The Structure-activity Relationship Of Graft Phase Change Copolymer Of Polyacrylonitrile

With the energy crisis and environmental pollution is becoming increasingly serious,rational and effective use of energy has been more and more attention.Phase change material(PCM)means a substance with temperature change state and provide a latent heat material.Process of transformation called a phase change of the physical properties of the process,when the phase change material will absorb or release a large amount of latent heat.Due to the phase change material has the advantages of energy storage and regenerative become the forefront of scientific research,it is widely used in aerospace,military,construction,clothing,and other fields.Polyethylene glycol has regular structure,easy to crystallize,a suitable phase transition temperature,stable performance,high latent heat,no cold and phase separation,etc.Green functional materials is one of the most effective means of energy storage.But the presence of polyethylene glycol is to heat solid-liquid phase transition and easy to leak.It is limited in practical applications.Therefore,the researchers are usually made of solid phase change material by means of support "package" by physically or chemically.Thus avoiding the use of the process fluid leaks.In this paper,the main chain is polyacrylonitrile.Polyethylene glycols large monomer(maleic acid-polyethylene glycol monomethyl ether(MAMPEG),allyl polyethylene glycol(APEG)and polyethylene glycol acrylate(ACPEG)is side chain by aqueous deposited polymerization of acrylamide as a third monomer.We have prepared poly(acrylonitrile-acrylamide)-g-maleic acid polyethylene glycol monomethyl ether(P(aN-AM)-g-MAMPEG),poly(acrylonitrile-acrylamide)-g-allyl polyethylene glycol(P(AN-AM)-g-APEG)and poly(acrylonitrile-acrylamide)-g-acrylate polyethylene glycol esters(P(AN-AM)-g-ACPEG)three kinds of copolymers.Respectively we investigate the effect of polyethylene glycol macromonomer with different molecular weights and different proportions of the thermal properties of the copolymer,crystalline properties.The results showed:(1)by Fourier transform infrared spectroscopy(FT-IR),differential thermal analysis(DSC),X-ray diffraction(XRD),thermal gravimetric analysis(TGA)and polarizing microscope MAMPEG,P(AN-AM)g-MAMPEG was characterized the strengthof maleic anhydride and polyethylene glycol monomethyl ether esterification esterification rate factors are: The molar ratio > Catalyst mass fraction > Toluene content > Reaction time.We test the horse melting enthalpy acid polyethylene glycol monomethyl ether(molecular weight 2000,4000,5000).The enthalpy of crystallization of polyethylene glycol monomethyl ether declined,infrared spectroscopy showed successfully with acrylonitrile copolymers together and get graft copolymers(polyethylene glycol monomethyl ether with a molecular weight 2000,4000,6000).The maximum enthalpy of crystallization of 40.15J/g.As the molecular weight of polyethylene glycol monomethyl ether is reduced.the crystallization enthalpy of the graft copolymer in reduced.XRD showed a crystallization ability is declining,thermal stability did not change much.(2)Acryloyl chloride with polyethylene glycol(2000,4000,6000)is prepared by reacting a macromonomer copolymerizable with acrylonitrile.It infrared displays both a good comonomer together and resulted in the three different molecular weight polyethylene glycol.The maximum crystallization enthalpy copolymer is 49.8J/g.With the decrease of the molecular weight,the crystallization enthalpy decreased.The ability of crystallize is in weakened under different proportions.With the PEG:AN ratio smaller,the crystallization enthalpy of the copolymer decreased.(3)Allyl polyethylene glycol(molecular weight 1200,2400)and acrylonitrile was stogether.The greatest value of the enthalpy of the copolymer was 44.4J/g,a molecular weight of less supercooling phenomenon is more evident with the APEG: AN ratio decreased,the crystallization enthalpy decreased.