Phase Structure And Self-healing Behavior Of Liquid Crystalline Block Copolymer Elastomer Cross-linked By Hydrogen Bonds

In this paper, we prepared a series ot self-healing LCEs which have the structure of thermoplastic elastomers (TPEs), that is, diblock copolymers (BCPs) consist of a side-chain liquid crystal polymer (SCLCP) chain and a soft polymer chain with hydrogen-bonding. The SCLCP chains embedded in soft chain matrix and exhibit physical crosslinking property as well as the enhancement of mechanical properties. As a result, this paper is focused on the phase study of the LC as well as the self-healing properties of BCPs. The content can be concluded as three chapters: 1. Random copolymer PMAzoC4-co-PHMAx (x=1,2,3,4,) were successfully synthesized using the designed monomer 6-(4-((4-butylphenyl)diazenyl)phenoxy)-hexyl methacrylate (MAzoC4) and HMA via RAFT. The phase transition and LC structure for these copolymers (Sx) have been carried out by DSC, PLM and X -ray experiments. The results showed that the presence of PHMA can lower the transition temperature of copolymers and prohibited the development of the LC Drdered structure.2. The diblock copolymers (BCPs) were prepared using Sx as the macro-chain transfer agent with the monomer of M(NCP)A containing hydrogen bond. GPC and 1H NMR are applied to confirm the structure of BCPs. In the meanwhile, the phase transition of these BCPs in detail as well as their LC ordered structure were investigated by DSC and PLM. The SAXS result showed that the introducing of PHMA and increasing temperature could promot the phase separation.3. Furthermore, the dynamic module mechanical experiments of BCPs with S2 and S3 were discussed as well as the self-healing properties of two certain samples. The inspiring results showed that both of these two samples could selfheal well even in room temperature.