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.     

Modification and properties of polypropylene fibers using aluminosiloxane

Siloxylated polypropylene fibers composed of polypropylene (PP) and aluminosiloxane (AS) were prepared by melt blending followed by spinning. The effects of blend compositions on the thermal behaviors, surface and tensile properties of PP/AS blend fibers were investigated by DSC, WAXD, SEM, static honestometer, etc. The heat of fusion of PP/AS blends decreased with increasing AS contents. In addition, the peak intensity of PP/AS blends in X-ray diffraction patterns decreased with increasing AS contents. It was observed that the silicone molecules exist and well distribute on the surface of siloxylated polypropylene fibers. From the results of the half-life period measurements, the anti-static properties of PP fibers siloxylated with AS was found to be significantly modified.     

Effect of extrusion process variables on physical and chemical properties of extruded oat products

The purpose of this research was tostudy the effects of initial moisture levels andextrusion temperatures on bulk density, waterabsorption and water solubility indexes, viscosity,and color of extruded oat products. The dehulledgrains were ground in a Brabender Quadrumat Seniormill and the coarse fraction, with higher amounts ofcrude protein, lipids, and dietary fiber content, wereconditioned to moisture levels of 15.5–25.5% andextruded in a Brabender single-screw laboratoryextruder. The water absorption index of extrudateswere relatively low (4.16–6.35 g gel/g sample) butincreased as the initial moisture of the raw materialas well as the extrusion temperature was elevated.The water solubility index was inversely proportionalto the extrusion temperature. Initial viscosity of thepaste increased with the increase of raw materialmoisture and extrusion temperature, while the maximumviscosity (at a constant temperature) diminished withthe increase of temperature. Products with lowervalues of L* (luminosity) and greater values ofa* (red) and b* (yellow) were obtained athigh moisture rates and at a 120 ^°C extrusiontemperature.     

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 boron phosphate on the mechanical, thermal and fire retardant properties of polypropylene and polyamide-6 fibers

The effect of boron phosphate (BPO₄) nanoparticles on the mechanical, thermal, and flame retardant properties of polypropylene (PP) and polyamide 6 (PA-6) fibers are investigated by tensile testing, thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), and micro combustion calorimeter (MCC). The addition of BPO₄ reduces the mechanical properties of the both PP and PA-6 fibers. According to the TGA results, the addition of BPO₄ does not change the thermal behavior of PP fiber and slightly reduces the thermal stability of PA-6 fiber by about 30 °C. According to MCC results, the addition of BPO₄ does not change the effective total heat evolution and heat release rate (HRR) peak for PP fibers. Although the inclusion of BPO₄ does not change the total heat evolution of PA-6 fiber, it reduces the HRR peaks due to increase in barrier effect of char.     

Effect of multi walled carbon nanotube on the crystalline structure of polypropylene fibers

Polypropylene fibers containing varying amounts of multi walled carbon nanotube (MWCNT) have been spun using a conventional melt spinning and drawing apparatus. Changes in morphology and crystalline structure of composite fibers induced by addition of MWCNT were studied by small angle X-ray scattering (SAXS), wide angle X-ray scattering (WAXS), Fourier transform infrared spectroscopy (FTIR) and birefringence measurements. The results of SAXS experiments showed an increase in lamellar thickness, long period and crystallinity of the composite fibers in comparison to pure polypropylene fibers. Molecular orientation and helical content of the fibers were increased due to the addition of MWCNT to the polypropylene matrix. WAXS results, being in agreement with the SAXS results, also showed an increase in crystallinity of the composite fibers due to the increase in MWCNT content. This is probably because of nucleating effect of nanotubes in the fiber matrix, causing more crystallization and orientation of molecules to take place around them.     

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.     

Improvements of surface functionality of cotton fibers by atmospheric plasma treatment

This study aims to investigate the viability of atmospheric plasma treatment over raw cotton fabric surfaces as an alternative method for superseding the wet textile pre-treatment processes. For this purpose, the fabric samples were treated with air plasma and argon atmospheric plasma. Thereafter, the hydrophilicity and the wickability of plasma treated samples increased, and also the contact angles decreased significantly. Chemical changes were analyzed by FTIR-ATR and XPS. Morphological changes were observed by SEM. The results were inspected for assessing to what extent the replacement might be achieved by inducing this surface modification method.     

Effect of monophenyl borate on properties of high-ortho phenolic fibers

A series of monophenyl borate (MPB) modified high-ortho phenolic copolymer fibers (BOPFs) were prepared by melt-spinning of the high-ortho phenol-formaldehyde resins with different content of MPB, and cured in a formaldehyde solution. The solution curing fibers were heated up to 240 °C at elevated temperatures in N₂. The effect of MPB on the structure and properties of the BOPFs was investigated by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The results show that a B-O linkage inserts into the high-ortho phenolic copolymer molecular chain with the addition of MPB, and increases the crosslinkage and thermal stability. The peak of O/P (ortho/para) value of fiber (1.94) and elongation (5.6 %) were obtained when BOPFs-4 was heat-cured at 240 °C for 2 h.     

