The Process Of Chloroprene Rubber Regulated With Dodecyl Mercaptan

Chloroprene rubber is a polar polymer materials, which mainly used in the manufacture of industrial rubber products, such as wire and cable sheathing, oil hose, offset, conveyor belts, conveyor belts and a variety of tape and footwear binder. Chloroprene rubber, more varieties of grades, which according to the different molecular weight regulator used can be divided into sulfur adjustment, non-sulfur adjustment and mixed adjustment neoprene. At present, the non-sulfur regulatory chloroprene rubber is the major varieties, they use the mercapten or XD as the adjustment. The foreign non-sulfur regulatory chloroprene rubber often use mercapten, compared with the XD adjustment Chloroprene rubber,the mercapten regulate product has good storage stability and good resistance to aging, resistance to compression deformation excellent. Therefore to increase research and development efforts on the mercapten-modulating Chloroprene rubber, and to carry out the mercapten regulate chloroprene rubber in its own technology research and development work is far-reaching.In this paper, we use dodecyl mercaptan as the molecular weight regulator, disproportionated rosin as emulsifier, sodium dodecyl sulfate as cosurfactants, the high-temperature polymerization using potassium persulfate as initiator, the low-temperature polymerization of potassium persulfate, formamidine sulfinic acid sodium salt as the redox initiator system. The high-temperature polymerization to control the polymerization temperature at40±2°C, and the low-temperature polymerization to control he polymerization temperature at10±2°C,by free radical emulsion polymerization method can get mercapten regulated Chloroprene rubber.We take repeatability test on the aggregate stability of the mercapten regulated Chloroprene rubber, and test the polymerization products of the Mooney viscosity, scorch time, tensile strength, elongation at break, permanent deformation and elongationstresses. We get he polymerization kinetics curves by the analysis of polymerization process by the dry matter. The Polymerization and the polymerization product of physical performance were investigated by the join method and its dosage. The stability of the emulsion were studied by static and dynamic analysis. By the aging experiments, the anti-aging properties of chloroprene rubber was investigated.The microstructure structure of chloroprene rubber was characterized by infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR), and the polymer’s glass transition temperature (Tg), molecular weight and its distribution were tested by the differential scanning calorimeter (DSC), gel permeation chromatography (GPC).The results show that:the mercapten regulated Chloroprene rubber can be get when mercaptan as the molecular weight regulator. The polymerization product has a stable Mooney viscosity, scorch time, tensile strength, elongation at break, permanent deformation, modulus and other physical properties. The mercaptan join method affect the polymerization, ultimately, the best time was fixed. With the increase of the amount of mercaptan,the Mooney viscosity and several average molecular weight were decreased, but had no significant effect on the burning time. The static and dynamic analysis showed that the emulsion has good stability. The mercapan regulated chloroprene rubber has superior anti-aging properties. The mercaptan-regulated CR was mainly trans-1,4-structure and head-tail structure and the trans-1,4-structure content is slightly higher than the regulater D-regulated CR.