• 한국의류학회지
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• 제13권1호
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• pp.89-97
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• 1989

Graft polymerization of MMA onto cotton fiber was carried out in two ways, two step graft polymerization and one step emulsion graft polymerization, using tetravalent cerium ion as an initiator. At two step graft polymerization, the first step was the pretreatment of cotton fiber with an aqueous initiator solution and the second was the grafting pretreated cotton fiber in the monomer solution. In case of one step emulsion graft polymerization, MMA was emulsified with SLS in initiator solution. Under the various graft polymerization conditions, graft yield, graft efficiency and from the Arrhenius plot the apparent activation energy were compared. The results of this study were as follows: 1. Graft yield and graft efficiency of emulsion graft polymerization were higher than those of two step graft polymerization. 2. In case of two step graft polymerization, graft yield was affected by the pretreatment time of cotton fiber with an aqueous initiator solution. And graft yield of emulsion graft polymerization was increased with the concentration of emulsifier below cmc of SLS and was decreased thereafter. 3. Elevation of temperature resulted increase in graft yield for both grafting methods. The apparent activation energy of emulsion graft pelymerzation was lower than that of two step graft polymerization. 4. Increased reaction time increased in graft yield, but decreased in graft efficiency. 5. Moisture regain of grafted cotton was decreased with graft yield.

• 한국의류학회지
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• 제15권3호
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• pp.271-280
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• 1991

Emulsion graft copolymerization of MMA onto cotton fiber using Ce(IV) salt as an initiator was carried out. Graft yield and graft efficiency were observed according to the kinds and concentrations of emulsifier and polymerization conditions. The physical properties of MMA grafted cotton fabric were investigated. The results of this study were as follows: 1. The heighest graft yield of emulsion graft polymerization occurred at the concentration below cmc of emulsifier, which was different from emulsion polymerization. Nonionic sur- factant as an emulsifier was more effective than anionic one. 2. The highest graft yield was obtained at the initiator concentration $1{\times}10^{-2}mol/l$. The viscometric molecular weight of PMMA was in the order of 106. 3. As reaction time increased, the graft yield increased but the graft efficiency decreased. 4. Elevation of reaction temperature resulted in increase of graft yield. The apparent activation energy of MMA graft polymerization was 4.72 Kcal/mol. 5. Physical properties of MMA grafted cotton fabric varied with increase of grafting. Thickness and stiffness showed a noticeable increase, whereas tensile strength and elongation was slightly increased. Crease recovery increased as the graft yield increase up to $50\%$ and decreased thereafter.

• 접착 및 계면
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• 제25권1호
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• pp.152-156
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• 2024

에폭시 접착소재의 단점인 경질화에 따른 성형성 부족을 개선하고자 무수말레인산을 이용한 산변성 폴리올레핀 기반 2액형 에폭시 접착소재를 연구하였다. 반응 조건에 따른 산변성도를 파악하기 위하여 공정별, 폴리올레핀 분자량/개시제 반감기/개시제 함량별 연구를 진행하였으며, 제조된 산변성 폴리올레핀을 에폭시 경화제와의 혼합 후 알루미늄과 CPP 필름 라미네이션 접착소재로 사용하였다. 용융공정 대비 용액공정의 산변성 효율이 약 30% 우수하였으며, 산변성율이 증가할수록 박리강도는 증가함을 확인하였다.

• 한국염색가공학회지
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• 제4권4호
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• pp.81-89
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• 1992

Graft polymers of alginic acid-PMMA, different in composition and Mv of branched PMMA, were prepared by emulsion graft polymerization at various MMA concentrations. In aqueous dispersion solution, the adsorption of graft polymer on the montmorillonite was carried out to modify the surface property of powder, and the adsorption of PMMA in organic solvents (acetone, benzene) on the modified surface of powder were observed. The results obtained were as follows. 1. In emulsion graft polymerization of MMA on the sodium alginate in aqueous solution, SA conversion, MMA conversion and % grafting were increased with increasing MMA concentration where as graft efficiency was decreased. 2. The adsorption amount of graft polymer was increased with the elevation of temperature and the increased of dispersion concentration and with the increase of branched PMMA composition of graft polymer. 3. In organic solvent, the adsorption of PMMA on the surface modified particle was proceeded by the orientation along the stretched branched PMMA of adsorbed graft polymer which is in radial direction to the particle surface. 4. The adsorbed amount of PMMA was increased as the temperature and concentration of PMMA solution, the branching of adsorbed graft polymer and the solvency of solvent were increased.

• 대한가정학회지
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• 제30권1호
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• pp.1-9
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• 1992

Graft polymerization mechanism and rate of polymerization of MMA and MMA/4-VP onto cellulose fiber using Ce(IV) salt as an initiatior were investigated. It was shown that the concentration of Ce(IV) salt affected on the graft yield, graft efficiency, total conversion and the rate of graft polymerization. The graft yield and total cenversion for MMA grafted polymer were significantly higher than those for MMA/4-VP grafted polymer with variation of CAN concentration. In this system the oxidative termination by Ce(IV) salt was considered particularly in higher concentration Ce(IV) ion. The change in the mode of termination reactions with variation of CAN concentration made possible the presence of an optimum Ce(IV) ion concentration for maximum graft yield.

