Synthesis, Modifined And Property Research Of Polycaprolactone Polyurethane Elastomer

With the increasing demand of polyurethane products in domestic and international market, high prices of raw material and undesirability material performance of polyurethane products are to be a pressing problem. In this paper, the research mainly includes: synthesis of the narrow distribution and molecular weight controlled PCL diol, preparation of TPU with PCL as soft segment, and on this basis, the introduction of polydimethyl siloxane(PDMS) with PCL as mixed soft segments to create block TPU. Then the structure and property of this material were studied systematically. The main research content was contained as follows:(1) The synthesis of molecular weight controlled PCL diol. Firstly, the influence of the dosage of initiator, reactive time and reactive temperature on the ring opening polymerization process was investigated. Results suggested that the optimized reactive temperature was 140 ℃ and the reaction duration was 7 h.The molecular weight of PCL was controlled by the feeding ratio of 1,4-butanediol(BDO) and caprolactone monomer(ε-CL). Then the molecular structure, molecular weight and molecular weight distribution of PCL were characterized by FT-IR、1H NMR and GPC. Then, in order to evaluate the catalytic capability of the Sn(Oct)2, a comparison between the PCL that was synthesized by the catalytic of activated carbon and that by the Sn(Oct)2 was carried out, the results suggests that the molecular structure and the molecular weight distribution of the two PCL were the same.(2) The synthesis of TPU with PCL as the soft segment. Firstly, a series of TPU was synthesized using different molecular weight of PCL as the soft segment. The molecular weight and molecular weight distribution of TPU was evaluated by FT-IR、GPC. Then, the mechanical property and crystallization property of the TPU were studied, the results showed that the crystallization ability became better, while the hardness were decreasing with the increasing of molecular weight of PCL. The synthetic TPU had the best comprehensive performance when the PCL molecular weight was 2000. In order to study the influence of the hard and soft segment ratio on the mechanical property and crystallization property, a series of TPU with different ratio of soft segments/hard segments were synthesized. The results indicated that the crystallization ability became poor, while the tensile strength and hardness were increasing with the increasing of hard segment content. In addition, a TPU with excellent strength and toughness was produced when the hard segment content reached 38.7 wt%. Finally, the influence of curing temperature and processing technology on the property of TPU was studied, and finding that the TPU possesses preferable apparent morphology, tensile strength and elongation at break through the direct injection molding processing method with the curing temperature at 100 ℃.(3) The synthesis of organic siloxane-modified polyester for TPU. TPU with different content of PDMS was synthesized using PCL together with PDMS as soft segment. Then, the structure, hydrophobic property, thermal property, and mechanical property were characterized and studied by GPC, contact angle, TG, and tensile test. The results showed that the mechanical property became poor, while the hydrophobic property and thermal stability improved obviously with the increasing of PDMS content. Particularly, the hydrophobic property was enhanced dramatically: the contact angle increased from 77° to 118° when the content of PDMS increased from 0 wt% to 22.5 wt %.