Development of High heat-resistant and High Toughened Thermosetting Resin for composite application

김지훈,천지원,김일진,이동진,이진홍 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Recently, composites are used a wide variety of fields. Representative resin materials for the production of composite materials include thermosetting resins such as epoxy resins, polyester resins, and phenol resins, and thermoplastic resins include acrylic resins. The epoxy resin is widely used as a matrix of thermosetting prepreg because of excellent interfacial adhesion with carbon fiber. Composite materials with thermoplastic resin matrix are simple, excellent in processability and excellent in impact resistance. But they have limitations in aviation and automotive parts due to their low heat resistance. Therefore, it is necessary to develop a resin that can satisfy both high heat resistance, high strength, and impact resistance in order to be applied to aviation and automobile parts. In this study, functional materials such as nanosilica and poly ethersulfone (PES) were selected to give high heat resistance,high strength and impact resistance to thermosetting resins.

Effect of natural rubber on toughness properties of epoxy resins

홍미경,최웅기,김병석,서민강 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Thermosetting resins are used in various performance applications. Especially, the epoxy resins have good dimensional stability, good stiffness, specific strength, chemical resistance, anti-corrosion, moisture resistance, and low shrinkage. However, the main disadvantages of epoxy resins are low toughness and poor resistance to crack propagation due to its brittleness. Epoxy resins need to be toughened with a second component to improve the mechanical properties. One of the successful methods is rubber toughening epoxy resins. The advantage of using the rubber toughening epoxy resins is that the fracture toughness increases without a reduction in other mechanical properties such as tensile strength and flexural strength. In this study, we investigated the properties of epoxy resins/natural rubber composites using X-ray diffraction analysis (XRD), probe tack test, thermo-gravimetric analysis (TGA), scanning electron microscope (SEM), and flexural test.

Hydrolytic stability of cured urea-formaldehyde resins modified by additives

Abdullah, Zaimatul Aqmar,Park, Byung-Dae Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of applied polymer science Vol.114 No.2

<P>Urea-formaldehyde (UF) resins are prone to hydrolysis that results in low-moisture resistance and subsequent formaldehyde emission from UF resin-bonded wood panels. This study was conducted to investigate hydrolytic stability of modified UF resins as a way of lowering the formaldehyde emission of cured UF resin. Neat UF resins with three different formaldehyde/urea (F/U) mole ratios (1.4, 1.2, and 1.0) were modified, after resin synthesis, by adding four additives such as sodium hydrosulfite, sodium bisulfite, acrylamide, and polymeric 4,4′-diphenylmethane diisocyanate (pMDI). All additives were added to UF resins with three different F/U mole ratios before curing the resin. The hydrolytic stability of UF resins was determined by measuring the mass loss and liberated formaldehyde concentration of cured and modified UF resins after acid hydrolysis. Modified UF resins of lower F/U mole ratios of 1.0 and 1.2 showed better hydrolytic stability than the one of higher F/U mole ratio of 1.4, except the modified UF resins with pMDI. The hydrolytic stability of modified UF resins by sulfur compounds (sodium bisulfate and sodium hydrosulfite) decreased with an increase in their level. However, both acrylamide and pMDI were much more effective than two sulfur compounds in terms of hydrolytic stability of modified UF resins. These results indicated that modified UF resin of the F/U mole ratio of 1.2 by adding acrylamide was the most effective in improving the hydrolytic stability of UF resin. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009</P>

고밀도 폴리에틸렌과 실란 처리된 분쇄페놀수지 복합재의 제조 및 특성

박준서(Jun-Seo Park),한창규(Chang-Gue Han),남병욱(Byeong-Uk Nam) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.9

