Study Of PS/PDMS Self-Healing Material

Self-healing polymer materials is a new kind of material that has great potentional in many fields.In this paper, PS/PDMS copolymer was synthesized by solution polymerization. Effects of factors such as composition of the copolymer, the outside force, annealing treatment were primarily studied to investigate how they influenced the phase structure and mechanical property of PS/PDMS copolymer; meanwhile the self-healing performance of PS/PDMS copolymer was also analyzed to determine their relationship the the phase structure of PS/PDMS copolymer.It could be demonstrated from the experimental results that although the bad compatibility of PS and PDMS, they can synthesized through the solution polymerization with appropriate propotion. And the copolymer possessed the bicontinuous phase structure. In the copolymer, PDMS content could be added until 45 wt % of the copolymer. However, if the PDMS content continued to increase, it would lead to a macroscopical separation of PS and PDMS and failed to form a complete copolymer. It could be seen from the atomic force microscopy and phase-contrast microscopy image that annealing treatment had an important effect on the PS/PDMS copolymer phase structure. Annealing treatment led to a transition of phase structure of the PS/PDMS copolymer from "sea-island" structure to bicontinuous phase structure, which had a close relationship with the performance self-healing of PS/PDMS copolymer. And higher annealing temperature was in favor of the emergence of a perfect bicontinuous phase structure.The propotion of PDMS in the copolymer also exerted significant influence on the copolymer phase structure. Before annealing, the size of PDMS phase in the "sea-island" structure of the PS/PDMS copolymer increased with the increasing of propotion of PDMS in the copolymer. When the propotion of PDMS reached to 45%, PS and PDMS had a serious macroscopical separation. After annealing treatment, the phase structure of PS/PDMS copolymer obtained the satisfactory bicontinuous structure when the PDMS propotion was 30%.Exerting an outside force and annealing treatment to the PS/PDMS copolymer will lead to an obvious circular phase transition process. When exerting outside force, the bicontinuous phase structure of the PS/PDMS copolymer would be distorted and the PDMS in the copolymer broke down; when annealing treatment was applied to the copolymer, the broken PDMS assembled again and the phase structure of the copolymer resumed the bicontinuous phase structure. And further study revealed that when the propotion of PDMS in the copolymer of PS/PDMS was 30%, the copolymer had the best mechanical property.