• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.172-176
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• 1998

Epoxy adduct carboxyl terminated butadiene acrylonitrile(CTBN) was prepared by blending of CTBN and epoxy resin. CTBN/PU/epoxy was prepared from polyurethane(PU), epoxy resin, and CTBN. The CTBN/PU/epoxy using 5 wt% of CTBN content showed shifting damping peak as PU content increased. It suggested that CTBN/PU/epoxy had good compatibility for all composition at 5 wt% of CTBN content. But miscibility of CTBN/PU/epoxy decreased with the increase of the CTBN content. PU content for maximum flexural properties of CTBN/PU/epoxy was 10 wt%, but decreased with the increase of the PU content. The fracture toughness of CTBN/epoxy was improved by addition of the PU. Fracture surfaces of CTBN/PU/epoxy showed the shear deformation and generation of stress whitening which is associated with the cavitation. Cavitation in the CTBN and shear defomation in the PU modified epoxy matrix are the toughening mechanisms for CTBN/PU/epoxy.

• Polymer(Korea)
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• v.32 no.1
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• pp.31-37
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• 2008

The effect of MMT on mechanical properties of CTBN toughened epoxy nanocomposite is studied. In case of CTBN toughened epoxy nanocomposite with modified MMT, it is found that the enhancement of toughness and tensile properties are exhibited in CTBN toughened epoxy nanocomposite with modified MMT From the results of fractured surface morphology of sample, it is clearly shown that the improved mechanical properties can be obtained in CTBN toughened nanocomposite due to the significant energy dissipation mechanism by MMT loading.

• Polymer(Korea)
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• v.25 no.2
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• pp.246-253
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• 2001

Amino terminated PES-CTBN-PES triblock copolymer was synthesized from PES oligomer and commercial CTBN rubber (CTBN1300$\times$13), and molecular weight of the copolymer was controlled to be 15000 g/mole. The copolymer was utilized to toughen diglycidyl ether of bisphenol-A (DGEBA) epoxy resin which was cured with 4,4'-diaminodi-phenylsulfone (DDS) and subjected to the measurement of thermal properties, fracture toughness ( $K_{IC}$), flexural properties and solvent resistance. The properties were compared with those from the samples modified by CTBN/PES blends. The maximum loading of copolymer into the epoxy resin was 40 wt% without utilizing solvent, at which $K_{IC}$ fracture toughness of 2.21 MPa${\cdot}m^{0.5}$ was obtained without sacrificing flexural properties and chemical resistance. However, the epoxy resin modified with PES/CTBN blend exhibited much lower $K_{IC}$ and flexural properties compared to the epoxy resins toughened by PES-CTBN-PES copolymers.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.172-176
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• 1999

에폭시 수지의 강인성 향상을 위하여 양말단에 아민 반응기를 가지는 PES-CTBN-PES triblock copolymer를 합성하여 이를 에폭시 수지의 강인화제로 사용하였으며 경화제로는 p-DDS(p-dichlorodiphenylsulfone)를 사용하였다. 또한 공중합체에 의한 물성 향상효과를 CTBN과 PES-NH$_2$의 블렌드에 의한 경우와 비교하였다. 강인화된 에폭시 수지의 물성은 강인성 및 굴곡특성을 측정하여 분석하였으며, 열특성은 DSC, TGA, 및 DMA에 의해 실시되었다. 그리고 강인화된 에폭시 수지의 강인성 향상 mechanism을 규명하기 위하여 파단면을 SEM으로 분석하여 상분리 거동을 고찰하였다. 높은 유리전이온도와 우수한 기계적 물성을 가지는 고성능 기능성 폴리설폰(PES-NH$_2$)과 상용 액상 고무 첨가제인 CTBN을 이용하여 합성된 공중합체를 강인화제로 사용함으로써 열안정성, 탄성률 및 내식성의 감소없이 에폭시 수지의 쳐대 단점인 강인성을 최적 수준으로 개선시킬 수 있었으며 공중합체의 에폭시 수지에 대한 우수한 용해도에 따른 가공성이 향상되었다.

• Composites Research
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• v.36 no.5
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• pp.355-360
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• 2023

Epoxy-based carbon fibers reinforced plastic (CFRP) exhibit limitations in their suitability for industrial applications due to high brittleness characteristics. To address this challenge, extensive investigations are underway to enhance their toughness properties. This research focuses on evaluating the toughening mechanisms achieved by Polyamide 6 particles(p-PA6) and Carboxyl-Terminated Butadiene-Acrylonitrile (CTBN) elastomer, with a specific emphasis on utilizing minimal additive quantities. The study explores the impact of varying concentrations of p-PA6 and CTBN additives, namely 0.5, 1, 2.5, and 5 phr, through comprehensive Mode I fracture toughness and tensile strength analyses. The inclusion of p-PA6 demonstrated improvements in toughness when introduced at a relatively low content of 1phr. This improvement manifested as a sustained fracture behavior, contributing to enhanced toughness, while simultaneously maintaining the material's tensile strength. Furthermore, the investigation revealed that the incorporation of p-PA6 affected in particle aggregation, thus influencing the overall toughening mechanism. Incorporation of CTBN, an elastomeric modifier, exhibited a pronounced increase in fracture toughness at higher concentrations of 2.5 phr and beyond. However, this increase in toughness was accompanied by a reduction in tensile strength, resulting in fracture behavior similar to conventional CFRP exhibiting brittleness. The synergy between pPA6, CTBN and CFRP appeared to marginally enhance tensile strength under specific content conditions. As a result of this study, optimized conditions for the application of the p-PA6, CTBN toughening technology have been identified and established.

• Elastomers and Composites
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• v.43 no.2
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• pp.113-123
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• 2008

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.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.10a
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• pp.15-15
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• 1997

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.181-181
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• 1996

• Elastomers and Composites
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• v.43 no.3
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• pp.147-156
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• 2008

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.

• Korean Journal of Materials Research
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• v.7 no.3
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• pp.229-233
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• 1997

Estimation of thermal stability for diglycidy1 ether of bisphenol A(DGEMA)/4, 4'-methylene dianiline (MDA)/pheny1 glycidy1 ether(PGE)-acetamide(AcAm)/carboxy1-terminated acrylonitrile butadiene copolymer (CTBN) system was studied by thermogravimetry(TG) analysis. To get activation energy for thermal degradation, Freeman & Carroll, Kissinger, and Flynn & Wall expressions were used. The activation energy of Freeman & Wall expression was 112.9kj/mol, that of Kissinger expression was 151.5 kj/mol and that of Flynn & Wall was 168.3kj/mol.