A new initiator for atom transfer radical polymerization（ATRP）,（Cl2HCCOO）3-C6H3,（TrDCAP）,has been designed and successfully synthesized.ATRP of styrene was carried out by using TrDCAP as hexafunctional initiator and the CuCl/bpy catalyst at 130℃ in 30% THF via core-first strategy.The Arm-6 PS-AAP was synthesized by etherealization of Arm-6 PS and 4-（4′-methoxyphenylazomethine）phenol（AAP）.The initiator and the architectures of the Arm-6 PS were confirmed by （）1H-NMR,FT-IR,UV-Vis and GPC.
In this paper, carbon fiber(CF)-filled low density polyethylene(LDPE)composite materials were prepared by conventional melt-mixing method. Wide angle X-ray diffraction(WAXD) observation shows that the addition of CF to LDPE does not influence the aggregate structure of the polymer. The change of the resistivity with increasing temperature is determined by two following factors: one is the expansion of the polymer which makes resistivity rise and leads to a positive temperature coefficient(PTC) effect; the other is the agglomeration of filler particles which makes resistivity drop and leads to a negative temperature coefficient(NTC) phenomenon. It is found that the crosslinking under γ-ray radiation can effectively eliminate the NTC phenomenon by forming a network and reducing movement of the CF. And a higher PTC intensity and PTC transition temperature are achieved for the radiated LDPE/CF composites.
