Effect of using cold plasma on dyeing properties of polypropylene fabrics

The low temperature plasma (LTP) technique is used widely to modify polymer and textile materials. This paper describes the development of a plasma system for textile treatment. Polypropylene (PP) has a very low value of the surface free energy (approximately 20–25 mJ/m²). Due to low surface energy, Polypropylene has very weak hydrophilic properties. By controlling the plasma variables, such as the nature of gas, the discharge power, the pressure and the exposure time, a great variety of surface effects can be generated. In this paper, we report the effect of cold plasma of O₂ and N₂ gases at various time of exposure on the dyeing and physical properties of PP fabrics. The results show a significant increase in the color depth upon dyeing after treating PP fabrics with low temperature plasma of O₂ and N₂. For comparing the amount of fabrics dye exhaustion, we have used reflective spectrophotometer. The morphology of the modified surfaces has also been investigated using scanning electron microscopy (SEM). And also FTIR was used to examine the functional groups of the corresponding samples.     

Helium/oxygen atmospheric pressure plasma treatment on poly(ethylene terephthalate) and poly(trimethylene terephthalate) knitted fabrics: Comparison of low-stress mechanical/surface chemical properties

Helium-oxygen plasma treatments were conducted to modify poly(trimethylene terephthalate)(PTT) and poly(ethylene terephthalate) (PET) warp knitted fabrics under atmospheric pressure. Lubricant and contamination removals by plasma etching effect were examined by weight loss (%) measurements and scanning electron microscopy (SEM) analysis. Surface oxidation by plasma treatments was revealed by x-ray photoelectron spectroscopy (XPS) analyses, resulting in formation of hydrophilic groups and moisture regain (%) enhancement. Low-stress mechanical properties (evaluated by Kawabata evaluation system) and bulk properties (air permeability and bust strength) were enhanced by plasma treatment. Increasing interfiber and interyarn frictions might play important roles in enhancing surface property changes by plasma etching effect, and then changing low-stress mechanical properties and bulk properties for both fabrics.     

Influence of the CF4 plasma treatments on the wettability of polypropylene fabrics

A plasma treatment using saturated CF₄ gas was employed to improve the resistance of polypropylene fabrics to water wetting. The fabrics were significantly fluorinated even within a short treatment time of 30 seconds. The result of contact angle measurement indicated that such highly hydrophobic surface was considerably durable even after 150 days of aging.     

A study on chitosan modification of polyester fabrics by atmospheric pressure plasma and its antibacterial effects

Chitosan is a natural nontoxic biopolymer used widely in various fields due to the antimicrobial activities. In this study, the properties of polyester fabrics grafted with chitosan oligomers/polymers after being activated by atmospheric pressure plasmas were evaluated. The antibacterial effect was most evident when the surface of fabrics was activated by atmospheric pressure plasma for 60 to 120 seconds and grafted with chitosan oligomers. The modified fabrics also exhibited good biocompatibility. This process can be applied to a large area and used to produce antibacterial polymer fibers.     

Comparison between oxygen and nitrogen plasma treatment on adhesion properties and antibacterial activity of metal coated polypropylene fabrics

In this paper, an attempt was made to apply low temperature plasma treatment to improve the adhesion property of polypropylene fabrics. Oxygen and nitrogen plasmas were used for pre-functionalization of polypropylene fabrics. Then treated and untreated samples were coated with copper using direct current magnetron sputtering for 10 minutes. And the effect of oxygen and nitrogen pre-functionalization on adhesion properties between copper particles and polypropylene surface were studied. The textile properties of treated and untreated samples were evaluated by different standard testing methods in terms of both physical and chemical performances. The morphology changes of fabrics after plasma treatment were characterized by scanning electron microscopy. Fourier transform infrared spectroscopy analyses revealed chemical surface modifications occurring after the plasma treatments. Experimental results of the adhesion properties and surface properties are presented for the metal coated-polypropylene samples before and after low pressure plasma treatment, and results are compared. The adhesion properties of the activated samples are determined by abrasion and rubbing tests. The antibacterial counting test was used for determination of antibacterial efficiency of both treated and untreated samples, and durability of antibacterial properties was compared. The adhesion improvement has been related to the formation of different functional groups and changes in the topology of the surface.     

The effect of carbon black nanoparticles on some properties of air plasma printed cotton/polyamide 6 fabrics

In this study, cotton/nylon blended fabrics were treated with atmospheric air plasma at various times (30–60 s) and were subsequently printed with pastes containing carbon black nanoparticles. Properties of plasma treated fabrics such as visible-near infrared (Vis-NIR) reflectance, water contact angle, air permeability, and color fastness were measured. It was shown that increasing plasma treatment time decreases reflection level of treated fabrics in Vis-NIR region. Plasma treatment also enhanced the hydrophobicity of cotton/nylon fabrics observed by an increase in water contact angle. Plasma treated samples for 60 s demonstrated lower air permeability than those treated for 30 s. Furthermore, printed samples possessed acceptable levels of fastness against washing, light and crocking.     

