL辐射交联行为在吸收剂量低于200kGy范围内符合Charlesby-Pinner关系式,为无规交联。

Fully vulcanized polybutadiene rubber particles （FVBR） were prepared by polybutadiene latex （PBL） vulcanization induced by 60^Co γ-rays irradiation, and the effect of absorbed dose on crosslinking behavior was studied. Mean diameter, diameter distribution and morphology of the particles in the PBL irradiated at different doses as well as in the FVBR were characterized by laser particle analyzer and AFM. The crosslinking effect on the mechanical properties of the films, by casting from PBL at different doses correspondingly, was evaluated by mechanical and dynamic mechanical analysis （DMA） respectively. The results showed that the diameter and swelling property decreased with absorbed dose, while crosslink density and gel fraction increased. Moreover, the decrease of the tensile strength and elongation at break, the increase of the hardness in shore A and young＇s modulus （E）, and the increase of storage modulus （E＇） and narrowing of loss tangent peak （Tan δ） were all accounted for the increment of crosslinking. The Charlesby-Pinner equation fits well with the PBL vulcanization in the range of absorbed doses from 0 to 200kGy.