Phase change materials have a key role for wearable thermal management,but suffer from poor water vapor permeability,low enthalpy value and weak shape stability caused by liquid phase leakage and intrinsic rigidity of...Phase change materials have a key role for wearable thermal management,but suffer from poor water vapor permeability,low enthalpy value and weak shape stability caused by liquid phase leakage and intrinsic rigidity of solid–liquid phase change materials.Herein,we report for the first time a versatile strategy for designed assembly of high-enthalpy flexible phase change nonwovens(GB-PCN)by wet-spinning hybrid grapheneboron nitride(GB)fiber and subsequent impregnating paraffins(e.g.,eicosane,octadecane).As a result,our GB-PCN exhibited an unprecedented enthalpy value of 206.0 J g^(−1),excellent thermal reliability and anti-leakage capacity,superb thermal cycling ability of 97.6%after 1000 cycles,and ultrahigh water vapor permeability(close to the cotton),outperforming the reported PCM films and fibers to date.Notably,the wearable thermal management systems based on GB-PCN for both clothing and face mask were demonstrated,which can maintain the human body at a comfortable temperature range for a significantly long time.Therefore,our results demonstrate huge potential of GB-PCN for human-wearable passive thermal management in real scenarios.展开更多
The preparation process parameters of intercalated meltblown nonwoven materials are complicated, and the relationship between process parameters, structural variables, and product performance needs to be investigated ...The preparation process parameters of intercalated meltblown nonwoven materials are complicated, and the relationship between process parameters, structural variables, and product performance needs to be investigated to establish a good mechanism for product performance regulation. In this study, we first used Wilcoxon test and Pearson correlation analysis to investigate the effect of intercalation rate on structural variables and product performance. Then, regression models were constructed to predict the values of each structural variable under different combinations of process parameters. Finally, we constructed a multi-objective constrained optimization problem based on the stepwise regression model and the product variable conditions. The problem was solved using the NSGA-II algorithm. The optimal was achieved when the acceptance distance was 2.892 cm and the hot air speed was 2000 r/min.展开更多
This paper is concerned with the relation between the parameters of nonwoven filter and removing of white cells. Melt-blown polypropylene nonwovens are used as filtration materials of white cells filter. According to ...This paper is concerned with the relation between the parameters of nonwoven filter and removing of white cells. Melt-blown polypropylene nonwovens are used as filtration materials of white cells filter. According to the combination of different fiber diameter, different product density and different weight, optimized combination of parameters of nonwoven filter with more effective removing of white cells is obtained. The result is that removing of white cells is 96.90 percent; recovery of red cells is 92.27 percent.展开更多
Main factors affecting the low temperature plasma initia-tion and graft modification of acrylic acid onto polybuty-lene terephthalate(PBT)meltblown nonwovens are stud-ied.The relations between hydrophilic performance ...Main factors affecting the low temperature plasma initia-tion and graft modification of acrylic acid onto polybuty-lene terephthalate(PBT)meltblown nonwovens are stud-ied.The relations between hydrophilic performance ofthe product and plasma power,treating time,andmonomer concentration are investigated.The surfaceperformances of grafted products are analyzed.It is ob-tained that hydrophilic performance of PBT nonwovens isgreatly improved due to the etching of the plasma andthe introduction of polar groups so as to meet the needsof leukocyte depleting materials.展开更多
In this paper, glucose was used as a green reducing agent and a capping reagent in the synthesis of water dispersible graphene, while using exfoliated graphite oxide (GO) as the precursor with the modified Hummers m...In this paper, glucose was used as a green reducing agent and a capping reagent in the synthesis of water dispersible graphene, while using exfoliated graphite oxide (GO) as the precursor with the modified Hummers method. Characterizations of the graphene were conducted by UV-visihle absorption spectroscopy and X-ray diffraction (XRD). Then the spunlaid-melthlowing-spuulaid (SMS) nonwovens were treated with the graphene solution via pad-dry-cure process. The surface and the antistatic property of the obtained nonwovens were tested. The results showed that O. 1 mg/mL graphene solution exhibited good stability in water. When treated with this solution, the graphene could be evenly dispersed on SMS nonwovens and the nonwovens had an excellent antistatic performance and a high relatively antistatic durability.展开更多
