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

• 한국인쇄학회지
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• 제14권1호
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• pp.17-29
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• 1996

N-substituted acrylamide hydrogel is reported to have the feature of bing transparent and sensitive enough to response to a temperature stimulus below the temperature of phase transition. Especially at the near of 35 C it becomes shrunk and opaque very quickly. It has also the characteristic of reversing swelling and shrinking. The experiment showed that it is possible to produce a functional gel of super water absorption with the process of free radical polymerizing PVA(polyvinylalcohol) and PAA(polyacrylamide), and crosslinking. The ratio of shrinking and swelling caused by copolymerization rises 10% to 80% at the each temperature of 20 C, 30 C, 40 C, respectively. Phase transition temperature of this gel by copolymerization is50 C while that of ordinary N-substituted acrylamides is between 32~35 C. This temperature reaches the rearing limit of animals and plants so that volumetric transition polymer gel can be ulilized in varying fields such as agriculture/gardening which are water-using field, on-off switch sensing temperature and volumetric variation, processing of liquid wastes and civil engineering works, architecture and electronics. We have no doubt that this material will be the high-functional resin in the hi-tech age of the near future.

• Elastomers and Composites
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• 제37권1호
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• pp.31-38
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• 2002

카르복실화 스티렌-부타디엔 라텍스의 중합시간은 사용되는 부타디엔 모노머가 공액 이중결합을 가진 화학적 구조로 인하여 라디칼 중합시 홀 전파의 비편재화로 인해 아크릴 에멀젼의 제조시 보다 중합시간이 매우 길다. 또한 라텍스 자체가 고분자와 분산매의 분리 없이 사용되기 때문에 라텍스의 안정성은 대단히 중요하다. 물성의 저하없이 반응시간을 단축하기 위하여 기존에 사용하던 연쇄이동제인 사염화탄소 대신 tert-dodecylmercaptane 과 ${\alpha}$-methylstyrene dimer를 혼합 사용하여 반응시간을 14시간에서 12시간으로 줄일 수 있었다. 반응 성장단계에서 아크릴산의 투입량을 0.3 part로 제한하여 라텍스의 점도 상승을 막고 초기중합단계 직후에 아크릴아미드를 0.1 part 첨가하여 라텍스 입자의 내부영역과 외부영역의 고분자 사슬의 상호간확산을 막아 단단하면서도 접착력을 유지할 수 있는 라텍스의 합성 결과를 얻었다.