페놀수지는 열경화성 수지로서 우수한 내열성 및 기계적 물성을 가지고 있다. 하지만 열경화 특성으로 인해 사용 후 재활용이 어렵고, 전체 생산량의 15∼20%가 스프루와 런너 형태로 폐기되고 있다. 4만 톤의 페놀수지 스프루와 런너가 버려지고 있으며 폐기된 페놀 스프루와 런너 처리비용은 연간 200억원으로 추정된다. 본 실험에서는 폐기되는 스프루와 런너를 분쇄하고 폴리에틸렌과의 표면접착력 향상을 위해 실란 표면처리를 하였다. 분쇄된 입자의 크기는 100∼1000um의 분체와 1∼100um의 미분으로 나누어 실험하였다. 분쇄된 페놀은 실란 작용기에 따른 특성을 평가하기 위해 3-(Methacryloyloxy) propyltrimethoxysilane 과 Vinyltrimethoxy silane으로 처리되었다. 입자의 크기를 분석하기 위해 입도분석기를 사용였다. 열적특성은 DSC(Differential Scanning Calorimetry)와 HDT(heat deflection temperature)를 통하여 분석하였다. 기계적 물성의 측정은 UTM(universal testing machine)과 notched izod impact tester로 평가하였다. 전처리한 페놀수지 파우더를 첨가시, 고밀도 폴리에틸렌(HDPE)의 열변형온도가 77℃에서 최대 96℃까지 향상되었으며, 결정화도와 결정화 온도가 증가하였다. 결론적으로, 실란 전처리 하지 않았을 경우와 비교했을 때 충격강도는 50%가 인장강도는 20%가 상승하였다. Phenolic resin has excellent heat resistance and good mechanical properties as a thermosetting resin. However, its thermosetting characteristics cause it to produce a non-recyclable waste in the form of sprue and runner which is discarded and represents up to 15∼20% of the overall products. Forty thousand tons of phenolic resin sprue and runner are disposed of (annually). The (annual) cost of such domestic waste disposal is calculated to be 20 billion won. In this study, discarded phenol resin scraps were pulverized and treated by silanes to improve their interfacial adhesion with HDPE. The sizes of the pulverized pulverulent bodies and fine particles were (100um∼1000um) and (1∼100um), respectively. The pulverized phenol resin was treated with 3-(methacryloyloxy) propyltrimethoxysilane and vinyltrimethoxy silane and the changes in its characteristics were evaluated. The thermal properties were evaluated by DSC and HDT. The mechanical properties were assessed by a notched Izod impact strength tester. When the silane treated phenol resin was added, the heat distortion temperature of HDPE increased from 77℃ to 96℃ and its crystallinity and crystallization temperature also increased. Finally, its impact strength and tensile strength increased by 20% and 50%, respectively, in comparison with the non-treated phenol resin.

Development of High Toughness Thermosetting Resin for High Heat-Resistant Carbon Fiber Prepreg

천지원,박현호,김일진,심재학,장지원,이동진,이진홍 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Typically textiles for application in composite materials are glass fiber, carbon fiber and UHMWPE. Matrix for the manufacture of prefreg type composite materials include epoxy, polyester, phenol resin. Of these, epoxy resin is widely used as a matrix of thermosetting prefregs due to its superior interface adhesion with carbon fiber, but recent improvements are required to satisfy the high-characteristics(high heat, high strength and impact resistance) of materials for aviation and automobiles. In this study, functional materials were selected that could give high functionality to thermosetting resin, and modifications were made to improve the dispersion in thermosetting resin, and glass preheating temperature, mechanical properties, impact resistance were evaluated.

Influence of Pyrolysis Conditions and Type of Resin on the Porosity of Activated Carbon Obtained From Phenolic Resins

Agarwal, Damyanti,Lal, Darshan,TripathiN, V.S.,Mathur, G.N. Korean Carbon Society 2003 Carbon Letters Vol.4 No.2

In polymer precursor based activated carbon, the structure of starting material is likely to have profound effect on the surface properties of end product. To investigate this aspect phenolic resins of different types were prepared using phenol, mcresol and formaldehyde as reactants and $Et_3N$ and $NH_4OH$ as catalyst. Out of these resins two resol resins PFR1 and CFR1 (prepared in excess of formaldehyde using $Et_3N$ as catalyst in the basic pH range) were used as raw materials for the preparation of activated carbons by both chemical and physical activation methods. In chemical activation process both the resins gave activated carbons with high surface areas i.e. 2384 and 2895 $m^2/g$, but pore size distribution in PFR1 resin calculated from Horvath-Kawazoe method, contributes mainly in micropore range i.e. 84.1~88.7 volume percent of pores was covered by micropores. Whereas CFR1 resin when activated with KOH for 2h time, a considerable amount (32.8%) of mesopores was introduced in activated carbon prepared. Physical activation with $CO_2$ leads to the formation of activated carbon with a wide range of surface area (503~1119 $m^2/g$) with both of these resins. The maximum pore volume percentage was obtained in 3-20 ${\AA}$ region by physical activation method.

