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에폭시 변성 실리카 나노입자/폴리우레탄-우레아 나노복합체 필름의 제조 및 특성 연구
주진 ( Jin Joo ),김현석 ( Hyeon Seok Kim ),김진태 ( Jin Tae Kim ),유혜진 ( Hye Jin Yoo ),이재륭 ( Jae Ryung Lee ),정인우 ( In Woo Cheong ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.2
Hydrophilic silica nanoparticles (SNPs) were treated by using 3-glycidoxypropyltrimethoxy silane (GPTMS) and then they were blended with polyurethane-urea (PUU) emulsions to obtain SNPs/PUU nanocomposite films. Thermo-mechanical properties of the nanocomposite films were investigated by varying the grafted amount of GPTMS onto SNPs and the contents of SNPs in the PUU matrix. The thermo-mechanical properties of the nanocomposite films were also compared in terms of the dispersibility of SNPs in the PUU matrix and thermal curing of the GPTMS-grafted SNPs, The maximum amount of grafted GPTMS was 1.99×10-6 mol/m2, and which covered ca, 53% of the total SNP surface area, 29Si CP/MAS NMR analyses with the deconvolution of peaks revealed the details of polycondensation degree and patterns of GPTMS in the surface modification of SNPs. The surface modification did not significantly affect colloidal stability of the SNPs in aqueous medium; however, the hydrophobic modification of SNPs offered a favorable effect on the dispersibility of SNPs in the PUU matrix as well as better thermal stability. XRD patterns revealed that GPTMS-grafted SNPs broadened the reduced the characteristic peak of polyol in PUU matrix. The composite films became rigid and less flexible as the SNP content increased from 5 wt% to 20 wt%. Particularly, Young`s modulus and tensile modulus significantly increased after the thermal curing reaction of the epoxy groups in the SNPs.
SPG 막유화 및 UV 광중합법에 의해 제조된 PNIPAAm 하이드로젤 입자의 형태학에 관한 연구
이윤직 ( Yun Jig Lee ),김미리 ( Mi Ri Kim ),정인우 ( In Woo Cheong ) 한국접착및계면학회 2015 접착 및 계면 Vol.16 No.2
SPG 막유화법에 의해 NIPAAm, MBA 및 APS를 용해시킨 수용액을 톨루엔과 미네랄오일의 혼합용액인 연속상에 HMP, Span80과 함께 유화(W/O emulsion)시킨 후, UV광중합법에 의해 PNIPAAm하이드로젤 입자를 제조하였다. 연속상 내 미네랄 오일의 비율이 증가할수록, PNIPAAm 하이드로젤의 입도와 입자 내 PNIPAAm의 밀도가 증가하였으며, 이에 따라서 VPTT 근처에서 온도 변화에 따른 하이드로젤의 팽윤도(V/Vo)도 크게 변화하였다. UV 광중합 시 20℃ 에서는 속이 꽉찬 형태의 하이드로젤이 제조되었으나 LCST보다 높은 40℃의 온도에서는 공동입자에서와 같이 하이드로젤의 외벽이 두껍게 형성되었다. 가교제인 MBA의 함량이 증가함에 따라서 가교도 및 입자 내 PNIPAAm의 밀도도 함께 증가하였다. W/O emulsions were prepared from the aqueous solution containing NIPAAm, MBA, and APS in the continuous phase of toluene and mineral oil mixture with HMP and Span80 by using SPG membrane emulsification, and followed by the formation of PNIPAAm hydrogel microspheres through UV photopolymerization. As the ratio of mineral oil to toluene increased in the continuous phase, both particle size of the hydrogel increased and density of PNIPAAm polymer in the hydrogel particle increased, and which significantly affected swelling/deswelling ratio (V/Vo) with temperature change around VPTT. When the polymerization temperature was below LCST (20℃), PNIPAAm hydrogel showed filled particle morphology; however, it was turned out to hollow particle morphology with thick shell layer with 40℃. Both density of PNIPAAm and gel content of the hydrogel increased with the increase in MBA concentration.
Olefin Metathesis를 이용한 황칠 Essential Oil의 경화 반응에 관한 연구
김미리 ( Mi Ri Kim ),이원휘 ( Won Hwi Lee ),유혜진 ( Hye Jin Yoo ),김종상 ( Jong Sang Kim ),정인우 ( In Woo Cheong ) 한국접착및계면학회 2015 접착 및 계면 Vol.16 No.4
황칠원액을 에탄올로 추출한 황칠의 essential oil을 올레핀 메타테시스(olefin metathesis) 반응의 하나인 ROMP(ring opening metathesis polymerization)법을 이용하여 경화 반응을 수행하였으며, 자연 경화 및 UV 광경화법의 경화 특성 및 경화된 필름의 물성에 대해서 비교 연구하였다. 경화 전후의 황칠의 조성 변화에 대해서 가스 크로마토그래피 질량분석법(GC-MS, gas chromatography mass spectrometry)을 통해 연구하였으며, ROMP법에 의해 경화된 필름의 겔 함량(gel contents, 40%)은 자연 경화(8%)나 UV 광경화법(25%)에 비해 높은 값을 보여주었다. 100°C의 온도 및 2 wt%의 Grubbs’catalyst 조건에서 ROMP 경화반응은 2 h 이내의 경화 반응이 완료되어 자연 경화에 비해 비교적 빠른 경화 속도를 보여주었으며, UV 광경화법에 비해 주름이 없으며 외관상 균일한 도막이 형성됨을 확인하였다. 또한 기존에 경화반응에 참여하는 것으로 알려져 있는 폴리아세틸렌계 성분 이외에 sesquiterpene류인 α-selinene, β-selinene, δ-cadinene 등도 ROMP 경화 반응에 참여함을 확인하였다. Raw sap of essential oil in Korean Dendropanax lacquer was extracted with ethanol, and which was cured by using ROMP (ring opening metathesis polymerization, one of olefin metathesis). Curing behavior with subsequent film properties were studied and compared with conventional curing (under ambient conditions) and UV photo curing. The compositional changes of major ingredients in the lacquer before and after curing were studied by using GC-MS (gas chromatography mass spectrometry). ROMP-cured coating film showed higher gel contents (40%) as compared to those of conventional (8%) and UV curing (25%). ROMP curing with 2 wt% Grubbs’ catalyst at 100°C completed curing reaction within 2 h, which was much faster than that of conventional curing. The quality of coating film prepared with ROMP was more homogeneous and wrinkle-free as compared with that with UV curing. It was found that major ingredients of sesquiterpenes, such as α-selinene, β-selinene, and δ-cadinene were reacted in ROMP, as well as polyacetylenes.