Large-Scale Preparation of Mechanically High-Performance and Biodegradable PLA/PHBV Melt-Blown Nonwovens with Nanofibers

Biodegradable polylactic acid(PLA)melt-blown nonwovens are attractive candidates to replace nondegradable polypropylene melt-blown nonwovens.However,it is still an extremely challenging task to prepare PLA melt-blown nonwovens with sufficient mechanical properties for practical application.Herein,we report a simple strategy for the large-scale preparation of biodegradable PLA/poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)melt-blown nonwovens with high strength and excellent toughness.In this process,a small amount of PHBV is added to PLA to improve the latter’s crystallization rate and crystallinity.In addition,when the PHBV content increases from 0 to 7.5 wt%,the diameters of the PLA/PHBV melt-blown fibers decrease significantly(with the proportion of nanofibers increasing from 7.7%to 42.9%).The resultant PLA/PHBV(5 wt%PHBV)melt-blown nonwovens exhibit the highest mechanical properties.The tensile stress,elongation,and toughness of PLA/PHBV(5 wt%PHBV)melt-blown nonwovens reach 2.5 MPa,45%,and 1.0 MJm3,respectively.More importantly,PLA/PHBV melt-blown nonwovens can be completely degraded into carbon dioxide and water after four months in the soil,making them environmentally friendly.A general tensile-failure model of melt-blown nonwovens is proposed in this study,which may shed light on mechanical performance enhancement for nonwovens.

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.

High Oil-absorptive Composites Prepared from Non-woven Fiber and Sponges with 4-tert- butylstyrene-EPDM-divinylbenzene Graft Polymer

4-tert-butylstyrene-EPDM-divinylbenzene graft terpolymer (PBED) was prepared by graft cross-polymerization in toluene using BPO as an initiator. The gel-PBED and solPBED were isolated from extraction of tetrahydrofuran (THF), and then they were identified by IR spectroscopy. The maximum oil-absorptivity of gel-PBED produced from the optinum reaction conditions was 8 420% but its swelling rate was very low. The highest oil-absorptivity of photocrosslinked sol-PBED film was 5 800%. Although its oil absorbency was not as high as gel-PBED' s, swelling rate was higher than that of gelPBED and was suitable for commercial purpose. After swelling in oil, neither gel PBED nor photocrosslinked sol-PBED film having high oil-absorptivity had sufficient mechanical strength to be taken out of oil wholly. As is known, composite technique is one of the useful methods for reinforcing them. Fibers, sponges and non-woven cloths were used as reinforcers or supporters in this work. Oil-absorptivities and swelling kinetics were evaluated by method ASTM (F726 - 81 ) and an experimental equation. The mechanical properties and the morphologies of some composites were measured by tensile tester and SEM , respectively.

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.

Hygrothermal/UV Aging Effect on Visual Aspect and Mechanical Properties of Non-Woven Natural-Fiber Composites

This work aims at studying the effect of hygrothermal and UV cyclic aging on the tensile properties and esthetic characteristics of non-woven composites.The composite materials were thermo-compressed from non-woven mats made up of PP and flax or kenaf fibers.This works included evaluating the change in color appearance and analyzing the variations in tensile properties and damage mechanisms,depending on the aging time.The presence of the UV protection film on the composite surface showed its effectiveness against aging.From visual observations and measurement of colorimetric parameters,it has been proved effective in the reduction of the bleaching and yellowing of the composites.As regards the tensile tests,the UV protection film enabled to stabilize the Young’s modulus after 1-week aging for Kenaf/PP and after 3-weeks for Flax/PP.After 4-weeks aging,it halved the number of acoustic emission events related to interfacial decohesion and fiber slippage/pull out for Flax/PP and Kenaf/PP composites.

MELT-BLOWN NONWOVEN FOR AIR FILTRATION

The technical parameters and the structural factors of melt-blown nonwovens used as filteringmedium are analysed,the orientation of particles filtered in a filter is described,and the optimalparameters for air filtration are obtained.The results are shown as follows:the ratio of tenacity oflongitudinal to cross direction has a close agreement with the random coefficient of fiber arrange-ment in practice;large particles are most likely trapped on the surface of a filter,and smaller parti-cles are filtered throughout the depth of a filter,and the deeper,the smaller;moreover,higher fil-tering efficiency and lower pressure drop can be effected through the optimization of parameters.

