Mechanical Performance and Oil Resistance Behavior of Modified Starch/Cellulose with Silica by Adsorption Method Filled into SBR Rubber Latex

Xiangxu Li(리시앙수),Ur-Ryong Cho(조을룡) 한국고분자학회 2018 폴리머 Vol.42 No.3

스티렌-부타디엔 고무 Latex 1502에 세가지 충전제(실리카, 실리카와 전분 혼성체, 실리카와 셀룰로오스 혼성체)를 콜로이드 흡착법으로 혼합하여 고무복합체를 제조하였다. 주사전자현미경을 통해서 가교 구성을 확인하였으며, 고무복합체의 비중, 경도, 인장강도, 저장탄성률, 동학역적 성능 및 내유성을 조사하였다. 실험의 결과에서 실리카와 전분/셀룰로오스 혼성체가 고무와 상호 침투 네트워크(Interpenetrating network)를 형성하여 좋은 보강 성능을 보였다. 그 중에서도 실리카와 셀룰로오스 10 phr 혼성체가 SBR 복합체에 가장 좋은 보강 효과를 보였다. Styrene-butadiene Rubber (SBR) composites were manufactured by colloidal adsorption method with three kinds of reinforcing agents (silica, starch-silica gel hybrid and cellulose-silica gel hybrid) and SBR l502 latex. The crosslink structure of compounds was observed with field-emission scanning electron microscope (FE-SEM). The density, hardness value, tensile strength, storage modulus, dynamic mechanical property, and oil resistance had been characterized. From the results of all tests, starch/cellulose-silica hybrid could make good reinforcement effect due to the interpenetrating network between hybrid and rubber matrix had been formed. The best filler was cellulose-silica hybrid 10 phr, which showed the best reinforcement effect with SBR compound.

Silica-Starch Reinforced Styrene-Butadiene Rubber Composites

Qingyuan Li,Xiangxu Li,Sun-Ho Jang(장선호),Dam-Hee Lee(이담희),Yuan Fan,Ur Ryong Cho(조을룡) 한국고분자학회 2017 폴리머 Vol.41 No.6

Silica-starch-reinforced styrene-butadiene rubber (SBR) was prepared by a modified sol-gel method of mixing the silica sol, the starch paste, and then in situ blending the SBR latex. The fracture surface of the samples after the tensile test was characterized by FE-SEM. The tensile strength, the storage modulus, the hardness and the swelling test of the vulcanized samples were systematically discussed. The results showed the elongation at break, the hardness and the storage modulus increased with the increasing of silica in the as-prepared samples. The swelling ratio decreased with increase in the content of silica, indicative of the excellent crosslink density in the silica-starch-reinforced SBR.

Mechanical Properties of Styrene-Butadiene Rubber Reinforced with Silica by in situ Tetraethoxysilane Hydrolysis over Acid Catalyst

( Qingyuan Li ),( Xiangxu Li ),( Ur Ryong Cho ) 한국고무학회 2018 엘라스토머 및 콤포지트 Vol.53 No.2

Styrene-butadiene rubber (SBR), reinforced with different contents of silica (with or without modification using silane coupling agents), was prepared by a modified sol-gel method involving hydrolyzation of tetraethoxysilane over an acid catalyst. The structures of the as-prepared samples were characterized using various techniques, such as scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The mechanical properties of the as-prepared samples were discussed in detail. The results revealed an increasing of the storage modulus (G’) with increase in the silica content without modification. In contrast, G’ decreased after modification using silane coupling agents, indicating a reduction in the silica-silica interaction and improved dispersion of silica in the SBR matrix. Both tensile stress and hardness increased with increase in the silica content (with modification) in the SBR matrix, albeit with low values compared to the samples with un-modified silica, except for the case of silica modified using (3-glycidyloxypropyl) trimethoxysilane (GPTS). The latter observation can be attributed to the special structure of GPTS and the effort of oxygen atom lone-pair.

Fermentation characteristics and microbial community composition of wet brewer's grains and corn stover mixed silage prepared with cellulase and lactic acid bacteria supplementation

Guoqiang Zhao,Hao Wu,Yangyuan Li,Li Li,Jiajun He,Xinjian Yang,Xiangxue Xie Asian Australasian Association of Animal Productio 2024 Animal Bioscience Vol.37 No.1

