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그라프트화 전분의 제조 : 중합방법에 따른 스티렌 그라프트 효율
조창기,이기호,우상원,황승식,최종범 ( C . G . Cho,K . H . Lee,S . W . Woo,J . B . Choi,S . S . Hwang ) 한국공업화학회 1997 공업화학 Vol.8 No.5
전분의 친수성 및 반응성을 조절하기 위하여 propylene oxide, 1,2-epoxybutane, glycidyl methacrylate, maleic anhydride, caprolactone 등을 반응시켰으며 건조되지 않은 전분을 사용할 경우 propylene oxide, maleic anhydride 외에는 반응 수율이 아주 낮아지는 것이 관찰되었다. 이렇게 개질된 전분을 스티렌과 반응시켜 그라프트 공중합물로 전환하였으며 여러가지 중합방법에 대한 그라프트 수율이 비교되었다. 그라프트 중합반응의 경우 용액중합 및 cerium(IV)이온에 의한 중합은 각각 낮은 효율과 수율을 보였다. 현탁중합 방법으로는 전분 입자의 친수성 때문에 폴리스티렌으로 전분을 encapsulation 하기가 어려웠으며, 유화중합이 스티렌을 그라프트 시키기에 제일 적당한 방법임을 알 수 있었다. The corn starch was treated with propylene oxide, 1,2-epoxybutane, glycidyl methacrylate, maleic anhydride, caprolactone, respectively, in order to alter the hydrophilicity and the reactivity of starch. When the starch was not dried, poor reaction was observed except the reaction with propylene oxide or maleic anhydride. The treated starches were grafted with styrene by several different polymerization methods. Solution polymerization and redox polymerization using cerium(IV) ion show poor grafting efficiency and poor yield. Encapsulation of starch with polystyrene by suspension polymerization was difficult due to the hydrophilicity of the starch. Among the examined methods, emulsion polymerization was found to be the suitable way to graft styrene onto starch.
폴리(스티렌-g-카프로락톤)을 이용한 폴리스티렌/폴리카보네이트 블렌드의 상용화
조창기,오병석 한국섬유공학회 2002 한국섬유공학회지 Vol.39 No.3
Well-defined poly(styrene-g-caprotactone) copolymers (PS-g-PCL) were synthesized and they were used as the compatibilizers for polycarbonate (PC) and polystyrene (PS) blends. For the PS-g-PCL graft copolymers, polycaprolactone macromer having M,, of 8,700 g/mole and polydispersity of 1.07 was copolymerized with styrene via radical polymerization. The PS/PCL weight ratio of the three obtained graft copolymers was 50/50, and the number of PCL branches per polymer chain were 3, 6, and 8. Thermal analysis showed that the three graft copolymers contain crystalline PCL phase. Scanning electron microscopy (SEM) pictures showed that the domain size of PS decreased when the contents of the graft copolymer containing 3 branches increased from 1 to 5 wt% in PC/PS ,)0170 wtfc blends. A weak melting endotherm on the differential scanning calorimetric analysis indicates that not all PCL branches are situated on the PC/PS interface when the content of the graft copolymer is more than 3 wt%. When 5 wt% of each graft copolymer wa.1 blended, the sizes of PS domain of the three PC/PS 30/70 wt% blends were similar but slightly larger when the number of branch of graft copolymer was 8.
Study on Moisture Absorption Characteristics of Superabsorbent/Sepiolite Composites
조창기,변성윤 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
Sepiolite is one of many naturally occurring nano needle-shaped clay materials, composed of hydrated magnesium silicate, and it has been used to increase the mechanical, physical, and thermal properties of a polymer. In this study sepiolite was used as a filler component in superabsorbent polymer composites to regulate the moisture absorption capability of a hydrophilic polymer. Water soluble monomers were polymerized in the presence of sepiolite dispersion, and the products were isolated to make sepiolite/polymer composites. Moisture absorption performance of the composites were evaluated at constant temperature and relative humidity using a thermo-hygrostat.
Preparation of Poly(AA-co-AM)/filler Composite by Inverse Suspension Polymerization
조창기,변성윤 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
Acrylic acid/acrylamide copolymer (Poly(AA-co-AM) is widely used as a superabsorbent polymer. And the copolymers containing different amount of sepiolite as a filler were prepared in this study by inverse suspension polymerization in cyclohexane medium. Obtained polymers were easily isolated, and the products were characterizaed by FT-IR, TGA and SEM. Moisture absorption performance of the composites were evaluated at constant temperature and relative humidity using a thermo-hygrostat.
Study on Flexible Humidity Sensor Printed on PET Film
조창기,신소영 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1
Carbon black is widely used as a conductive material due to its superior electrical conductivity, heat resistance, and low cost. In this study, a conductive paste was prepared from carbon black, and printed on a flexible polyethylene terephthalate (PET) substrate for humidity sensing electrodes. Then the obtained electrodes were coated with a humidity sensing solution to create a wearable humidity sensor. For the humidity sensing solution, polymer composites were formulated by mixing polyvinyl alcohol (PVA), a water-soluble polymer, and polydiallyldimethylammonium chloride (PDDA), a polyelectrolytic polymer. Resistance change of the wearable sensor created was measured using thermo-hygrostat with varying relative humidity at predetermined temperatures.