• Journal of Pharmaceutical Investigation
• /
• 제19권4호
• /
• pp.173-178
• /
• 1989

Drug release rates from copolymer hydrogels were controlled by their hydrophilic-hydrophobic balances. As a model copolymer hydrogel, poly(acrylamide-co-styrene) was synthesized at different monomer composition. Release mechanisms of propranolol-HCI from the copolymer matrices were investisated. Swelling rates of the copolymer hydrogels retarded as their hydrophobicity increased. Swelling kinetics of the copolymer hydrogels regulated drug release rates via polymer relaxation controlled release mechanisms. Zero order drug release could thus be achieved within certain periods.

• 한국미생물·생명공학회지
• /
• 제17권5호
• /
• pp.429-435
• /
• 1989

A bacterial strain of Brevibaterium sp. CH1 was isolated and used to produce an enzyme (nitrile hydratase) necessary for earring out the bioconversion of acrylonitrile to acrylamide. The culture and reaction conditions, and medium optimization were studied for the strain. The conversion yield was nearly 100％ with a trace amount of acrylic acid produced. The strain showed strong activity of nitrile hydratase toward acrylonitrile and extremely low activity of the amidase toward acrylamide. We sought optimum culture conditions for the formation of nitrile hydratase by Brevibacterium sp. CH1. The effects of temperature and pH on the activity of free and immobilized tells were investigated. The nitrite hydratase of Brevibacterium sp. CH1 acted not only on various aliphatic nitrites such as acrylonitrile, propionitrile and acetonitrile, but also on aromatic nitrile as nicotinonitrile.

• Coupled systems mechanics
• /
• 제6권3호
• /
• pp.369-376
• /
• 2017

Intermolecular interaction energies and conformer geometries of the hydrogen bonded acrylamide dimers have been studied by using the second-order Møller-Plesset (MP2) perturbation theory and the density functional theory (DFT) with 17 density functionals. Dunning's correlation consistent basis sets (up to aug-cc-pVTZ) have been used to study the basis set effects. The DFT calculated interaction energies are compared to the reference energy data calculated by the MP2 method and the coupled cluster method at the complete basis set (CCSD(T)/CBS) limit in order to determine the relative performance of the studied density functionals. Overall, dispersion-energy-corrected density functionals outperform uncorrected ones. The ${\omega}B97XD$ density functional is particularly effective in terms of both accuracy and computational cost in estimating the reference energy values using small basis sets and is highly recommended for similar calculations for larger systems.

• Elastomers and Composites
• /
• 제51권3호
• /
• pp.181-187
• /
• 2016

Transparent acrylic pressure sensitive adhesives (PSAs) were successfully prepared by photopolymerization with 2-ethylhexyl acrylate (2-EHA) and 2-hydroxyethyl acrylate (2-HEA) as a default constituent and with isobornyl acrylate (IBOA) and N-(isobutoxymethyl)acrylamide (IBMA) as a variable constituent. The IBMA mole fraction effect in the acrylic PSAs was investigated on adhesion performances and the optical properties including 85/85 test as well as the characteristics (solid content, and molecular weight) of the PSA syrups were also investigated. Regardless increasing the IBMA mole fraction in the acrylic PSAs, the acrylic PSAs exhibited almost the same adhesion performance such as $180^{\circ}$ peel strength (~4.0 kg/25 mm) and probe tack (~0.27 kg). All the acrylic PSA samples also showed high transmittance (more than 91%), low haze (less than 1.0%) and low color-difference (less than 1.0) before and after 85/85 test.

• 한국염색가공학회지
• /
• 제16권1호
• /
• pp.26-33
• /
• 2004

Two reactive disperse dyes having $\alpha$-bromoacrylamide or acrylamide group were synthesized and their dyeing properties were compared with a disperse dye. Dyeing properties of reactive disperse dyes were strongly influenced by the chemical structure of reactive group. The amount of absorbed reactive disperse dye containing $\alpha$-bromoacrylamide group on polyester fiber was less than the disperse dye, and that on nylon fiber was much higher. When polyester and nylon fiber were simultaneously dyed in a dye pot, nylon fiber absorbed the reactive disperse dye more than polyester fiber. The reactive disperse dye having acrylamide group could reduces difference in color depth to a large extent, but the application of carrier or variation of dyebath pH were not sufficient for giving the same color depth to both fibers. The N/P union fabric could be dyed with the reactive disperse dye and its wash fastness were good to excellent.

