Article
  • A Study on the Controlled Rheology Polypropylene
  • Choi BO, Yoon HS, Zhoh CK
  • Controlled Rheology 폴리프로필렌에 관한 연구
  • 최병오, 윤홍식, 조춘구
Abstract
The controlled rheology products(CR products) were obtained from the degradation reaction of normal polypropylene resin(blow molding grade) with mixing of organic peroxide in the extruder. Molecular weight distribution and rheological, mechanical and optical properties of CR products were measured according to the peroxide content. Polydispersity index of CR products were decreased from 8.2 to 4 with the increasing the peroxide content. And from the relationship of melt flow rate and intrinsic viscosity, it show that degradation was occured more effective at higher molecular weight portion than the lower molecular portion. The shear stress of CR products was higher than the normal polypropylene which has simillar melt flow rate at low shear rate region, but reverse pattern was showed at high shear rate. High transparency film could be obtained from the controlled rheology of polypropylene with the peroxide mixing, without the loss of stereo regularity, crystallinity, melt flow properties and mechanical properties such as tensile strength and elongation.

압출기를 이용하여 blow 성형용 프로필렌수지(normal PP)에 유기과산화물을 첨가하여 controlled rheology(CR) PP를 제조하였다. 과산화물 첨가량에 따른 PP의 분자량과 분자량분포를 측정하고, 각 CR PP의 유변학적성질과 기계적성질 및 투명성을 측정, 비교하였다. 유기과산화물의 첨가량이 증가됨에 따라 CR PP의 다분산성지수는 8.2에서는 4.0으로 감소되었다. 용융지수와 고유점도의 변화로부터 과산화물에 의한 PP연쇄의 분해는 분자량이 높은 PP분자쪽에서 보다 현저하게 일어나는 것을 확인할 수 있었다. 전단강도 실험에서는 용융지수가 비슷한 값을 가지더라도 전단속도가 낮은 영역에서는 CR PP쪽이 normal PP보다 높은 강도를 표시하지만 전단속도가 높은 영역에서는 normal PP보다 낮은 강도를 표시하였다. 한편, 과산화물 첨가에 따른 PP의 입체규칙성, 결정성, 인장강도 및 신장율등은 크게 저하되지 않으면서 CR PP 필름의 투명성은 크게 향상됨을 알 수 있었다.

  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2022 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 1989; 13(10): 839-847

    Published online Dec 25, 1989

  • Received on Mar 14, 1989