• 폴리머
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• 제37권2호
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• pp.204-210
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• 2013

첨가제(윤활제 및 산화방지제)와 용융혼합 조건(온도, 시간 및 로터 속도)이 폴리프로필렌(PP) 기반 WPC(wood polymer composite)의 기계적 특성에 미치는 영향을 조사하였다. WPC는 용융혼합 후 압축성형하여 제조하였다. 용융혼합 과정을 이해하기 위해 WPC 용융혼합물의 토크 변화를 측정하였다. 말레산무수물로 개질된 폴리프로필렌을 상용화제로, 나노점토를 보강재로 각각 사용하였다. WPC의 기계적 특성을 측정하기 위해 UTM과 충격시험기를 이용하였고 색차계를 이용하여 WPC의 용융혼합 조건에 따른 변색을 측정하였다. 기계적 특성 분석에 따른 최적용융혼합 조건은 $170^{\circ}C$, 15분, 60 rpm인 것으로 나타났다. 윤활제와 산화방지제의 함량이 증가할수록 WPC의 기계적 특성이 하락함을 확인하였다. 용융혼합 과정에서 목분만을 별도로 나중에 투입하는 이단계 방법이 전형적인 일단계 방법보다 WPC의 기계적 특성 향상에 더 효과적이었다.

• 폴리머
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• 제24권3호
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• pp.333-341
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• 2000

선형 폴리락틱산/스타형 폴리락틱산 블렌드를 용융 및 용액 블렌딩에 의해 제조하여 이들의 열적 특성 및 결정화 거동을 살펴보고 블렌딩 방법이 이들에 미치는 영향을 살펴보았다. 분지형 구조를 갖는 스타형 폴리락틱산은 선형 폴리락틱산에 비하여 용융 및 용액 가공에서의 분자량 감소가 적음을 확인하였으며, 용융 가공에 비하여 용액 가공에서 분자량 분포가 넓어짐을 확인하였다. 스타형 폴리락틱산을 선형 폴리락틱산에 블렌딩하였을 경우 용융온도의 감소와 유리전이온도의 감소를 확인하였으며, 용액 블렌딩에 의하여 얻어진 블렌드는 용융 블렌딩에 의하여 얻어진 블렌드에 비하여 낮은 유리전이온도를 갖음을 알 수 있었다. 분지형 구조로 인하여 상대적으로 결정화가 어려운 스타형 폴리락틱산과 스타형 폴리락틱산 함량이 높은 블렌드의 경우, 용액 가공에 의하여 용융 가공에서 보다 높은 결정화도를 얻을 수 있었다.

• Fibers and Polymers
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• 제4권3호
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• pp.107-113
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• 2003

The branched polypropylene (b-PP) was prepared by melt blending process with initiator, antioxidant, and functional monomers to improve the melt strength through the melt grafting. The melt flow index (MFI) of the b-PP was increased with increasing the initiator content. On the introduction of the alkylamine as the branching agents the MFI of the b-PP was increased, while that of the b-PP with the pentaerythritol triacrylate (PT) was decreased. It may be caused by the chain scission of the i-PP backbone due to the reduced thermal stability of the i-PP on the melt blending. The MFI of the b-PP without the antioxidant was increased due to the chain scission occurred during the melt processing, while on the introduction of the antioxidant, the MFI of the b-PP was decreased. The crystallization temperature of the b-PP was higher than that of PP, which was attributed to the branched chain structure. It was found that the PT was the most effective functional monomers for enhancing the melt properties of the b-PP.

• Fibers and Polymers
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• 제7권1호
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• pp.36-41
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• 2006

PVC and SAN are often mixed to compensate for the disadvantages of each polymer. Miscibility and thermal stability of PVC/SAN blend were investigated in this study by blending SAN polymer having 20, 24, 28, 32 % of acrylonitrile contents. Two polymers were mixed using a melt blending method with a single screw extruder. DSC thermogram was used to evaluate miscibility of the two polymers. SAN having 24 % of acrylonitrile showed the best miscibility with PVC. In order to evaluate degradation behavior, blended polymer was heat treated in DSC furnace and glass transition temperature was measured consecutively. Glass transition temperature increased continuously with annealing time due to degradation and cross-linking of polymer chains. Melt index of blended polymer was always higher than that of PVC.

• 폴리머
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• 제30권2호
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• pp.118-123
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• 2006

폴리(부틸렌 테레프탈레이트)(PBT)와 폴리(에틸렌 테레프탈레이트)(PET)의 용융 가공시 발생하는 상호에스테르 교환반응이 PBT/PET 블렌드의 유변 물성에 미치는 영향에 대하여 살펴보았다. PBT에 PET를 용융 블렌딩하면 PET의 상대적인 낮은 점도에 의하여 PET의 함량이 증가할수록 PET의 점도가 감소됨을 알 수 있었으며 이와 함께 용융가공시 발생하는 분자량 감소와 PBT와 PET 상호간에 발생하는 상호에스테르 교환반응에 의하여 추가적인 용융점도 감소가 있음을 확인하였다. 또한 PBT와는 달리 윤활제로 사용한 calcium stearate(CaST)는 PBT/PET 블렌드에서 윤활 작용은 미약한 반면 이들 블렌드의 열분해에 따른 분자량 감소와 상호에스테르 교환반응을 촉진하여 추가적인 용융점도 감소를 초래함을 알 수 있었다.