Influence of Pyrolysis Conditions and Type of Resin on the Porosity of Activated Carbon Obtained From Phenolic Resins

Damyanti Agarwal,Darshan Lal,V.S. TripathiN,G.N. Mathur 한국탄소학회 2003 Carbon Letters Vol.4 No.2

In polymer precursor based activated carbon, the structure of starting material is likely to have profound effect on the surface properties of end product. To investigate this aspect phenolic resins of different types were prepared using phenol, mcresol and formaldehyde as reactants and Et3N and NH4OH as catalyst. Out of these resins two resol resins PFR1 and CFR1 (prepared in excess of formaldehyde using Et3N as catalyst in the basic pH range) were used as raw materials for the preparation of activated carbons by both chemical and physical activation methods. In chemical activation process both the resins gave activated carbons with high surface areas i.e. 2384 and 2895 m2/g, but pore size distribution in PFR1 resin calculated from Horvath-Kawazoe method, contributes mainly in micropore range i.e. 84.1~88.7 volume percent of pores was covered by micropores. Whereas CFR1 resin when activated with KOH for 2h time, a considerable amount (32.8%) of mesopores was introduced in activated carbon prepared. Physical activation with CO2 leads to the formation of activated carbon with a wide range of surface area (503~1119 m2/g) with both of these resins. The maximum pore volume percentage was obtained in 3-20 a region by physical activation method.

Polymer matrices for carbon fiber-reinforced polymer composites

Fan-Long Jin,Seul-Yi Lee,Soo-Jin Park 한국탄소학회 2013 Carbon Letters Vol.14 No.2

Carbon fibers (CFs) have high service temperature, strength, and stiffness, and low weight. They are widely used as reinforcing materials in advanced polymer composites. The role of the polymer matrix in the composites is to provide bulk to the composite laminate and transfer load between the fibers. The interface between the CF and the resin matrix plays a critical role in controlling the overall properties of the composites. This paper aims to review the synthesis, properties, and applications of polymer matrices, such as thermosetting and thermoplastic resins.

Tung oil을 이용한 바이오 기반 열경화성 수지 합성 및 이의 열적·물리적 특성 연구

김한얼(Han-Eol Kim),이종은(Jong-eun Lee),남병욱(Byeong-Uk Nam) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.11

식물유는 자연 유래 물질로 낮은 가격 및 친환경적이라는 장점으로 최근 다양한 연구가 진행되고 있다. 하지만 식물유 내의 이중결합의 낮은 반응성으로 인해 고분자 합성의 기반 물질로 사용하기 위해서는 반응성이 높은 관능기로 치환하여 사용하는 경우가 많다. Tung oil은 α-eleostearic acid를 주성분으로 하는데, 이 구조는 3개의 이중결합이 공명구조로 되어있기 때문에 다른 식물유와는 달리 높은 반응성을 보인다. 본 연구에서는 이러한 tung oil을 styrene 및 divinylbenzene 등의 단량체와 양이온 중합을 통해 tung oil의 관능기 치환 과정이 없는 열경화성 수지를 합성하였으며, 각 단량체의 조성이 합성된 열경화성 수지에 미치는 영향을 확인하기 위해 열적·기계적 물성을 측정하였다. 그 결과, tung oil-styrene-divinylbenzene 공중합체는 단일 Tg를 갖는 균일(homogeneous)한 열경화성 고분자를 형성하는 것을 확인하였으며, 기계적 물성의 변화를 통해 tung oil 및 styrene은 soft segment로써 합성된 공중합체에 탄성(elasticity)을 부여하고, divinylbenzene은 hard segment로 작용하여 합성된 공중합체에 취성(brittleness)을 부여하는 것을 확인하였다. Various investigations of vegetable oil extracted from natural resources are underway because of their low cost and environmental value. On the other hand, the double bonds in vegetable oil should be substituted to other high reactive functional groups due to their low reactivity for synthesizing bio-polymeric materials. α-eleostearic acid, which consists of a conjugated triene, is the main component of tung oil, and the conjugated triene allows tung oil to have higher reactivity than other vegetable oils. In this study, tung oil was copolymerized with styrene and divinylbenzene to make a thermoset resin without any substitution of functional groups. The thermal and mechanical properties were measured to examine the effects of the composition of each monomer on the synthesized thermoset resin. The results showed that the products have only one Tg, which means the synthesized thermoset resins are homogeneous at the molecular level. The mechanical properties show that tung oil acts as a soft segment in the copolymer and makes a more elastic product. On the other hand, divinylbenzene acts as a hard segment and makes a more brittle product.

셀룰로스 나노크리스탈이 충전된 폴리벤조옥사진 복합재료의 물성

박규설,김호동 한국섬유공학회 2019 한국섬유공학회지 Vol.56 No.3

BA-a polybenzoxazine composite reinforced with cellulose nanocrystals was successfully prepared to improve the brittleness of polybenzoxazine resin. The thermally induced crosslinking behavior was investigated using differential scanning calorimetry (DSC), and the thermal stability of the composites was evaluated using thermogravimetric analysis (TGA). The brittleness of the composites was also evaluated using measures of flexural strength and strain. We demonstrate that the flexibility and thermal stability of the composites can be improved using cellulose nanocrystals (CNCs) as reinforcements.