Objective: The objective of this study was to investigate how cellulase or/and lactic acid bacteria (LAB) affected the fermentation characteristic and microbial community in wet brewer's grains (WBG) and corn stover (CS) mixed silage. Methods: The WBG was mixed thoroughly with the CS at 7:3 (w/w). Four treatment groups were studied: i) CON, no additives; ii) CEL, added cellulase (120 U/g fresh matter [FM]), iii) LAB, added LAB (2×10⁶ cfu/g FM), and iv) CLA, added cellulase (120 U/g FM) and LAB (2×10⁶ cfu/g FM). Results: All additive-treated groups showed higher fermentation quality over the 30 d ensiling period. As these groups exhibited higher (p<0.05) LAB counts and lactic acid (LA) content, along with lower pH value and ammonia-nitrogen (NH₃-N) content than the control. Specifically, cellulase-treated groups (CEL and CLA) showed lower (p<0.05) neutral detergent fiber and acid detergent fiber contents than other groups. All additives increased the abundance of beneficial bacteria (Firmicutes, Lactiplantibacillus, and Limosilactobacillus) while they decreased abundance of Proteobacteria and microbial diversity as well. Conclusion: The combined application of cellulase and LAB could effectively improve the fermentation quality and microbial community of the WBG and CS mixed silage.

Effect of Coupling Agents and Ionic Liquid on the Properties of Rice Bran Carbon/Carboxylated Styrene Butadiene Rubber Composites

Yinhang Zhang,조을룡,Xiangxu Li,Xin Ge,Fei Deng 한국고분자학회 2015 Macromolecular Research Vol.23 No.10

Latex compounding method (LCM) was applied to ensure a better dispersion state of filler in rubber matrix. In order to enhance the compatibility and interfacial interaction between carboxylated-styrene butadiene rubber (XSBR) and rice bran carbon (RBC), a series of coupling agents i.e., N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AAPTS), 3-mercaptopropyltrimethoxysilane (MPTMS), 4,4-methylene bis(phenyl isocyanate) (MDI) and ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF6) were applied. Morphology of the fracture surface, mechanical property, thermal stability, vulcanization characters and dynamic mechanical property were investigated. The characterization on the resultant composites demonstrated that the MDI exhibited the superior reinforcing effect, of which the tensile strength and 300% modulus reached to 16.43 and 16.33 MPa, respectively. The study on fracture surface, Raman spectrum, thermal stability and storage modulus confirmed the strong interfacial interaction resulted from MDI. In addition, ionic liquid also exhibited coupling activity, improving the mechanical properties of the composites.

Comparative study on carboxylated styrene butadiene rubber composites reinforced by hybrid fillers of rice bran carbon and graphite carbon

Yuan Fan,Qingyuan Li,Xiangxu Li,Dam hee Lee,Ur Ryong Cho 한국탄소학회 2018 Carbon Letters Vol.27 No.-

In the present work, a comparative study of the mechanical behavior of two series of elastomeric composites, based on carboxylated styrene butadiene rubber (X-SBR) and reinforced with rice bran carbon (RBC) and graphite, is reported. Hybrid composites of X-SBR filled with RBC-graphite were also investigated in terms of the cure characteristics, hardness, tensile properties, abrasion resistance, and swelling. It was observed that the cure times decreased with the incorporation of a carbon filler whereas the torque difference, tensile strength, tensile modulus, hardness, and swelling resistance increased compared to the neat X-SBR revealing a favorable characteristic of crosslinking. Dynamic rheological analysis showed that the G values of the composites, upon the addition of RBC-graphite, were changed to some extent. This demonstrates that the presence of a strongly developed network of fillers will ensure a reinforcing characteristic in a polymer matrix.

Effects of applying cellulase and starch on the fermentation characteristics and microbial communities of Napier grass (Pennisetum purpureum Schum.) silage

( Guoqiang Zhao ),( Hao Wu ),( Li Li ),( Jiajun He ),( Zhichao Hu ),( Xinjian Yang ),( Xiangxue Xie ) 한국축산학회 2021 한국축산학회지 Vol.63 No.6

This study investigated the effects of applying cellulase and starch on the fermentation characteristics and microbial communities of Napier grass silage after ensiling for 30 d. Three groups were studied: No additives (control); added cellulase (Group 1); and added cellulase and starch (Group 2). The results showed that the addition of cellulase and starch decreased the crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and pH significantly (p < 0.05) and increased water-soluble carbohydrate (WSC) content (p < 0.05). The addition of additives in two treated groups exerted a positive effect on the lactic acid (LA) content, lactic acid bacteria (LAB) population, and lactic acid / acetic acid (LA/AA) ratio, even the changes were not significant (p > 0.05). Calculation of Flieg’s scores indicated that cellulase application increased silage quality to some extent, while the application of cellulase and starch together significantly improved fermentation (p < 0.05). Compared with the control, both additive groups showed increased microbial diversity after ensiling with an abundance of favorable bacteria including Firmicutes and Weissella, and the bacteria including Proteobacteria, Bacteroidetes, Acinetobacter increased as well. For alpha diversity analysis, the combined application of cellulase and starch in Group 2 gave significant increases in all indices (p < 0.05). The study demonstrated that the application of cellulase and starch can increase the quality of Napier grass preserved as silage.