The three-dimensional(3D)model is of great significance to analyze the performance of nonwovens.However,the existing modelling methods could not reconstruct the 3D structure of nonwovens at low cost.A new method based...The three-dimensional(3D)model is of great significance to analyze the performance of nonwovens.However,the existing modelling methods could not reconstruct the 3D structure of nonwovens at low cost.A new method based on deep learning was proposed to reconstruct 3D models of nonwovens from multi-focus images.A convolutional neural network was trained to extract clear fibers from sequence images.Image processing algorithms were used to obtain the radius,the central axis,and depth information of fibers from the extraction results.Based on this information,3D models were built in 3D space.Furthermore,self-developed algorithms optimized the central axis and depth of fibers,which made fibers more realistic and continuous.The method with lower cost could reconstruct 3D models of nonwovens conveniently.展开更多
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 ...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.展开更多
Poly <span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><spa...Poly <span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> (PLA) is a biodegradable polymer which originates from natural resources such as corn</span><span style="font-family:Verdana;"> and</span><span style="font-family:Verdana;"> starch</span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> offering excellent strength, biode</span><span style="font-family:Verdana;">gradability</span></span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> nevertheless its inherent brittleness and low impact resistance</span><span style="font-family:Verdana;"> properties ha</span><span style="font-family:Verdana;">ve</span><span style="font-family:Verdana;"> limited its application. On the other hand</span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> Thermoplastic Polyu</span><span style="font-family:Verdana;">rethane (TPU) has high toughness, durability and flexibility</span></span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> which </span><span style="font-family:Verdana;">is</span><span style="font-family:Verdana;"> one of</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the </span><span style="font-family:Verdana;">most potential alternatives for enhancing the flexibility and mechanical</span><span style="font-family:Verdana;"> strength of Poly </span></span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> (PLA) by blending it with a compati</span><span style="font-family:Verdana;">bilizer. With the aim to improve the mechanical and thermal properties of</span><span style="font-family:Verdana;"> Poly </span></span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> (PLA) </span><span style="font-family:Verdana;">meltblown nonwovens, The Thermoplastic Polyurethane (TPU) was melt</span><span style="font-family:Verdana;"> blend</span></span><span style="font-family:Verdana;">ed with Poly </span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> (PLA) at the different corresponding proportions for toughening the Poly </span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> and the corresponding PLA/TPU MBs (meltblown nonwovens) were also manufactured. Joncryl ADR 4400 </span><span style="font-family:Verdana;">is</span><span style="font-family:Verdana;"> mixed </span><span style="font-family:Verdana;">in</span><span style="font-family:Verdana;">to the PLA matrix during processing. It was found that Joncryl had </span><span style="font-family:Verdana;">a </span><span style="font-family:;" "=""><span style="font-family:Verdana;">much higher chain extension that substantially in</span><span style="font-family:Verdana;">creased the molecular weight of the PLA matrix. SEM study revealed that Joncryl ADR 4400 is a good compatibi</span><span style="font-family:Verdana;">lizer</span></span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> Moreover, in this study</span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the crystallization, thermal and rheological behaviors </span><span style="font-family:Verdana;">of the corresponding PLA and TPU blends were also investigated. PLA/TPU</span><span style="font-family:Verdana;"> MBs were also characterized by</span> <span style="font-family:Verdana;">morphology and mechanical properties. The rheological property of the</span><span style="font-family:Verdana;"> PLA/TPU meltblown nonwoven revealed that the viscosity </span><span style="font-family:Verdana;">is increasing as the amount of TPU is increasing in the blend, PLA/TPU</span><span style="font-family:Verdana;"> melt</span></span><span style="font-family:Verdana;">blown nonwovens exhibited excellent mechanical properties;they are soft, </span><span style="font-family:;" "=""><span style="font-family:Verdana;">elas</span><span style="font-family:Verdana;">tic, and have certain tensile strength. New materials have potential applica</span><span style="font-family:Verdana;">tions in the medical and agri</span><span style="font-family:Verdana;">cultural field</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">. Joncryl ADR 4400 compatibilized blends showed higher</span><span style="font-family:Verdana;"> strength than simple PLA/TPU blends at the same PLA/TPU ratio.</span>展开更多