• Fibers and Polymers
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• 제5권4호
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• pp.264-269
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• 2004

The present paper deals with improvement in disperse dyeablility as well as imparting of cationic dyeablility to difficultly dyeable polypropylene by a melt blending technique. Isotactic polypropylene (PP) was blended with fibre grade polybutylene terephthalate (PBT), cationic dyeable polyethylene terephthalate (CDPET) and polystyrene (PS), individually. The resulting binary blends were spun and drawn into fibres at draw ratio 2, 2.5, and 3. The compatibility of blends, structural changes of fibres in terms of X-ray crystallinity, relative crystallinity, sonic modulus, birefringence and thermal stability were examined. The blended fibres were found to be disperse dyeable by the conventional method of high temperature and high pressure dyeing. And this dye ability increased with increase in the level of substitution. PP/CDPET blend also exhibited dyeablility with cationic dyes in addition to that with disperse dyes. The optimum level of blending was predicted keeping in view of tenacity and thermal stability of melt blend fibres. The wash fastness properties of the dyed fibres were found to be of high rate.

• 폴리머
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• 제26권4호
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• pp.483-491
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• 2002

나일론 6의 상온 및 저온에서의 내충격성을 개선할 목적으로 폴리우레탄 (PU)/나일론 6 용융블렌드를 Haake Rheomix를 사용해 제조한 후 PU 함량 (10, 20, ,30, 40, 50 wt%) 및 블렌딩 시간 (5, 10, 15, 20분)에 따른 결정구조, 동역학적 특성, 인장특성 및 충격거동을 WAXD, DMA, UTM 및 notched Izod 충격시험기 등을 이용하여 조사하였다. PU 함량 및 블렌딩 시간이 증가할수록 블렌드의 결정회절피크의 형태는 넓어지고 회절피크의 강도는 감소하였다. 블렌드의 유리전이온도, 인장강도, 인장탄성률로 감소하였으며, 신도는 증가하였다. 또한 PU 함량이 블렌딩 시간보다 결정구조, 동역학적 특성 (tan $\delta$) 및 인장특성 등에 더 큰 영향을 미침을 알 수 있었다. PU/나일론 6 (10/90 wt%) 블렌드 상온 ($20^{\circ}C$) 및 저온 ($-35^{\circ}C$)에서의 충격강도가 크게 향상될 수 있음을 확인하였다.

• Macromolecular Research
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• 제13권3호
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• pp.223-228
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• 2005

In the present work, a low-density polyethylene (LDPE) composite, filled with Zn-ion coated structural silica encapsulated with the diglycidyl ether of bisphenol-A (DGEBA), was synthesized using the conventional melt-blending technique in a sigma internal mixer. The catalytic activity of the Zn-ions (originating from the structural silica) towards the oxirane group (diglycidyl ether of bisphenol-A (DGEBA): encapsulating agent) was assessed by infrared spectroscopy. Two composites, each with a filler content of $2.5 wt\%$ were developed. The first one was obtained by melt blending the Zn-ion coated structural silica with LDPE in a co-rotating sigma internal mixer. The second one was obtained by melt blending the same LDPE, but with DGEBA encapsulated Zn-ion coated structural silica. Epoxy resin encapsulation of the Zn-ion coated structural silica resulted in its having good interfacial adhesion and a homogeneous dispersion in the polymer matrix. Furthermore, the encapsulation of epoxy resin over the Zn-ion coated structural silica showed improvements in both the mechanical and thermal properties, viz. a $33\%$ increase in the elastic modulus and a rise in the onset degradation temperature from 355 to $371^{\circ}C$, in comparison to the Zn-ion coated structural silica.

• Fibers and Polymers
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• 제5권2호
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• pp.145-150
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• 2004

Blends of poly(phenylene sulfide) (PPS) and polyethylene, either linear low density polyethylene (LLDPE) or metallocene-catalyzed polyethylene (MPE), that were prepared by melt blending, were investigated. From the rheological properties as determined by capillary rheometry, the melt viscosity of both PPS/LLDPE and PPS/MPE blends was low when PE was in dispersed phase, but high melt viscosity was observed for both blends with PPS in dispersed phase. Significant differences depending on the composition were found in the mechanical properties such as percent elongation at break and notched Izod impact strength. In addition, dispersed phase morphology of the blends was analyzed by a scanning electron microscope (SEM), together with brief discussion about the difference between them.

• Fibers and Polymers
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• 제4권2호
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• pp.59-65
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• 2003

PLA/LPCL/HPCL blends composed of poly(lactic acid) (PLA), low molecular weight poly($\varepsilon$-caprolactone) (LPCL), and high molecular weight poly($\varepsilon$-caprolactone) (HPCL) were prepared by melt blending for bioabsorbable fila-ment sutures. The effects of blend composition and blending time on the ester interchange reaction by alcoholysis in the PLA/LPCL/HPCL blends were studied. Their thermal properties and the miscibility due to the ester interchange reaction were investigated by $^1{H-NMR}$, DSC, X-ray, and UTM analyses. The hydroxyl group contents of LPCL in the blends decreafed by the ester interchange reaction due to alcoholysis. Thus, the copolymer was formed by the ester interchange reaction at $200^{\circ}C$ for 30-60 minutes. The thermal properties of PLA/LPCL/HPCL blends such as melting temperature and heat of fusion decreased with increasing ester interchange reaction levels. However, the miscibility among the three poly-mers was improved greatly by ester interchange reaction. Tensile strength and modulus of PLA/LPCL/HPCL blend fibers increased with increasing HPCL content, while the elongation at break of the blend fibers increased with increasing LPCL content.