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장영욱,Joon-Phil Eom,Jae-Gu Kim,Hee-Taik Kim,Dong-Kook Kim 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.2
Shape memory polymer networks were prepared from blends of end-carboxylated telechelic poly(ecaprolactone) (XPCL) and epoxidized natural rubber (ENR). The XPCL/ENR blends can form cross linked structure via interchain reaction between the reactive groups of each polymer during molding at high temperature. Degree of crosslinking of the blend network and their thermomechanical properties were characterized by gel content measurement, DSC and DMA. We found that the degree of crosslinking and crystalline melting transition temperatures was dependent upon the blend compositions as well as the molecular weight of the XPCL segment in the blends. The blends showed a good shapememory behavior such as good shape fixity as well as a high final recovery rate when they exhibit crystalline melting transition with a sufficiently high degree of crosslinking. And the response temperature of the recovery was well matched with Tm of the samples.
김동국,김기섭,장영욱 ( Dong Kook Kim,Ki Seab Kim,Young Wook Chang ) 한국공업화학회 1996 공업화학 Vol.7 No.5
생분해성 지방족폴리에스터인 poly(butylene succinate) (PBS)의 기계적 물성을 변화시키기 위해서 에스터주쇄 구조에 카보네이트 구조를 도입시킨 에스터-카보네이트 공중합체를 합성하였다. 이 공중합체는 일단계에서 succinicacid와 1,4-butanediol(BD)을 에스터 반응시켜 oligo(butylone succinate)를 합성하였고, 이 단계에서 oligohexamethylenecarbonate diol(OHMCG)을 첨가하고 고진공하에서 축중합하여 제조하였다. 촉매로는 titanium(IV) isopropoxide (TIP)를 사용하였다. 합성된 공중합체의 구조는 FT-IR과 ¹H-NMR을 이용하여 확인하였으며, 열적, 기계적 물성은 각각 DSC와 UTM을 이용하여 조사하였다. 고분자량의 공중합체를 얻을 수 있는 적정 촉매양은 succinic acid에 대해서 lwt% 였다. Diol 혼합물의 몰비(BD:OHMCG)가 249:1∼149:1일 때, 높은 점도를 갖는 공중합체를 얻을 수 있었다. 또한, OHMCG의 함량이 증가함에 따라 공중합체의 용융점은 계속 감소하였다. 혼합물의 몰비가 149:1인 경우의 공중합체의 물성은 PBS에 비해 초기탄성율은 약간 감소하였지만 파단신장율은 2배 정도 증가되었다. An ester-carbonate copolymer was synthesized, in which carbonate was inserted into a biodegradable aliphatic polyester, poly(butylene succinate) (PBS), to modify its mechanical properties. The synthesis was carried out by condensation reactions in two steps. In the first step, oligo(butylene succinate) was prepared by the reaction of succinic acid with 1,4-butanediol (BD). In the second step, it was reacted with oligohexamethylenecarbonate diol (OHMCG) to prepare the ester-carbonate copolymer. Titanium(IV) isopropoxide (TIP) was used as a catalyst for the reaction. The structure of the copolymer was confirmed by FT-IR and ¹H-NMR and the thermal behavior and mechanical properties were investigated by differential scanning calorimetry (DSC) and universal testing machine (UTM), respectively. It was found that optimum amount of the catalyst for the formation of high molecular weight copolymer was lwt% for succinic acid. When the BD:OHMCG is in the range 149:1-249:1, the copolymer with high viscosity was obtained. As the OHMCG content was increased, melting temperature (T_m) of the copolymer was decreased. When BD:OHMCG is 149:1, the copolymer showed a increase in ultimate strain by two times and the slight decrease in modulus compared to those of PBS.
張瑛郁,金容眞,金東國 漢陽大學校 基礎科學硏究所 1995 基礎科學論文集 Vol.14 No.-
다양한 에스터 중합용 금속 촉매중에서 ε- caprolactone을 중합하는데는 tin octoate가 가장 우수한 촉매활성을 나타내었다. 괴상중합에서 촉매농도가 증가하면 분자량이 감소하였고 반응온도가 높아지면 분자량과 수율이 증가하였으며 중합온도 180℃, 촉매 0.036㏖%, 중합시간 50분에서 분자량이 41,000인 polycaprolactone을 얻었다. 용액 중합에서도 유사한 경향을 보였다. Lipase가 용해되어 있는 pH 7.4인 완충용액에서 30일간 침지한 polycaprolactone은 분자량이 높을수록 분해가 느려지는 현상을 파단신율의 측정으로 알 수 있었다. The investigation of effective catalyst system for the polymerization of ε- caprolactone showed that tin octoate, among the various catalysts used for polycondensation, was exhibited as having the high catalyst activity. In bulk polymerization the molecular weight of resulting polycaprolactone was decreased with increasing the concentration of tin octcate, while yields and molecular weight were increased with increasing of reaction temperature. The polymerization of ε- caprolactone was carried out using 0.036㏖% catalyst at 140℃ for 50min to give polycaprolactone with a molecular weight of 41,000. The solution polymerization underwent in the same manner as the bulk polymerization. The prepared polycaprolactone was hydrolysed with lipase in pH. 7.4 buffer solution for 30days and its lose of elongation at breaking point determined revealed that polycaprolactone with high molecular weight was degradated slower than that with low molecular weight.