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 filtrat...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.展开更多
In this paper, the influence of processing parameters and powder binder content was studied and analysed on the properties of high loft nonwoven fabrics mainly using statistical analysis method. The relationship betwe...In this paper, the influence of processing parameters and powder binder content was studied and analysed on the properties of high loft nonwoven fabrics mainly using statistical analysis method. The relationship between the bulkiness and the warmth retention property was also tested. The analytical results reveal that the increase of the powder content, heating temperature and pressure will affect the tensile strength of nonwovens. Moreover, there are interactions between these parameters. The compression properties only change a little for a powder binder content of 15%—20%. However, with the increase of the heating temperature and pressure, the bulkiness and compression rate will reduce significantly. For the bulk density of high loft nonwoven fabrics, there exists a heat transter mechanism of air convection, but the higher the bulkiness of nonwovens, the larger the thickness and the better the warmth retention property of nonwoven fabrics.展开更多
Melt blown nonwovens are good filtration media for leukocyte depletion in view of their excellent structures.And the critical wetting surface tension(CWST)of nonwovens media affects the adhesion to leukocytes.The surf...Melt blown nonwovens are good filtration media for leukocyte depletion in view of their excellent structures.And the critical wetting surface tension(CWST)of nonwovens media affects the adhesion to leukocytes.The surface modification of polybutylene terephthalate(PBT) melt blown nonwovens is realized by plasma induced and grafted process.Main parameters affecting low temperature plasma inducement and graft modification of acrylicacid onto PBT melt blown nonwovens are studied.展开更多
It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is adva...It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is advanced in this paper. The equivalent diameter of the pore of a fibre web is used to calculate the valid opening size instead of the maximum diameter of inscribed circle used, because the fibres in practical fibre webs are flexible elastomers with definite diameters and the pore of fibre web may produce deformation in screening teat and engineering usage. The results show that the theoretical calculations coincide well with the engineering measurements. This method offers a theoretical basis for computer simulation to the performance of filters of heatbonded nonwoven fabrics.展开更多
Highloft nonwoven was produced by heat bonding of bicomponent polyester fibers. The effect of fiber properties and processing parameters on the mechanical properties of the nonwoven was investigated. The heat bonding ...Highloft nonwoven was produced by heat bonding of bicomponent polyester fibers. The effect of fiber properties and processing parameters on the mechanical properties of the nonwoven was investigated. The heat bonding processing parameters for the nonwoven were optimized. The results show that the range of processing temperature is wider while the shell melting point of the bicomponent fibers (Tm1) is lower. The best processing temperature is about 15℃ higher than Tm1 while the shell melting point (Tm1) is higher.展开更多
The paper deals with the properties of wetlaid nonwovens and their composites in two different blended fibers (polyester and aromatic fiber pulp) and ceramic fiber pulp mainly. The conclusion is that high blending rat...The paper deals with the properties of wetlaid nonwovens and their composites in two different blended fibers (polyester and aromatic fiber pulp) and ceramic fiber pulp mainly. The conclusion is that high blending ratio of blended fiber will lead to the worse properties of the products.展开更多
The filtration coefficient before filtration (λ-0)is intro-duced and a mathematical model for the leukocyte filtra-tion process, which relates to the filtration efficieney,capacity and leukoeyte concentration, filter...The filtration coefficient before filtration (λ-0)is intro-duced and a mathematical model for the leukocyte filtra-tion process, which relates to the filtration efficieney,capacity and leukoeyte concentration, filter thickness and fliter surface area, is established according to the mass balance for particles in a filter and the particle concen-tration decrease per unit of filter depth. The model can be uded to calculate the filtration efficiency or capacity.It is found that the filtration performance observed dur-ing the experiments could be explained well by the mod-el.The established model can be applied to the design and optimization of ungrafted and grafted melt blown nonwoven filtration materials.展开更多
