自然凝固和乙酸凝固的天然橡胶动态性能的比较

Effect of Two Coagulation Processes on the Dynamic Properties of Natural Rubber Analyzed by RPA and DMA

用橡胶加工分析仪(RPA)和动态力学热分析仪(DMA)对同一批新鲜天然胶乳的乙酸凝固和自然凝固工艺制备的天然橡胶(NR)生胶、混炼胶及硫化胶的弹性模量(G,)、弹性扭矩(S,)、损耗因子(tanδ)、储能模量(E,)、玻璃化转变温度(Tg)及损耗模量(E")进行研究。结果表明:自然凝固的生胶、混炼胶及硫化胶的G,及S,比乙酸凝固的生胶、混炼胶及硫化胶的高,tanδ较乙酸凝固的生胶、混炼胶及硫化胶的小;在低温时,自然凝固NR硫化胶的E,比乙酸凝固NR硫化胶的低,Tg及E"较乙酸凝固NR硫化胶的高,但当温度大于-80℃时,自然凝固的硫化胶的E,则稍高。

The dynamic mechanical properties of raw rubbers, compounds and vulcanizates of natural rubbers obtained from biological and acetic acid coagulations of the same batch of field latex were analyzed by Rubber Processing Analyzer（RPA） and Dynamic Mechanical Analyzer（DMA）, respectively. The results indicated that the biologically coagulated raw natural rubber and its compound and vulcanizate had higher elastic moduli（G＇） and elastic torques （S＇）, but lower loss factors （tand）, as compared to those from acetic acid coagulation when analyzed using RPA at 100 ℃. When the dynamical mechanical properties of vulcanizates were analyzed using DMA at a range of -120 ℃-25 ℃, the storage modulus （E＇） of the vulcanizates from the biological coagulation was lower than that from the acetic acid coagulation, whereas the glass transition temperature （Tg） was higher than that from the acetic acid coagulation.