| 초록 |
Polypropylene is very widely used in various area because of its excellent properties. But polypropylene is restricted in several applications in foam, thermoforming and blow molding regions because of its poor melt strength cause by linear structure and crystallinity. To improve melt strength of polypropylene, branched polypropylene was prepared by reactive extrusion method. Melt strength behavior and branching number of various branched polypropylene prepared with several kind of reaction conditions was measured. And extrusion foaming test was carried out. Branched polypropylene showed not only remarkably improved melt strength behavior but also strain hardening phenomenon. In addtion, it was possible to prepare good extrusion foam with this novel polypropylene but impossible with general linear polypropylene. It was presumed that melt strength improvement cause by chain entanglement of long chain branch. |