Filtering materials are chosen according to the mechanism of blood filtration and mathematics model, then the material is treated with amine and alkali solution. There is cooperation and synergism between alkali and a...Filtering materials are chosen according to the mechanism of blood filtration and mathematics model, then the material is treated with amine and alkali solution. There is cooperation and synergism between alkali and amine, and the actions are realized in three stages. After modification the material treated has accessibility groups NH 2 , and slits appeared in the surface of fiber, so the wettability of materials is improved distinctly; the diameter and aperture of fiber have no changes basically.展开更多
In this paper, two types of high loft nonwoven fabrics have been constructed in the laboratory apparatus made by ourselves with different binders (polyamide and polyethylene powder) and varying binder contents (10%, 2...In this paper, two types of high loft nonwoven fabrics have been constructed in the laboratory apparatus made by ourselves with different binders (polyamide and polyethylene powder) and varying binder contents (10%, 20%, 30% and 40%). The tensile and compression properties of these nonwoven fabrics were tested. It was found that one can reduce powder binder content to increase loft and softness of nonwoven fabrics, but it has to sacrifice its tensile strength. Adhesion force between binder and single fibre was also explored. The experiments showed that the adhesion force at the interface between binder and fibre depends on the fibre variety, the fibre surface morphology, heating temperature and heating time etc..展开更多
All types of surfactants (cationic, anionic and nonionic) reported in this paper could enhance the surficial wettability of polypropylene (PP) and polyethylene terephthalate (PET) nonwoven fabrics. However, the effect...All types of surfactants (cationic, anionic and nonionic) reported in this paper could enhance the surficial wettability of polypropylene (PP) and polyethylene terephthalate (PET) nonwoven fabrics. However, the effects of cationic and nonionic surfactants were better. The longer the treatment time of surfactants on the nonwoven fabrics, the better the surficial wettability. The surficial rewetting time would no longer change above a certain treatment time. The rewettability of nonwoven fabrics could be evidently improved just when the concentration of surfactants was just above the CMC, except for sodium dodecylbenzene sulfonate (LAS). The finer the fibers and the looser the structures, the better the surficial rewettability of nonwoven fabrics.展开更多
Nonwoven was selected as filtration materials in submerged membrane bioreactor( MBR) for domestic wastewater reclamation. For its hydrophobic membrane surface,diatomite was precoated on nonwoven to improve membrane hy...Nonwoven was selected as filtration materials in submerged membrane bioreactor( MBR) for domestic wastewater reclamation. For its hydrophobic membrane surface,diatomite was precoated on nonwoven to improve membrane hydrophilicity. In the precoating stage,diatomite dynamic membrane could be formed on10 μm polyethylene nonwoven surface efficiently and effluent turbidity could be below 5 nephelometric turbidity units( NTU).The MBR system was operated steadily under gravity flow and scanning electron microscope( SEM) analysis showed that nonwoven membrane was only partially fouled at the membrane flux of 5 L/( m2·h). Average removal efficiencies of chemical oxygen demand( COD) and NH +4-N were above 86 % and 50 %,respectively. The effluent turbidity and chromaticity were below 5 NTU and 25°,respectively. Those results could meet the requirements for wastewater reuse.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21903082,22003065,22125903,51872283,22075279,21805273,22273100)Dalian Innovation Support Plan for High Level Talents(2019RT09)+3 种基金Dalian National Laboratory For Clean Energy(DNL),CAS,DNL Cooperation Fund,CAS(DNL201912,DNL201915,DNL202016,DNL202019)DICP(DICP I2020032,DICP I202036,I202218)The Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(YLU-DNL Fund 2021002,YLU-DNL 2021007,YLU-DNL 2021009)Q.Shi would like to thank Dalian Outstanding Young Scientific Talent Program(Grant 2019RJ10).
文摘Phase change materials have a key role for wearable thermal management,but suffer from poor water vapor permeability,low enthalpy value and weak shape stability caused by liquid phase leakage and intrinsic rigidity of solid–liquid phase change materials.Herein,we report for the first time a versatile strategy for designed assembly of high-enthalpy flexible phase change nonwovens(GB-PCN)by wet-spinning hybrid grapheneboron nitride(GB)fiber and subsequent impregnating paraffins(e.g.,eicosane,octadecane).As a result,our GB-PCN exhibited an unprecedented enthalpy value of 206.0 J g^(−1),excellent thermal reliability and anti-leakage capacity,superb thermal cycling ability of 97.6%after 1000 cycles,and ultrahigh water vapor permeability(close to the cotton),outperforming the reported PCM films and fibers to date.Notably,the wearable thermal management systems based on GB-PCN for both clothing and face mask were demonstrated,which can maintain the human body at a comfortable temperature range for a significantly long time.Therefore,our results demonstrate huge potential of GB-PCN for human-wearable passive thermal management in real scenarios.
