研究了PVC树脂基本性能(聚合度、分子质量分布、表观密度)、助剂(发泡剂、发泡调节剂)、木粉及加工工艺(加工温度、挤出速度)对PVC木塑发泡材料性能的影响,并进行了工业化加工试验。结果表明:PVC树脂聚合度越高,发泡材料泡孔壁厚越大,...研究了PVC树脂基本性能(聚合度、分子质量分布、表观密度)、助剂(发泡剂、发泡调节剂)、木粉及加工工艺(加工温度、挤出速度)对PVC木塑发泡材料性能的影响,并进行了工业化加工试验。结果表明:PVC树脂聚合度越高,发泡材料泡孔壁厚越大,发泡及加工都变得较为困难,适宜的聚合度为650~700;PVC树脂分子质量分布变宽,则发泡材料的密度增大,泡孔数量减少,泡孔增大,泡壁增厚,有串泡现象,适宜的分子质量分布指数为1.9~2.0;表观密度越高,机身压力越大,发泡材料泡孔数量越多,泡孔结构越均匀,适宜的表观密度为0.57~0.60 m L/g。对于S-700型PVC树脂而言,发泡剂AD C与助发泡剂Z n O的适宜质量比为1∶0.1,且二者的总用量以1.0份为宜;发泡调节剂ZB-530的适宜用量为8份;适宜的加工温度为185℃,适宜的挤出速度为20 r/min。宜采用硅烷偶联剂对木粉进行表面改性,发泡剂、发泡调节剂的用量应随着木粉用量的变化而调整。工业化加工试验结果表明:根据制品及生产设备的不同对试验得出的配方和加工工艺进行调整后,可顺利生产出质量优良的产品。展开更多
Using biodegradable material derived from renewable resources as petroleum-based plastics replacement is a promising way towards sustainable development.However,the insufficient mechanical properties and complex manuf...Using biodegradable material derived from renewable resources as petroleum-based plastics replacement is a promising way towards sustainable development.However,the insufficient mechanical properties and complex manufacturing process of bioplastics still need to be improved for high-quality food packages.Herein,we report a top-down strategy to transform natural wood into a clear wood packaging film through scalable delignification and polyvinyl alcohol(PVA)infiltration.The wood packaging film demonstrates a laminated structure with completely collapsed cell walls and PVA intertwined together after energy-saving air drying,resulting in high light transmittance with low haze,good mechanical performance,and high barrier performance for oxygen and water vapor.Molecular dynamics simulations reveal the underlying fracture mechanism between cellulose and PVA,which effectively enhances the Young’s modulus and strength of the wood packaging film.These findings contribute to the development of biodegradable and strong packaging materials,as well as other food-related applications,using sustainable wood.展开更多
To make full use of plant shellfibers(rice husk,walnut shell,chestnut shell),three kinds of wood-plastic com-posites of plant shellfibers and polyvinyl chloride(PVC)were prepared.X-ray diffraction analysis was carried o...To make full use of plant shellfibers(rice husk,walnut shell,chestnut shell),three kinds of wood-plastic com-posites of plant shellfibers and polyvinyl chloride(PVC)were prepared.X-ray diffraction analysis was carried out on three kinds of plant shellfibers to test their crystallinity.The aging process of the composites was conducted under 2 different conditions.One was artificial seawater immersion and xenon lamp irradiation,and the other one was deionized water spray and xenon lamp irradiation.The mechanical properties(tensile strength,flexural strength,impact strength),changes in color,water absorption,Fourier transform infrared spectroscopy(FTIR),and microstructures of the composites before and after the two aging experiments were analyzed.The results showed that the chestnut shell had the highest crystallinity,which was 42%.The chestnut shell/PVC composites had the strongest interface bonding,the least internal defects,and the best general mechanical properties among the three composites.Its tensile strength,bending strength and impact strength were 23.81 MPa,34.12 MPa,and 4.32 KJ·m^(-2),respectively.Comparing the two aging conditions,artificial seawater immersion and xenon lamp irradiation destroyed the quality of the combination of plant shellfibers and PVC,making the internal defects of the composites increase.This made the water absorption ability and changes in the color of the composites more obvious and led to a great decrease in the mechanical properties.The general mechanical properties of the chestnut shell/PVC composites were the best,but their water absorption ability changed more obviously.展开更多
Four kinds of iron oxide pigments were added into wood-fiber/high-density-polyethylene composites （WF/HDPE） at three different concentrations, to determine the effects of pigments on the changes in the color and mec...Four kinds of iron oxide pigments were added into wood-fiber/high-density-polyethylene composites （WF/HDPE） at three different concentrations, to determine the effects of pigments on the changes in the color and mechanical properties of the composites before and after UV accelerated weathering. HDPE, wood fibers, pigments and other processing additives were dry-mixed in a high-speed mixer. The mixtures were extruded by two-step extrusion process with a self-designed twin-screw/single-screw extruder system. Color of the samples was determined according to CIE 1976 L^＊a^＊b^＊ system by a spec- trophotometer and the bending properties were tested to evaluate the mechanical properties before and after accelerated UV weathering. The result shows that the modulus of elasticity of WF/HDPE did not obvi- ously changed after incorporating with the pigments, but the bending strength increased. After accelerated aging for 2000 h, both color and mechanical properties significantly changed. Iron oxide red and black performed better than the other two pigments, and the pigments dosage of 2.28% in the composites is favourable.展开更多