개질된 폐타이어 분말을 이용한 열가소성 폴리우레탄의 물성 개선

강신혜(Shin Hye Kang),오지환(Ji-Hwan Oh),리시앙수(Xiangxu Li),조을룡(Ur Ryong Cho) 한국고분자학회 2017 폴리머 Vol.41 No.4

열가소성 폴리우레탄(thermoplastic polyurethane, TPU)이 가지는 경제적, 환경적 문제를 해결함과 동시에 TPU 물성 개선을 위한 방안으로 TPU에 폐타이어 분말을 적용하였다. 사용된 폐타이어(waste tire rubber, WTR)는 폐타이어를 변안활성기계(metactivator)에 통과시킨 것으로, 열역학적으로 불안정하며 미세 균열 입자의 형태를 보이고, 가교결합은 끊어진 상태로 존재한다. 단순히 TPU와 WTR을 혼합한 복합체와 2-hydroxyethyl methacrylate와 dicumyl peroxide를 사용하여 가교를 형성시킨 복합체를 제조하였다. WTR의 구조를 FTIR로 관찰하고, TPU와 두 종류의 TPU/WTR 복합체를 DSC를 통해 유리전이온도(Tg)를 측정하였다. 가교로 개질된 TPU/WTR 복합체는 내수성, 내화학성이 크게 향상되었고, 극성 비양성자성 용매에서의 팽윤 특성 또한 우수하였다. 또한 저장탄성률의 증가와 함께 영구압축 줄음률 또한 크게 향상되었다. To solve the economic and environmental problems of thermoplastic polyurethane (TPU), waste tire powder (WTR) was applied to improve the physical properties of TPU. The waste tire rubber is a waste tire that has passed through a metactivator and is thermodynamically unstable, showing the shape of microcracked particles, and the crosslinking is broken. The composites were prepared by simply mixing of TPU and WTR and a crosslinking agent using 2- hydroxyethyl methacrylate and dicumyl peroxide. The structure of WTR was observed by FTIR, and the glass transition temperature (Tg) of TPU and two kinds of TPU/WTR composites were measured by DSC. The modified TPU/WTR composites showed significant improvements in water resistance, chemical resistance, and swelling properties in polar aprotic solvents. As the storage modulus increased, the compression set was also remarkably improved.

방열 아크릴 점착제의 제조를 위한 개질 알루미나의 효과

오지환(Ji-Hwan Oh),강신혜(Sinhye Kang),리시앙수(Li Xiangxu),노성래(Seong-Rae No),유성식(Seong-Sik You),조을룡(Ur-Ryong Cho) 한국고분자학회 2016 폴리머 Vol.40 No.5

용액중합을 통해 합성한 아크릴 점착제에 실란커플링제로 전처리한 알루미나(30, 60, 90 wt%)를 혼합하여 열전도성 복합체를 제조한 후 접착특성 및 열전도도를 조사하였다. 접착특성은 180° 박리강도, 유지력 및 초기점착력을 측정하였고, 열전도도는 laser flash 법을 이용하여 측정하였다. 박리강도와 초기점착력은 알루미나의 함량의 따라 감소하였고, 유지력은 향상되는 경향을 보였으며, 열전도도는 크게 향상되었다. 전처리한 알루미나를 사용한 점착테이프는 전처리하지 않은 알루미나를 사용한 것에 비해서 상대적으로 점착력이 낮아지며, 열전도도는 10% 가량 향상되었다. 이는 커플링제로 인하여 점착제 매트릭스와 알루미나 필러 사이의 계면결합이 증가한 것으로 추정된다. 개질된 90 wt%의 알루미나를 포함한 경우 열전도도는 0.242 W/mK 값을 나타내어 알루미나를 포함하지 않은 점착테이프에 비해 크게 향상됨을 확인할 수 있었다. Thermal conductive acrylic pressure sensitive adhesives (PSA) were synthesized by solution polymerization. The adhesive was mixed with (30, 60, 90 wt%) alumina (Al) pretreated by silane coupling agent. Adhesion properties of the PSA/Al composites were investigated by measuring peel strength, holding power, and initial tack. Thermal conductivity was measured by a laser flash analyzer. Peel adhesion and intial tack decreased with the alumina content, and holding power tended to increase. Adhesion properties of adhesive tape using modified alumina decreased compared with using pristine alumina, and thermal conductivity was increased by 10%. It was confirmed that the interfacial bonds between the PSA and the modified alumina increased because of silane coupling agent. Thermal conductivity of adhesive sheet containing 90 wt% modified alumina as filler was 0.242W/mK, which was significantly improved compared to pure PSA sheet.