文摘The preparation process parameters of intercalated meltblown nonwoven materials are complicated, and the relationship between process parameters, structural variables, and product performance needs to be investigated to establish a good mechanism for product performance regulation. In this study, we first used Wilcoxon test and Pearson correlation analysis to investigate the effect of intercalation rate on structural variables and product performance. Then, regression models were constructed to predict the values of each structural variable under different combinations of process parameters. Finally, we constructed a multi-objective constrained optimization problem based on the stepwise regression model and the product variable conditions. The problem was solved using the NSGA-II algorithm. The optimal was achieved when the acceptance distance was 2.892 cm and the hot air speed was 2000 r/min.
文摘This paper is concerned with the relation between the parameters of nonwoven filter and removing of white cells. Melt-blown polypropylene nonwovens are used as filtration materials of white cells filter. According to the combination of different fiber diameter, different product density and different weight, optimized combination of parameters of nonwoven filter with more effective removing of white cells is obtained. The result is that removing of white cells is 96.90 percent; recovery of red cells is 92.27 percent.
基金Science and Technoloy Foundation of Municipal Education Commission Shanghai
文摘Main factors affecting the low temperature plasma initia-tion and graft modification of acrylic acid onto polybuty-lene terephthalate(PBT)meltblown nonwovens are stud-ied.The relations between hydrophilic performance ofthe product and plasma power,treating time,andmonomer concentration are investigated.The surfaceperformances of grafted products are analyzed.It is ob-tained that hydrophilic performance of PBT nonwovens isgreatly improved due to the etching of the plasma andthe introduction of polar groups so as to meet the needsof leukocyte depleting materials.
基金the Fundamental Research Funds for the Central Universities,China
文摘In this paper, glucose was used as a green reducing agent and a capping reagent in the synthesis of water dispersible graphene, while using exfoliated graphite oxide (GO) as the precursor with the modified Hummers method. Characterizations of the graphene were conducted by UV-visihle absorption spectroscopy and X-ray diffraction (XRD). Then the spunlaid-melthlowing-spuulaid (SMS) nonwovens were treated with the graphene solution via pad-dry-cure process. The surface and the antistatic property of the obtained nonwovens were tested. The results showed that O. 1 mg/mL graphene solution exhibited good stability in water. When treated with this solution, the graphene could be evenly dispersed on SMS nonwovens and the nonwovens had an excellent antistatic performance and a high relatively antistatic durability.
基金National Natural Science Foundation of China(No.61771123)。
文摘The three-dimensional(3D)model is of great significance to analyze the performance of nonwovens.However,the existing modelling methods could not reconstruct the 3D structure of nonwovens at low cost.A new method based on deep learning was proposed to reconstruct 3D models of nonwovens from multi-focus images.A convolutional neural network was trained to extract clear fibers from sequence images.Image processing algorithms were used to obtain the radius,the central axis,and depth information of fibers from the extraction results.Based on this information,3D models were built in 3D space.Furthermore,self-developed algorithms optimized the central axis and depth of fibers,which made fibers more realistic and continuous.The method with lower cost could reconstruct 3D models of nonwovens conveniently.
基金the Priority Academic Development Program for Textile Science and Textile Engineering of Jiangsu Higher Education Institutions,Chinathe Environmental Protection Department of Jiangsu Province,China(No.2012009)Suzhou Municipal Government,China(No.SYG201202)
文摘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.
