Polyketone/Polyamide-6 블렌드의 등온 및 비등온 결정화 연구

박민정,배민기,고은빈,박병식,윤근병 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

결정성 고분자인 Polyketone은 우수한 열적, 화학적, 기계적 성질을 가지고 있지만, 열에 의한 분해가 잘 일어나고 가공범위가 좁다는 단점이 있다. 이러한 단점을 보완하기 위하여 공중합이나 블렌드에 대한 연구가 많이 진행되고 있다. Polyketone과 다양한 고분자와의 블렌드를 통하여 성질을 개선하는 연구가 진행 되었지만, 대부분의 고분자와 상용성이 없으나 Polyamide-6와의 경우는 상용성이 있는 것으로 알려져 있다. Polyketone/Polyamide-6 블렌드의 상용성에 관한 연구에서 결정화 거동 및 상호인력에 관한 상세한 연구는 보고되지 않고 있다. 본 연구에서는 Polyketone/Polyamide-6 블렌드의 상용성을 Tg분석과 자외선 분광법, 녹는점 강하법으로 알아보았다. Polyketone/Polyamide-6 블렌드 조성에 따른 결정화 거동은 등온결정화와 비등온결정화 방법으로 조사하여 결정화 속도, Avrami 상수 등을 구하였으며, spherulite 형상 및 성장 속도와 등온결정화에서 구한 결정화 속도와 비교하였다. Polyketone/Polyamide-6 블렌드의 Tg는 전 조성에서 하나로 관찰되었으며, 각각의 Tg 값의 중간 값을 가지는 것을 보아 비결정성 영역에서의 상용성을 확인하였고, 자외선 분광분석에서의 특정 피크 이동을 통해 수소결합 형성을 확인하였다. 녹는점 강하법으로 얻은 상호인력지수 값이 음의 값을 나타내어 결정성 영역에서의 상용성도 확인하였다. Polyketone/Polyamide-6 블렌드의 결정화 거동은 등온결정화법을 통해 Avrami 상수와 결정화 속도를 구하였다. 또한 spherulite의 형상과 성장속도를 관찰하여 등온결정화법과 비교하였다. 블렌드의 결정화속도 변화와 spherulite 형상의 변화 없이 크기가 작아지고 그 수가 증가하는 것으로 보아 Polyamide-6는 Polyketone의 결정화 메커니즘 변화는 일어나지 않으면서 결정성장 속도를 가속시키는 것을 확인하였다. 비등온 결정화법은 변형 Avrami-Ozawa 모델을 적용하였을 때 등온결정화법과 일치하였다. 이 모델의 속도상수인 F(t)는 Polyketone의 값보다 낮았으며, 동일한 결정화도에서 Polyamide-6의 함량이 증가할수록 감소하였다. 상수는 거의 일정하였으며 이는 Polyketone에 Polyamide-6를 첨가하여도 결정의 성장이나 핵생성 메커니즘에 영향을 주지 않는 것으로 판단된다.

SLS 공정에서의 Polyamide-6 파우더 소결과 그 영향에 관한 연구

배성우(Sung-Woo Bae),김동수(Dong-Soo Kim),김형일(Hyung-Il Kim),김충환(Chung-Hwan Kim),조정대(Jung-Dae Cho),최병오(Byung-Oh Choi) 한국기계가공학회 2006 한국기계가공학회 춘추계학술대회 논문집 Vol.2006 No.-

In the solid freeform fabrication (SFF) system using selective laser sintering (SLS), polyamide-12 powder is currently recognized as general material. In this study, some kinds of polyamide-6 powders with different shape and particlesize were fabricated to investigate the formability, the microstructure and mechanical properties. Also, to develop a more elaborate and rapid system, this study employs a new SLS device with a 3-axis dynamic focusing scanner system instead of the existing f θ lens used in commercial SLS. Polyamide-6 powders having the average size of 100 m were treated thermally in order to keep the spherical symmetry in shape. These polyamide-6 powders were mixed with polyamide-12 powders having the average size of 50 m to give the bimodal distribution of size. These mixed powders showed the better fabrication in the selective laser sintering processbecause the smaller particles of polyamide-11 played an important role in the compact packing of powders by filling the void space between the large particles of polyamide-6. Also, Experiments have performed to evaluate the effect of a scanning path and sintering parameters by fabricating the various 3D objects.

