• 폴리머
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• 제25권6호
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• pp.811-817
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• 2001

용매와 비용매의 다양한 비율에 따라서 bisphenol A polycarbonate(PC)의 무정형에서 결정성의 상변화를 확인하였다. 용매로 chloroform을, 비용매로 isopropanol을 사용하였다. 결정화된 PC는 광학현미경과 SEM, XRD, DSC를 이용하여 조사하였고, DSC와 XRD의 측정값은 PC의 결정화도를 판단하는데 이용하였다. 용해도 상수는 PC의 결정화도를 조절하는데 중요한 인자로 PC 결정화도 차이는 혼합용매의 용해도 상수 차이로 설명하였다. 용매와 비용매 비율이 75/25 wt%의 PC 용액에서 고결정화도를 가진 PC powder로 얻을 수 있었다. 이런 결과는 혼합용매의 용해도 상수(9.85)가 PC의 용해도 상수(9.9)와 유사하였기 때문이라고 판단된다.

• Macromolecular Research
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• 제10권3호
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• pp.135-139
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• 2002

Blends of the linear bisphenol-A polycarbonate (L-PC) and randomly branched bisphenol-A polycarbonate (Br-PC), prepared by co-rotating twin screw extrusion, were investigated using differential scanning calorimetry (DSC), sag resistance time tester, extensional rheometry, and advanced rheometric expansion system (ARES). From the DSC results, the glass transition temperature (T$_{g}$) of the L-PC/Br-PC blend was increased with the increase of Br-PC in the blend, and the blend showed a single T$_{g}$, which suggests a miscible blend. The sag resistance time of the L-PC/Br-PC blend was increased with the increase of Br-PC in the blends. From the results of rheological measurements of the L-PC/Br-PC blends, the extensional viscosity and the complex viscosity of the blends were found to increase with the increase of Br-PC in the blends. The increase of extensional viscosity and complex viscosity was related with the increase of sag resistance time with the Br-PC in the L-PC/Br-PC blends.nds.

• Macromolecular Research
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• 제9권3호
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• pp.129-142
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• 2001

To efficiently demonstrate the molecular motion, physical properties, and mechanical properties of polycarbonates, we studied the differences between bisphenol-A polycarbonate(BPA-PC) and tetramethyl bisphenol-A-polycarbonate(TMBPA-PC) using molecular modeling techniques. To investigate the conformations of BPA-PC and TMBPA-PC and the effect of the conformation on mechanical properties, we performed conformational energy calculation, molecular dynamics calculation, and stress-strain curves based on molecular mechanics method. From the result obtained from conformational energy calculations of each segment, the molecular motions of the carbonate and the phenylene group in BPA-PC were seen to be more vigorous and have lower restriction to mobility than those in TMBPA-PC, respectively. In addition, from the results of radial distribution function, velocity autocorrelation function, and power spectrum, BPA-PC appeared to have higher diffusion constant than TMBPA-PC and is easier to have various conformations because of the less severe restrictions in molecular motion. The result of stress-strain calculation for TMBPA-PC seemed to be in accordance with the experimental value of strain-to-failure ∼4%. From these results of conformational energy calculations of segments, molecular dynamics, and mechanical properties, it can be concluded that TMBPA-PC has higher modulus and brittleness than BPA-PC because the former has no efficient relaxation mode against the external deformations.

• 한국산학기술학회논문지
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• 제15권2호
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• pp.1216-1221
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• 2014

PEIT는 옥수수와 같은 재생 가능한 자원에서 유래한 isosorbide monomer를 이용하여 bio-contents를 함유하고 있는 PET이다. 하지만 isosorbide contents가 향상될수록 기계적물성이 감소하는 단점이 있다. 본 연구에서는 우수한 기계적 물성을 가지고 있는 polycarbonate를 이용하여 PEIT의 단점을 보완하고, 또한 PEIT를 이용하여 PC의 인장신율 향상을 통해 성형가공성을 개선하고자 하였다. 이축압출기를 통해 제조한 PEIT/PC 블렌드에서 polycarbonate가 모폴로지, 유리전이온도거동, 열적안정성 및 기계적 물성에 미치는 영향을 확인하기 위해 FE-SEM, DMA, TGA, UTM 및 Izod impact tester를 통하여 분석을 수행하였다. 이로써 우수한 기계적 물성을 가진 polycarbonate는 PEIT와 상용성이 있음을 확인하였으며, 특히 PEIT25PC75 조성에서 열적 안정성 및 기계적 특성의 향상이 뛰어난 것을 알 수 있었다.

• Korean Chemical Engineering Research
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• 제48권2호
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• pp.164-171
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• 2010

최근 폴리카보네이트의 수요가 증가에 따라 폴리카보네이트의 폐기물이 많이 발생하고 있다. 폐 폴리카보네이트를 재활용하여 새로운 소재 원료로 주목을 받고 있는 diol 형태의 bisphenol A계 bishydroxyethyl ether(BHE-BPA)를 얻고자 하였다. 이 물질은 폴리카보네이트계 폴리우레탄 합성에 좋은 소재로 사용될 수 있다. 본 연구에서는 에틸렌글리콜과 수산화나트륨(NaOH)을 각각 용매와 촉매로 사용하였고, 분해반응 생성물 중 하나인 에틸렌카보네이트(Ethylenecarbonate, EC)를 첨가하여 생성물의 전환율을 조사하였다. 알칼리촉매 사용에 따라 단순 글리콜리시스 반응에서 관찰되지 않았던 ether 화합물들이 합성되었으며 온도 $220^{\circ}C$, 10% 촉매/PC 몰비, EC 20 mmol 조건에서 폴리카보네이트로부터 수율 92% 이상의 BHE-BPA를 얻었고 재결정을 통하여 99% 이상의 순도를 얻는 것이 가능하였다.

