Parametric study of CF4-plasma on the hydrophobicity of polyester synthetic leather

Atmospheric pressure plasma (APP) technology has been proven to be an effective method for improving the hydrophobicity of fabric surface. While many researchers have worked on apparel fabrics, polyester and synthetic leather fabrics, popular in the luxury textile market, have been examined rarely. In this regard, this paper reports the effects of APP treatment using tetrafluoromethane (CF₄) as the polymerizing monomer on hydrophobicity of polyester synthetic leather. The polyester synthetic leather samples were treated under various parameters and hydrophobicity was found to be greatly enhanced under a certain range of treatment conditions. An optimization of the treatment parameters was conducted and the results showed that a hydrophobic surface with a contact angle of 106 ° was achieved, compared to the untreated sample’s 0 °.     

Imparting hydrophobicity to natural leather through plasma polymerization for easy care effect

This study reports on the deposition of a hydrophobic coating on natural leather through a plasma polymerization method and investigates the hydrophobic behavior of the plasma coated substrate. The silicon compound of hexamethyldisiloxane (HMDSO), inactive gas argon (Ar) and toluene were used to impart surface hydrophobicity to a natural leather substrate. Surface hydrophobicity was analyzed by water contact angle, absorption time, and surface free energy measurements. The water contact angle and absorption time results showed that the surface hydrophobicity of natural leather sample was clearly improved after plasma polymerization of HMDSO on the material surface. XPS analysis showed that plasma polymerization of HMDSO/toluene compositions led to a significant increase in atomic percentage of Si compound responsible for hydrophobic surface. These atomic ratios showed that the highest amount of Si and lowest amount of N were obtained with 100 % HMDSO plasma process, confirming the higher degree of plasma polymerization than the other plasma processes. A decrease was observed in total surface free energies of the natural leather samples after plasma deposition indicating improvement in surface hydrophobicity.     

Classification of synthetic polyurethane leather by mechanical properties according to consumers’ preference for fashion items

This study aims to evaluate the effect of mechanical properties on consumers’ preference for fashion leather items, and to classify them by the mechanical properties of synthetic leather. Mechanical properties were measured by the KES-FB system and a survey of experts was conducted with a preference evaluation for various items using 15 types of synthetic polyurethane leather. More easily transformable and lighter leathers are preferred for clothing, while the leathers that have better dimensional stability are preferred for purses, bags, shoes, and boots, and those with smooth surface are preferred for furniture. Furthermore, synthetic leathers were classified into three clusters by mechanical properties. There was no difference between clusters in preference for non-clothing item, because no perception of various mechanical properties was caused by the structural characteristics of each items by design. On the other hand, for clothing items, consumers’ preferences are significantly affected by mechanical properties.     

Design,characterization, dyeing properties,and application of acid-dyeable polyurethane in the manufacture of microfiber synthetic leather

The difficulty in dyeing microfiber synthetic leather filled with ordinary polyurethane presents a significant challenge in maintaining the uniformity and highly realistic appearance of the resulting products. In the present study, a type of acid-dyeable polyurethane (PU-MDEA; MDEA=N-methyldiethanolamine) was synthesized, and its chemical structure and dyeing properties were investigated. Nuclear magnetic resonance analysis indicated that cationic groups were successfully incorporated into the PU-MDEA backbone via chain extension using MDEA. The amorphous nature of PU-MDEA was determined by differential scanning calorimetry, X-ray diffraction, and polarizing optical microscopy. Owing to the strong binding between these cationic groups and acid dye, as well as the reduced resistance to dye penetration, PU-MDEA showed better dyeability toward the acid dyes studied herein when compared with the control sample (microfiber synthetic leather filled with ordinary polyurethane). The adsorption isotherm experiment revealed that the dyeing process conformed to the Langmuir model, thereby indicating that the acid dyes attached to PU-MDEA via strong ionic bonding rather than van der Waals forces or hydrogen bonding. Additionally, it was found that the wastewater resulting from the dyeing of the microfiber synthetic leather filled with PU-MDEA exhibited environmentally friendly characteristics when compared with that displayed by the control sample (microfiber synthetic leather filled with ordinary polyurethane). Thus, the current results show the potential of PU-MDEA, as a filler, in the manufacture of microfiber synthetic leather to achieve fast dyeing rate, high dye uptake, and good color fastness, thereby improving the uniformity and highly realistic appearance of the resulting products.     

