High-density polyethylene (HDPE) films were irradiated by 60Co gamma ray with a dose of 100 kGy in air and then immersed in aqueous solution of acrylic acid (AA) and sodium styrene sulfonate (SSS) at different tempera...High-density polyethylene (HDPE) films were irradiated by 60Co gamma ray with a dose of 100 kGy in air and then immersed in aqueous solution of acrylic acid (AA) and sodium styrene sulfonate (SSS) at different temperature. The effects of grafting conditions such as temperature, reaction time, Mohr’s salt concentration, and total concentration of monomer on grafting yield were studied. Both grafting yield of AA and SSS onto HDPE respectively increases with total concentration of monomers. The highest grafting yield was observed at 3 mol/L monomers where the grafted PE swelled to the largest extent in the monomers mixture. The grafting yield increases with reaction time and then levels off. At higher temperature, the grafting yield decreases with Mohr’s salt concentration, but increases at low temperature when Mohr’s salt concentration is 0.083%. Which can be interpreted that in the presence of Fe2+ diperoxides and hydroperoxides may decompose at low temperature to form radical which can initiate the grafting. The physical and chemical properties of grafting films were also investigated.展开更多
The surface performances of directly fluorinated high density polyethylene （HDPE） are studied with Fourier transform infrared （FT-IR） spectra, scanning electron microscopy （SEM） and contact angle （CA） system. ...The surface performances of directly fluorinated high density polyethylene （HDPE） are studied with Fourier transform infrared （FT-IR） spectra, scanning electron microscopy （SEM） and contact angle （CA） system. The SEM images show that there is a three-layer structure called the reaction, virgin and boundary layer structure. The depth of fluorinated layer is 5.75 ~m with 1 h fluorination time and 7.86 b^m with 2 h. The depths are 5.46 /~m and 5.07 /~m when fluorine density is 2G and 1~/0, respectively. CA indicates that the HDPE surface property becomes more hydrophobic with the increasing water contact angle from 78.5~ to 104.5~. Oleophobic and hydrophobic features of HDPE are identified by comparison of mass change experiments. It is shown that the in- crement rate of fluorinated HDPE is much lower than that of un-fluorinated HDPE filled in neither distilled water nor jet fuel.展开更多
Noil discarded fibers from fiber production for textile industry have short length and are always considered less valuable.Here,noil ramie fibers/HDPE composite is prepared using twin-screw extruder and the dynamic me...Noil discarded fibers from fiber production for textile industry have short length and are always considered less valuable.Here,noil ramie fibers/HDPE composite is prepared using twin-screw extruder and the dynamic mechanical and thermal properties are studied.The influence of ramie fiber and maleic anhydride-grafted polyolefin(MA-g-PO)on mechanical,dynamic mechanical and thermal properties is investigated.It is observed that the tensile,flexural and impact properties of the composites treated with MA-g-PO are all improved in comparison to the untreated composites.Dynamic mechanical properties of the composite with MA-g-PO show an increase in the storage modulus with a higherαrelaxation peak,together with the micromorphology analysis,indicating an improved interfacial bonding between fiber and matrix by the MA-g-PO addition.Furthermore,the change in TGA thermograms of composite caused by MA-g-PO exhibits that the addition of MA-g-PO is also helpful to increase the thermal stability of noil ramie fiber/HDPE composites.展开更多
本研究旨在探究高密度聚乙烯(high density polyethylene,HDPE)护套的老化机理及其在自然环境下的服役寿命。对HDPE护套在湿热气候(海南琼海市)和干热气候(新疆吐鲁番市)下进行了3a的自然老化试验和在干热气候(美国凤凰城)下进行1a的太...本研究旨在探究高密度聚乙烯(high density polyethylene,HDPE)护套的老化机理及其在自然环境下的服役寿命。对HDPE护套在湿热气候(海南琼海市)和干热气候(新疆吐鲁番市)下进行了3a的自然老化试验和在干热气候(美国凤凰城)下进行1a的太阳跟踪聚光加速老化试验,对HDPE老化试验中的力学性能、分子结构、热性能、反应动力学、反应级数进行分析。结果表明,黑色HDPE护套在自然老化和太阳跟踪聚光加速老化过程中产生的特征官能团相似,热分解活化能基本相同,反应机理也一致;基于试验数据,提出了HDPE护套服役寿命模型,得出HDPE护套在中东特殊干热地区的服役寿命为15~28a,东南亚特殊湿热地区为14~20a,气候环境温和地区超过40a。本研究为预测HDPE护套在各种环境下的服役寿命提供了理论依据,也为HDPE护套材料的研发与应用提供了参考。展开更多
文摘High-density polyethylene (HDPE) films were irradiated by 60Co gamma ray with a dose of 100 kGy in air and then immersed in aqueous solution of acrylic acid (AA) and sodium styrene sulfonate (SSS) at different temperature. The effects of grafting conditions such as temperature, reaction time, Mohr’s salt concentration, and total concentration of monomer on grafting yield were studied. Both grafting yield of AA and SSS onto HDPE respectively increases with total concentration of monomers. The highest grafting yield was observed at 3 mol/L monomers where the grafted PE swelled to the largest extent in the monomers mixture. The grafting yield increases with reaction time and then levels off. At higher temperature, the grafting yield decreases with Mohr’s salt concentration, but increases at low temperature when Mohr’s salt concentration is 0.083%. Which can be interpreted that in the presence of Fe2+ diperoxides and hydroperoxides may decompose at low temperature to form radical which can initiate the grafting. The physical and chemical properties of grafting films were also investigated.
