Research On The Synthesis And Properties Of D4/CL Copolymer

With the rapid development of science and technology, organic silicon compounds with its superior performance had attracted more and more attention from people, at present, which have been widely used in every sector of human production and living. Octamethyl cyclotetrasiloxane (D4) was one of the most important monomer among the organosilicone compounds for preparation of the silicone oil, silicone rubber and other organosilicone polymers, which was widely used in construction, textile, protection products and other fields. In this paper, considering the features of caprolactam (CL) and octamethylcyclotetrasiloxane could each polymerize through anionic catalytic polymerization, we reported a simple and effective method to prepare D4/CL copolymers via in-situ anionic ring-opening polymerization. In the preparation of copolymers, sodium hydroxide and 2,4-toluenediisocyanate were used as initiator and activator agents, respectively. By adding different content of D4, we successfully prepared a series of D4/CL copolymers.A lot of analysis methods were performed to study performance of the copolymers, including thermal properties, mechanical properties, crystallization and melting behaviors, rheological behaviors and so on. The results of 1HNMR and IR. confirmed that the copolymerization reaction had taken place between octamethyl cyclotetrasiloxane and caprolactam, and siloxane segment indeed had been grafted onto the nylon 6 chains segment. The results of TG analysis showed that the good thermal stability of PA6 hadn’t been affected with the addition of D4. The results of DSC testing showed that the crystallization and melting behaviors of PA6 had been influenced with the addition of D4 on a certain level. With the increasing content of D4, the crystallization temperature and melting temperature of D4/CL copolymers first increased and then decreased. In addition, the addition of D4 to a certain extent could improve the crystallinity of PA6. The XRD testing results showed that the addition of D4 was conducive to weak the power of forming y crystal. Mechanical and thermal performance testing results showed that the addition of a small amount of D4 had been beneficial to improving the elongation at break and thermal conductivity of PA6, which could increase the toughness and thermal conductivity performance of PA6. Rheological testing results showed that the addition of D4 helped to reduce the complex viscosity and shear viscosity of copolymer, which increased the liquidity of copolymer melts. At the same time, the energy storage modulus and loss modulus of polymers decreased with the increasment of D4. Relative water absorption testing results showed the relative bibulous rate of D4/CL copolymer could fall to 0.237% when the addition content of D4 was 5wt%, which much smaller than that of the pure PA6. The results of GPC analysis showed that the addition of D4 didn’t change the molecular weight and molecular weight distribution of PA6.