不同杜仲胶接枝配方对橡胶沥青储存稳定性的影响

Influence of Different Eucommia Ulmoides Gum Grafting Formulas on Rubber Asphalt Storage Stability

利用杜仲胶双键结构特性,通过桥接作用分别将橡胶粉与沥青接枝到杜仲胶上,形成沥青-杜仲胶-橡胶粉的结构形式,提升橡胶沥青储存稳定性。首先采用AIBN和BPO两种引发剂,与不同掺量的马来酸酐和杜仲胶制备多组接枝杜仲胶,通过测定接枝杜仲胶的接枝率标准曲线,分析引发剂、马来酸酐和杜仲胶含量对接枝率的影响;然后用不同接枝杜仲胶制备了橡胶沥青,采用DSR试验的剪切模量和离析试验的软化点差作为橡胶沥青储存稳定性评判指标,评价不同接枝杜仲胶改性橡胶沥青的储存稳定性;最后通过荧光显微镜观察了橡胶沥青的微观表征,从微观层面分析了不同接枝杜仲胶组对橡胶沥青储存稳定性的影响。试验结果表明橡胶沥青储存稳定性的高低与胶粉是否改性、改性效果呈正相关,采用接枝率高的杜仲胶改性胶粉效果更好,制备的橡胶沥青存储稳定性也优于未采用杜仲胶改性橡胶沥青;在引发剂类型选择方面,宏观微观试验都验证了采用AIBN作为引发剂制备的接枝杜仲胶采用BPO为引发剂制备的接枝杜仲胶对橡胶沥青体系稳定性的提升作用更为显著;在接枝物比例方面,当m(EUG)∶m(MAH)∶m(AIBN)=4∶1∶0.15时杜仲胶接枝率最高,接枝杜仲胶与橡胶粉能在沥青中稳定悬浮与有序扩散,不会在沥青中发生沉降,建议可采用该掺配比例生产橡胶沥青。

The rubber powder and asphalt were grafted to eucommia ulmoides gum by using the double-bond structural characteristics of eucommia ulmoides gum.The structure form of asphalt,eucommia ulmoides gum and rubber powder was formed.The storage stability was improved.First,two initiators,AIBN and BPO,were used with different dosages of maleic anhydride and eucommia ulmoides gum to prepare the multi-group grafted eucommia ulmoides gum.The influecne of initiators,maleic anhydride and eucommia ulmoides gum contents on the grafting rate were analyzed by measuring the standard curves of grafting rate of grafted eucommia ulmoides gum.Then,the rubber asphalt was prepared with different grafted eucommia ulmoides gums.Taking the DSR test shear modulus and the softening point difference as the rubber asphalt storage stability evaluation indicators,the storage stability of grafted eucommia ulmoides gum modified rubber asphalt was evaluated.Finally,the rubber asphalt microscopic characterization was observed by using fluorescence microscopy.The influences of different grafted eucommia ulmoides gum groups on the rubber asphalt storage stability were analyzed in the microscopic way.The result indicates that the rubber asphalt storage stability is positively correlated with whether the rubber powder is modified and the modification effect.The eucommia ulmoides gum modified rubber powder with high grafting rate has better effect;and the storage stability of prepared rubber asphalt is better than that without eucommia ulmoides gum modification.The macroscopic and microscopic tests verify that the grafted eucommi a ulmoides gum prepared with AIBN as initiator has more significant effect on the rubber asphalt system stability than that prepared with BPO.When m(EUG)∶m(MAH)∶m(AIBN)=4∶1∶0.15,the grafting rate of eucommia ulmoides gum is the highest.The grafted eucommia ulmoides gum and rubber powder can be stably suspended and diffused in asphalt;and the settlement does not occur in asphalt.It is suggested to prepare rubber asphalt with such mix proportion.