Article
  • Change of Properties of Polymer with Polymerization Model in Ethylene Polymerizaton
  • Yu EY, Choi BR, Moon HJ
  • 에틸렌 중합에서 중합방식에 따른 중합체 물성의 변화
  • 유의연, 최병렬, 문한주
Abstract
Ethylene polymerizations using highly active Ziegler-Natta catalyst were carried out with various polymerization modes in a batch slurry reactor. The influences of basic properties(molecular weight, molecular weight distribution, and density) for polymer according to polymerization parameter(hydrogen/ethylene mole ratio, temperature, pressure, comonomer content) in a single polymerization were investigated. Molecular weight was governed by hydrogen concentration and density was controlled by comonomer content. From these results, correlative equation between the molecular weight and hydrogen concentration was derived, and another correlative equation between density and comonomer content based on MI = 1.0 was obtained. Parallel and cascade polymerizations with two reactors were carried out to obtain polyethylene haying bimodal molecular weight distribution. Polyethylene with bimodal molecular weight distribution was obtained by controlling blend ratio and basic properties of polymers which are formed in each reactor with using correlative equations for single polymerization mode. A cascade polymerization mode in obtaining bimodal molecular weight distribution was more effective than a parallel polymerization mode. The reason is that a cascade polymerization mode shows homogeneity of polymers and good productivity for polymer with low molecular weight. To evaluate characteristics of processibility for polymers obtained in single, parallel and cascade polymerizations, the behaviors of she melts were investigated by capillary rheometer. Melting properties have been related with molecular weight and molecular weight distribution of polymers.

회분식의 슬러리반응기에서 고활성 Ziegler-Natta촉매계를 사용하여 여러 가지의 중합방식으로 에틸렌 중합을 실시하였다. 단중합에서 중합인자(수소/에틸렌 몰비, 온도, 압력, 공단량체의 함량)에 따른 고분자의 기본물성(분자량, 분자량분포, 밀포)영향을 조사하였다. 분사량은 수소농도에 의해 지배되었고, 밀도는 공단량체의 함량에 의하여 제어되었다. 이들 길험결과로부터 분자량과 수소의 상관관계식과 MI=1.0을 기준으로 밀도와 공단량체 함량의 상관관계식을 유도하였다. Bi-modal형의 분자량분포를 갖는 폴리에틸렌을 얻기 위하여 반응기 두 개를 사용하여 평행중합과 연속중합을 실시하였다. 단중합에서 얻은 상관관계식을 이용하여 각 반응기에서 생성되는 중합체의 기본물성을 제어하고, 블렌드 비를 제어하여 bimodal형의 분자량분포를 갖는 폴리에틸렌을 얻을 수 있었다. Bimodal형의 고분자 생성에는 평행중합방식보다 연속중합방식이 효과적임을 알 수 있었는데, 그 이유는 연속중합에서 중합체의 균일성과 저분자량체의 생산성이 양호하기 때문이었다. 단중합, 평행중합, 연속중합에서 얻은 중합체의 가공성을 평가하기 위하여 capillary rheometer를 사용하여 용융거동을 검토하였다. 용응물성은 생성된 분자량 및 분자량분포와 상관성이 있었다.

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  • 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

  • 1996; 20(2): 260-270

    Published online Mar 25, 1996