Effect of Entanglement Degree on Condensed State Structure and Impact Strength of Ultra-High Relative Molecular Mass Polyethylene
A disentangled ultra-high relative molecular mass polyethylene(UHMWPE)together with 11 commercial samples were systematically studied to investigate the influence of entanglement on the condensed state structure and to correlate the condensed state structure of UHMWPE to its impact strength.It was found that with the increase of entanglement degree the crystallization activation energy decreases at first and then grows rapidly,while the degree of crystallinity is not influenced greatly.The long spacing period of UHMWPE behavior the same trend of crystallization activation energy with the growth of entanglement degree.High degree of melt entanglement will promote UHMWPE to have thick lamellar stacking structure.Finally,by correlating the condensed state structure with the impact strength,it is discovered that there is a strong linear correlation between the impact strength and the thickness of the amorphous phase with a goodness of fit up to 0.94.The impact strength of UHMWPE can be improved by reducing the thickness of the amorphous region.
Ultra-high molecular mass polyethyleneEntanglementLong spacing periodCondensed state structureIzod notched impact strength
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