文摘研究了PVC树脂基本性能(聚合度、分子质量分布、表观密度)、助剂(发泡剂、发泡调节剂)、木粉及加工工艺(加工温度、挤出速度)对PVC木塑发泡材料性能的影响,并进行了工业化加工试验。结果表明:PVC树脂聚合度越高,发泡材料泡孔壁厚越大,发泡及加工都变得较为困难,适宜的聚合度为650~700;PVC树脂分子质量分布变宽,则发泡材料的密度增大,泡孔数量减少,泡孔增大,泡壁增厚,有串泡现象,适宜的分子质量分布指数为1.9~2.0;表观密度越高,机身压力越大,发泡材料泡孔数量越多,泡孔结构越均匀,适宜的表观密度为0.57~0.60 m L/g。对于S-700型PVC树脂而言,发泡剂AD C与助发泡剂Z n O的适宜质量比为1∶0.1,且二者的总用量以1.0份为宜;发泡调节剂ZB-530的适宜用量为8份;适宜的加工温度为185℃,适宜的挤出速度为20 r/min。宜采用硅烷偶联剂对木粉进行表面改性,发泡剂、发泡调节剂的用量应随着木粉用量的变化而调整。工业化加工试验结果表明:根据制品及生产设备的不同对试验得出的配方和加工工艺进行调整后,可顺利生产出质量优良的产品。
基金the support of the National Natural Science Foundation of China(No.32371790)the Fundamental Research Funds for the Central Universities(Nos.2572024AW61 and 2572023CT07)+4 种基金the National Key R&D Program of China(No.2023YFD2201404)China Postdoctoral Science Foundation(No.2020M681067)Special Funding Project of Postdoctoral in Heilongjiang Province(No.LBH-TZ2001)the National Natural Science Foundation of China(No.12302143)the National Key Research and Development Program of China(No.2023YFC3806300).
文摘Using biodegradable material derived from renewable resources as petroleum-based plastics replacement is a promising way towards sustainable development.However,the insufficient mechanical properties and complex manufacturing process of bioplastics still need to be improved for high-quality food packages.Herein,we report a top-down strategy to transform natural wood into a clear wood packaging film through scalable delignification and polyvinyl alcohol(PVA)infiltration.The wood packaging film demonstrates a laminated structure with completely collapsed cell walls and PVA intertwined together after energy-saving air drying,resulting in high light transmittance with low haze,good mechanical performance,and high barrier performance for oxygen and water vapor.Molecular dynamics simulations reveal the underlying fracture mechanism between cellulose and PVA,which effectively enhances the Young’s modulus and strength of the wood packaging film.These findings contribute to the development of biodegradable and strong packaging materials,as well as other food-related applications,using sustainable wood.
基金This study was supported by the financial support of Natural Science Research Projects in Higher Education Institutions in Jiangsu Province(No.18KJD430002).
文摘To make full use of plant shellfibers(rice husk,walnut shell,chestnut shell),three kinds of wood-plastic com-posites of plant shellfibers and polyvinyl chloride(PVC)were prepared.X-ray diffraction analysis was carried out on three kinds of plant shellfibers to test their crystallinity.The aging process of the composites was conducted under 2 different conditions.One was artificial seawater immersion and xenon lamp irradiation,and the other one was deionized water spray and xenon lamp irradiation.The mechanical properties(tensile strength,flexural strength,impact strength),changes in color,water absorption,Fourier transform infrared spectroscopy(FTIR),and microstructures of the composites before and after the two aging experiments were analyzed.The results showed that the chestnut shell had the highest crystallinity,which was 42%.The chestnut shell/PVC composites had the strongest interface bonding,the least internal defects,and the best general mechanical properties among the three composites.Its tensile strength,bending strength and impact strength were 23.81 MPa,34.12 MPa,and 4.32 KJ·m^(-2),respectively.Comparing the two aging conditions,artificial seawater immersion and xenon lamp irradiation destroyed the quality of the combination of plant shellfibers and PVC,making the internal defects of the composites increase.This made the water absorption ability and changes in the color of the composites more obvious and led to a great decrease in the mechanical properties.The general mechanical properties of the chestnut shell/PVC composites were the best,but their water absorption ability changed more obviously.
基金supported by the National Natural Science Foundation of China (30671644, 30771680)
文摘Four kinds of iron oxide pigments were added into wood-fiber/high-density-polyethylene composites （WF/HDPE） at three different concentrations, to determine the effects of pigments on the changes in the color and mechanical properties of the composites before and after UV accelerated weathering. HDPE, wood fibers, pigments and other processing additives were dry-mixed in a high-speed mixer. The mixtures were extruded by two-step extrusion process with a self-designed twin-screw/single-screw extruder system. Color of the samples was determined according to CIE 1976 L^＊a^＊b^＊ system by a spec- trophotometer and the bending properties were tested to evaluate the mechanical properties before and after accelerated UV weathering. The result shows that the modulus of elasticity of WF/HDPE did not obvi- ously changed after incorporating with the pigments, but the bending strength increased. After accelerated aging for 2000 h, both color and mechanical properties significantly changed. Iron oxide red and black performed better than the other two pigments, and the pigments dosage of 2.28% in the composites is favourable.