Synthesis and α-glucosidase inhibitory mechanisms of bis(2,3-dibromo-4,5-dihydroxybenzyl) ether, a potential marine bromophenol α-glucosidase inhibitor

Bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (BDDE), derived from the marine algae, is a potential α-glucosidase inhibitor for type 2 diabetes treatment. In the present study, a synthetic route was established as a valid approach to obtain BDDE. Fluorescence spectra, circular dichroism spectra and molecular docking methods were employed to elucidate the inhibitory mechanisms of BDDE against α-glucosidase. The results showed that BDDE could be prepared effectively and efficiently with the established synthetic methods. Synthetic BDDE bound with α-glucosidase and induced minor conformational changes of the enzyme. The docking results indicated the interaction between BDDE and α-glucosidase was driven by both hydrophobic forces and hydrogen bonds. The docked BDDE molecule was completely buried in the α-glucosidase binding pocket with part of the molecule reaching the catalytic center and overlapping with the position of glucose, and the rest of the molecule extending towards protein surface. This study provides useful information for the understanding of the BDDE-α-glucosidase interaction and for the development of novel α-glucosidase inhibitors.     

Antimicrobial polyurethane synthetic leather coating with In-situ generated Nano-TiO2

By incorporating organic-inorganic nano-hybridization into wet phase inversion coating-forming method, a novel antimicrobial polyurethane synthetic leather coating with in-situ generated nano-TiO₂ (PUT) was prepared. The antibacterial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Micrococcus luteus, antifungal activity against Aspergillus niger and toxicity of this PUT coating were investigated respectively. Experimental results showed that the antimicrobial activity of the PUT coating increased with increasing nano-TiO₂ concentration. Low nano-TiO₂ concentration (≤0.50 wt%) resulted in negligible or limited antimicrobial activity. When the nano-TiO₂ concentration increased up to 0.75 and 1.00 wt%, the antibacterial activity of the PUT coating exceeded 82 and 93 % respectively, and no Aspergillus niger growth was observed on the coating surface within 28 days. Cell culture assay indicated that the PUT coating had no detrimental effect on the morphologies and proliferation rate of normal human dermal fibroblasts, which indicated a non-toxic and skin-friendly characteristic. According to these results, the PUT coating was capable of reducing the risk of microbial contamination while remained skin-friendly to wearers. More importantly, the organic-inorganic nano-hybridization technique developed in this study was carried out simultaneously during the established wet phase inversion coating-forming method for PU leather manufacture, which promised its possible application on an industrial scale.     

Antistatic effect of atmospheric pressure glow discharge cold plasma treatment on textile substrates

Hydrophobic synthetic textile substrates, nylon and polyester fabrics, were continuously treated in an atmospheric-pressure-glow-discharge-cold-plasma reactor using He and air. The samples were evaluated for antistatic properties by measuring the static charge build-up and half charge decay time. The 60 sec air-plasma treated nylon fabric produced only 1.53 kV of charge and showed a significantly smaller half decay time of 0.63 sec compared to static voltage of 2.76 kV and a half decay time of 8.9 sec in the untreated nylon fabric. In comparison, the He plasma treated nylon fabrics showed relatively less improvement by producing static charge built-up of 2.12 kV and half charge decay time of 1.1 sec. Similar improvements were obtained for polyester (PET) fabrics as well. The treated samples showed good antistatic properties even after five laundry wash cycles. The surface characteristics of the samples were investigated using SEM, AFM, and ATR-FTIR. The results revealed that the improvement on antistatic properties are attributable to increase in the surface energy of the fabrics due to the formation of hydrophilic groups and increase in the surface area due to the formation of nano-sized horizontal and vertical channels on the fibre surface. The study suggests that plasma treatment may be used for imparting effective antistatic finish on otherwise hydrophobic substrates.     

