Ur Ryong Cho

Emulsion grafting vinyl monomers onto starch for reinforcement of styrene-butadiene rubber

AbstractThree types of modified starches (MST): Starch-g-poly(butyl acrylate) (ST-g-PBA), starch-g-poly (methyl methacrylate) (ST-g-PMMA) and starch-g-polystyrene (ST-g-PS) latexes were successfully synthesized by emulsion polymerization. These synthesized MST latexes were then directly compounded with styrene-butadiene rubber (SBR) latex in order to prepare MST/SBR compounds. The vulcanization characteristics, morphology, swelling ratio, mechanical and dynamic mechanical properties were investigated. Results indicated that the incorporation of starch or MST led to both an increase in the torque values and the cure rate of SBR compounds. MST with a particle size of approximately 200–400 nm uniformly dispersed in the SBR matrix, indicating the significantly improved dispersion. MST/SBR compounds exhibited better mechanical properties compared with starch/SBR (ST/SBR) compounds. Among the MST/SBR compounds, ST-g-PMMA/SBR compounds showed optimum tensile strength, which was even higher than that of carbon black/SBR (CB/SBR) compounds with the same loading of fillers. Finally, the reinforcing mechanism of MST in the SBR matrix was discussed.

Mechanical Performance, Water Absorption Behavior and Biodegradability of Poly(methyl methacrylate)-Modified Starch/SBR Biocomposites

AbstractNatural corn starch was modified by surface grafting with poly(methyl methacrylate) (PMMA) through emulsion copolymerization and then compounded with styrene-butadiene rubber (SBR) latex in order to prepare PMMA-modified starch/SBR biocomposites. The effect of methyl methacrylate (MMA) and starch concentration on the mechanical properties, morphology, toluene swelling behavior, water absorption behavior and biodegradability of PMMA-modified starch/SBR biocomposites was investigated. Results showed that the optimum mechanical properties were achieved when the concentrations of MMA and starch were 10 and 30 phr, respectively, which could be also confirmed through the observations from FE-SEM micrographs and equilibrium welling test. Guth-Gold and Halpin-Tsai models were employed to predict the modulus of PMMA-modified starch/SBR biocomposites. Halpin-Tsai model was better fitted with the experimentally measured data than Guth-Gold model. The water absorption ratio of PMMA-modified starch/SBR biocomposites was strongly influenced by the immersion time and the starch concentration, which further caused a significant effect on the biodegradability of biocomposites.

Effect of coupling agents and ionic liquid on the properties of rice bran carbon/carboxylated styrene butadiene rubber composites

AbstractLatex 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.

Surface modification of novel rice bran carbon functionalized with (3-Mercaptopropyl) trimethoxysilane and its influence on the properties of styrene-butadiene rubber composites:

In the present study, surface modification of novel environment-friendly Rice Bran Carbon was carried out by mixed acid treatment followed by reaction with multifunctional silane, (3-Mercaptopropyl) trimethoxysilane. Then a new class of styrene-butadiene rubber/Rice Bran Carbon composites were prefabricated by using latex compounding method on the basis of pretreatment of RBC. Specifically, extra 3phr 3-MPTMS was added into the composites to construct a systematic filler-silane-matrix net framework. The chemical interaction mechanism of silane agent with the oxidized RBC was confirmed by Fourier Transform Infrared Spectroscopy, Energy Dispersive Spectroscopy, Thermogravimetric Analysis and Field Emission Scanning Electron Microscopy. The effect of silane modified RBC on the mechanical, wear and friction property of SBR vulcanizates was investigated.

술폰화된 뱀부차콜-키토산 혼성체가 SBR 고무의 보강에 미치는 영향

Styrene-butadiene rubber (SBR) composites, incorporated with four kinds of fillers (chitosan, bamboo charcoal powder, sulfonated bamboo charcoal and sulfonated bamboo charcoal-chitosan hybrid) with similar filling ratio, were fabricated by a latex compounding method. Field emission scanning electron microscopy and carbon black dispersion tests were employed to confirm the uniform dispersion of filler in the matrix. The tensile strength, storage modulus, abrasion resistance, friction coefficient, swelling property, and oxygen transmission rates of the vulcanized rubber composites were investigated. The sulfonated bamboo charcoal-chitosan hybrid (sBC-CS) showed a smaller particle size and a better dispersion state compared with those of other fillers. In addition, this compound exhibited the best mechanical reinforcing performance among the four fillers with its great hydrophobic property and good dispersion rate.

실리카와 전분이 보강된 스티렌-부타디엔 고무 복합체

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.

Starch in Rubber Based Blends and Micro Composites

In this chapter, we will report the most recent investigations on modification of starch and their application as reinforcing filler in rubber composites. First, we will give a brief introduction on the characteristics of native starch, e.g., chemical structure, amylose content, morphology and crystallinity. Then, a brief review on different treatments used for starch modification, including gelatinization, plasticization, nanoparticles fabrication, and chemical grafting will be carried out. Finally, in order to prepare high performance starch reinforced rubber composites, three primary strategies reported so far, including (1) the addition of coupling agent, (2) modification of starch and (3) modification of rubber matrix will be highlighted.

Fabrication of Sulfonated Bamboo Charcoal-Chitosan (sBC-CS) Hybrid and its Applications for Reinforcement of Styrene-Butadiene Rubber

Styrene-Butadiene Rubber (SBR) composites incorporated with different fillers with similar filling ratio, were fabricated by latex compounding method. The particle size, tensile strength, abrasion resistance of the vulcanized rubber composites were investigated. The sulfonated bamboo charcoal-chitosan hybrid (sBC-CS) showed great dispersion rate and smaller particle size compared with those of other fillers. In addition, this composite exhibited the best mechanical reinforcing performance among the four fillers.

Starch/SBR Biocomposites Prepared by Solid Blend Method: Effect of Surface Modification and Coupling Agent

Starch/Styrene Butadiene Rubber (SBR) biocomposites were prepared by directly blending of starch and SBR on a two-roll miller. Two types of starch: pure starch and modified starch (M-starch) were used as rubber fillers. M-starch were synthesized by grafting of methyl methacrylate (MMA) monomer onto starch backbone using ceric ammonium nitrate-initiated radical polymerization. Coupling agent styrene-g-(maleic anhydride) (SMA) was used to further improve the interfacial interaction between the filler and rubber matrix. The morphology and mechanical properties of unmodified starch/SBR and M-starch/SBR biocomposites with SMA content of 0, 1, 3, and 5 phr were investigated. SEM observations showed the particle size of M-starch decreased and their dispersion in the SBR matrix significantly improved than unmodified starch. Mechanical properties of M-starch/SBR biocomposites were superior than those of unmodified starch/SBR biocomposites.