文摘Poly <span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> (PLA) is a biodegradable polymer which originates from natural resources such as corn</span><span style="font-family:Verdana;"> and</span><span style="font-family:Verdana;"> starch</span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> offering excellent strength, biode</span><span style="font-family:Verdana;">gradability</span></span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> nevertheless its inherent brittleness and low impact resistance</span><span style="font-family:Verdana;"> properties ha</span><span style="font-family:Verdana;">ve</span><span style="font-family:Verdana;"> limited its application. On the other hand</span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> Thermoplastic Polyu</span><span style="font-family:Verdana;">rethane (TPU) has high toughness, durability and flexibility</span></span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> which </span><span style="font-family:Verdana;">is</span><span style="font-family:Verdana;"> one of</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the </span><span style="font-family:Verdana;">most potential alternatives for enhancing the flexibility and mechanical</span><span style="font-family:Verdana;"> strength of Poly </span></span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> (PLA) by blending it with a compati</span><span style="font-family:Verdana;">bilizer. With the aim to improve the mechanical and thermal properties of</span><span style="font-family:Verdana;"> Poly </span></span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> (PLA) </span><span style="font-family:Verdana;">meltblown nonwovens, The Thermoplastic Polyurethane (TPU) was melt</span><span style="font-family:Verdana;"> blend</span></span><span style="font-family:Verdana;">ed with Poly </span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> (PLA) at the different corresponding proportions for toughening the Poly </span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">Lactic Acid</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> and the corresponding PLA/TPU MBs (meltblown nonwovens) were also manufactured. Joncryl ADR 4400 </span><span style="font-family:Verdana;">is</span><span style="font-family:Verdana;"> mixed </span><span style="font-family:Verdana;">in</span><span style="font-family:Verdana;">to the PLA matrix during processing. It was found that Joncryl had </span><span style="font-family:Verdana;">a </span><span style="font-family:;" "=""><span style="font-family:Verdana;">much higher chain extension that substantially in</span><span style="font-family:Verdana;">creased the molecular weight of the PLA matrix. SEM study revealed that Joncryl ADR 4400 is a good compatibi</span><span style="font-family:Verdana;">lizer</span></span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> Moreover, in this study</span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the crystallization, thermal and rheological behaviors </span><span style="font-family:Verdana;">of the corresponding PLA and TPU blends were also investigated. PLA/TPU</span><span style="font-family:Verdana;"> MBs were also characterized by</span> <span style="font-family:Verdana;">morphology and mechanical properties. The rheological property of the</span><span style="font-family:Verdana;"> PLA/TPU meltblown nonwoven revealed that the viscosity </span><span style="font-family:Verdana;">is increasing as the amount of TPU is increasing in the blend, PLA/TPU</span><span style="font-family:Verdana;"> melt</span></span><span style="font-family:Verdana;">blown nonwovens exhibited excellent mechanical properties;they are soft, </span><span style="font-family:;" "=""><span style="font-family:Verdana;">elas</span><span style="font-family:Verdana;">tic, and have certain tensile strength. New materials have potential applica</span><span style="font-family:Verdana;">tions in the medical and agri</span><span style="font-family:Verdana;">cultural field</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">. Joncryl ADR 4400 compatibilized blends showed higher</span><span style="font-family:Verdana;"> strength than simple PLA/TPU blends at the same PLA/TPU ratio.</span>
文摘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.
文摘In this paper, the influence of processing parameters and powder binder content was studied and analysed on the properties of high loft nonwoven fabrics mainly using statistical analysis method. The relationship between the bulkiness and the warmth retention property was also tested. The analytical results reveal that the increase of the powder content, heating temperature and pressure will affect the tensile strength of nonwovens. Moreover, there are interactions between these parameters. The compression properties only change a little for a powder binder content of 15%—20%. However, with the increase of the heating temperature and pressure, the bulkiness and compression rate will reduce significantly. For the bulk density of high loft nonwoven fabrics, there exists a heat transter mechanism of air convection, but the higher the bulkiness of nonwovens, the larger the thickness and the better the warmth retention property of nonwoven fabrics.
基金Sponaored by the Science & Tochnology Fund of Shanghai Education Commission
文摘Melt blown nonwovens are good filtration media for leukocyte depletion in view of their excellent structures.And the critical wetting surface tension(CWST)of nonwovens media affects the adhesion to leukocytes.The surface modification of polybutylene terephthalate(PBT) melt blown nonwovens is realized by plasma induced and grafted process.Main parameters affecting low temperature plasma inducement and graft modification of acrylicacid onto PBT melt blown nonwovens are studied.
