• Polymer(Korea)
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• v.35 no.2
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• pp.99-105
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• 2011

To optimize the properties of compounds, effective mixing is of importance to achieve adequate distribution and dispersion of filler particles. A variety of mixing elements have been used for twin-screw extruders in order to improve the mixing efficiency. In this study, the effects of 10 screw configurations on the filler dispersion were investigated for the calcium carbonate filled polystyrene processed in a co-rotating twin-screw extruder. The state of filler dispersion was characterized by equipped with a photodiode. The experimental results indicated that the type and position of mixing elements primarily affected the degree of filler dispersion.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.305-315
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• 2021

An intermeshing corotating twin screw extruder is mainly used for compounding polymeric materials. Twin screw extruder can adopt modular-type screw configurations, which directly controls the quality and productivity of the products. The types, shapes, and specifications of the screw and kneading elements are summarized, and the effects of screw configuration on the processabiliy of the materials are discussed. The principles of screw configuration universally applied to mass production of general-purpose resins are explained, and the guidelines of screw combination according to the roles of feeding, melt mixing, and metering zones are listed. The strategies of screw combination suitable for various cases, such as side feeding of liquid additives or inorganic fillers, reactive extrusion, devolatilization process, production of products requiring bright color and transparency, and processing of materials with low apparent specific gravity, are presented.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.1 s.244
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• pp.32-41
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• 2006

We analyzed the non-Newtonian and non-isothermal flow in the melt conveying zone in co-rotating and counter-rotating screw extruder system with the commercial code, STAR-CD, and compared the mixing performance with respect to screw speed and rotating direction. The viscosity of fluid was described by power-law model. The dynamics of mixing was studied numerically by tracking the motion of particles in a twin screw extruder system. The extent of mixing was characterized in terms of the residence time distribution and average strain. The results showed that high screw speed decreases the residence time but increases the shear rate. Therefore higher screw speed increases the strain and has better mixing performance. Counter-rotating screw extruder system and co-rotating screw extruder has the similar shear rate with the same screw speed in spite of different rotating direction. However, the counter-rotating screw has good mixing performance, which is resulted from longer residence time than that of co-rotating screw extruder.

• Polymer(Korea)
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• v.37 no.3
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• pp.342-346
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• 2013

In this study, it was attempted to disperse carbon nanotubes (CNTs) in a polymer matrix using a twin-screw extruder which was good for dispersing fillers of micron sizes but not suitable for dispersing nanometer-sized materials. Improved dispersion of CNTs could be achieved by the addition of inorganic fillers with different geometrical shapes. An increase in the matrix viscosity provided a high shear stress on aggregated CNTs, leading to a good dispersion of CNTs. The presence of the inorganic fillers was supposed to suppress the re-aggregation of CNTs in the regions where a lower shear stress was applied. As a result, the CNTs dispersion was well stabilized.

• Elastomers and Composites
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• v.40 no.3
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• pp.159-165
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• 2005

Reactive monomer, glycidyl methacrylate (GMA), was grafted onto low density polyethylene (LDPE) using peroxide and then reactive blend with nylon-6 was rallied out by corotating twin screw extruder. Grafting of GMA was identified using FT-IR. Graft ratio or GMA increased with reaction temperature, peroxide concentration and styrene comonomer concentration. It is observed that tensile elongation and tensile strength or LDPE-g-GMA/nylon-6 blend were higher than those of LDPE/nylon-6 blend. Morphology of blend was analyzed using SEM.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.26-29
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• 2012

본 연구에서는 목분-폴리프로필렌 복합재의 연소성 및 열적특성을 평가하기 위하여 한계산소지수 실험 및 열중량 분석실험을 실시하였다. 목분-폴리프로필렌 복합재의 제조를 위하여 이축압출기를 활용한 압출공정과 사출성형기를 활용한 사출공정을 이용하였다. 그리고 복합재의 난연성능 향상을 위하여 난연제(4종류)를 첨가한 복합체의 화재성능을 평가하였다.

• The Korean Journal of Rheology
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• v.10 no.3
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• pp.152-159
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• 1998

폴리카보네이트와 스티렌-아크릴로니트릴 공중합체의 블렌드를 이축 압출기에서 용 융혼련할 경우의 분산혼련 작용기구를 연구하였다. 분산상 형성에 관계되는 지배적인 과정 은 sheet, lace 및 ligament 생성에 이어 Rayleigh 형태의 불안정성에 기인한 구형의 분산상 (droplet) 형성으로 확인되었다. 분산상과 연속상의 점도비와 분산상의 크기에 대한 상관관 계의 조사에서는 주어진 점도비의 범위에서 점도비 약 70인 경우를 제외하고는 거의 무관한 관계를 나타내었으며 이는 이축 압출기의 강력한 혼련요소인 kneading 부위에서 주어지는 연신 흐름장에 의한 영향을 반영한 것으로 해석되었다. 분산상의 최종크기는 오히려 분산상 들간의 coales-cence 정도에 크게 영향을 받았으며 연속상의 점도가 상대적으로 낮은 경우 에 동일한 분산상에 대한 coalescence 정도가 심화되어 분산상의 크기가 증가되었다.

• Rubber Technology
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• v.7 no.1
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• pp.1-7
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• 2006

• Rubber Technology
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• v.7 no.2
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• pp.71-81
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• 2006

• Proceedings of the Korean Society of Rheology Conference
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• 2006.06a
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• pp.153-156
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• 2006