基金Supported by the National Natural Science Foundation of China for Innovative Research Group(50921002)the Quartermaster Materials and Fuel Ministry of PLA Air Force Logistics Department(BKJ10C043)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The surface performances of directly fluorinated high density polyethylene （HDPE） are studied with Fourier transform infrared （FT-IR） spectra, scanning electron microscopy （SEM） and contact angle （CA） system. The SEM images show that there is a three-layer structure called the reaction, virgin and boundary layer structure. The depth of fluorinated layer is 5.75 ~m with 1 h fluorination time and 7.86 b^m with 2 h. The depths are 5.46 /~m and 5.07 /~m when fluorine density is 2G and 1~/0, respectively. CA indicates that the HDPE surface property becomes more hydrophobic with the increasing water contact angle from 78.5~ to 104.5~. Oleophobic and hydrophobic features of HDPE are identified by comparison of mass change experiments. It is shown that the in- crement rate of fluorinated HDPE is much lower than that of un-fluorinated HDPE filled in neither distilled water nor jet fuel.
基金supported by the National Scientific and Technical Supporting 12th Five-year Plan Project(No.2012BAD23B0203)
文摘Noil discarded fibers from fiber production for textile industry have short length and are always considered less valuable.Here,noil ramie fibers/HDPE composite is prepared using twin-screw extruder and the dynamic mechanical and thermal properties are studied.The influence of ramie fiber and maleic anhydride-grafted polyolefin(MA-g-PO)on mechanical,dynamic mechanical and thermal properties is investigated.It is observed that the tensile,flexural and impact properties of the composites treated with MA-g-PO are all improved in comparison to the untreated composites.Dynamic mechanical properties of the composite with MA-g-PO show an increase in the storage modulus with a higherαrelaxation peak,together with the micromorphology analysis,indicating an improved interfacial bonding between fiber and matrix by the MA-g-PO addition.Furthermore,the change in TGA thermograms of composite caused by MA-g-PO exhibits that the addition of MA-g-PO is also helpful to increase the thermal stability of noil ramie fiber/HDPE composites.
文摘本研究旨在探究高密度聚乙烯(high density polyethylene,HDPE)护套的老化机理及其在自然环境下的服役寿命。对HDPE护套在湿热气候(海南琼海市)和干热气候(新疆吐鲁番市)下进行了3a的自然老化试验和在干热气候(美国凤凰城)下进行1a的太阳跟踪聚光加速老化试验,对HDPE老化试验中的力学性能、分子结构、热性能、反应动力学、反应级数进行分析。结果表明,黑色HDPE护套在自然老化和太阳跟踪聚光加速老化过程中产生的特征官能团相似,热分解活化能基本相同,反应机理也一致;基于试验数据,提出了HDPE护套服役寿命模型,得出HDPE护套在中东特殊干热地区的服役寿命为15~28a,东南亚特殊湿热地区为14~20a,气候环境温和地区超过40a。本研究为预测HDPE护套在各种环境下的服役寿命提供了理论依据,也为HDPE护套材料的研发与应用提供了参考。