文摘It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is advanced in this paper. The equivalent diameter of the pore of a fibre web is used to calculate the valid opening size instead of the maximum diameter of inscribed circle used, because the fibres in practical fibre webs are flexible elastomers with definite diameters and the pore of fibre web may produce deformation in screening teat and engineering usage. The results show that the theoretical calculations coincide well with the engineering measurements. This method offers a theoretical basis for computer simulation to the performance of filters of heatbonded nonwoven fabrics.
文摘Highloft nonwoven was produced by heat bonding of bicomponent polyester fibers. The effect of fiber properties and processing parameters on the mechanical properties of the nonwoven was investigated. The heat bonding processing parameters for the nonwoven were optimized. The results show that the range of processing temperature is wider while the shell melting point of the bicomponent fibers (Tm1) is lower. The best processing temperature is about 15℃ higher than Tm1 while the shell melting point (Tm1) is higher.
文摘The paper deals with the properties of wetlaid nonwovens and their composites in two different blended fibers (polyester and aromatic fiber pulp) and ceramic fiber pulp mainly. The conclusion is that high blending ratio of blended fiber will lead to the worse properties of the products.
文摘The filtration coefficient before filtration (λ-0)is intro-duced and a mathematical model for the leukocyte filtra-tion process, which relates to the filtration efficieney,capacity and leukoeyte concentration, filter thickness and fliter surface area, is established according to the mass balance for particles in a filter and the particle concen-tration decrease per unit of filter depth. The model can be uded to calculate the filtration efficiency or capacity.It is found that the filtration performance observed dur-ing the experiments could be explained well by the mod-el.The established model can be applied to the design and optimization of ungrafted and grafted melt blown nonwoven filtration materials.
文摘Filtering materials are chosen according to the mechanism of blood filtration and mathematics model, then the material is treated with amine and alkali solution. There is cooperation and synergism between alkali and amine, and the actions are realized in three stages. After modification the material treated has accessibility groups NH 2 , and slits appeared in the surface of fiber, so the wettability of materials is improved distinctly; the diameter and aperture of fiber have no changes basically.
文摘In this paper, two types of high loft nonwoven fabrics have been constructed in the laboratory apparatus made by ourselves with different binders (polyamide and polyethylene powder) and varying binder contents (10%, 20%, 30% and 40%). The tensile and compression properties of these nonwoven fabrics were tested. It was found that one can reduce powder binder content to increase loft and softness of nonwoven fabrics, but it has to sacrifice its tensile strength. Adhesion force between binder and single fibre was also explored. The experiments showed that the adhesion force at the interface between binder and fibre depends on the fibre variety, the fibre surface morphology, heating temperature and heating time etc..
文摘All types of surfactants (cationic, anionic and nonionic) reported in this paper could enhance the surficial wettability of polypropylene (PP) and polyethylene terephthalate (PET) nonwoven fabrics. However, the effects of cationic and nonionic surfactants were better. The longer the treatment time of surfactants on the nonwoven fabrics, the better the surficial wettability. The surficial rewetting time would no longer change above a certain treatment time. The rewettability of nonwoven fabrics could be evidently improved just when the concentration of surfactants was just above the CMC, except for sodium dodecylbenzene sulfonate (LAS). The finer the fibers and the looser the structures, the better the surficial rewettability of nonwoven fabrics.
基金China State Construction Innovation Project(No.CSCEC-2012-Z-14)Shanghai Education Research and Innovation Project,China(Nos.11ZZ176,12YZ153,and ZZGJD12052)
文摘Nonwoven was selected as filtration materials in submerged membrane bioreactor( MBR) for domestic wastewater reclamation. For its hydrophobic membrane surface,diatomite was precoated on nonwoven to improve membrane hydrophilicity. In the precoating stage,diatomite dynamic membrane could be formed on10 μm polyethylene nonwoven surface efficiently and effluent turbidity could be below 5 nephelometric turbidity units( NTU).The MBR system was operated steadily under gravity flow and scanning electron microscope( SEM) analysis showed that nonwoven membrane was only partially fouled at the membrane flux of 5 L/( m2·h). Average removal efficiencies of chemical oxygen demand( COD) and NH +4-N were above 86 % and 50 %,respectively. The effluent turbidity and chromaticity were below 5 NTU and 25°,respectively. Those results could meet the requirements for wastewater reuse.