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지상규,Lawrence T. Drzal,조동환 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.102 No.-
In the present study, exfoliated graphite nanoplatelets (EGN) were chemically modified with carboxylterminatedpoly(butadiene-co-acrylonitrile) (CTBN) liquid rubber via carboxylation, acylation, and subsequentlyesterification. Multiple characterizations by means of attenuated total reflectance-Fourier transforminfrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffractionspectroscopy, thermogravimetric analysis, and scanning electron microscopy demonstrated the chemicalmodification. For comparison, neat vinyl ester resin (VE), EGN/VE and CTBN-EGN/VE composites wereprepared by using a free-standing Teflon mold to avoid pressure during curing. The amounts of EGNand CTBN-grafted EGN containing in EGN/VE and CTBN-EGN/VE composites were 1, 3, and 5 wt%, respectively. The impact strength of EGN/VE and CTBN-EGN/VE composites was strongly dependent upon theCTBN-grafted EGN concentration incorporated into neat VE. It was remarkably enhanced up to 220–240% even with low contents (5 wt%) of CTBN-grafted EGN in comparison to neat VE and unmodifiedEGN/VE. The result revealed that a small amount of EGN chemically modified with liquid rubber CTBNplayed an important role in increasing the impact toughness of thermosetting resin.
에폭시 복합체의 표면 및 기계적 특성에 미치는 액상고무의 효과
추정민 ( Jeoung Min Chu ),이은경 ( Eun Kyoung Lee ),최세영 ( Sei Young Choi ) 한국고무학회 2008 엘라스토머 및 콤포지트 Vol.43 No.2
Epoxy resins are thermoset polymers that exhibit good adhesion, creep resistance, heat resistance, and chemical resistance. These polymers, however, give poor resistance to crack propagation and low impact strength. In this study, epoxy/carboxyl-terminated butadiene acrylonitrile (CTBN) and epoxy/amine-terminated butadiene acrylonitrile (ATBN) composites were prepared with different ratio of CTBN and ATBN to improve low impact strength of epoxy resin. The impact strength of epoxy/elastomeric composites shows high values with increasting nonpolar surface free energy while the tensile strength and the glass transition are decreased. The highest surface free energy, impact strength observed when 15 phr CTBN and 15 phr ATBN added, respectively. It can be concluded that as liquid rubber to improve impact strength of epoxy resin, ATBN is more preferable to CTBN.
실란 커플링제로 처리된 실리카가 탄성에폭시의 경화온도 및 기계적 물성에 미치는 영향
최선미 ( Sun Mi Choi ),이은경 ( Eun Kyoung Lee ),최세영 ( Seo Young Choi ) 한국고무학회 2008 엘라스토머 및 콤포지트 Vol.43 No.3
본 연구에서는 실란 커플링제을 변량 배합하여 습식법과 건식법으로 실리카를 전처리하여 epoxy/carboxyl-terminated butadiene acrylonitirile (EP/CTBN) 복합체를 제조하였다. EP/CTBN 복합체의 경화특성 및 표면자유에너지, 인장강도 및 충격강도의 기계적 특성과 계면 특성을 건식법과 습식법에 따라 고찰하였다. Differential scanning calorimetry(DSC)의 결과 실란커플링제의 양이 증가함에 따라 실리카의 기공을 막아 경화제의 양을 증가시켜 경화온도가 감소되었으며, 건식법보다는 습식법이 EP/CTBN 복합체의 경화온도를 감소시킴을 알 수 있었다. 또한 실란커플링제의 양이 증가함 따라 표면자유에너지와 충경강도가 증가되었으나, 인장강도는 실란커플링제의 양이 4 wt%일 때 감소되었으며, 습식법보다는 건식법이 더 물성을 향상시킴을 알 수 있었다. In this work, epoxy/carboxyl-terminated butadiene acrylonitirile (EP/CTBN) composites were prepared by employing a reinforcing filler, silica treated with silane coupling agent in different ratio by dry and wet method. Their curing characteristics, surface free energy, interface morphologies and mechanical properties such as tensile strength and impact resistance were carefully investigated. Differential scanning calorimetry(DSC) results showed that curing temperature was lowered with the increase of silane coupling agent because of the increase of relative curing agent cotent by filling the pores of silica. Wet method was proved to be more effective for lowering curing temperature of EP/CTBN composite. In general, surface free energy and impact resistance were increased with the increase of silane coupling agent in this work. Tensile strength, however, was observed to be decreased at 4 wt% of silane coupling agent. It was found that the dry method was proved to be preferable for pretreatment of silica with coupling agent.
Effect of Carbon-based Nanofillers on the Toughening Behavior of Epoxy Resin
( Gi-bbeum Lee ),( Haeran Kim ),( Wonjae Shin ),( Jinseok Jeon ),( In-seok Park ),( Changwoon Nah ) 한국고무학회 2021 엘라스토머 및 콤포지트 Vol.56 No.3
Carbon-based nanofillers, including nanodiamond (ND) and carbon nanotubes (CNTs), have been employed in epoxy matrixes for improving the toughness, using the tow prepreg method, of epoxy compounds for high pressure tanks. The reinforcing performance was compared with those of commercially available toughening fillers, including carboxyl-terminated butadiene acrylonitrile (CTBN) and block copolymers, such as poly(methyl methacrylate)-b-poly(butyl acrylate)- b-poly(methyl methacrylate) (BA-b-MMA). CTNB improved the mechanical performance at a relatively high filler loading of ~5 phr. Nanosized BA-b-MMA showed improved performance at a lower filler loading of ~2 phr. However, the mechanical properties deteriorated at a higher loading of ~5 phr because of the formation of larger aggregates. ND showed no significant improvement in mechanical properties because of aggregate formation. In contrast, surface-treated ND with epoxidized hydroxyl-terminated polybutadiene considerably improved the mechanical properties, notably the impact strength, because of more uniform dispersion of particles in the epoxy matrix. CNTs noticeably improved the flexural strength and impact strength at a filler loading of 0.5 phr. However, the improvements were lost with further addition of fillers because of CNT aggregation.