Effect of the atmospheric plasma treatment parameters on surface and mechanical properties of jute fabric

Plasma treatment is a kind of environmentally friendly surface modification technology, which has been widely used to modify various materials in many industries. Plasma treatment improves the fiber-matrix adhesion largely by roughening the surface of fibers to increase mechanical interlocking between the fiber and the matrix. For this aim, the effect of atmospheric air plasma treatment on jute fabrics has been discussed in this study. The plasma treatment has been employed at different powers and time intervals. The effects of plasma treatment on fiber properties were revealed by wickability, surface roughness, fiber tensile test and pull-out tests. The effect of plasma treatment on functional groups of jute fibers was observed by attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR). Scanning electron microscopy (SEM) images showed the etching effect of plasma treatment on the surface. It can be concluded that plasma treatment is an effective method to improve the surface and mechanical properties of jute fabrics to be used for composite materials.     

Study on the surface modification of PBO fiber under dielectric barrier discharge treatment

In order to improve the interfacial adhesion property between Poly(p-phenylene benzobisoxazole) (PBO) fiber and epoxy, the surface modification effects of PBO fiber under dielectric barrier discharge treatments in different time were investigated. The samples were tested for surface morphology, functional groups, surface wettability and interfacial shear strengths (IFSS) in epoxy using scanning electron microscope, Fourier transform infrared spectroscopy, water contact angle measurements and Micro-bond pull out tests, respectively. The results indicated that fiber surface morphology after plasma treatment was rougher than untreated one. Some polar groups were introduced on fiber surface in plasma treatment. Moreover, surface wettability and the IFSS between fiber and epoxy had much improvement after plasma treatment, the contact angle decreased with the treatment time increasing and reached the lowest value when the treated time was 60 s, and the IFSS was improved by 117.3 %. On the other hand, no significant difference in single fiber tensile test was observed between treated and untreated fibers when the processing time was shorter than 75 s, but the tensile strength declined by more than 10 % after 75 s treatment as a result of the excessive plasma etching.     

Fabrication and surface modification of melt-electrospun poly(D,L-lactic-co-glycolic acid) microfibers

In this study, biodegradable poly(D,L-lactic-co-glycolic acid) (PLGA) fibers were prepared by a melt-electrospinning and treated with plasma in the presence of either oxygen or ammonia gas to modify the surface of the fibers. The effects of processing parameters on the melt-electrospinning of PLGA were examined in terms of fiber morphology and diameter. Among the processing parameters, the spinning temperature and mass flow rate had a significant effect on the average fiber diameter and its distribution. The water contact angle of melt-electrospun PLGA fibers decreased significantly from 123 ° to 55 ° (oxygen plasma treatment) or to 0 ° (ammonia plasma treatment) by plasma treatment for 180 sec, while their water content increased significantly from 2.4 % to 123 % (oxygen plasma treatment) or to 189 % (ammonia plasma treatment). Ammonia gas-plasma enhanced the surface hydrophilicity of PLGA fibers more effectively compared to oxygen gas-plasma. X-ray photoelectron spectroscopy analysis supported that the number of polar groups, such as hydroxyl and amino groups, on the surface of PLGA fibers increased after plasma treatment. Overall, the microfibrous PLGA scaffolds with appropriate surface hydrophilicity and fiber diameter could be fabricated by melt electrospinning and subsequent plasma treatment, without a significant deterioration of fiber structure and dimensional stability. This approach of controlling the surface properties and structures of fibers could be useful in the design and tailoring of novel scaffolds for tissue engineering.     

Effect of surface treatment of jute fibers on the interfacial adhesion in poly(lactic acid)/jute fiber biocomposites

Jute fibers have immense potential to be used as natural fillers in polymeric matrices to prepare biocomposites. In the present study jute fibers were surface treated using two methods: i) alkali (NaOH) and ii) alkali followed by silane (NaOH+Silane) separately. Effects of surface treatments on jute fibers surface were characterized using fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) analyses. Further, the effects of surface treatments on jute fibers properties such as crystallinity index, thermal stability, and tensile properties were analyzed by X-ray diffraction method (XRD), thermo gravimetric analysis (TGA), and single fiber tensile test respectively. The effects of surface treatment of jute fibers on interphase adhesion between of poly(lactic acid) (PLA) and jute fibers were analyzed by performing single fiber pull-out test and was examined in terms of interfacial shear strength (IFSS) and critical fiber length.     