• Macromolecular Research
• /
• 제10권3호
• /
• pp.140-144
• /
• 2002

Dispersion polymerization of acrylamide was carried out in the media of methyl alcohol/$H_2O$ mixtures using hydroxypropyl cellulose and ammonium persulfate as steric stabilizer and initiator, respectively. The effects of concentrations of initiator and steric stabilizer, amount of monomer, polymerization temperature, methyl alcohol/$H_2O$ ratio, and purification of monomer and nitrogen purge on the particle size of the latices and molecular weight of the polymers were investigated. The average particle diameter increased with increasing concentration of initiator, water content in methyl alcohol/$H_2O$ media, and polymerization temperature, but decreased with monomer and stabilizer concentrations. The viscosity average molecular weight increased with increasing concentrations of monomer, steric stabilizer, and water content in dispersion media, but decreased with initiator concentration and polymerization temperature. The PAM polymers prepared with the purified monomer and the nitrogen purging before the reaction showed the highest molecular weight.

• Macromolecular Research
• /
• 제8권4호
• /
• pp.147-152
• /
• 2000

The activity of periodic acid as an initiator for the polymerization of acrylamide in aqueous medium was investigated. The rate of polymerization was found to be proportional to the monomer concentration to the 1.5th power in the range of 1.41-5.64 mol/L. The reaction order to the periodic acid concentration was 0.49, which indicated a bimolecular mechanism for the termination reaction in the range of 0.5-4.0$\times$10$\^$-2/ mol/L. Propagation rate increased with raising the temperature according to an Arrhenius expression resulting in the exhibition of an apparent activation energy of 87.8 kJ/mol in the temperature range of 60-80$\^{C}$. The addition of hydroquinone as a radical scavenger stopped the polymerization of acrylamide initiated by periodic acid. These results support that the polymerization proceeds via a radical chain mechanism .

• Elastomers and Composites
• /
• 제57권2호
• /
• pp.48-54
• /
• 2022

A polymeric adhesion promoter was synthesized to improve the adhesive strength of the Ni lead frame/epoxy composite. Poly(itaconic acid-co-acrylamide) (IAcAAM) was prepared by copolymerizing itaconic acid and acrylamide. We compared the adhesive strength between the Ni lead frame and epoxy composite according to the molecular weight of IAcAAM. The molecular weight of IAcAAM was controlled using an initiator, which made it possible to use IAcAAM in the epoxy molding compound (EMC) manufacturing process by modulating the melting temperature. The adhesive strength of Ni lead frame/epoxy composite increased with the addition of IAcAAM to the epoxy composite. In addition, as the molecular weight of IAcAAM increased, the adhesive strength of the Ni lead frame/epoxy composite slightly increased. We confirmed that IAcAAM with an appropriate molecular weight can be used in the EMC manufacturing process and increase the adhesive strength of the Ni lead frame/epoxy composite.

• 원예과학기술지
• /
• 제30권5호
• /
• pp.603-612
• /
• 2012

본 연구는 콜드칩 가공용 감자 계통을 선발하고자, 47계통과 대조구 품종인 '대서', '수미', '구이벨리'의 수확 후, $4^{\circ}C$, $8^{\circ}C$ 저온저장 및 $20^{\circ}C$ 가온 조정처리에 따른 glucose 함량, 아크릴아마이드 함량 및 두 형질 간의 상관성을 비교 분석하였다. 대조구 품종 및 47계통 모두에서 수확 후, glucose 함량이 0.25% 이하, 아크릴아마이드 함량 1000ppb 이하로 나타났고, $4^{\circ}C$ 저온저장에 의해 glucose와 아크릴아마이드 함량 모두 급격히 증가하였으며, H7, H13, H16, H40 등 4계통에서만 500ppb 이하로 검출되었다. $8^{\circ}C$ 저온저장 역시 두 함량 모두 증가하였으나, $4^{\circ}C$ 저온저장에 비해 비교적 낮게 나타났으며, $20^{\circ}C$ 가온 조정에 의해서도 두 함량 모두 감소한 것으로 나타났다. 저온저장에 따른 glucose 함량과 아크릴아마이드 함량 간의 상호관계를 분석한 결과 정의 상관성을 확인할 수 있었다. 결론적으로 저온처리에도 낮은 glucose 함량을 나타낸 H7, H13, H16, H40계통들이 낮은 함량의 아트릴아마이드 함유한 것으로 나타나 콜드 칩 가공용 우수 감자 계통으로 선발할 수 있었다.

• 한국미생물생명공학회:학술대회논문집
• /
• 한국미생물생명공학회 1977년도 추계학술발표회 및 특별 강연초록
• /
• pp.198.1-198
• /
• 1977

Aspergillus nidulans가 생산하는 naringinase를 acrylamide gel을 이용한 entrapping moth길에 의하여 고정화하여 그 고정화 효소의 물리, 화학적인 성질에 대하여 검토한 결과 다음과 같았다. 1) Acrylamide의 농도는 10% 일때 enzyme activity가 가장 좋았다. 2) Immobilized enzyme의 최적온도는 $50^{\circ}C로서$ 유리효소의 경우보다 $10^{\circ}C정도$ 증가 하였고 최적 pH는 유리효소의 경우와 마찬가지로 pH 40이었다.(중략)