Preparation And Properties Of Macromonomer-Polyacrylonitrile Graft Copolymer

In order to improve energy efficiency and alleviate the energy crisis,this paper successfully developed a new type of solid-solid phase change energy storage material by macromonomer technique.This solid-solid phase change energy storage material is a novel ternary graft copolymer made from PEG macromonomer,acrylonitrile monomer and a third monomer by aqueous phase precipitation polymerization method,and it has high phase transition enthalpy and is a very good phase change material,Furthermore,since the polyacrylonitrile rigid backbone limits the macroscopic flow of the PEG macromonomer branch chain when phase transition occurs,so the new ternary graft copolymer showed solid-solid phase transition characteristics.In this paper,the physical and chemical properties,choice of the third monomer and synthesis process of the new ternary graft copolymer was studied,and the effect of PEG macromonomer with different molecular weight on properties of the new ternary graft copolymer properties was investigated.In addition,in order to explore the practical application of the new ternary graft copolymer,the preparation and performance of the new ternary graft copolymer fibers was studied in this paper,and the new ternary graft copolymer was blended with cellulose,mainly in order to improve the mechanical properties of the new ternary graft copolymer fibers.In addition,with the rise of today’s electrospinning technology,this technology was tried to be prepared for novel ternary graft copolymer nanofibers and the preparation process were preliminary researched in this paper.In this paper,the main research results obtained are as follows:(1)Acrylamide is more suitable for acting as the third monomer of novel ternary graft copolymer than vinyl acetate and styrene monomer,and it can improve the phase change ability of the new ternary graft copolymer,make the melting enthalpy reach 66.39 J/g and crystallization enthalpy of 56.68 J/g.(2)The optimum proportion of each component of synthesising MAPEG4000-PAN-AM is:mass ratio(MAPEG4000:AN)is 1:1,acrylamide mass fraction of 10%,catalyst concentration is 0.5%,mass ratio(water:AN)is 15:1.(3)With the increase of molecular weight of the macromonomer,phase transition temperature,crystallinity and enthalpy of MAPEG-PAN-AM ternary graft copolymer increases,however,its thermal stability is increased firstly and then decreased.(4)The introduction of acrylamide improved the mechanical properties and hygroscopicityof the graft copolymer PEG4000-PAN fibers,in addition,with the increase of molecular weight of MAPEG branch chain,the breaking strength and elongation of MAPEG-PAN-AM ternary graft copolymer fibers increased,but hygroscopicity decreased.(5)Introducing cellulose can significantly improve the mechanical properties of the MAPEG4000-PAN-AM ternary graft copolymer fibers.(6)In the preparation process of MAPEG4000-PAN-AM nanofibers,with the pinhole diameter and spinning solution concentration increases,the fiber diameter is increased,when the spinning solution concentration is more than 25%,the fiber diameter increased sharply,but the greater the spinning voltage,the smaller the fiber diameter,in addition,when the solvent is DMSO,the fiber diameter is thicker than that of the solvent of DMF.