Isothermal crystallization behavior of highdensity polyethylene (HDPE) was studied experimentally by using a rotary rheometer with parallel plates fixturesIt was found that the crystallization rate depended on the surface roughness of the fixtures with the same chemical compositionAs the surface roughness increased，the crystallization rate first increased then decreased which meant that there was a range of surface roughness where the crystallization rate could reach a maximum valueSurface roughness effectively enhanced the interfacial area and decreased heat resistance

but possibly trapped air pockets in the valley of the rough surface produced a considerable interfacial heat resistance，both affecting the crystallization rate of HDPEThe isothermal crystallization rate decreased in sequence as the HDPE specimen contacted with aluminum，brass and stainless steel plates whose surface roughness were on the same levelThe sample crystallizes more quickly on the fixtures with higher heat conduction coefficient

thus lowering heat resistance.