The inclusion of CaCO3 and kaolin in polyvinyl chloride (PVC) polymer matrices greatly enhances the physical and mechanical properties of the composite. In this study, the effects of kaolin and surface treatment of Ca...The inclusion of CaCO3 and kaolin in polyvinyl chloride (PVC) polymer matrices greatly enhances the physical and mechanical properties of the composite. In this study, the effects of kaolin and surface treatment of CaCO3 and kaolin particles on the microstructure and mechanical properties of PVC composites filled with kaolin particles via melt blending method were studied by means of SEM, tensile, Charpy impact testing, and FTIR. Treated and untreated kao-lin particles were dispersed in matrices of PVC resin at different concentrations up to 30 wt percentage. The tensile strength, elastic modulus, strain to failure and morphology of the resulting composites were measured for various filler loadings. Uniform dispersion of the fillers into the matrix proved to be a critical factor. SEM images revealed that small sized particles were more agglomerated than micron-sized particles and the amount of agglomerates increased with increasing particle content. Silane treated Kaolin-CaCO3/PVC composites had superior tensile and impact strengths to untreated kaolin-CaCO3/PVC composites. The Young’s modulus of all composites increased with increasing particle content up to maximum at 10% filler loading followed by gradually decreasing as content increased.展开更多
The mechanical and thermal properties of solution-cast blends of Polyvinyl chloride (PVC) and Epoxidized Liquid Natural Rubber having 30 mole % epoxidation (ELNR-30) have been examined using Zwick materials testing ma...The mechanical and thermal properties of solution-cast blends of Polyvinyl chloride (PVC) and Epoxidized Liquid Natural Rubber having 30 mole % epoxidation (ELNR-30) have been examined using Zwick materials testing machine and heating in air circulating oven (200°C) at different time intervals respectively. The ELNR was prepared by oxidative degradation of natural rubber latex using Phenylhydrazine/Oxygen system and subsequent epoxidation with formic acid and 30% H2O2. Tensile strength of unblended PVC was 26.5 ± 0.5 MPa. The blends had lower tensile strength which decreased with increase in blend ratio of ELNR-30. Experimental data revealed that there was greater homogeneity in the PVC/ELNR-30 (80/20) compared with PVC/ELNR-30 (90/10). The PVC/ELNR-30 (80/20) also showed superior elongation at maximum (%) than the unblended PVC and PVC/ELNR-30 (90/10) in that order. Thermal stability decreased in the order PVC, PVC/ELNR-30 (90/10), PVC/ELNR-30 (80/20).展开更多
With the rapid development of information technology,higher vocational computer education is facing an unprecedented change.Under the background of information technology,this paper discusses the construction and prac...With the rapid development of information technology,higher vocational computer education is facing an unprecedented change.Under the background of information technology,this paper discusses the construction and practice of blended teaching mode of higher vocational computer education.By analyzing the theoretical basis of the blended teaching mode and combining the actual needs of higher vocational computer education,a blended teaching mode combining online and offline is proposed,aiming at enhancing students’independent learning ability,practical operation skills,and teamwork spirit,and providing new ideas and methods for the development of higher vocational computer education.展开更多
文摘The inclusion of CaCO3 and kaolin in polyvinyl chloride (PVC) polymer matrices greatly enhances the physical and mechanical properties of the composite. In this study, the effects of kaolin and surface treatment of CaCO3 and kaolin particles on the microstructure and mechanical properties of PVC composites filled with kaolin particles via melt blending method were studied by means of SEM, tensile, Charpy impact testing, and FTIR. Treated and untreated kao-lin particles were dispersed in matrices of PVC resin at different concentrations up to 30 wt percentage. The tensile strength, elastic modulus, strain to failure and morphology of the resulting composites were measured for various filler loadings. Uniform dispersion of the fillers into the matrix proved to be a critical factor. SEM images revealed that small sized particles were more agglomerated than micron-sized particles and the amount of agglomerates increased with increasing particle content. Silane treated Kaolin-CaCO3/PVC composites had superior tensile and impact strengths to untreated kaolin-CaCO3/PVC composites. The Young’s modulus of all composites increased with increasing particle content up to maximum at 10% filler loading followed by gradually decreasing as content increased.
文摘The mechanical and thermal properties of solution-cast blends of Polyvinyl chloride (PVC) and Epoxidized Liquid Natural Rubber having 30 mole % epoxidation (ELNR-30) have been examined using Zwick materials testing machine and heating in air circulating oven (200°C) at different time intervals respectively. The ELNR was prepared by oxidative degradation of natural rubber latex using Phenylhydrazine/Oxygen system and subsequent epoxidation with formic acid and 30% H2O2. Tensile strength of unblended PVC was 26.5 ± 0.5 MPa. The blends had lower tensile strength which decreased with increase in blend ratio of ELNR-30. Experimental data revealed that there was greater homogeneity in the PVC/ELNR-30 (80/20) compared with PVC/ELNR-30 (90/10). The PVC/ELNR-30 (80/20) also showed superior elongation at maximum (%) than the unblended PVC and PVC/ELNR-30 (90/10) in that order. Thermal stability decreased in the order PVC, PVC/ELNR-30 (90/10), PVC/ELNR-30 (80/20).
文摘With the rapid development of information technology,higher vocational computer education is facing an unprecedented change.Under the background of information technology,this paper discusses the construction and practice of blended teaching mode of higher vocational computer education.By analyzing the theoretical basis of the blended teaching mode and combining the actual needs of higher vocational computer education,a blended teaching mode combining online and offline is proposed,aiming at enhancing students’independent learning ability,practical operation skills,and teamwork spirit,and providing new ideas and methods for the development of higher vocational computer education.
