混炼温度对杜仲胶/天然橡胶共混胶性能的影响

Effect of Mixing Temperature on the Properties of Eucommia Ulmoides Gum/Natural Rubber Blend

将杜仲胶(EUG)与天然橡胶(NR)按照一定的比例进行共混,研究不同的混炼温度对混炼胶及硫化胶性能的影响。通过橡胶加工分析仪(RPA)对体系中的炭黑分散性进行分析,利用差示扫描量热法(DSC)对体系中结晶进行表征,借助扫描电子显微镜(SEM)对硫化胶拉伸断面进行观察。结果表明,随着混炼温度的升高,混炼胶及硫化胶的结晶度逐渐降低,炭黑分散更加均匀,混炼胶硬度升高。当混炼温度在25~50℃范围内,随着混炼温度的降低,断裂伸长率和拉伸强度逐渐下降,100%定伸应力和300%定伸应力逐渐上升。通过DSC、SEM和RPA分析,产生这一现象与EUG与NR的结合状态改变有关。

The eucommia ulmoides gum(EUG) and natural rubber(NR) were blended according to a certain ratio. The effects of different mixing temperatures on the mechanical properties of the rubber compounds and vulcanizates were investigated by changing the mixing temperature. The carbon black dispersibility in the system was analyzed by rubber processing analyzer(RPA). The internal crystal was characterized by differential scanning calorimetry(DSC). The tensile section of vulcanizate was observed by scanning electron microscopy(SEM). The results show that the crystallinity of the rubber compounds and vulcanizates decreases with the increase of the mixing temperature;the carbon black dispersion is more uniform;the Shore A hardness of rubber compounds also increases;when the mixing temperature is in the range of 25 ℃ to 50 ℃, as the mixing temperature decreases, the elongation at break and the tensile strength gradually decrease;the 100% modulus and 300% modulus increase gradually. The results of DSC, SEM and RPA demonstrate that this phenomenon can be attributed to the change of the binding state of EUG and NR.