Effect of lipases on the surface properties of wheat straw

Surface characteristics of untreated and lipase-treated wheat straw (WS) have been investigated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and SEM–Energy dispersive X-ray spectroscopy (SEM–EDX). Static contact angle of WS surface was determined by the pendant drop method. The WS thermal stability was also investigated using the thermogravimetric analysis (TGA). It was shown that the lipases from Candida cylindracea insignificantly changed the chemical group, microscopic morphology, and wettability of the WS inner surface. However, FTIR showed the lipases could effectively remove the hydrophobic lipophilic extractives and silica from the outer surface of untreated WS, and increased the hydroxyl group content in the outer surface. SEM images also exhibited the lipases stripped off the dense hydrophobic layer on the WS outer surface with the help of shear force. SEM–EDX analysis showed that the lipase treatment reduced Si content on the WS outer surface from 12.44 to 1.33%. The water contact angle of the WS outer surface decreased from 92.7° to 65.2° after lipase treatment, which indicated that the wettability of the lipase-treated WS outer surface was equivalent to that of the inner surface with a water contact angle of about 63°. Lipase-treated and untreated WS had a similar thermal stability. Therefore, the lipase treatment was one of the potential methods to improve the wettability of natural fibers in composite material processing. Comparative testing of particleboards produced from the whole WS untreated and treated by the lipases is under way to evaluate the overall effects of the lipase treatment on the improvement in their mechanic performances.     

Dieckol Ameliorates Aβ Production via PI3K/Akt/GSK-3β Regulated APP Processing in SweAPP N2a Cell

The proteolytic processing of amyloid precursor protein (APP) by β-secretase (BACE1) and γ-secretase releases amyloid-β peptide (Aβ), which deposits in amyloid plaques and contributes to the initial causative events of Alzheimer’s disease (AD). In the present study, the regulatory mechanism of APP processing of three phlorotannins was elucidated in Swedish mutant APP overexpressed N2a (SweAPP N2a) cells. Among the tested compounds, dieckol exhibited the highest inhibitory effect on both intra- and extracellular Aβ accumulation. In addition, dieckol regulated the APP processing enzymes, such as α-secretase (ADAM10), β-secretase, and γ-secretase, presenilin-1 (PS1), and their proteolytic products, sAPPα and sAPPβ, implying that the compound acts on both the amyloidogenic and non-amyloidogenic pathways. In addition, dieckol increased the phosphorylation of protein kinase B (Akt) at Ser473 and GSK-3β at Ser9, suggesting dieckol induced the activation of Akt, which phosphorylated GSK-3β. The specific phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 triggered GSK-3β activation and Aβ expression. In addition, co-treatment with LY294002 noticeably blocked the effect of dieckol on Aβ production, demonstrating that dieckol promoted the PI3K/Akt signaling pathway, which in turn inactivated GSK-3β, resulting in the reduction in Aβ levels.     

Optimization and extraction of extra and intracellular color from <Emphasis Type="Italic">Penicillium minioluteum</Emphasis> for application on protein fibers

Precedence of microbial colorants can be seen in almost all the industrial sectors viz. food, textile, paper, agriculture, pharmaceutical, and cosmetics. These colorants are gaining popularity due to their salient advantages over synthetic and natural dyes. This study deals with the optimization and extraction of such colorants from Penicillium minioluteum for the purpose of dyeing different protein fibers. Penicillium minioluteum was cultured under different growth conditions to optimize the extracellular color production. The extracellular colorant grown under optimized fermentation conditions (medium-sabouraud; pH-5.6; temperature-15 °C; time-20 days; incubation-static) in 3000 ml haffkine flask showed maximum color or highest optical density of 1.014 at λ _max=490 nm. Later on, this colorant was extracted using nbutanol. The remaining mycelial mat obtained after filtration was extracted using different chemical and mechanical procedures to get the intracellular colorant. Highest O.D of 0.897 was recorded at λ _max=490 nm when desiccated powdered mycelial mat was extracted with methanol. Dyed silk and leather with the extracellular colorant showed color strength (K/S) as 3.88 and 3.81, respectively, whereas silk and leather dyed with the intracellular colorant showed K/S as 0.56 and 0.55, respectively. The color strength of extracellular dyed samples was found to be three times higher as compared to the samples dyed with the intracellular aqueous colorant of the same optical density. After dyeing, two different shades were obtained viz. deep red with the extracellular colorant and beige with the intracellular colorant on mulberry silk and wet blue goat nappa skin leather. Fastness towards rubbing was found to be good for both the samples. Wash fastness was excellent on silk. Fastness towards light was poor for both silk and leather. Furthermore, the color yield of the extracellular colorant (0.62 %) was found to be approximately five times more than the color yield of the intracellular colorant (0.14 %).     

