The properties of styrene-butadiene rubber (SBR) reinforced by modified silica was investigated according to national standards. Silica was modified by silane coupling agents KH-570, KH-590, and KH-792. The optimized ...The properties of styrene-butadiene rubber (SBR) reinforced by modified silica was investigated according to national standards. Silica was modified by silane coupling agents KH-570, KH-590, and KH-792. The optimized geome-tries of molecular modified silica reinforced SBR were obtained by using B3LYP calculation of density functional theory with the 6-31+G basis sets. The natural bond orbital analyses were carried out. The Si—O bond length of silica modified by KH-792 was the shortest and the electronegative of O was the highest. It indicated that the connection between silica and KH-792 was the tightest. Higher tensile strength and elongation of reinforced SBR was obtained by silica modified with the KH-792. It was caused by large delocalization of lone pair electrons of the two N atoms in KH-792. The S—C bond length in silica modified by KH-590 was longer than the ordinary S—C bond length. Then the sulfur free radical (·S·) was produced more easily in vulcanization. The degree of crosslink was increased by the cross-linkage of the rubber molecule and the sulfur free radical. That was why the highest stress and tear strength of reinforced SBR was produced when silane coupling agent KH-590 was used. The calculation results was in accord with experimental data.展开更多
The reaction of ZnO nanoparticles grafted with KH570 silane coupling agent was carried out in water-alcohol mixed solvent. Several characterization methods were applied to analyzing the results of surface modification...The reaction of ZnO nanoparticles grafted with KH570 silane coupling agent was carried out in water-alcohol mixed solvent. Several characterization methods were applied to analyzing the results of surface modification such as Soxhlet extraction, Fourier transform infrared spectroscopy （FT-IR）, transmission electron microscopy （TEM）, thermogravimetry （TG）, differential scanning calorimetry （DSC） and zeta potential （ζ）. The results of FT-IR and TG-DSC show that the desired reaction chains have been covalently bonded on the surface of ZnO nanoparticles. Zetasizer results reveal that the maximal absolute value of ζ of the modified ZnO particles in acetone medium was 67.0 mV, which was much higher than that of the unmodified ZnO particles. So the surface of nanosized ZnO changed from hydrophilicity to hydrophobicity and the dispersity of ZnO nanoparticles were improved simultaneously. Finally, the mechanism of graft modification was discussed.展开更多
The surface modification of clay fines was carried out by using silanecoupling agent. By means of IR spectra etc, a study was made on the combined state ofcoupling agent and clay. A rubber--clay composite material wit...The surface modification of clay fines was carried out by using silanecoupling agent. By means of IR spectra etc, a study was made on the combined state ofcoupling agent and clay. A rubber--clay composite material with excellent performancehas been prepared.展开更多
Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonat...Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonate coupled with silane grafted polypropylene (PP-g-Si) were made, their mechanical properties and thermal properties were investigated, respectively. Results As compared with the non-coupled composites, the mechanical properties of PP/Ta/PP-g-Si composites were improved to some extent, though the values of tensile modulus and the strain at peak were decreased. But for PP/BaSO4 and PP/CaCO3 composites, the values of their mechanical properties varied slightly or even decreased with increasing PP-g-Si content within the experimental component. Meanwhile, PP-g-Si also affected the melting and crystallization behavior of PP in the composites. Conclusion PP-g-Si offers compatibilization in PP/Ta composites, but offers no-compatibilization in PP/BaSO4 and PP/CaCO3 composites within the extent of the present range of PP-g-Si, which shows that PP-g-Si can be used as the macromolecular coupling agent of PP and Ta composite.展开更多
文摘The properties of styrene-butadiene rubber (SBR) reinforced by modified silica was investigated according to national standards. Silica was modified by silane coupling agents KH-570, KH-590, and KH-792. The optimized geome-tries of molecular modified silica reinforced SBR were obtained by using B3LYP calculation of density functional theory with the 6-31+G basis sets. The natural bond orbital analyses were carried out. The Si—O bond length of silica modified by KH-792 was the shortest and the electronegative of O was the highest. It indicated that the connection between silica and KH-792 was the tightest. Higher tensile strength and elongation of reinforced SBR was obtained by silica modified with the KH-792. It was caused by large delocalization of lone pair electrons of the two N atoms in KH-792. The S—C bond length in silica modified by KH-590 was longer than the ordinary S—C bond length. Then the sulfur free radical (·S·) was produced more easily in vulcanization. The degree of crosslink was increased by the cross-linkage of the rubber molecule and the sulfur free radical. That was why the highest stress and tear strength of reinforced SBR was produced when silane coupling agent KH-590 was used. The calculation results was in accord with experimental data.
基金the Foundation of National Key Technologies R&D Program-Shanghai World Exposition Special Project (Grant No.04DZ05803)the Special Project of Shanghai Nano-technology (Grant No.05nm05011)
文摘The reaction of ZnO nanoparticles grafted with KH570 silane coupling agent was carried out in water-alcohol mixed solvent. Several characterization methods were applied to analyzing the results of surface modification such as Soxhlet extraction, Fourier transform infrared spectroscopy （FT-IR）, transmission electron microscopy （TEM）, thermogravimetry （TG）, differential scanning calorimetry （DSC） and zeta potential （ζ）. The results of FT-IR and TG-DSC show that the desired reaction chains have been covalently bonded on the surface of ZnO nanoparticles. Zetasizer results reveal that the maximal absolute value of ζ of the modified ZnO particles in acetone medium was 67.0 mV, which was much higher than that of the unmodified ZnO particles. So the surface of nanosized ZnO changed from hydrophilicity to hydrophobicity and the dispersity of ZnO nanoparticles were improved simultaneously. Finally, the mechanism of graft modification was discussed.
文摘The surface modification of clay fines was carried out by using silanecoupling agent. By means of IR spectra etc, a study was made on the combined state ofcoupling agent and clay. A rubber--clay composite material with excellent performancehas been prepared.
文摘Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonate coupled with silane grafted polypropylene (PP-g-Si) were made, their mechanical properties and thermal properties were investigated, respectively. Results As compared with the non-coupled composites, the mechanical properties of PP/Ta/PP-g-Si composites were improved to some extent, though the values of tensile modulus and the strain at peak were decreased. But for PP/BaSO4 and PP/CaCO3 composites, the values of their mechanical properties varied slightly or even decreased with increasing PP-g-Si content within the experimental component. Meanwhile, PP-g-Si also affected the melting and crystallization behavior of PP in the composites. Conclusion PP-g-Si offers compatibilization in PP/Ta composites, but offers no-compatibilization in PP/BaSO4 and PP/CaCO3 composites within the extent of the present range of PP-g-Si, which shows that PP-g-Si can be used as the macromolecular coupling agent of PP and Ta composite.
