The performance of oil palm trunk wastes from Banjarbaru of South Kalimantan was improved with the help of chemical modification in a two-step treatment.The first was formalization with formaldehyde solution with vary...The performance of oil palm trunk wastes from Banjarbaru of South Kalimantan was improved with the help of chemical modification in a two-step treatment.The first was formalization with formaldehyde solution with varying pH,and the second was impregnation with melamine-formaldehyde resin under 5 bar pressure for an hour.In these processes,the samples were cured at 120℃ for 10 min and then dried in an oven at(103±2)℃ in order to attain a moisture content of less than 6%.These treatments improved the physical properties(density,moisture content,and volume swelling),mechanical resistance,dynamic-mechanical and acoustic performance of the woods.The combination of impregnation and formalization changed the structure and the morphology of the woods such that the surface became flatter and denser.This was confirmed by results from FTIR,SEM,and DMA.Samples with alkaline modification displayed the best results for dimensional stability,storage modulus,and damping factor in varied frequencies.The treatments in this study also heightened acoustic performances as evidenced by the resulting characteristics of sound absorption coefficient and acoustic impedance.展开更多
This paper is concerned with the synthesis of poly (ether-urethane) with pendant amino groups. The copolyether produced by ring opening copolymerization of tetrahydrofuran and epibromohydrin was treated with sodium az...This paper is concerned with the synthesis of poly (ether-urethane) with pendant amino groups. The copolyether produced by ring opening copolymerization of tetrahydrofuran and epibromohydrin was treated with sodium azide in dimethylformamide to form azido substituted copolyether. The poly (ether-urethane) made from it was subjected to reduction reaction to convert azido group to amino group. The stress-strain behavior and dynamic-mechanical properties of poly (ether-urethane) containing pendant amino groups were studied.展开更多
A study was conducted to investigate the effects of compatibilizers, including Maleic anhydride grafted polypropylene （MA-PP） and maleic anhydride grafted ethylene-propylene-diene copolymer （MA-EPDM）, on wood-flou...A study was conducted to investigate the effects of compatibilizers, including Maleic anhydride grafted polypropylene （MA-PP） and maleic anhydride grafted ethylene-propylene-diene copolymer （MA-EPDM）, on wood-flour/polypropylene （WF/PP） composites. WF/PP composites were prepared by direct extrusion profiles using a twin-screw/single-screw extruder system. DMA analysis showed that the loss factor of composites decreased and the storage modulus improved in the presence of MA-PP, which indicated much better interfacial adhesion between the PP matrix and wood flour filler than in the absence of compatibilizer. Morphological feature based on SEM observation showed that MA-PP and MA-EPDM improved the dispersion of the wood particles in the plastic matrix. MA-EPDM is a soft segment, although it improved the interfacial adhesion, storage modulus decreases with adding of MA-EPDM. As compatibilizer of wood-flour/polypropylene composites, both DMA analysis and SEM feature proved that MA-PP was superior to MA-EPDM.展开更多
采用劈裂拉伸和三点弯曲法研究了 Bukit Timah 花岗岩的动态拉伸力学特性。实验结果表明,当加载速率每增加一个量级,用两种方法得到的花岗岩抗拉强度增加了10%;对于同种加载速率的花岗岩试样,由三点弯曲法得到的岩石抗拉强度约为劈裂拉...采用劈裂拉伸和三点弯曲法研究了 Bukit Timah 花岗岩的动态拉伸力学特性。实验结果表明,当加载速率每增加一个量级,用两种方法得到的花岗岩抗拉强度增加了10%;对于同种加载速率的花岗岩试样,由三点弯曲法得到的岩石抗拉强度约为劈裂拉伸法得到的2.5倍。与抗拉强度相比,实验得到的花岗岩弹性模量数据比较离散,但变化幅度不大。基于实验结果,对岩石拉伸力学机理进行了初步分析。展开更多
基金The authors would like to acknowledge the Beasiswa Pendidikan Pascasarjana Dalam Negeri(BPPDN)KEMDIKBUD Indonesia who provided doctoral scholarship.
文摘The performance of oil palm trunk wastes from Banjarbaru of South Kalimantan was improved with the help of chemical modification in a two-step treatment.The first was formalization with formaldehyde solution with varying pH,and the second was impregnation with melamine-formaldehyde resin under 5 bar pressure for an hour.In these processes,the samples were cured at 120℃ for 10 min and then dried in an oven at(103±2)℃ in order to attain a moisture content of less than 6%.These treatments improved the physical properties(density,moisture content,and volume swelling),mechanical resistance,dynamic-mechanical and acoustic performance of the woods.The combination of impregnation and formalization changed the structure and the morphology of the woods such that the surface became flatter and denser.This was confirmed by results from FTIR,SEM,and DMA.Samples with alkaline modification displayed the best results for dimensional stability,storage modulus,and damping factor in varied frequencies.The treatments in this study also heightened acoustic performances as evidenced by the resulting characteristics of sound absorption coefficient and acoustic impedance.
文摘This paper is concerned with the synthesis of poly (ether-urethane) with pendant amino groups. The copolyether produced by ring opening copolymerization of tetrahydrofuran and epibromohydrin was treated with sodium azide in dimethylformamide to form azido substituted copolyether. The poly (ether-urethane) made from it was subjected to reduction reaction to convert azido group to amino group. The stress-strain behavior and dynamic-mechanical properties of poly (ether-urethane) containing pendant amino groups were studied.
基金This paper was supported by National Foundation of Application of Agricultural Scientific and Technological Achievements (2006GB23600450).
文摘A study was conducted to investigate the effects of compatibilizers, including Maleic anhydride grafted polypropylene （MA-PP） and maleic anhydride grafted ethylene-propylene-diene copolymer （MA-EPDM）, on wood-flour/polypropylene （WF/PP） composites. WF/PP composites were prepared by direct extrusion profiles using a twin-screw/single-screw extruder system. DMA analysis showed that the loss factor of composites decreased and the storage modulus improved in the presence of MA-PP, which indicated much better interfacial adhesion between the PP matrix and wood flour filler than in the absence of compatibilizer. Morphological feature based on SEM observation showed that MA-PP and MA-EPDM improved the dispersion of the wood particles in the plastic matrix. MA-EPDM is a soft segment, although it improved the interfacial adhesion, storage modulus decreases with adding of MA-EPDM. As compatibilizer of wood-flour/polypropylene composites, both DMA analysis and SEM feature proved that MA-PP was superior to MA-EPDM.
文摘采用劈裂拉伸和三点弯曲法研究了 Bukit Timah 花岗岩的动态拉伸力学特性。实验结果表明,当加载速率每增加一个量级,用两种方法得到的花岗岩抗拉强度增加了10%;对于同种加载速率的花岗岩试样,由三点弯曲法得到的岩石抗拉强度约为劈裂拉伸法得到的2.5倍。与抗拉强度相比,实验得到的花岗岩弹性模量数据比较离散,但变化幅度不大。基于实验结果,对岩石拉伸力学机理进行了初步分析。