Nano-sized albumin-copolymer micelles for efficient doxorubicin delivery

We present the discovery of a nano-sized protein-derived micellar drug delivery system based on the polycationic albumin precursor protein cBSA-147. The anticancer drug doxorubicin (DOX) was efficiently encapsulated into nanosized micelles based on hydrophobic interactions with the polypeptide scaffold. These micelles revealed attractive stabilities in various physiological buffers and a wide pH range as well as very efficient uptake into A549 cells after 1 h incubation time only. In vitro cytotoxicity was five-times increased compared to free DOX also indicating efficient intracellular drug release. In addition, multiple functional groups are available for further chemical modifications. Based on the hydrophobic loading mechanism, various classical anti-cancer drugs, in principle, could be delivered even synergistically in a single micelle. Considering these aspects, this denatured albumin-based drug delivery system represents a highly attractive platform for nanomedicine approaches towards cancer therapy.     

Surface chemical modification of thermoplastic starch: reactions with isocyanates,epoxy functions and stearoyl chloride

Thermoplastic starch (TPS) films plasticized with 20 and 30 wt.% of glycerol were treated with various reagents in order to make their surface less sensitive to moisture. Phenyl isocyanate (PhNCO), a phenol blocked polyisocianate of trimethylol propane and toluene diisocyanate (TMP-TDI-Phenol), a styrene-co-glycidyl methacrylate (PS-GMA) co-polymer and stearoyl chloride (StCl) were used for these superficial chemical modifications. Two reaction procedures were adopted, viz., suspension at room temperature or under reflux and dipping in the reactant solution followed by heating. The treated films were characterized by contact angle measurements, from which the corresponding surface energies were calculated in terms of, polar and dispersive components. In all instances, the polar contribution was drastically reduced by the treatment, indicating that the surfaces had become more hydrophobic. The most effective treatment was achieved with phenyl isocyanate in xylene. The dipping + heating treatment seems to be the most appropriate procedure for practical applications.     

Preparation of Polyurethane Silicon Oxide Nanomaterials as a Binder in Leather Finishing

Leather finishing processes using toxic organic solvent based produce volatile organic compounds (VOC), chronic exposure to this chemicals effect on workers' health causing many diseases especially lung cancer. So, polyurethane waterbased was synthesized for application in leather finishing instead of organic solvent based because it’s economic and safety for industry and workers. Preparation of water-based polyurethane (PU) depends on the reaction of polyethylene glycol (PEG, 300) with isophorone diisocyanate (IPDI) and the reaction of IPDI-1,4-butanediol (BDO) together with dimethylolpropionic acid (DMPA), was synthesized by poly-addition polymerization reaction. PU was then modified with different amounts of silicon dioxide nanoparticles (1-5 % SiO₂), used as a binder in leather finishing. Leather coated was characterized physically, chemically and thermally by FTIR, GPC, DLS, TEM, SEM and TGA. The results revel that, water vapor permeability (WVP) of leather coated with PU modified with SiO₂ showed improvement due to the existence of SiO₂ particles which increases the interspaces of the polyurethane coating. SEM showed that when the amount of SiO₂ nanoparticles increases, there is uniform nanoparticles accumulated can be observed. EDX prove the presence of Si and O₂ elements and the formation of SiO₂ nanoparticles. Mechanical properties discussed that tensile strength; tear strength and elongation at break % increase with increase SiO₂ concentration until 3 % SiO₂ nanoparticles. TGA showed an improvement of thermal stability of coated leather modified with SiO₂. Therefore, this study succeeded in preparation of safe, ecofriendly of water-based polyurethane binders which modified with SiO₂ for using in leather finishing.     