Use of Polypropylene Non-woven as Sorbent of Oil Small

In this work, the mechanical tensile and elongation properties and the non-woven polypropylene flammability were evaluated, with variations of gratings, compared to non-woven fabrics prepared with thermo film and TNT （fabric non-fabric）, for applications such as geotextile sorption of oil spills. The results showed high values of tensile strength for non-woven fabric prepared for application as geotextile, improving the mechanical properties of rupture.

A STUDY OF THE SPECIMEN SIZE OF STRIP TENSILE TEST FOR NEEDLE-PUNCHED NON-WOVEN GEOTEXTILES

In this paper,the failure features of strip tensile specimen were observed and analysed for need-le-punched non-woven geotextiles.A mechanical model which expresses the relation between thetensile modulus,the strip specimen size,contraction factor and the tensile strength of non-wovenfabric was derived.The theoretical prediction showed that the main factor influencing tensilestrength of non-woven geotextile specimens with different size is the contraction factor of specimenor the specimen aspect ratio(width/length).The larger the aspect ratio,the higher the tensilestrength test value of geotextiles,but the experiments showed that the specimen tensile strength isnot increased with increasing the width of specimen.The reason was discussed and it seemed thatthe deviation could be served as an indication of the degree of imperfectness of the non-wovenstructure.

A Cell-Based Smoothed Finite Element Method for Modal Analysis of Non-Woven Fabrics

The combination of a 4-node quadrilateral mixed interpolation of tensorial components element(MITC4)and the cell-based smoothed finite element method(CSFEM)was formulated and implemented in this work for the analysis of free vibration and unidirectional buckling of shell structures.This formulation was applied to numerous numerical examples of non-woven fabrics.As CSFEM schemes do not require coordinate transformation,spurious modes and numerical instabilities are prevented using bilinear quadrilateral element subdivided into two,three and four smoothing cells.An improvement of the original CSFEM formulation was made regarding the calculation of outward unit normal vectors,which allowed to remove the integral operator in the strain smoothing operation.This procedure conducted both to the simplification of the developed formulation and the reduction of computational cost.A wide range of values for the thickness-to-length ratio and edge boundary conditions were analysed.The developed numerical model proved to overcome the shear locking phenomenon with success,revealing both reduced implementation effort and computational cost in comparison to the conventional FEM approach.The cell-based strain smoothing technique used in this work yields accurate results and generally attains higher convergence rate in energy at low computational cost.

Preparation of UV-curable Nano-silver Antimicrobial Agent and Its Application in Non-woven Fabric

Nano-silver and waterborne polyurethane(WPU)composite emulsion was synthesized.The average diameter of silver nanoparticles(SNPs)was about 20 nm,and the average diameter of WPU was 101.32 nm.The anti-bacteria finishing of a polypropylene non-woven fabric(NWF)was carried out by ultraviolet finishing technology and the double dipping twin-roll method.The standard AATCC100 was used to test the antimicrobial activity of the samples.The results showed that the antimicrobial rates of Klebsiella pneumoniae(K.pneumoniae)and Staphylococcus aureus(S.aureus)were above 90%,which indicated that the NWF finishing had good antimicrobial activity.In addition,the thermal stability,mechanical properties,whiteness and contact angle of antimicrobial finishing nonwovens were characterized.The results showed that the performance of antimicrobial nonwovens was stable at 300℃.The breaking strength was better than that of untreated nonwovens,and the contact angle reached 119.1°.

Beijing Dayuan Non-woven Fabric Co.Ltd

Situated in the Shilong Industrial District of Mentougou, Beijing, the Beijing Dayuan Non-woven Fabric Co. Ltd is a Sino-foreign joint venture producing non-woven fabrics, set up in 1991.

