Study On Modification Of Chloroprene Rubber

Chloroprene rubber is a kind of universal and special rubber, occupying an important position in synthetic rubber. It not only has the general rubber properities, but also has other unique performance, such as oil resistance, weather resistance, chemicals resistance, etc. However, the unique and neat molecular chain structure connecting with polarity of chlorine atom in chloroprene rubber which make chlorine atom and double bond unactive and dhloroprene rubber vulcanization difficultly. So, the toxic and carcinogenic accelerator which affects the health of operator seriously is used in vulcanization of chloroprene rubber at present.In this paper, the experimental studies about brominated modification and filling modification of chloroprene rubber were carried out to solve the above problem. On the one hand, bromination of chloroprene rubber was adopt to introduce C-Br with lower bond energy in the structure. Because of the changing molecular chain stucture of rubber, the vulcanization activity and vulacanization rate of chloroprene rubber were improved. On the other hand, the study of rare earth modified chloroprene rubber.was put forward. Rare earth oxides was mixed with chloroprene rubber to improve the properties, especially vulcanization property, mechanical property and so on.Brominated chloroprene rubber and rare earth/chloroprene rubber composites were prepared by above methods, and the following aspects were investigated:①Brominatied chloroprene rubber was prepared by using HBr/H2O2 as brominating reagent,the chloroform as solvent. it was characterized by a series of characterization. Bromine content of brominated chloroprene rubber was determinated by using ion chromatograph. Structure of chloroprene rubber before and after brominated reaction were characterized by UV, IR, NMR. It was derived that the brominated reaction of chloroprene rubber was mainly a substitution reaction. Glass transition temperature(Tg), mooney viscosity, vulcanization rate and the mechanical properties of chloroprene rubber were characterized at the same time. The detection results showed that the glass transition temperature of brominated chloroprene rubber decreased. The mooney viscosity of brominated chloroprene rubber decreased, the vulcanization performance improved, curing time of brominated chloroprene rubber was significantly shorter. However, the mechanical properties of brominated chloroprene rubber declined.②Surface modification process of cerium oxide(Ce O2) by stearic acid was investigated, and modified Ce O2/CR composites was prepared. The structure of modified Ce O2 was characterized by SEM, XRD, IR. After modification, the reunion phenomenon of cerium oxide was improved, and the crystal structure of modified Ce O2 was not changed by modification process. IR characterization results showed that a cerium salt of stearic acid was generated on the surface of cerium oxide. A series of experiments were did to determine the optimal adding amount of modified cerium oxide. When adding 1.0% modified cerium oxide, the mechanical properties and aging properties of modified Ce O2/CR composites achieved optimal. The vulcanization properties, mechanical properties, aging properties and thermal stability of modified Ce O2/CR composites were detected. After adding modified Ce O2, curing time of chloroprene rubber was shorter, mechanical properties was greatly improved, aging resistance was improved.