Study On Natural Rubber Latex Coagulated By Aluminum Salt

Natural rubber is a kind of important strategic material, is also a kind of renewable material. Because of its excellent comprehensive properties, it has been widely used in many trades. The process of natural rubber is complex, the solidification is an important part in the quality of natural rubber. At present, our country is still widely used method of acid coagulated latex. Although there are many disadvantages, new coagulated method can completely substitute of acid coagulated has not yet found, and could not give up. Therefore, it still has an important meaning to carry out the study on natural rubber latex solidificated.This paper mainly introduced that natural rubber latex coagulated by aluminum salt. It studied on the related process, physico&chemical properties, the rubber vulcanization characteristics, mechanical properties and dynamic performance.First of all, it appled that skim serum coagulated by aluminum sulfate or aluminum chloride. The results showed that:the same volume of skim serum, the content of aluminium trichloride used less than aluminum sulfate. It established the mathematical model on the content of the skim serum and aluminium trichloride. Compared with the sulfuric acid or natural solidification on skim serum, skim rubber solidificated by aluminium trichloride is more excellent in mechanical performance.Secondly, it applied that aluminum salt in the different types of anionic coagulated fresh latex. The results showed that the least dosage of solidificating fresh latex is aluminium trichloride, and the concentration relatively of coagulating fresh latex is suitable for0.2mol/L. Because of the ash content, the PRI of physical&chemical properties do not meet the relevant national standards, yet there is not testing the properties of vulcanized rubber.Again, it used that polyaluminium chloride coagulated fresh latex. Through orthogonal designing test of three factors and three levels. The results showed that the optimum synthesis conditions of polyaluminum chloride was alkalization degree B=0.3, temperature T=95℃, time t=5h, polymerization aluminum chloride was synthesized through the conditions and its amount of coagulated fresh latex was least. Because of the ash content, the PRI of physical&chemical properties do not meet the relevant national standards, yet there is testing the property of vulcanized rubber.Finally, it used that mixture of aluminum chloride and hydrochloric acid to coagulant fresh latex. The results showed that the consumption of mixed aluminum salt solution in solidificating fresh latex through adding9mL36%HC1solution to200mL5%AlCl3solution is minimum. And to further reduce the dosage, the physico&chemical properties of natural rubber is better through increasing the park time. Although the curing time becomes longer on aluminum salt coagulated rubber, the processing safety of natural rubber is better. At the same time, it obtained vulcanized formulations&technology of mixed aluminum salt coagulated rubber by orthogonal experiment design. The mechanical property of vulcanizated rubber on the mixed aluminum salt coagulated is better than hydrochloric acid coagulation.Rubber processing analyzer results showed that the dynamic mechanical properties of rubber by aluminum chloride, hydrochloric acid and mixed them, no matter strain scanning, frequency scanning and temperature scanning of the raw rubber or mixed rubber, the change trend of the three is basically same, yet the measured value is slightly different.DMA results showed that the Tan δ and E "of the aluminum coagulated rubber is slightly higher, while E’is slightly lower.IR results showed that the characteristic absorption peak of the protein is weaker on rubber coagulated by aluminum salt.DSC results showed that the different of glass transition temperature is much small about aluminum salt solidification and hydrochloric acid coagulation.