| 摘要 |
PURPOSE: A process for enhancing the melt strength of a polypropylene (co)polymer with the aid of initiator dispersions is provided. CONSTITUTION: A process for enhancing the melt strength of a polypropylene (co)polymer is conducted by mixing an initiator with the polypropylene (co)polymer at a temperature below the decomposition temperature and heating the mixture, with most of the initiator decomposing before the polymer has melted and with the formed radicals reacting with the polymer. The polypropylene (co)polymer is contacted with an initiator dispersion in a polar medium, with at least 90wt.% of the initiator particles being smaller than 50um and at least 99wt.% of the initiator particles being smaller than 65um. The use of initiator dispersions with a particulate initiator instead of the corresponding non-dispersed initiators or their dilutions or solutions results in a significant enhancement of the melt strength of the modified polymer, and a wide range of initiators are serviceable.
|