Properties of polymers as a nanoscale material for fibers in leather

Hyperbranched polymers, an innovative class of nano-polymers, could enhance the properties of fibers owning to their unique structures. In this study, the ester compound (HPAE) of 3-(bis(2-hydroxyethyl)amino)propionic acid and pentaerythritol was treated with undecylenic acid to obtain novel hyperbranched multiterminal alkenyl polymers (HPAE-UAs). The sizes of the HPAE-UAs could be controlled conveniently from 400 to 1300 nm by adjusting the capped fraction of the hydroxyl groups with undecylenic acids. The molecular structures of HPAE-UAs were characterized by means of FT-IR and ¹H-NMR. Then, the effect of the HPAE-UAs on the structures, thermal, and mechanical properties of the wet blue leather were investigated. TEM and SEM demonstrated that the spacing between fibers was enlarged. The thermogravimetric analysis showed that the residual volume of leather could reach up to 30.3 % at about 500 °C. Furthermore, the shrinkage temperature increased to 89.4 °C. It was found that the HPAE-UAs used in leather could improve the thermal performance, physical and mechanical properties. All of these results indicate that HPAE-UAs can be used as a fatliquor with retanning in leather process.     

Microwave-mediated rapid tailoring of PET fabric surface by using environmentally-benign,biodegradable Urea-Choline chloride Deep eutectic solvent

Deep eutectic solvent, urea-choline chloride (URC), was used to control surface of poly(ethylene terephthalate) (PET) fabric under microwave irradiation with or without sodium hydroxide (NaOH) for hydrophilic-hydrophobic properties. Wicking and contact angle evaluations indicated that the URC-treated PET fabric drastically changed its surface characteristics from highly hydrophobic to highly hydrophilic (or vice versa) by carefully adjusting alkali concentration and microwave irradiation time. For instance, an instant wicking was achieved on URC-treated PET with 1 % NaOH at 60 s of microwave irradiation, whereas highly hydrophobic PET surface with 2600 s wicking time and 135.6 ° contact angle was acquired by adding 5 % NaOH at the same microwave irradiation. Methylene Blue staining and FTIR analyses suggested that a minimal hydrolysis occurred through URC-treatment with NaOH under microwave irradiation and hydrophilicity was mainly achieved by physical disruption of the fiber. The treated fabrics were further analyzed by DSC, TGA, and SEM. Therefore, a rapid control of hydrophilic-hydrophobic surface of PET fabric was achieved with a little side reaction by using environmentally-benign, biodegradable URC deep eutectic solvent.     

萌发花生胚轴中蛋白质、RNA和DNA合成及PEG渗调和多胺对其影响

不同活力花生种子的蛋白质、RNA和DNA合成能力不同。用PEG渗调或多胺预处理,可提高劣变花生种子的活力和胚轴大分子合成能力。劣变种子在萌发初期(20小时内),~3H—dT渗入量反比高活力种子增高,表明存在非按期DNA合成,这一增多部份可为咖啡碱所抑制,其剩余部分与高活力种子相似。应用PEG渗调或多胺预处理可使非按期DNA合成部分减弱,而萌发后期的复制部分加强。     

Superhydrophobic and Antibacterial Properties of Cotton Fabrics Treated with PVDF and nano-ZnO through Phase Inversion Process

Cotton fabrics exhibiting superhydrophobic and antibacterial properties were prepared through a non-solvent induced phase separation method using hydrophobic poly(vinylidene fluoride) (PVDF) and its hybrids with photocatalytic zinc oxide nanoparticles (nano-ZnO) as surface modifying agents for cotton fabric. The effects of coagulating medium and temperature on microstructural morphology and surface hydrophobictity of the cotton fabrics were investigated by FE-SEM observation and contact angle measurement. Superhydrophobic cotton fabrics exhibiting water contact angle higher than 150 ° could be obtained by coating the fabrics with solutions of PVDF and nano-ZnO followed by coagulation in ethanol as non-solvent. This phenomenon is considered to be originated from both chemically hydrophobic PVDF layer and physical micro- and nano-bumps formed on the surface of cotton fabric, which are essential requirements for Lotus effect. Moreover, antibacterial properties could be synergistically obtained by utilizing photocatalytic effect of nano-ZnO.     