Characteristics of silver-plated silk fabric with plasma pre-treatment

Plasma gases of oxygen and argon were employed for pre-treating silk fabric before conducting electroless silver plating in this study. The effect of plasma pre-treatment with oxygen and argon gases on the electroless silver-plated silk fabric was investigated. Based on the observation of micro-structure using SEM, it was found that there was an increase in the amount of silver particles deposited on the silk fibre surface after plasma pre-treatment. The functional properties of plasmainduced electroless silver-plated silk fabrics were also evaluated. The increase in weight of the silver-plated silk after plasma pre-treatment was determined. When compared, the oxygen plasma treatment could improve the effect of silver plating on the silk fabric. Additionally, anti-static, anti-bacterial, UV protection and water-repellent properties of the silver-plated silk fabric were determined in this study.     

Properties and performance of polypyrrole (PPy)-coated silk fibers

Different silk substrates in form of spun silk tops, nonwoven web, yarn, and fabric were coated with electrically conducting doped polypyrrole (PPy) by in situ oxidative polymerization from an aqueous solution of pyrrole (Py) at room temperature using FeCl₃ as catalyst. PPy-coated silk materials were characterized by optical (OM) and scanning electron (SEM) microscopy, FT-IR spectroscopy, and thermal analysis (DSC, TG). OM and SEM showed that PPy completely coated the surface of individual silk fibers and that the polymerization process occurred only at the fiber surface and not in the bulk. Dendrite-like aggregates of PPy adhered to the fiber surface, with the exception of the sample first polymerized in the form of tops and then spun into yarn using conventional industrial machines. FT-IR (ATR mode) showed a mixed spectral pattern with bands typical of silk and PPy overlapping over the entire wavenumbers range. DSC and TG showed that PPy-coated silk fibers attained a significantly higher thermal stability owing to the protective effect of the PPy layer against thermal degradation. The mechanical properties of silk fibers remained unchanged upon polymerization of Py. The different PPy-coated silk materials displayed excellent electrical properties. After exposition to atmospheric oxygen for two years a residual conductivity of 10–20 % was recorded. The conductivity decreased sharply under the conditions of domestic washing with water, while it remained essentially unchanged upon dry cleaning. Abrasion tests caused a limited increase of resistance. PPy-coated silk tops were successfully spun into yarn either pure or in blend with untreated silk fibers. The resulting yarns maintained good electrical properties.     

The modification of Kevlar fibers in coupling agents by <Emphasis Type="Italic">γ</Emphasis>-ray co-irradiation

Kevlar fibers were treated in three kinds of coupling agents’ solutions by Co⁶⁰ γ-ray co-irradiation. After the treatment, the interlaminar shear strength (ILSS) values of Kevlar fibers/epoxy composites were all improved. Surface elements of the fibers were determined by energy dispersive X-ray microanalysis (EDX). X-ray photoelectron spectroscopy (XPS) indicated that the oxygen/carbon ratio of the treated fibers was increased and Fourier transform infrared (FT-IR) spectrum confirmed the increase in the polar groups at the fiber surface. The tensile strength of the fibers was evaluated by statistical analysis using the Weibull distribution. The wettability of the fiber surface was also enhanced by the treatment. The possible mechanisms of γ-ray co-irradiation treatment are proposed by the radical reactions. The results indicated that γ-ray co-irradiation technique modified the physicochemical properties of Kevlar fibers and improved the interfacial adhesion of its composites.     

Surface characterization of low temperature plasma treated wool fiber

Previous investigation results revealed that after the Low Temperature Plasma (LTP) treatment, the hydrophilicity of wool fiber was improved significantly. Such improvement enhances the wool dyeing and finishing processes which might be due to the changes of the wool surface to a more reactive one. In this paper, wool fibers were treated with LTP with different gases, namely, oxygen, nitrogen and gas mixture (25 % hydrogen/75 % nitrogen). Investigations showed that chemical composition of wool fiber surface varied differently with the different plasma gas used. The surface chemical composition of the different LTP-treated wool fibers was evaluated with different characterization methods, namely FTIR-ATR, XPS and saturated adsorption value. The experimental results were thoroughly discussed.     

The effects of humidity on the surface modification of wool fabric through atmospheric pressure plasma jet

Current research was carried out on hydrophilic wool fibers at three different humidity conditions through atmospheric pressure plasma jet (APPJ). Samples were taken to evaluate surface microscopic morphology, surface roughness, directional friction effect (DFE), and surface chemical composition. The scanning electron microscope (SEM) and fiber friction coefficient test (FFT) results show that wetting pretreatment has significant effect on surface etching and DFE, but very limited effect on surface roughness. Allwörden reaction and X-ray photoelectron spectroscopy (XPS) results reveal that extra moisture changes C, O, N, S contents and their related characteristic functional groups, therefore increases etching degree on wool fiber surface scales. It was concluded that APPJ treatment is effective in processing wool fiber with high moisture contents.     

