Efficient and selective removal of Pb(Ⅱ) from landfill leachate using L-serine-modified polyethylene/polypropylene nonwoven fabric synthesized via radiation grafting technique

In this study,to efficiently remove Pb(Ⅱ) from aqueous environments,a novel L-serine-modified polyethylene/polypropylene nonwoven fabric sorbent(NWF-serine)was fabricated through the radiation grafting of glycidyl methacrylate and subsequent L-serine modification.The effect of the absorbed dose was investigated in the range of 5–50 kGy.NWF-serine was characterized by Fourier transform infrared spectroscopy,thermogravimetric analysis,and scanning electron microscopy.Batch adsorption tests were conducted to investigate the influences of pH,adsorption time,temperature,initial concentration,and sorbent dosage on the Pb(Ⅱ) adsorption performance of NWF-serine.The results indicated that Pb(Ⅱ) adsorption onto NWF-serine was an endothermic process,following the pseudo-second-order kinetic model and Langmuir isotherm model.The saturated adsorption capacity was 198.1 mg/g.NWF-serine exhibited Pb(Ⅱ) removal rates of 99.8% for aqueous solutions with initial concentrations of 100 mg/L and 82.1% for landfill leachate containing competitive metal ions such as Cd,Cu,Ni,Mn,and Zn.Furthermore,NWF-serine maintained 86% of its Pb(Ⅱ) uptake after five use cycles.The coordination of the carboxyl and amino groups with Pb(Ⅱ) was confirmed using X-ray photoelectron spectroscopy and extended X-ray absorption fine structure analysis.

Mechanical, Thermal and Interfacial Properties of Jute Fabric-Reinforced Polypropylene Composites: Effect of Potassium Dichromate

Composites based on jute fabrics and polypropylene was fabricated by heat-press molding technique. The mechanical properties of the composites such as tensile strength, tensile modulus, bending strength, bending modulus and impact strength were measured in dependence of fiber contents. In order to improve fiber-matrix interaction, jute fabrics were treated with aqueous solutions of K2Cr2O7 (0.005-0.05% w/v). Composite prepared with 0.02% K2Cr2O7 treated jute fabrics showed the highest values of the mechanical properties. Thermogravimetric (TG/DTG) data of PP, jute fabrics and composites showed that thermal degradation temperatures of composites shifted to higher temperature regions compared to PP or jute fabrics. Treatment of jute fabrics improved the thermal stability of the composite considerably. Scanning electron microscopic images of tensile fractured sides of untreated and treated composites illustrated that better fiber-matrix interfacial interaction occurred in treated composite. The relative tendency of water absorption of both untreated and treated composites was also explored.

Ultravilolet-radiation-induced graft polymerization of acrylamide onto the melt-blown polypropylene filter element by dynamic method

By dynamic method under UV irradiation, commercial melt-blown polypropylene （PPMB） filter element was modified with acrylamide （AAm） using benzophenone （BP） as initiator. Attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscope verified that polyacrylamide chain was grafted on the fiber surface of PPMB filter element. Elemental content analysis with energy dispersive X-ray of fibers revealed that the polymerization content in the inner part of filter element was relatively higher than that in the outer. Degree of grafting changed with initiator concentration, monomer concentration, reaction temperature and reached 2.6% at the reaction condition： CBp=0.06 mol/L, CAAm=2.0 mol/L, irradiation time： 80 min, temperature： 60℃. Relative water flux altered with the hydrophilicity and pore size of filter element. In the antifouling test, the modified filter gave greater flux recovery （approximately 70%） after filtration of the water extract of Liuweidihuang, suggesting that the fouling layer was more easily reversible due to the hydrophilic nature of the modified filter.

Comparative Study of Polypropylene Non-Woven Surgical Mask and Locally Manufactured Woven and Knitted Fabrics Facial Masks

The outbreak of coronavirus has led to an increase in the demand for facemasks globally. Unavailability of appropriate polypropylene non-woven fabrics face masks as a result of inadequate supply to satisfy the growing population has brought about the manufacturing of locally fabrics masks to augment or substitute standard medical class facemasks. The study aims at analyzing airflow of these locally manufactured fabrics to determine possible means of transmitting the virus as well as establish comfort of the user of these masks. Standard polypropylene non-woven, woven and knitted fabrics were considered for the study. Air permeability test was conducted on these fabrics using Frazier Air permeability tester. Depending on the property significant variation in the textile fabrics, polypropylene non-woven is widely accepted for facial masks. Nevertheless, this study illustrates that woven and knitted fabrics have more open structures, which allow a high rate of air penetration and so may require two or three layers to prevent antimicrobial or antiviral potential.

