原位聚合法制备吸水膨胀天然橡胶的研究.doc

摘 要 采用过硫酸盐/硫代硫酸钠氧化还原引发体系，在天然胶乳中原位引发聚丙烯酸钠聚合并接枝到天然橡胶烃上，制备出高吸水性天然橡胶，开辟了一条制备吸水天然橡胶的新途径。考察了引发剂的用量及体系中的氧化剂和还原剂的配比，复合氧化剂间的交互作用，反应温度、时间，吸水单体的用量，交联剂用量等对WSNR的接枝率、接枝效率、吸水倍率、吸水速率等性能的影响，并考察了吸水单体用量、硫化体系、硫磺用量和补强剂对WSNR的吸水性能和物理机械性能的影响，采用红外光谱（FTIR）、差热扫描量热法（DSC）、热重分析（TG/DTG）、动态力学分析（DMA）等分析手段对天然橡胶接枝产物，吸水单体均聚物作了分析表征。 实验结果表明：引发剂剂用量、反应温度、时间、和单体用量在制备腻子型吸水膨胀天然橡胶中对天然橡胶的接枝率有显著的影响，在本实验研究范围内的最佳工艺为：反应温度为40℃，反应时间为1小时，引发剂用量为0.50%，单体用量为100%，交联剂用量为2.0×10-4mol。两种过硫酸盐（过硫酸钾—过硫酸铵）间在引发制备腻子型吸水膨胀天然橡胶的接枝反应中具有协同效应。采用多种硫化体系对腻子型吸水膨胀天然橡胶进行硫化，得到吸水膨胀天然橡胶的最佳性能为拉伸强度0.83/MPa、断裂伸长率2230.00%、撕裂应力6.35KN·m-1、首次吸水倍率13.09倍；而补强剂苯乙烯的引入能大大提高吸水膨胀天然橡胶的吸水倍率和反复吸水能力；傅立叶红外光谱分析表明该实验方法能有效地使聚聚丙烯酸钠单体接枝到天然橡胶分子链上；TG和DTG分析表明接枝改性的天然橡胶比天然橡胶的耐热性高；DSC分析表明吸水膨胀天然橡胶的水分主要以“三相态”存在；DMA测试分析表明，随着天然橡胶分子链上接枝的聚聚丙烯酸钠量的增多，橡胶的玻璃化温度随之提高，动态储能摸量也随着增大。 关键词：原位聚合 聚聚丙烯酸钠 吸水膨胀 天然橡胶 Abstract A kind of water swelling natural rubber was made with natural latex grafted sodium acrylate by in-situ polymerization. Persulfates and Sodium Thiosulfate was used as redox initiator. A new method to prepare WSR form Natural latex is found. Effect of quantity of initiator 、 ratio between persulfates、 dosage ratio between persulfates and Sodium Thiosulfate、reaction temperature、reaction time、crosslinking agent and the of AANa on grafting ratio (GR) 、grafting effection (GE)、water absorbing ratio (WAR)、water absorbing velocity etc was studied, in addition, effect of the dosage of AANa、cure systems、the dosage of sulfur and strengthening agents on water-swelling capacity and physical mechanical properties was studied. The structure and the thermo-property of water-swelling natural rubber were studied by FTIR 、TG and DTG.orage modulus of WSNR were investigated by DMA. The results show that the effect was noticeably of quantity of initiator 、 ratio between persulfates、 dosage ratio between persulfates and Sodium Thiosulfate、reaction temperature、reaction time、crosslinking agent and the of NaAA onGR、GE and WAR. And a synergistic function of initiators in initiating efficienc