CO₂ Laser에 의한 Polyamide-6 소결과 그 영향에 관한 연구

배성우(S. W. Bae),김동수(D. S. Kim),안영진(Y. J. Ahn),김형일(H. I. Kim),최기섭(K. S. Choi) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월

In the solid freeform fabrication (SFF) system using selective laser sintering (SLS), polyamide-12 powder is currently recognized as general material. In this study, some kinds of polyamide-6 powders with different shape and particlesize were fabricated to investigate the formability, the microstructure and mechanical properties. Also, to develop a more elaborate and rapid system, this study employs a new SLS device with a 3-axis dynamic focusing scanner system instead of the existing f θ lens used in commercial SLS. Polyamide-6 powders having the average size of 100 m were treated thermally in order to keep the spherical symmetry in shape. These polyamide-6 powders were mixed with polyamide-12 powders having the average size of 50 m to give the bimodal distribution of size. These mixed powders showed the better fabrication in the selective laser sintering process because the smaller particles of polyamide-11 played an important role in the compact packing of powders by filling the void space between the large particles of polyamide-6. Also, Experiments have performed to evaluate the effect of a scanning path and sintering parameters by fabricating the various 3D objects.

Effect of Solvents on High Aspect Ratio Polyamide-6 Nanofibers via Electrospinning

Nirmala, R.,Panth, Hem Raj,Yi, Chuan,Nam, Ki-Taek,Park, Soo-Jin,Kim, Hak-Yong,Navamathavan, R. 한국고분자학회 2010 Macromolecular Research Vol.18 No.8

The effect of the solvent on the formation of high aspect ratio ultrafine fibers in polyamide-6 using an electrospinning technique was examined systematically. In this study, formic acid, dichloromethane, acetic acid, chlorophenol, hexafluoroisopropanol, and trifluoroacetic acid via single and mixed solvent system were used for the production of high aspect ratio nanofibers in polyamide-6. Formic acid and mixtures of formic acid/dichloromethane, formic acid/acetic acid, and formic acid/chlorophenol can lead to the very clear dissolution of polyamide-6, enabling their subsequent electrospinning to obtain high aspect ratio nanofibers. Formic acid was found to be the most suitable solvent system for obtaining high aspect ratio nanofibers in polyamide-6. The conductivity of polyamide-6 in formic acid was very high demonstrating an increasing level of free ions in solution. The average diameter of the high aspect ratio nanofibers was approximately one order of magnitude lower than that of main fibers. These findings suggest that the formation of high aspect ratio nanofibers relies strongly on the specific properties, such as the poly-electrolytic behavior of polyamide-6 in the solvent.

Rheological and Thermal Properties of Polyamide 6 and Polyamide 6/Glass Fiber Composite with Repeated Extrusion

이경환,김우년,임승준 한국고분자학회 2014 Macromolecular Research Vol.22 No.6

In this study, the rheological, mechanical, and thermal properties of polyamide 6 (PA6) and PA6/glassfiber (GF) composite with repeated extrusions were investigated. The complex viscosity of the PA6 was found todecrease with the increase of repeated extrusion. The decrease in complex viscosity was due to the decrease in themolecular weights of the PA6. The decrease in tensile strength of the PA6(GF) was due to the continuous choppingof the glass fibers with repeated extrusion, as well as the decrease in molecular weight of the PA6. The half crystallizationtime of the PA6 and PA6(GF) decreased, with the increase of repeated extrusion. The fraction of the 1-timerepeated extrusion of the PA6 (PA6-A) in the PA6/PA6-A blend was obtained from the ratio of the complex viscosityof the PA6-A blend, and the complex viscosity of the PA6. A rheological method is presented that can estimate thefraction of the repeated extrusion of the polymer from the virgin polymer/repeated extrusion of the polymer mixtures.