A STUDY OF FINE DENIER POLYPROPYLENE FIBER KNITTED FABRICS' WET COMFORT——THE WET COMFORT STUDIED BY THE NORMAL OBJECTIVE TEST

Based on the theory of moisture vapor permeability and liquid moisture transmission through fabric, this paper is mainly concerned with the wet comfort of the fine denier polypropylene fiber knitted fabrics. The liquid water transport property the liquid water retention property, the moisture permeability property, the moisture releasing and drying property of these fabrics are tested by normal objective ways and discussed. At last, according to these properties these fabries are classified by grey model synthetic evaluation method.

Grafting Copolymerization of Styrene and Acrylic Acid onto Pre-irradiated Polypropylene Fabric

Grafting copolymerization of styrene and acrylic acid onto polypropylene fabric had been studied by using a pre-irradiation technique. The polypropylene fabric Samples were irradiated by Y-ray and electron beam under the conditions of air and nitrogen gas, respectively. The effect of absorbed dose, monomer concentration in solvent, reaction temperature and reaction time on the degree of grafting were determined. The effects of metallic salts and sulphuric acid on the grafting yield of acrylic acid were also examined. The samples irradiated by electron beam give a much higher degree of grafting than those by Y -ray when styrene was grafted to polypropylene fabric. However, the grafting yield of acrylic acid on polypropylene fabric in the presence of metallic salts and sultric acid showed the opposite results from the case of styrene. This effect is reasonably interpreted by assuming that the grafting is dominated by trapped radicals and peroxides in pre-irradiated polypropylene.

Influence Factors on the Moisture Transmission of the Pure Polypropylene Knitted Fabrics

This paper analyses the principle of wicking effect of the polypropylene filament yarn. By means of theoretical and experimental analysis, some factors affecting the moisture transmission of the pure polypropylene knitted fabrics are discussed.

Analysis of the Thermohydro - comfort Durability for Microfil - polypropylene Knitted Fabric under Grey System

Thin microfll - polypropylene knitted fabric that is knitted to use new single plated theory on large diameter circular weft knitting machine is a new functional fabric. After military use, the reflective opinions are that it is light, thin, soft, smooth - touch, and it has excellent elasticity, good air perviousness, large water vapor permeability . In this paper, an analysis is held to use grey system theory, and the thermohydro - comfort durability of this microfil - polypropylene knitted fabric is compared with that of common knitted fabrics. The analytical result proves the microfil - polypropylene knitted fabric is satisfactory under the climatic conditions that human body needs to eliminate or retain the quantity of heat. It can be use to seam up not only physical ability training uniform of serviceman but also civil sporty and sportswear et cetera.

Recipe Development and Mechanical Characterization of Carbon Fibre Reinforced Recycled Polypropylene 3D Printing Filament

Recycled polypropylene filaments for fused filament fabrication were investigated with and without 14 wt% short fibre carbon reinforcements. The microstructure and mechanical properties of the filaments and 3D printed specimens were characterized using scanning electron microscopy and standard tensile testing. It was observed that recycled polypropylene filaments with 14 wt% short carbon fibre reinforcement contained pores that were dispersed throughout the microstructure of the filament. A two-stage filament extrusion process was observed to improve the spatial distribution of carbon fibre reinforcement but did not reduce the pores. Recycled polypropylene filaments without reinforcement extruded at high screw speeds above 20 rpm contained a centreline cavity but no spatially distributed pores. However, this cavity is eliminated when extrusion is carried out at screw speeds below 20 rpm. For 3D printed specimens, interlayer cavities were observed larger for specimens printed from 14 wt% carbon fibre reinforced recycled polypropylene than those printed from unreinforced filaments. The values of tensile strength for the filaments were 21.82 MPa and 24.22 MPa, which reduced to 19.72 MPa and 22.70 MPa, respectively, for 3D printed samples using the filaments. Likewise, the young’s modulus of the filaments was 1208.6 MPa and 1412.7 MPa, which reduced to 961.5 MPa and 1352.3 MPa, respectively, for the 3D printed samples. The percentage elongation at failure for the recycled polypropylene filament was 9.83% but reduced to 3.84% for the samples printed with 14 wt% carbon fiber reinforced polypropylene filaments whose elongation to failure was 6.58%. The SEM observations on the fractured tensile test samples showed interlayer gaps between the printed and the adjacent raster layers. These gaps accounted for the reduction in the mechanical properties of the printed parts.