• Korea-Australia Rheology Journal
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• 제18권1호
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• pp.1-8
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• 2006

Blend of bisphenol-A polycarbonate (PC) and (acrylonitrile-styrene-acrylic rubber) terpolymer (ASA) having excellent balance in the interfacial properties and mechanical strength was developed for the automobile applications. Since interfacial adhesion between PC and styrne-acrylonitrile copolymer (SAN) matrix of ASA is not strong enough, two different types of compatibilizers, i.e, diblock copolymer composed of tetramethyl polycarbonate (TMPC) and SAN (TMPC-b-SAN) and poly(methyl methacrylate) (PMMA) were examined to improve interfacial adhesion between PC and SAN. TMPC-b-SAN was more effective than PMMA in increasing interfacial adhesion between PC and SAN matrix of ASA (or weld-line strength of PC/ASA blend). When blend composition was fixed, PC/ASA blends exhibited similar mechanical properties except impact strength and weld-line strength. Impact strength of PCI ASA blend at low temperature was influenced by rubber particle size and its morphology. PC/ASA blends containing commercially available PMMA as compatibilizer also exhibited excellent balance in mechanical properties and interfacial adhesion.

• 폴리머
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• 제25권6호
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• pp.818-825
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• 2001

폴리카보네이트 (PC)와 몬모릴로나이트 (montmorillonite, MMT)의 나노복합체를 용액 및 용융 혼합 방법으로 층간삽입시켜 제조하여 X-ray 실험으로 MMT의 층간간격 변화를 조사하였다. MMT로는 $Na^+$를 양이온으로 갖는 순수 MMT (MMT-Na)와 도데실암모늄 (MMT-DA) 및 dimethyl hydrogenated tallow 2-ethylhexyl ammonium으로 개질된 MMT (MMT-25A)를 사용하였다. PC/MMT-25A와 PC/MMT-DA가 PC/MMT-Na보다 층간거리의 증가폭이 컸으며, 혼합방법에 따라 최대 $37AA$까지 층간간격이 증가하였다. 또 PC의 분자량이 작을수록, 혼합시간이 증가할수록 삽입이 잘 일어났다. 열중량분석법 (TGA)으로 측정한 열안정성은 PC/MMT-25A가 PC/MMT-Na와 순수한 PC보다 우수함을 나타내었다.

• 한국생산제조학회지
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• 제20권5호
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• pp.523-527
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• 2011

Polycarbonate (PC) polymer is an engineering plastic which has large tensile strength and impact resistance and is wildly used as functional parts like micro mold. Direct machining of PC materials produces lots of burrs and rough surface due to large ductility and weak heat resistance and hence it is very difficult to machine PC materials using cutting tool to make micro-parts. In this study, elliptical vibration cutting (EVC) or 2-dimensional vibration cutting was performed to minimize the size of micro V-grooves on PC material. From the experimental results, it was observed that as the cutting depth and pattern size become smaller, the better machining quality was obtained, which is attributed to the positive effect of EVC that is dependent on the ratio of vibration amplitude to cutting depth. As the height of V-groove becomes less than $1.8{\mu}m$, however, the machining quality becomes lower as the pattern size decreases.

• Korea-Australia Rheology Journal
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• 제20권4호
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• pp.245-251
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• 2008

Two polysiloxanes having different chemical structures were blended with polycarbonate (PC) under ultrasonic irradiation in solution. The polysiloxanes used were poly(methylphenyl siloxane) and vinyl-terminated poly(dimethyl siloxane). It was of primary interest to investigate the effect of polysiloxane structure on the rheological properties of PC/polysiloxane blends. It was found that a small amount (1.5 phr) of polysiloxanes greatly altered the melt viscosities and elasticity of PC. In particular, incorporation of poly(methylphenylsiloxane) led to a notable increase in elasticity with greater shear sensitivity of PC. The observed rheological behaviors of PC/polysiloxane blends were partly explained in conjunction with the tendencies found in ultrasonic degradation of polysiloxanes. Thermal stability and morphology in sonicated blends of PC/polysiloxane blends were also discussed.

• Elastomers and Composites
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• 제39권4호
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• pp.324-329
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• 2004

인계난연제가 함유된 Polycarbonate (PC)/Acrylonitrile-Butadiene-Styrene (ABS) 블렌드에서 사출온도가 상승될 경우 모폴로지 변화와 크레이즈 (Craze) 발생 정도 및 기계적 강도와의 상관관계에 대하여 연구하였다. 사출온도가 상승될 경우 분산상의 합체현상(Coalescence)이 나타났으며 파괴시편에서 크레이즈가 많이 발생하였음을 관찰하였다. 또한 급격한 충격강도의 저하가 발생하였다. 소량의 상용화제를 첨가한 경우 합체현상이 억제됨을 관찰하였으며 크레이즈도 많이 줄여 들었음을 관찰하였다.