Effect of pineapple protease on the characteristics of protein fibers

A pineapple protease, bromelain, was used to improve the dyeing properties of protein fibers such as wool and silk. The optimal condition for the activity of the pineapple protease was about 60 °C at pH 7. The wool and silk were treated with the protease extracted from a pineapple and the K/S values of the dyed wool and silk were measured using a spectrophotometer in order to compare the dye uptake. The protease treatment enhanced the dyeing properties of protein fibers without severe changes in mechanical properties. The surface appearances of protease-treated fibers were observed by microscopy.     

Effect of surface treatment on the structure and properties of para-aramid fibers by phosphoric acid

The surface of para-aramid fiber was modified by phosphoric acid solutions (H3PO4) based on an orthogonal experimental design and analysis method. Statistical results indicate that treatment temperature is the most significant variable in the modification processing, while treatment time was the least important factor. The structure and morphology of the modified fiber were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction instrument (XRD), and scanning electron microscope (SEM). The results showed that some polar groups were introduced into the molecular structure of aramid fibers and the physical structure of the treated fibers was not etched obviously. The interfacial properties of aramid fiber/epoxy composites were investigated by the single fiber pull-out test (SFP), and the mechanical properties of aramid fibers were investigated by the tensile strength test. The results showed that the interfacial shear strength (IFSS) of aramid/epoxy composites was remarkably improved and the breaking strength of aramid fibers was not affected appreciably after surface modification.     

Effect of surrounded air atmospheric plasma treatment on polypropylene dyeability using cationic dyestuffs

The dyeing properties of the polypropylene (PP) fabrics using cationic dyestuffs were investigated after surrounded air atmospheric cold-plasma treatment. Surrounded air plasma (SAP) was used to modify fabric surface and to optimize the effects of some discharge parameters on dyeability. Surface morphology and physical-chemical properties of plasma treated fibers were also characterized by Fourier transform infrared attenuated total reflection spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Activated surfaces by SAP were grafted with different compounds: 6-aminohexanoic acid, acrylic acid, and hexamethyldisiloxane. Dyeing the plasma-induced grafted PP fabric with basic dye was quite satisfactory when high color strength and good fasteness were considered.     

Preparation and characterization of (POSS/TiO2)n multi-coatings based on PBO fiber surface for improvement of UV resistance

The application of poly (p-phenylene-2, 6-benzobisoxazole) (PBO) fiber as reinforcement in composite material was restricted by its photo-degradation, therefore, some measures should be considered to protect PBO fiber against UV aging. In this study, A series of multilayer coating for (POSS/TiO₂)_n was prepared on PBO fiber surface via LbL assembly technique for enhancement of UV resistance. TiO₂ as UV absorbing material was used to relieve UV-degradation of PBO. Surface elemental composition, surface morphology, mechanical and interfacial properties, and UV resistance of uncoated and coated PBO fibers were investigated. These experimental results show multilayer coating of (POSS/TiO₂)_n was uniform deposition on fiber surface after treatment, tensile strength decreased to certain extent, interfacial shear strength increased in a small range and UV resistance is obvious enhanced. After the same accelerated aging time under UV irradiation, the retention of tensile strength and intrinsic viscosity of coated PBO fibers were much better than that of untreated PBO fibers.     

Microwave assisted fabrication of Nano-ZnO assembled cotton fibers with excellent UV blocking property and water-wash durability

Nano-ZnO assembled cotton fibers, with excellent UV blocking property and good water-wash durability, have been successfully fabricated using microwave assisted precipitation and crystallization process synchronously in situ for the first time. Here, zinc nitrate hexahydrate was used as zinc resource and sodium hydroxide was used as precipitate. The asobtained samples were characterized by powder X-ray diffractometer (XRD), filed emission scanning electron microscopy (FESEM), and energy-dispersive spectrometry (EDS), UV/Visible spectroscopy and Fourier transformation infrared spectroscopy (FTIR). Wurtzite ZnO with about 30–40 nm in diameter was fabricated in the lumen as well as in mesoporous structures of cotton fibers. The as-prepared samples have excellent UV absorbing activity over a broad range in the region from 225 nm to 380 nm. The crystallinity and UV blocking properties keep unchangeable as the former after being washed for 60 min in 33 l water. FTIR results reveal that there is no peak shift and new peak occurred, which indicates that no chemical bond exist between nano-ZnO and cotton fibers. Mechanical force is the only way to bond nano-ZnO to cotton fibers in the experimental condition. ZnO nanoparticles and wax existing in cotton fibers can combine to a firmly hybrid layer in the surface and the inner of cotton fibers during microwave treatment, which may bring the good water-wash durability.     

