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Peroxide 개질에 따른 Nylon 12 elastomer의 특성 연구
최명찬 ( Myung Chan Choi ),정지연 ( Ji Yeon Jung ),장영욱 ( Young Wook Chang ) 한국고무학회 2013 엘라스토머 및 콤포지트 Vol.48 No.1
용융상태에서 nylon 12 elastomer에 소량의 dicumyl peroxide (DCP) 와 triallyl cyanuate (TAC)를 첨가하여 nylon 12 elastomer를 부분적으로 가교시켰으며, 이에 따른 nylon 12 elastomer의 기계적, 동적기계적 그리고 유변학적 특성을 tensile test, DMA, small amplitude oscillating rheometer를 이용하여 각각 알아보았다. TAC의 함량이 증가함에 따라 인장탄성률과 영률은 증가하고, 파단신율은 감소하였다. DMA 측정결과, DCP로 부분적으로 가교시킨 nylon 12 elastomer의 PTMG상의 유리전이온도는 순수한 nylon 12 elstomer에 비해 증가하였고, storage modulus는 nylon 12상의 용융온도 이상에서도 거의 일정한 값을 나타내었다. 부분적으로 가교시킴에 따른 유변학적 특성의 변화는 TAC의 함량이 증가함에 따라 solid like behavior와 shear thinning behavior가 점점 뚜렷하게 나타남을 알 수 있었다. 이로부터 nylon 12 elastomer를 용융상태에서 부분적으로 가교시킴으로써 용융가공성을 저하시키지 않으면서, 기계적 물성은 효과적으로 향상시킬 수 있었으며, 특히, nylon 12 elastomer의 사용가능 온도범위를 증가시킬 수 있었다. Nylon 12 elastomer was slightly crosslinked in molten state by the addition of small amount of dicumyl peroxide (DCP) as a crosslink agent and triallycyanuate (TAC) as a co-agent during melt compounding at 160 oC in an internal mixer. The effect of the peroxide crosslinking on mechanical, dynamic mechanical and rheological properties of the nylon 12 elastomer was investigated by means of tensile testing, dynamic mechanical analysis (DMA) and small amplitude oscillating rheometer, respectively. With modification, there is an improvement in tensile modulus and Young`s modulus with decease in elongation at break. DMA results for peroxide modified nylon 12 elastomers demonstrated that the glass transiaiton temperature of PTMG segment shifted to higher temperature and the storage modulus remained constant above the melting temperature of nylon 12 segments. Melt rheological studies revealed that the peroxide modified nylon 12 elastomer exhibited a more solid like behavior and stronger shear thinning behavior compared to neat nylon 12 elastomer, which was more prominent at higher TAC content in the polymer matrix. The peroxide modified nylon 12 elastomer exhibited good elastic recoverability and improved mechanical properties without sacrificing melt processibilty, and especially the service temperature range increased as compared to neat nylon 12 elastomer.
장영욱(Young Wook Chang),김재범(Jae Beum Kim),정경호(Kyung Ho Chung),전영식(Young Sik Chun),정진수(Jin Soo Jung) 한국고무학회 1998 엘라스토머 및 콤포지트 Vol.33 No.4
N/A Isocyante terminated urethane prepolymers were synthesized by the reaction of 4,4`-dimethyl phenyldiisocyanate(MDI) and ester type polyols such as ethylene glycol/butanediol adipate(EBA), neopentylglycol/butanediol adipate(NBA) and hexanediol adipate (HA). All of the NCO-terminated urethane prepolymers are solid at room temperature, but they become mobile enough to be disposed onto a substrate upon heating about 80℃. Subsequently, they are solidified and cured through the reaction with moisture. Tensile behavior of the urethane hotmelt exhibits characteristic features depending on the type of polyol. The adhesive strength determined by single lap shear joint is higher in order of HA, NBA and EBA based urethane hotmelt., which can be correlated with the magnitude of breaking energy of the cured films. The failure mode are cohesive for all cases and the adhesive strength increases as the test is performed faster. This indicates that the strength of the adhesive joint is primarily dependent upon the bulk properties of the adhesives.
Transoctylene rubber ( TOR ) 의 첨가가 NR / isotactic pp 블렌드의 물성에 미치는 영향
장영욱(Young Wook Chang),양영철(Yung Chul Yang),나창운(Chang Woon Nah) 한국고무학회 2001 엘라스토머 및 콤포지트 Vol.36 No.3
N/A Thermoplastic elastomers based on dynamically vulcanized NR/TOR/PP (rubber/PP=70/30) blends were prepared in a Haake banbury mixer. Effect of TOR content on the mechanical, dynamic mechanical and thermal stability of the rubber/plastic blends was characterized by UTM, DMTA, and TGA. On the addition of traps-polyoctylene rubber(TOR) to the rubber phase, there was a decrease in compression set and increase in tensile properties, hardness and dynamic properties as well as thermal stability of the elastomeric blends. Improvements in the properties were believed to be due to an increase in crosslink density of the rubber phase and increase in homogeneity of the blends.
화학적으로 가교된 EPDM (Nordel(R) IP)의 열적기계적 특성 및 형상기억거동
장영욱 ( Young Wook Chang ),한정은 ( Jung Eun Han ),강신춘 ( Shin Choon Kang ),조을룡 ( Ur Ryong Cho ) 한국고무학회 2007 엘라스토머 및 콤포지트 Vol.42 No.4
결정성을 갖는 에틸렌프로필렌디엔 고무(Nordel(R)IP)를 과산화물로 가교시키고 열적, 기계적특성과 형상기억거동을 조사하였다. 겔함량 측정결과 가교도는 DCP 함량에 따라 증가되었으며, DSC 분석결과 가교된 고무는 결정상이 존재하고 있음을 알 수 있었다. 인장시험 결과 가교도가 증가함에 따라 고무의 모듈러스는 증가되며 파단신율은 감소되었다. 이와 같이 가교 구조 내에 결정상을 함유하는 고무는 우수한 형상기억 특성을 나타내었다. 즉, 이러한 고무는 결정상의 용융온도 이상에서 쉽게 원하는 형태로 변형되고, 변형된 상태에서 냉각시키면 변형된 형태로 잘 고정되었으며, 또한 이렇게 변형된 형상의 시료를 용융온도 이상으로 가열하면 원래의 모양으로 신속히 되돌아오는 것을 관찰할 수 있었다. Thermomechanical and shape memory properties of dicumyl peroxide(DCP) cured semicrystalline EPDM(Nordel(R) IP) were investigated. From gel content analysis, it can be seen that Nordel can be crosslinked by small amount of DCP and the degree of crosslinking increased with the increase of DCP content. DSC analysis revealed that the melting temperature and degree of crystallinity of the crosslinked rubber decreased with the increase of DCP. Tensile test showed that tensile modulus increased and elongation at break of the rubber decreased with an increase in the degree of crosslinking. The chemically crosslinked semi-crystalline EPDM exhibited excellent shape memory behavior, i.e. the sample was easily deformed to have an arbitrary secondary shape above its melting temperature and was fixed well in its deformed state when it is cooled, and then the fixed shape was recovered to its original shape very fast upon heating above its melting temperature.