Curing and Phase Separation of Crosslinkable Monomer in Polycarbonate Matrix
|School||Wuhan University of Technology|
|Course||Composite materials science|
|Keywords||Diallyl orthophthalate Polycarbonate Reactive plasticizer Curing reaction Phase separation|
Polycarbonate(PC) has very good mechanical property and heat resisting.Due to their high melt viscosities,the molding temperature is also very high.Small amounts of crosslinkable monomer,diallyl orthophthalate(DAOP),can be used as a reactive plasticizer to low down the temperature during processing.Anyway,the polymeration of DAOP and phase separation may greatly affect the properties of the blends.In this paper,we explored the curing reactions,phase structure,thermal, mechanical properties of PC/DAOP/DMDPB blends,based on the investigation of curing reactions of DAOP monomer and kinetic parameters of DAOP/2,3 -dimethyl -2,3-diphenylbutane(DMDPB) blend.The laboratorial report of DAOP/DMDPB solidify blend have shown that DAOP monomer could be initiated at 180-210℃with the presence of DMDPB.And good results were shown when the weights percentage of DMDPB was 2%around 200℃. And the curing process and kinetic parameters of DAOP/DMDPB(2%) curing system were achieved by DSC.The PC/DAOP/DMDPB blends experimental results have shown that the curing rate and curing degree of the blends would be reduced gradually if the PC content was increased,the curing rate of the blends will be inproved at elevated temperature, but the curing temperature should be controlled at less than 220℃.Optical microscope had undertaken on observe the separation process of the blends.The initial phase separation of the blends is according with the traditional separation theory of thermodynamics,with the increasing of the polymerization degree of DAOP, the structure of blends changed,DAOP particle size grows,and the second phase separation is occurred.Melt blending was used to blend the PC/DAOP/DMDPB blends in different ratio. Mechanical properties testing and scanning electron microscopy studied of their mechanical properties and morphology section.It showed that the Young’s modulus, bending modulus,hardness and toughness of blend were improved,which meaned that incorporation DAOP into the PC matrix increased the toughness and rigidity of PC.While as the tensile strength and bending strength of blends dropped with the increase of DAOP content.Anyway,taking into account the low level of curing of DAOP in blends,it can be drawn that,the mechanical properties of the blends will be increased if the conversion degree of DAOP is improved,the superiority of the material can be fully displayed.