聚丙烯织物表面超亲水涂层构筑及其油水分离性能

[目的]为得到具有优秀耐久性和高油水分离效率的超亲水性聚丙烯(PP)分离材料。[方法]通过将天然来源的羧甲基纤维素(CMC)与聚丙烯织物共价结合,制备出一种具有超亲水-水下超疏油性能涂层的改性PP织物。通过扫描电镜(SEM)、红外光谱(IR)、X射线光电子能谱(XPS)等手段对改性后的样品进行分析,利用接触角测量仪和自建油水分离装置测试了改性PP织物的润湿性及油水分离性能。[结果]改性PP织物在空气中的水接触角低至0°,在水下对不同油(包括正己烷、甲苯、煤油、柴油、汽油和石油醚)的接触角都不低于150°,对油水混合物的分离效率都可达到98%以上,分离时的水通量高达69449 L/(m^(2)·h)以上。经过50次循环分离、酸碱盐溶液腐蚀浸泡8 h、砂纸刮擦30次、高含沙量水冲刷2 h等多项测试后,改性PP织物均保持优异的水下疏油性和大于97%的油水分离效率。从微观结构与化学组成的角度揭示了是表面粗糙度与亲水基团的协同作用使PP织物由最初的疏水亲油转变为超亲水-水下超疏油。[结论]通过化学键连接的方式可以在PP织物表面成功构筑牢固结合的超亲水涂层。该改性过程绿色、简便、低成本,能赋予PP织物优异、耐久的油水分离性能。改性后的PP织物有望在复杂水体环境下的油水分离场景中应用。

过滤吸油用PP/PE双组分熔喷非织造布的性能测试研究

以不同质量比的聚丙烯(PP)、聚乙烯(PE)为原料制得PP/PE双组分熔喷非织造布,测试分析了PP/PE双组分熔喷非织造布的性能。结果表明:PP/PE双组分熔喷非织造布的纤网呈现蓬松杂乱的三维结构,纤维直径较细,孔隙率较高;随着PE添加比例增大,PP/PE双组分熔喷非织造布的面密度和厚度增大,拉伸断裂强力、顶破强力略有下降,硬挺度下降,透气性增大;当PP/PE质量比为73时,PP/PE双组分熔喷非织造布的水接触角在129°左右,吸油倍数为18.75,20 s内吸油高度为1.7 mm,空气过滤效率为56.82%,综合性能较好,可应用于过滤、吸油等领域。

超吸水织物的制备及性能研究

以丙烯酸为单体,过硫酸钾、亚硫酸氢钠为氧化还原引发剂,与聚乙烯醇共混,采用溶液聚合法制备了丙烯酸高聚物溶液,浸轧丙纶热熔无纺布织物,经烘干得到超吸水织物,通过傅里叶变换红外光谱仪、场发射扫描电子显微镜、同步热分析仪对超吸水织物的结构、形貌和热性能进行分析,考察了聚合反应水浴温度、丙烯酸中和度、聚乙烯醇添加量、带液率对吸水倍率的影响,并对吸水机理进行探讨。结果表明:在聚合反应水浴温度为75℃,丙烯酸中和度75%,聚乙烯醇添加量(对单体)为5%(质量分数),带液率为500%,烘干温度为120℃条件下,制备的超吸水织物吸蒸馏水倍率为109.82g/g。

