スクリュ押出機によるポリプロピレンの酸化熱分解I. Ｔ−ダイキャス1フィルム 1. 分解度の影響
Thermo-Oxydative Degration of Polypropylene by Use of Screw ExtrudersI. T-Die Cast Film 1. Effect of Degree of Degradation
藤山光美・脇野哲夫
Fjiyama, Mitsuyoshi / Wakino, Tetsuo
A homo polypropylene and two polypropylene copolymers with ethylene were thermo-oxidatively degraded by use of screw extruders. They were cast into films with a T-die extruder and the effects of degree of degradation on the processabilities and film properties were studied. The structures of the films were also studied by measurements of dynamic viscoelasticity, infrared spectrum, and wide-angle X-ray diffraction.
The degraded polypropylenes show low degrees of edge fluctuation in the casting process and hence have good high-speed processabilities. This is assumed to originate from their narrow molecular weight distributions. Films cast from degraded polypropylenes show superior transparency, dart impact strength, and heat sealability and show low stiffness and slipperiness. This is because the films cast from degraded polypropylenes are rich in smectic and amorphous phases while the films cast from undegraded polypropylenes are rich in α-crystal phase.
Key words: Polypropylene / Thermo-oxidative degradation / Screw extruder / T-die cast film / Property / Structure