Effect of polypropylene fiber cross sectional shapes on some structural/mechanical fiber properties and compressibility behaviour of plain knitted fabrics

Synthetic fibers are generally produced with circular cross sectional shapes. Other cross sectional shaped fibers such as trilobal, triangular, hollow and pentagonal fibers are also produced to improve some properties of fibers and fabrics such as lustre, handle, wicking rate, strength, stiffness and bulkiness. In this research we aimed to investigate compressional behaviours of fabrics knitted from polypropylene fibers having three different cross sectional shapes; namely circular, trilobal and triangular. Morphological, structural and mechanical properties of produced fibers were evaluated by using scanning electron microscopy, X-ray diffractometry, differential scanning calorimetry and tensile tester, respectively. In terms of structural and mechanical properties, no significant differences were found related to fiber cross sectional shapes. Then, plain knitted farbrics were produced and compressional properties of these fabrics were investigated. Fabrics knitted from trilobal fibers showed the highest compressibility properties and it is followed by fabrics which are produced from triangular and circular fibers.     

Effects of low temperature plasma on wool and wool/nylon blend dyed fabrics

Knitted wool and wool/nylon blend dyed fabrics were treated with low temperature plasma (LTP) to achieve optimum shrink-resistance without impairing surface topography, colour or fastness to washing of the fabrics. As LTP tends to impair handle of the fabrics, both wool and wool/nylon blend fabrics were submitted to industrial softening and/or biopolymer treatments after LTP treatment, leading to hydrophilic wool and wool/nylon blend fabrics with improved shrink-resistance without any colour changes and good fastness to washing. The results obtained were compared with those obtained by an industrial shrink-resist treatment.     

Chitosan-filled polypropylene composites: The effect of filler loading and organosolv lignin on mechanical,morphological and thermal properties

In this work, the effect of organosolv lignin on properties of polypropylene (PP)/chitosan composites was investigated. Mechanical and thermal properties of the composites were analyzed by means of ASTM D 638-91, ASTM D 256, thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). Tensile strength and elongation at break of the PP composites decreased upon the presence of chitosan filler, but Young’s modulus improved. Impact strength was found to increase with the maximum value at 30 php of filler loading. At a similar loading, treated PP/chitosan composites were found to have higher tensile strength, elongation at break, Young’s modulus as well as impact strength than untreated composites. Furthermore, the presence of organosolv lignin imparted a plasticizing effect. Thermal properties of the treated PP/chitosan composites were better as compared with the untreated PP/chitosan composites; although the chemical treatment did not alter the thermal degradation mechanism. In addition, the obtained results were comparable to results from previous studies. This finding implied that the organosolv lignin could be a potential reagent to replace its synthetic counterpart.     

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.     

Surface treatments of jute fabric: The influence of surface characteristics on jute fabrics and mechanical properties of jute/polyester composites

In this study, jute fabrics were modified by alkali, micro-emulsion silicon (MS) and fluorocarbon based agents (FA) in order to enhance the interfacial adhesion between the polyester matrix and the jute fiber. X-ray photoelectron spectroscopy (XPS) and contact angle measurements were used to characterize fiber surfaces. The effects of various surface treatments on the mechanical and morphological of jute/polyester composites were also studied. All surface treatments were shown to improve the tensile, flexural strengths and interlaminar shear strengths of the composites. Moreover, the maximum improvement in the mechanical properties was obtained for the FA treated jute/polyester composites. SEM micrographs of the tensile fracture surface of jute/unsaturated polyester composites also exhibited improvement of interfacial and interlaminar shear strengths by the alkali, MS and FA treatments of jute fibers.     

Thermoplastic starch modified during melt processing with organic acids: The effect of molar mass on thermal and mechanical properties

Thermoplastic starch (TPS) was modified with ascorbic acid and citric acid by melt processing of native starch with glycerol as plasticizer in an intensive batch mixer at 160 °C. It was found that the molar mass decreases with acid content and processing time causing the reduction in melting temperature (T_m). As observed by the results of X-ray diffraction and DSC measurements, crystallinity was not changed by the reaction with organic acids. T_m depression with falling molar mass was interpreted on the basis of the effect of concentration of end-chain units, which act as diluents. FTIR did not show any appreciable change in starch chemical compositions, leading to the conclusion that the main changes observed were produced by the variation in molar mass of the material. We demonstrated that it is possible to decrease melt viscosity without the need for more plasticizer thus avoiding side-effects such as an increase in water affinity or relevant changes in the dynamic mechanical properties.     

Influence of citric acid and water on thermoplastic wheat flour/poly(lactic acid) blends. I: Thermal, mechanical and morphological properties

Wheat flour was plasticized with glycerol and compounded with poly(lactic acid) in a one-step twin-screw extrusion process in the presence of citric acid with or without extra water. The influence of these additives on process parameters and thermal, mechanical and morphological properties of injected samples from the prepared blends, was then studied.Citric acid acted as a compatibilizer by promoting depolymerization of both starch and PLA. For an extrusion without extra water, the amount of citric acid (2 parts for 75 parts of flour, 25 parts of PLA and 15 parts of glycerol) has to be limited to avoid mechanical properties degradation. Water, added during the extrusion, improved the whole process, minimizing PLA depolymerization, favoring starch plasticization by citric acid and thus improving phases repartition.