聚苯胺/MXene@聚丙烯复合非织造柔性pH值传感器的制备及其传感性能

为制备基于聚丙烯纺黏非织造材料(Polypropylene spunbonded nonwoven fabric,PP SF)的双电极柔性pH值传感器,在PP SF表面涂覆油性聚氨酯(Oil-based polyurethane,OPU),制备得到OPU/PP SF,采用丝网印刷技术将作为参比电极的银/氯化银(Ag/AgCl)浆料和导电碳浆料分别移印至OPU/PP SF表面;利用化学氧化聚合法制备了酸掺杂聚苯胺(Polyaniline,PANI),将其与经超疏水改性的F-Ti_(3)C_(2)T_(x)MXene结合,再涂覆在C层表面,形成PANI/F-Ti_(3)C_(2)T_(x)MXene@PP SF柔性pH值传感器。结果表明:PANI/F-Ti_(3)C_(2)T_(x)MXene@PP SF柔性pH值传感器表面呈现珊瑚状结构,在pH值为2~10时,PANI/F-Ti_(3)C_(2)T_(x)MXene@PP SF柔性pH值传感器表现出良好的力学性能,其拉伸强度和断裂伸长率均比PP SF有所提高,灵敏度(-37.07 mV/pH)高,线性度(R2=0.98)好,具有低电位变化率(0.092 mV/h)和良好的重现性(灵敏度标准偏差为0.36%)。该研究可为基于聚丙烯纺黏非织造材料基材的柔性pH值传感器的研究提供参考。

高阻隔性熔喷无纺布的制备及性能研究

本文采用茂金属聚丙烯(mPP)进行控制降解,制备了适于熔喷加工工艺的专用料。实验证明,采用mPP制备的熔喷无纺布较齐格勒-纳塔催化聚合等规聚丙烯(znPP)熔喷无纺布具有更出色的过滤性能,得益于其更加纤细且均匀的熔喷纤维和优异且稳定的驻极性能。无驻极添加剂的mPP熔喷无纺布表现出了出色的驻极性能,主要原因是mPP熔喷无纺布具有更高的表面电阻、更强的疏水性以及mPP熔喷无纺布专用料更小的结晶尺寸和更快的结晶速率。

氟改性硅溶胶的制备及性能

[目的]具有特殊润湿性的透明疏水材料在自清洁、金属防腐、微流体运输、防结冰、油水分离等领域具有广阔的应用前景。[方法]以正硅酸乙酯(TEOS)作为前驱体,十七氟硅烷偶联剂(FAS)和环氧硅烷偶联剂(KH560)为改性剂,采用两步法制备了氟改性硅溶胶,并将其涂覆在载玻片和聚丙烯(PP)纤维织物表面,制成了疏水材料。采用接触角测量仪、傅里叶变换红外光谱仪和扫描电镜对其进行表征,考察了改性剂的用量、水解时乙醇的比例及稀释倍数对材料疏水性能的影响。[结果]在乙醇与水的质量比为3∶2,偶联剂总用量为3%(质量分数),FAS与KH560的质量比为1∶1的条件下制备的硅溶胶稀释10倍后可以在载玻片和织物表面形成致密的涂层,它们对水的接触角分别达到了112°和153°,且具有优异的自清洁性能。[结论]通过溶胶-凝胶法,利用TEOS与FAS共水解的方式,可以获得性能优异的疏水材料。

医用防护服用聚丙烯SMS抗菌面料制备与表征

为解决医用防护服用聚丙烯SMS非织造布耐久性抗菌问题,利用课题组制备的银氮共掺杂纳米二氧化钛(Ag-N-TiO_(2))光催化抗菌剂,以聚丙烯SMS非织造布为基材,采用浸渍法,通过优化工艺制备出Ag-N-TiO_(2)/聚丙烯SMS非织造布抗菌试样。以大肠杆菌和金黄色葡萄球菌为目标菌种,采用振荡法测试分析了Ag-N-TiO_(2)/聚丙烯SMS非织造布试样的抗菌性能。利用扫描电子显微镜(SEM)表征试样的微观形貌,同时还测试了负载抗菌剂前后试样的主要性能。结果表明:Ag-N-TiO_(2)成功负载到聚丙烯SMS非织造布上,试样对大肠杆菌和金黄色葡萄球菌的抑菌率分别为100%和100%,洗涤20次后其抑菌率分别为100%和96.1%,抗菌耐久性优于AA级,且主要性能良好,均符合医用防护服面料相关标准要求。

