| Research Abstract |
Nucleation and growth mechanism of polymers with high purity was studied based on the new experimental findings on the molecular weight (M) dependence of nucleation and growth rates, 1 and V.respectively. Pure and well fractionated Polyethylene (PB) and isotactic polypropylene (iPP) were isothermally crystallized at atmospheric pressure or under high pressure (P=4kb). It is found on PE that V ocM^-^H, where His a constant, which was named "power law of lateral growth rate". Similar law was also found on iPP.It is also found on PE for the first time that I ocM^-^H which was named "power law of nucleation rate". These results suggest the universality of the "power law" in crystallization mechanism. A topological model was proposed to explain the results that the nucleation and growth of polymers is a process of disentanglement and chain sliding diffusion within the melt, nucleus, crystal and interface between the melt and crystals.
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