Effect of the low and radio frequency oxygen plasma treatment of jute fiber on mechanical properties of jute fiber/polyester composite

We investigated the surface modification of jute fiber by oxygen plasma treatments. Jute fibers were treated in different plasma reactors (radio frequency “RF” and low frequency “LF” plasma reactors) using O₂ for different plasma powers to increase the interface adhesion between jute fiber and polyester matrix. The influence of various plasma reactors on mechanical properties of jute fiber-reinforced polyester composites was reported. Tensile, flexure, short beam shear tests were used to determine the mechanical properties of the composites. The interlaminar shear strength increased from 11.5 MPa for the untreated jute fiber/polyester composite to 19.8 and 26.3 MPa for LF and RF oxygen plasma treated jute fiber/polyester composites, respectively. O₂ plasma treatment also improved the tensile and flexural strengths of jute fiber/ polyester composites for both plasma systems. It is clear that O₂ plasma treatment of jute fibers by using RF plasma system instead of using LF plasma system brings about greater improvement on the mechanical properties of jute/polyester composites.     

Influence of temperature on corona discharge treatment of cotton fibers

In this study, corona discharge treatment was applied to modify the surface of cotton fibers at various temperatures. The fiber surface was roughened during this treatment and the surface oxygen content increased at a considerably low temperature, and then declined when temperature increased. Weight loss rate showed the treatment was fiercer as treated temperature increased. The breaking strength and surface adhesion property of the fabric treated with starch sizing increased to a certain extent and then decreased. These results suggest that the treated temperature plays a great role in the surface properties of cotton fiber when treated via corona discharge.     

Effects of high energy electrons on physical and tensile properties of non-mulberry silk fibers

Tassar silk fiber (Antheraea mylitta) was irradiated with the available maximum dose range upto 100 kGy using 8 MeV electron beam at room temperature. Irradiation effect in these fibers is quantified in terms of the changes in microstructural parameters studied using wide-angle X-ray scattering data (WAXS). The crystal imperfection parameters such as crystallite size (〈N〉), lattice strain (g in %), and surface weighted crystallite size (D_s in Å) have been determined by line profile analysis (LPA) using Fourier method of Warren. For this purpose, exponential, lognormal, and Reinhold functions for column length distribution have been used for the determination of these parameters. These parameters were compared with tensile properties of the fibers. The increasing trend of crystallite size values (〈N〉 as well as D_s in Å) and tenacity (gf/den) with increasing dosage of radiation clearly indicates the cross linking polymer network in fiber. Comparison of SEM photographs also confirms the X-ray results.     

Atmospheric plasma advantages for mohair fibers in textile applications

In this study, mohair fibers were treated by air and argon plasma for modifying some properties of fibers. The fibers were evaluated in terms of their hydrophilicity, grease content, fiber to fiber friction, shrinkage, dyeing, and color fastness properties. The surface morphology was characterized by SEM images. The results showed that the atmospheric plasma has an etching effect and increases the functionality of a wool surface, which is evident from SEM and FTIR-ATR analysis. The hydrophilicity, dyeability, fiber friction coefficient, and shrinkage properties of mohair fibers were improved by atmospheric plasma treatment.     

A new consolidation system for aged silk fabrics: Interaction between ethylene glycol diglycidyl ether,silk Fibroin and Artificial Aged Silk Fabrics

Consolidation of fragile historic silks is of great importance for further displays and researches. An effective and convenient method to consolidate aged silk fabric has been proposed by using a silk fibroin (SF)/ethylene glycol diglycidyl ether (EGDE) consolidation system. Artificial aged silk fabrics treated with SF/EGDE show great improvement in mechanical properties. The chemical reaction between EGDE and silk fabrics has been proved in previous paper. And in this paper, mechanical test, field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrum (FTIR) test and amino acid analysis (AAA) were applied to illustrate the interactions between SF and silk fabric, EGDE and SF. Results show that SF takes part in the consolidation in the form of adhesions on the surface of silk fibers. The chemical reactions and film adhesion are both responsible for the improvements of mechanical properties in the consolidation.     

Improved interfacial properties of carbon fiber/unsaturated polyester composites through coating polyhedral oligomeric silsesquioxane on carbon fiber surface

Carbon fibers were coated with E51 plus Methacryl-POSS together in an attempt to improve the interfacial properties between carbon fibers and unsaturated polyester resins matrix. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were performed to characterize the changes of carbon fiber surface. AFM results show that the coating of E51 plus POSS significantly increased the carbon fiber surface roughness. XPS indicates that silicon containing functional groups obviously increased after modification. Dynamic mechanical analysis was carried out to investigate the surface energy of carbon fiber. Force modulation atomic force microscopy (FMAFM) and Interlaminar shear strength (ILSS) were used to characterize the interfacial properties of the composites. ILSS was increased by 21.9 % after treatment.