PP熔喷非织造布原料性能及关键工艺研究

为研究高效低阻熔喷布的关键生产工艺,选取四种不同的熔喷专用聚丙烯原料,采用毛细管流变仪对聚丙烯原料的流变性能进行分析,并进一步在熔喷生产过程中考察不同模头孔径和温度、不同热风风温和风量以及不同接收距离(DCD)对熔喷布颗粒物过滤效率的影响。结果表明,四种聚丙烯熔体的非牛顿指数均小于1,熔体表现出切力变稀现象;同一剪切速率下,四种聚丙烯熔体的黏流活化能各不相同,生产过程中需根据原料特性严格控制温度;四种聚丙烯熔体的结构黏度指数均小于0.005,结构化程度均较小,可纺性好;同时,减小模头孔径,提高模头温度及在熔喷布克重相同的条件下,增加热风风温和风量及DCD距离,有利于降低熔喷纤维的平均直径,提高过滤效率。确定了熔喷非织造布的关键生产工艺:模头孔径0.28mm,热风风温275℃,热风风量32%,DCD 180 mm,开发出25 g/m 2熔喷布,在32 L/min流量下,盐性颗粒物过滤效率98.8%,过滤阻力17.9 Pa。

Photo-Grafting Copolymerization of PP Nonwoven Fabric and Its Application for Acidic Dye Adsorption and Filtration

The monomer methacrylamido propyl trimethy ammonium chloride( MAPTAC) was copolymerized onto the fiber surface of polypropylene( PP) nonwoven fabric under ultroviole radiation. The weak acid red GN dye adsorption and adsorptive filtration performance of the resulted PP fabrics were investigated.The results showed that the grafting copolymerization preferred to happen in the inner layer of the fabrics. The water flux of the grafted fabrics decreases with the increase of grafting yield. The collapse of the grafted polymer chains causes the flux increase in acidic condition,or vice versa at alkaline version. The coiling of the polyelectrolyte chains upon the dye adsorption seems to violate the routine assumption of the rigid substrate, and this gets the adsorption energy constant negative. The static adsorption process follows the Lagergren's pseudo-second order kinetic equation. The removals of circa( ca.) 100% of the total permeation volume3 500 mL simulated dye wastewater was reached during permeation.The dye adsorbed fabrics were regenerated by the mixed media of the cationic surfactant / ethanol /water. The grafted fabric assumes stable fabric integrity and stability during permeation,and presents excellent dye adsorption capacity,easy desorption, and repeatable utilization.

防护口罩用改性长效聚(偏氟乙烯-三氟乙烯)压电纤维膜的制备及其性能

聚丙烯(PP)熔喷布表面自由电荷易在湿气等作用下流失,导致过滤层及口罩快速失效。针对以上问题,采用静电纺丝技术在PP熔喷布基体上制备压电聚(偏氟乙烯-三氟乙烯)(P(VDF-TrFE))纤维层,得到PP熔喷布/P(VDF-TrFE)改性过滤层。探究了纺丝工艺对压电纤维形貌和结构的影响,进一步分析了改性过滤层经过水洗、蒸汽等耐久性处理后的静电压、烟雾过滤效率和透气性的变化。结果表明:PP熔喷布/P(VDF-TrFE)改性过滤层对PM_(2.5)的过滤效率较PP熔喷布提高了25%,在进风量为85 L/min时的过滤效率提升了27.5%;经过2次水洗、紫外线照射、蒸煮消毒等方式处理后的改性过滤层,其表面电荷具有多次弯折后可再生的特点,过滤效率维持在90%,有效提高了口罩的防护效率和使用寿命,压电材料在外力作用下可产生束缚电荷,改善了过滤层负载电荷的稳定性,从而提升了口罩防护的长效性和安全性。

聚丙烯纤维再生混凝土内隔墙板性能研究

内隔墙板的发展需要解决自重大、干缩性大、开裂多等问题。聚丙烯纤维具有密度小、价格低廉、韧性好、强度高等优势,对混凝土来说,聚丙烯纤维的加入可以提高混凝土的抗冲击、韧性、抗裂等性能。研究发现,聚丙烯纤维对再生混凝土的抗拉性能有显著的提高作用,在再生粗骨料替代率为50%的条件下,使用0.5 kg/m3的聚丙烯纤维可使再生混凝土的劈裂抗拉强度提高至2.9 MPa,符合C60混凝土强度等级的要求。选用再生粗骨料体积替代率为50%和纤维掺量为0.5 kg/m3的配合比制备内隔墙板完全符合GB/T 23451—2009《建筑用轻质隔墙条板》。