Article
  • Rheology of Crosslinking and Degradation of Polypropylene During Reactive Extrusion
  • Kim KJ, Ha HS, Kim SJ, Lee JC, Kim BK
  • 프로필렌의 반응동안 압출 과정에서의 가교 및 분해 유변학
  • 김국중, 하현수, 김상준, 이종철, 김병규
Abstract
Isotatic polypropylene(PP) powder was extruded in the presence of peroxide and polyfunctional monomer at 230℃. The merit flow index(MI) of extrudate and injection molded specimen, together with the linear viscoelastic properties of melt at 230℃ was measured. With the increase of peroxide concentration, MI increased almost linearly, and the viscosity function tended to define a Newtonian plateau, indicative of increased rate of degradation accompanied by narrowed molecular weight distribution. On the contrary, the MI of pellet was reduced asymptotically in the presence of pentaerythritoltriacrylate(PETA) and trimethylolpropanetriacrylate(TMPTA), and showed a drop at the initial addition of triallylisocyanurate(TAIC) and p-benzoquinone(PBQ). Addition of polyfunctional monomer to peroxide system produced MI lower than the one obtained with the peroxide alone, and higher than the one obtained with polyfunctiollal monomer alone. By injection, MI increased over several times with PETA and TMPTA, and by a factor less than 2 with peroxide, TAIC and PBQ. Form the viscosity measurements, it was inferred that the extent of crosslinking obtained during extrusion is similar to that of chain scission during injection molding.

Polypropylene 분말을 과산화물 및 다기능성 단량체 존재하에서 230℃에서 압출, 압출물과 사출 시편의 용융흐름지수 및 230℃에서의 선형 점탄성을 측정하였다. 과산화물의 함량이 증가함에 따라 용융흐름지수는 거의 선형적으로 증가하였고, 점성함수는 Newtonian plateau를 보였으며 이로부터 과산화물 처리로 분해와 더불어 분자량 분포가 좁아짐을 짐작할 수 있었다. 한편. PETA(pentaerythritoltriacrylate) 및 TMPTA(trimethylolpropanetriacrylate) 존재하에서는 압출물의 용응흐름 지수는 농도와 더불어 점근적으로 감소하였으며, TAIC(triallylisocyanurate) 및 PBQ(p-benzoquinone)의 경우에는 초기에 감소한 후 일정하게 유지되었다. 다기능성 단량체와 과산화물을 함께 사용했을 때의 용융흐름지수는 과산화물 단독 사용시보다는 작고, 다기능성 단량체 단독 사용시보다는 큰 값을 나타내었다. PETA 및 TMPTA를 사용했을 경우 사출에 의해 용융흐름지수는 수 배 증가하였으나, 파산화물, TAIC 및 PBQ의 경우에는 1.5배 이하로 증가하였다. 점성 곡선으로부터 압출과정의 가교와 사출과정의 사슬 절단반응은 거의 대등한 정도로 일어남을 짐작할 수 있었다.

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  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2023 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 1993; 17(1): 1-7

    Published online Jan 25, 1993