Extraction of natural dye from <Emphasis Type="Italic">Coreopsis tinctoria</Emphasis> flower petals for leather dyeing − An eco-friendly approach

This study evaluated the extraction of two colors of dye (yellow and brown) from Coreopsis tinctoria flower petals using ultrasound and the dyeing of leather with the extracted dyes as a source of nontoxic and eco-friendly dye. The results showed an increase in the dye extraction values with increasing time at 100 W ultrasonic power at 80 °C for 1 h. Leather dyeing was optimized with the aid of ultrasound and magnetic stirring. The optimum leather dyeing conditions, with respect to the dye uptake, dye penetration and intensity of the color, were determined to be 12 % dye concentration, 100 W power, 1,000 rpm, and pH 7.0 for 60 min at 80 °C. It was shown that sonication improves dye exhaustion from a 90 % to 60 % rating for 1 h of dyeing time. The dyed leather was assessed by reflectance measurements and compared with visual assessment data. The fastness properties of dyed leather samples showed good fastness against washing, light, and dry and wet rubbing. The strength properties were not significantly altered and the bulk properties, such as softness, were found to be improved by the use of Coreopsis tinctoria yellow and brown dyes using an ultrasonic and magnetic stirring dyeing process.     

Facile Fabrication of Electrospun Silica Nanofibrous Membrane with Hydrophobic,Oleophilic and Breathable Performances

We report a simple and versatile method to prepare hydrophobic composite SiO₂ membrane. The electrospun SiO₂ membrane was selected due to its good flexibility and thermal stability. The hydrophobic SiO₂ membrane was succussfully prepared by simply evaporating a thin polydimethylsiloxane (PDMS) layer on the fiber surface. The characterization results show that the PDMS layer is too thin to be observed. The PDMS coating has no influence on the porous structure of the fibrous membrane, but imparts the good hydrophobicity and oleophilicity to the SiO₂ nanofibers. As demonstration, the hydrophobic SiO₂-PDMS membrane displays good oil absorption performance from the oil/water mixture, as well as filtration membrane for oil/water separation. Additionally, due to the proper pore size and hydrophobic surface, the SiO₂- PDMS membrane shows good waterproof performance and breathability at the same time.     

Synthesis and characterization of a novel charring agent and its application in intumescent flame retardant polyethylene system

A novel charring agent poly(pentaerythritol spirocyclic phosphorusoxy spirocyclic diethanolamine borate) (PPSPSDB) was synthesized successfully with diethanolamine borate (DEAB) and spirocyclic pentaerythritol bisphosphorate disphosphoryl chloride (SPDPC), which was combined with ammonium polyphosphate (APP) to endow linear low-density polyethylene (LLDPE) with flame retardance. The structure of PPSPSDB was characterized by FTIR and 1H-NMR. The study of thermal stability of various LLDPE composites showed that PPSPSDB/APP system could effectively improve the thermal degradation and thermal-oxidative stability of the char residues, and PE3 containing 30 wt% APP/ PPSPSDB with a 2 weight ratio left the highest amount of char residue at 800 oC. The results of flammability revealed that PE3 had the best combination property; the limited oxygen index value was 29.6, and vertical burning reached UL-94 V-0 rating, and the tensile strength and notched impact strength were 11.853 MPa and 28.8 kJ/m2 respectively. The investigation of structure and morphology of char residue indicated that the compact foaming char layer, as a good barrier against the transmission of heat and volatiles, was formed for PE3 during combustion.