탄소섬유/폴리아미드 6 복합재료의 비등온 결정화 거동 및 냉각속도에 따른 물성 분석

정진욱,조원기,이하람,원종성,배일준,이승구,Jeong, Jin Wook,Cho, Won Gi,Lee, Ha Ram,Won, Jong Sung,Bae, Il Joon,Lee, Seung Goo 한국섬유공학회 2018 한국섬유공학회지 Vol.55 No.6

Carbon fiber/polyamide 6 (CF/PA6) composites were prepared via film melt impregnation and their crystallization and mechanical properties were studied. The non-isothermal crystallization behavior and mechanical properties of polyamide 6 and CF/PA6 were investigated at different cooling rates. The crystallization time of CF/PA6 decreased depending on the cooling rate compared to that of polyamide 6. The carbon fibers likely acted as nucleating agents in the polyamide 6 matrix. The flexural strength of the composites increased when manufactured at lower cooling rates due to the effects of increased crystallinity as the crystallization continued for a long time. In addition, as the cooling rate increased, the impact resistance increased.

산업용 SFF System에서의 Polyamide-6 파우더 소결 공정 개발

배성우(Sung-Woo Bae),김동수(Dong-Soo Kim),김형일(Hyung-Il kim),김충환(Chung-Hwan Kim),조정대(Jung-Dae Cho),최병오(Byung-Oh Choi) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

In this study, some kinds of polyamide-6 powders with different shape and particle size were fabricated to investigate the formability, the microstructure and mechanical properties. Also, to develop a more elaborate and rapid system, this study employs a new SLS device with a 3-axis dynamic focusing scanner system instead of the existing fθ lens used in commercial SLS. Polyamide-6 powders having the average size of 100 ㎛ were treated thermally in order to keep the spherical symmetry in shape. These polyamide-6 powders were mixed with polyamide-12 powders having the average size of 50㎛ to give the bimodal distribution of size. These mixed powders showed the better fabrication in the selective laser sintering process because the smaller particles of polyamide-11 played an important role in the compact packing of powders by filling the void space between the large particles of polyamide-6. Also, Experiments have performed to evaluate the effect of a scanning path and sintering parameter.

Polyamide 6,6 alloy의 강인화

최필성,배한나,김재익,( A. M. Shanmugharaj ),류승훈 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

Polyamide 6,6는 물리적 특성, 내열성, 내마모성, 내약품성 등이 우수한 고분자 이다. 그러나 우수한 기계적 물성에 비해 내충격성이 약한 단점을 가지고 있다. 이러한 내충격성을 보강하기 위해 glass fiber, carbon fiber를 첨가한 복합재료가 적용되고 있으나 polyamide 6,6의 약한 toughness의 개선에는 한계가 있어왔다. 따라서 본 연구에서는 toughness를 개선하기 위해 반응성 수지를 첨가, alloy 화하여 압출 및 사출을 거쳐 시험편을 제작하였다. 제작된 시험편은 UTM을 이용하여 기계적 물성을 평가하고, FE-SEM을 이용하여 모폴로지와 기계적 물성과의 상관관계를 확인하고, 유변학적 특성을 연구할 예정이다.

Polyamide 6의 산업적인 적용을 위한 음이온 개환 중합의 최적화 연구

민진홍,강지선,허몽영,윤석일 한국섬유공학회 2020 한국섬유공학회지 Vol.57 No.1

To achieve fast synthesis (10 minutes after injection into a mold) of polyamide 6 by anionic ring-opening polymerization of the monomer, ε-caprolactam, the effects of fabrication parameters, such as the concentration of the initiator or activator, reaction temperature, moisture content of the monomer, commercial additives to the polymerization, and properties of polyamide 6, were investigated. The polyamide 6 synthesized at a reaction temperature of 150 °C, and an initiator or activator concentration of 2.5/1.67 wt%, showed a high reaction conversion, molecular weight, and excellent mechanical strength. Applying these parameters to the thermoplastic resin-transfer molding process led to the successful fabrication of thermoplastic carbon fiber-reinforced composites. Anionic polymerization was successful only for monomers with a moisture content of less than 200 ppm. Applying dried N2 gas to the molten ε-caprolactam effectively reduced the moisture content of ε-caprolactam, converting the humid monomers into polymerizable monomers with a low moisture content of less than 200 ppm. The effect of commercial modifiers,BRUGGOLEN® TP-C1608 and NYRIM ADDITIVE 6 plus (Bruggeman, Germany) on the thermal stability and toughness of PA6 was also investigated.

Polyamide-6 파우더를 이용한 SLS 공정 최적화 연구

배성우(S. W. Bae),김동수(D. S. Kim) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.10월