• Elastomers and Composites
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• 제14권1호
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• pp.7-12
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• 1979

Graft copolymerization of methlymethacrylate(MMA) onto sodium alginate(SA) aqueous solution by sodium metaperiodate$(NaIO_4)$ as an initiator was carried out with the variation of the reaction time, the reaction temperature and the concentrations of initiator and monomer. The results obtained were as follows: 1. SA was easily separated from the reaction mixture of homopolymer, graft polymer and sodium alginate ungrafted by the treatment of concentrated boiling $Na_3PO_4$, solution with the small amount of $Na_2SO_3$ to the mixture and then isolated as the acid form by acidifying the salts solution containing SA. 2. The amount of graft polymer was larger than that of homopolymer below $70^{\circ}C$ whereas above $70^{\circ}C$ the amount of homopolymer was larger. 3. The sum of each amount of graft polymer ana homopolymer was always increased with increase of the reaction time, the reaction temperature and the concentrations of initiator and monomer. 4. With increase of the concentration of initiator, the graft efficiency was increased below $70^{\circ}C$ while decreased above $70^{\circ}C$. 5. Graft copolymerization of MMA onto SA in aqueous solution was carried out without initiator.

• Nuclear Engineering and Technology
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• 제9권2호
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• pp.65-74
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• 1977

High dose rates꼭 전자선을 이용하여 Polyester 직포에 acrylic acid를 중합 반응시켰다. Homopolymerization inhibitor로서 cation 을 첨가시키면 hoinopolymerization 뿐만 아니라 graft효율도 감소되었다. Graft 중합 반응 속도는 선량율이 1.6$\times$$10^{6}$rad/sec에서부터 10$\times$$10^{6}$ rad/sec 사이에서 선량율의 0.82승에 비례하였다. Acrylic acid가 graft 중합 반응된 Polyester 직포는 흡습성, 제전성 효과 등이 크게 증진되었다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1996년도 추계 학술발표회
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• pp.53-58
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• 1996

The Chitin Thiocarbonate-Fe(II)-H2O2 redox initiator system was investigated for the graft copolymerization of acrylonitrile(AN) and acrylic acid(AA) monomers onto chitin powder. The reactions with vinyl monomers onto chitin were carried out under various the graft copolymerization conditions to elucidate the polymerization behavior in terms of graft yield. Reactions of chitin-acrylonitrile graft copolymer with hydroxyl amine hydrochloride and those with sodium hydroxide were conducted in order to obtain chitin-(amidoxime-co-acrylonitrile) and chitin-(acrylate-co-acrylamide) graft copolymers, respectively. The reaction efficiency was observed to depend on the alkali concentration, time, temperature, and the reactant concentrations. The prepared chitin derivatives were evaluated to find potential applications for use in wastewater treatments for adsorption and desorption of heavy metal ions as well as acidic and basic dyes.

• 한국의류학회지
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• 제17권3호
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• pp.347-358
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• 1993

Graft copolymerization of MMN4-VP onto cotton fiber using Ce(IV) salt as an initiator and triton X-100 as an emulsifier was performed under various polymerization conditions. In cograft polymerization, the polymeization behavior according to variation of 4-VP feed composition and the characteristics of MMA/4-VP graft polymer such as affinity for acid dye owing to cationization of cotton, antibacterial activity and thermal behavior were investigated. The results of this study were as follows : 1. While in copolymerization of MMA and 4-VP, 4-VP content in copolymer was more than that of monomer feed composition. 2. Increasing 4-VP content, graft yield was decreased, but graft efficiency was increased. In case of MMA/4-VP graft polymerization, the highest graft yield was obtained at higher CAN concentration than in MMA graft polymerization, the reason is that the behavior of 4-VP was disturbed by Ce(IV) sail 3. Elevation of temperature resulted in increase of graft yield and the apparent activation energy of MMA/4-VP graft polymerization was higher than that of MMA graft polymerization. 4. MMA/4-VP grafted cotton fiber showed affinity for acid dye, antibacterial activity and higher moisture regain than MMA grafted cotton fiber. MMA/4-VP grafted cotton fabric showed improvement of wrinkle recovery up to 40~50% graft yield and decreased thereafter. MMA/4-VP and MMA grafted cotton fabric did not showed significant difference in wrinkle recovery and stiffness.

• Journal of Chest Surgery
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• 제26권2호
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• pp.80-85
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• 1993

Synthetic and biosynthetic vascular grafts of small diameter have long been considered to be prone to thrombosis, ultimately leading to the complete graft occlusion. Endothelial cell seeding onto synthetic blood-contacting surfaces has been suggested to be an ideal means to solve this problem. This study described a culture method of bovine endothelial cells and evaluated blood-compatibility and seeding efficiency of cultured endothelial cells. Bovine pulmonary artery endothelial cells were harvested enzymatically and grown to confluence on polystyrene culture flask surfaces using established techniques. The identification of endothelial cells was made through the demonstration of expression of factor VIII R:Ag by immunofluorescent technique. To quantitate the effect of improvement in blood-compatibility of viable endothelial cells, endothelial monolayers were exposed to blood containing $\^$111/In-oxine labeled platelets. Viable endothelial monolayers retained less labeled platelets than control surfaces. The Indium-labeled endothelial cells were seeded onto three different blood-contacting surfaces of Dacron vascular graft immobilized in specially equipped wells and incubated for specific time intervals (t=15, 30, 60, 120 minutes). Longer incubation times showed improved cell adherence in collagen-coated and fibrin-coated Dacron vascular graft groups. However in untreated Dacron grafts, no direct relationship was observed between incubation time and endothelial cell seeding efficiency. This may be due to leakage of endothelial cells through porosity of Dacron grafts in this in-vitro experimental condition.