The Synthesis And Property Of Novel Polyurethane Elastomers

Recently, in order to enlarge polyurethane's application fields, improving the thermal performances of polyurethane has been became one of the key point in the field. In this dissertation, it consists of three main parts about synthesis as follows: the choice of soft main chain, synthesis of organic montmorillonite nanocomposite and reinforcement of adjacent cross-linked network.The effect of the soft segment based on liquid hydroxyl terminated polybutadine-acrylonitrile copolymer glycol(HTBN) on the performance of PU were discussed, then polytetramethylene ether glycols(PTHF), poly-ε-caprolactone polyol, polycarbonatediols were separately blended with HTBN to synthesize polyurethane elastomers and the mechanical and thermal properties were studied. The effect of crosslinking agent was discussed. The results showed that the polyurethane based on HTBN possessed excellent thermal properties,the first thermal decomposition temperature was among 450℃-460℃; The HTBN and PTHF were blended by the weight ratio of 8/2 and prepared the polyurethane elastomers,which tensile strength was 25MPa and possessed good thermal property. The TMP cross-linked agent was introduced into the polyurethane and cross-linked network structure was obtained, the mechanical and thermal properties were improved;The double bond of HTBN reacted with B25 and the degree of cross-link was reinforced ,the properties were enhanced.The OMMT nanocomposite were used to prepare polyurethane nanocomposites. The thermal property of polyurethane nanocomposites were studied in details by DSC and TGA. It showed that the tensile strength of polyurethane which was prepared by the blends of OMMT and different polyols systems was enhance about 3~4MPa. The Tg of PU/OMMT nanocomposites increased with increasing the OMMT, and the thermal stability was improved.The free-radical polymerization between unsaturated bond in the bismaleimide (e.g. HVA-2) and unsaturated bond in the soft segment (NBR) was studied and prepared the adjacent crosslinked network polyurethane elastomers. The mechanical and thermal stability properties with degree of adjacent crosslinked network was investigated. It was found that the first thermal decomposition temperature was improved with the increasing of HVA-2,which was 290.4℃higher than 279℃before, and the mechanical property was improved.