| 摘要 |
PURPOSE: A modified polypropylene, its preparation method, a composition containing the modified polypropylene and a foamed product obtained from the polypropylene or the composition are provided, to improve the foam properties, the food hygienic qualities, the lightweight properties, the rigidness and the chemical resistance. CONSTITUTION: The modified polypropylene has a melt flow rate of 0.1-10 g/10 min (ASTM D1238, 230 deg.C, load of 2.16 kg), a melt tension of 3-20 g, and gel fraction (determined by boiling paraxylene extraction) of 0.01-25 wt.%. Preferably the modified polypropylene is prepared by melt stirring a mixture of 98.5-99.7 wt.% of a polypropylene having a melt flow rate of 0.4-15 g/10 min and 0.3-1.5 wt.% of peroxydicarbonate at a temperature of 170-250 deg.C. The peroxydicarbonate is bis(4-t-butylcyclohexyl)peroxydicarbonate or dicetylperoxydicarbonate. The composition comprises 1-99 wt.% of polypropylene; and 1-99 wt.% of the modified polypropylene. Also the composition comprises 1-50 wt.% of high pressure low density polyethylene; and 50-99 wt.% of the modified polypropylene.
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