Study On The Effect Of Lanthanum Histidine On The Vulcanization Properties Of Natural Rubber

In this thesis,lanthanum histidine was synthesized by double decomposition method,and the molecular formula of the product was determined by a series of characterization methods: LaCl3(His)3·1.5H2 O.Then the synthetic product was added to natural rubber for rubber compounding to study the effect of lanthanum histidine on the vulcanization performance of natural rubber.The results show that: under the three vulcanization systems,lanthanum histidine can increase the cross-linking density and The degree of vulcanization crosslinking and reduces the fluidity of the vulcanizate.Compared with the blank compound,the compound T10 after the addition of lanthanum histidine is larger than the blank compound,and the positive curing time T90 is slightly shorter than the blank compound,which shows that the histidine lanthanum plays a good role in preventing coke The effect of burning guarantees the safety of scorch and the effect of lanthanum histidine can shorten the curing time.In addition,the slope of the curve of the rubber during the thermal vulcanization stage with lanthanum histidine is greater than the slope of the blank rubber under the corresponding system and the vulcanization index CRI is also greater than the CRI of the blank rubber under the corresponding system,indicating that lanthanum histidine can improve the natural The vulcanization rate of rubber.Subsequently,on the basis of the original formula,the accelerators M,DM,zinc oxide and stearic acid were replaced with synthetic lanthanum histidine in proportion to study its vulcanization performance.The results show that: under the three vulcanization systems,the vulcanization curve of histidine lanthanum substitutes accelerator M has increased significantly,MH and MH-ML have increased to varying degrees,but the vulcanization rate has decreased.Under the three vulcanization systems,the effect of replacing DM is not ideal.Under the three vulcanization systems,lanthanum histidine could not completely replace zinc oxide and stearic acid,but the vulcanization characteristics shown at a certain substitution ratio were superior to the blank compound,that is,it could only be partially replaced.All three vulcanization systems are equivalent to zinc oxide: stearic acid: histidine lanthanum is 3:3.75:0.5.The overall vulcanization characteristics are better.Finally,under the three vulcanization systems,the accelerators M and DM were doped with the synthesized lanthanum histidine to study its vulcanization performance.It was found that the combination of lanthanum histidine with accelerators M and DM can greatly increase the maximum torque(MH)and MH-ML of the vulcanized rubber.Under the conventional vulcanization system,the ratio of accelerator M,DM and histidine lanthanum is 0:1.6:1,under the effective vulcanization system,the ratio of the three is 0.3:3.2:0.5,under the semi-effective vulcanization system,When the ratio of the three is 0.11:1.2:1,the vulcanized rubber has the best vulcanization characteristics.At this time,the maximum torque(MH)and MH-ML of the vulcanized rubber are the largest.