The Research On The Theory And Application Of Functional Materials Prepared Through Polymer Phase Separation

The research was based on the polymer phase separation and contained mainly three parts,the shape memory polymer blend of SBS/PCL and SBS/PLA,the low dielectric constant HDPE-grafted-maleic anhydride(HDPE-g-MAH) protection coating and the heat-resistant polyetherimide porous films prepared by a triple system of thermally induced phase separation(TIPS).In each part,the connection of theory and application was studied with details listed below.(1) The shape memory polymer blends of SBS/PCL and SBS/PLA.The current study of shape memory polymers can be classified into two main groups,namely the chemical-crosslinked and physical-crosslinked networks.Each network contains crystalline or amorphous chains to fix and unfix the deformation using their crystallization or glass transition,respectively.The common disadvantages of the current shape memory polymers are the intricacies of fabrication and characterization,plus the incapability of the performance optimization through the shape memory mechanism.To address these issues,a novel approach of shape memory polymer blends was proposed and demonstrated.The blends contained two immiscible components,namely the elastomer and the transition polymer.The elastomer gave the properties of deformation and the transition polymer gave the properties of fixing and unfixing.The SBS/PCL and SBS/PLA blends were selected to go though with the investigation of the novel approach.The phase morphology,the thermal,mechanical,theological and shape memory properties were studied and then the shape memory mechanism and the optimization design of the shape memory performances were generated.(2) The low dielectric constant HDPE-g-MAH protection coating. The application of the low dielectric constant materials covers various fields, such as integrate circuit,printed circuit board,microwave sender and receiver coatings,etc.For the coatings,the approach of thermally induced phase separation (TIPS) was proposed to introduce pores into the dense coatings so as to reduce the dielectric constant.By TIPS approach,the dielectric constant of HDPE-g-MAH coating was reduced from 2.60 to 1.56 at 1MHz at most.In addition,the control of the dielectric constant by the process of TIPS approach was proved good and effective and could be outlined by the two correlations.One was the correlation of polymer contents,cooling rates and porosity,the other was the correlation of dielectric constant and porosity.Since it may be the first introduction of TIPS approach to fabricate low dielectric constant coatings,our research may be the opening of the new TIPS application.(3) The heat-resistant polyetherimide porous films.The heat-resistant porous films have been attracting enthusiasm of research over the latest decades.One of the candidates is the polyetherimide porous film with good thermal,mechanical and wearable properties.In order to maintain the mechanical properties under high porosity,the TIPS approach was selected to introduce pores. The TIPS system was polyetherimide/benzophenone/triethylene glycol.Unlike the ordinary triple systems in the literature,it was a novel one which was found unsuitable to be simplified to binary system by taking two diluents as one phase.The benzophenone was proved remained in the polyetherimide rich phase by a large amount during phase separation,which resulted in the distinctions from the binary and the ordinary triple systems.Moreover,the amorphous polyetherimide may add bonus to the distinctions comparing with the ordinary crystalline polymer systems. Both the similarity and distinctions of phase diagrams,phase separation courses,the obtained pore structures were studied in this paper.Also,since it may be the first that prepared polyetherimide porous films by this novel triple TIPS system,our research may add zeal to the study of phase separation courses in triple TIPS system.