Cost analysis and comparison of plain cotton and disposable non-woven treatment towels

Objective: To choose a reasonably priced and low-cost treatment towel suitable for clinical application of hospital so as to reduce the cost of the hospital and make a reasonable use of resources through the cost analysis and comparison of the plain cotton and disposable non-woven treatment towels. Methods: The cost of the single pack plain cotton towel and disposable non-woven towel were analyzed and at the same time, 49185 packs of plain cotton towels which were the total consumption quantity of our hospital in 2017 and the same quantity of disposable non-woven towers were analyzed in the cost for comparison. Results:A single pack of disposable non-woven towel was RMB 2.50 cheaper than the plain cotton towel and the use of disposable non-woven towel can save the cost of RMB 2.50 per pack. In 2017, 49185 packs of plain cotton towel were used in total, which cost RMB 122962.50 less than the same quantity of disposable non-woven towels and using the disposable non-woven towel could save RMB 122962.50 annually. Conclusion: Compared with the plain cotton towel, the non-woven shares the advantages of none flocculation, longer storage time and better antibacterial effect as well as the material, cleaning and labor costs-saving. The cost of the disposable non-woven treatment towel is lower than that of the reusable plain cotton towel. Therefore, it is recommended to use the disposable non-woven treatment towel.

Modelling the Influence of Air Jet Configurations on Non-Woven Steel Fibre Mixing in the Melt Overflow Process

The mixing of non-woven steel fibres in melt overflow process for use in automotive muffler systems was simulated. The aim was to identify optimum parameters for achieving a good fibre mix. Numerical models of mixing chambers of melt overflow process were developed. Multiphysics analyses involving heat transfer, fluid flow and particle tracking were carried out using COMSOL code. The influence of air jet configurations on the fibre distribution was studied. The fibres settled on the moving bed within the mixing chamber were examined for their uniformity. The effect of additional air jets to the existing chamber in a range of regions was explored. An optimum configuration was identified by analyzing the compactness of the particle clusters deposited in the simulation and validated using pixel data acquired from real time imaging. The results showed that by employing dual air jets at the front end of the chamber, the density of the fibre material has improved. We conclude that through multi-physics modelling, it was possible to identify the optimum air-jet configurations leading to fibre uniformity and its distribution. This work also paves the way for incorporating a vision system to evaluate fibre density in real time.

Non-woven Industry Weaves a Beautiful Pattern

As one of the three backbone con- sumptions (apparel, home-textile, tech- textile or industrial applications), non- woven textile industry performed well in 2005, but problems still remain. An official from the State Development and Reform Commission - China’s top planner, mapped out economic blue- prints for this fast-growing sector in 2006.

Non-wovens Satisfy the Textile Industry at the Beginning of 2006

The economic performance of China’s non-woven industry in the first two months of

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。

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。

紫外接枝双单体制备熔喷聚丙烯非织造布吸油材料

以熔喷聚丙烯非织造布(MBPP)为基材,甲基丙烯酸丁酯(BMA)、甲基丙烯酸十二酯(LMA)单体复配,二苯甲酮(BP)为光敏剂,异丙醇和去离子水为溶剂,通过紫外辐射的方法将两种单体接枝到非织造布上,制备了可以吸附极性更为广泛的熔喷聚丙烯非织造布吸油材料。利用傅里叶红外光谱对接枝改性后的非织造布进行了表征分析。通过正交试验确定了最佳工艺路线:BMA、LMA质量比为4∶4,辐照时间90min,BP质量分数0.5%,溶剂异丙醇与去离子水体积比为1∶4。试验证明,接枝改性后的非织造布对原油的饱和吸附倍率及保油率都有提高,断裂强力和拒水接触角也得到了改善。

锂离子电池隔膜用熔喷非织造布的性能

选取3种熔喷非织造布,观察表面形态,测试厚度、面密度、孔隙率、吸液率及电化学性能。厚度为0.23 mm、面密度为41 g/m^2的试样2所组装的锂离子电池,具有较好的性能。在2.0~4.3 V充放电,电流为0.5 C时的放电比容量达到115 m Ah/g,在大电流放电时仍有较好的性能,如电流为5.0 C时,放电比容量约为80 m Ah/g。