The effects of UV irradiation exposure on the structure and properties of polypropylene/ZnO nanocamposite fibers

Unfilled polypropylene and polyropylene/ZnO nanocomposite fibers were produced using a melt spinning apparatus; then the fibers were exposed to UV irradiation. The structure and properties of the fibers were examined using scanning electron microscopy, tensile measurements, wide angle X-ray diffraction (WAXD), Fourier transform infrared (FTIR) spectroscopy, birefringence measurements and differential scanning calorimetry (DSC). Following 150 hours of exposure to UV irradiation, some transverse cracks on the surface of unfilled polypropylene fibers were observed. It was observed that both carbonyl and hydroperoxide indexes, which are the criteria for the detection of UV degradation of the fibers, were increased due to the increase in the UV irradiation exposure time and the increase in these indexes was smaller for nanocomposite fibers than those of unfilled Polypropylene fibers. It was also observed that crystallinity, crystallite size and total molecular orientation of UV irradiated nanocomposite fibers were increased in comparison with non-irradiated nanocomposite fibers. It was also found that the extent of increase in molecular orientation of the fibers was higher comparing to that for the nanocomposite fibers due to the UV irradiation exposure for the unfilled polypropylene fibers. Tensile properties of both unfilled and nanocomposite fibers were decreased after UV irradiation; this reduction correlated with the extent of the increase in molecular degradation of the fibers, as determined by measuring carbonyl and hydroperoxide indexes.     

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.     

Effect of silk protein fibers on properties of thermoplastic rice starch

Biodegradable polymer was prepared as thermoplastic starch (TPS). Due to poor mechanical properties and high water absorption of TPS, thermoplastic rice starch (TPRS) was modified by reinforcing with natural silk protein fibers, as an alternative choice of fiber reinforcement. Different contents and lengths of silk fibers were varied and used as the reinforcement. Internal mixer and compression molding machine were used to mix and shaped the TPRS/silk composites. It was found that stress at maximum load and Young??s modulus of the TPRS/silk composites significantly increased with the incorporation of silk fibers. Water absorption of the TPRS/silk composites was also dropped by the addition of silk fibers. Moreover, thermal degradation temperatures of the TPRS/silk composites shifted to higher temperatures by the inclusion of the silk fibers. Functional group analysis and X-ray diffraction patterns were analyzed by FI-IR and XRD techniques, respectively. Furthermore, color measurement, morphology and biodegradation by soil burial test were carried out for different TPRS/silk composites.     

Interferometric investigation of the optical and structural properties of thermally treated polyethylene fibers

This work throws the light on the variation of the optical and structural properties of high-density polyethylene (HDPE) fibers at different temperatures (0 °C to 50 °C). The experimental data of this work has been done using the optothermomechanical (OTM) device attached to the interference Pluta microscope. The density of HDPE fibers was determined at different temperatures. Gladstone and Dale’s equation is corrected to be valid with PE fibers. Both of the shift factor and average work per chain were presented against average refractive index of PE fiber. Two different types of polarization; the induced polarizability and the permanent dipole moment were carried out for PE fibers.     

Matrix-fibril morphology development of polypropylene/poly(butylenes terephthalate) blend fibers at different zones of melt spinning process and its relation to mechanical properties

Different shapes of dispersed phase such as sphere, laminar and fibrillar can form in the matrix phase of polymer blends. Production of blend fibers in melt spinning process can result more effective in fibrillar phase morphology formation than in other processes. In this research, the matrix-fibril morphology development during the melt spinning of polypropylene/poly(butylenes terephthalate) was studied. The shapes of blend dispersed phase collected from different zones of the melt spinning line were evaluated by scanning electron micrographs (SEM) and rheological mechanical spectra (RMS). The results showed that fibrillar shape could not be created in the PP/PBT blend fiber samples exited from the spinneret orifice (gravity spun fibers) at low contents (5 percent) of the PBT dispersed phase. However, a complete fibrillar structure was formed in all the as-spun PP/PBT blend fiber samples (melt drawn). The rheological evaluations confirmed a network structure resulting from fibril formation for the samples with high contents (20–40 %) of the PBT dispersed phase and the formation of spherical shape with low contents (5–10 %) of the PBT dispersed phase in matrix of the blend fibers. It was observed that the flow fields of processing zones and blend ratio, in producing the blend fibers, have intensive effects on morphological variations; besides there was a strong relation between the mechanical and morphological properties.     

Effect of enzymatic treatment on the dyeing properties of protein wool fibers

Two proteolytic enzymes were used as auxiliaries in the dyeing of wool fabrics with acid dyes. The effect of the enzymes on dye exhaustion (%E) and dye uptake (K/S) was studied at 70, 85, and 98 °C and compared to the corresponding values obtained for the control samples which were dyed without enzymes under the same conditions. Two commercially available dyeing auxiliaries commonly used for the dyeing of wool at low temperatures were also used under the same conditions and compared with the dyeings made with and without enzymes. Treatment with transglutaminase was done in order to compensate the damaging effects of protease. The study shows that the enzymes could be used as auxiliaries in the dyeing of wool at lower temperatures.     

Effect of water and fiber length on the mechanical properties of polypropylene matrix composites

This paper presents the results of a current study on polypropylene matrix composites processed by injection, with two different glass fiber lengths and five different volume fractions. Physical and mechanical properties were obtained, namely flexural strength, stiffness modulus and fracture toughness. The mechanical properties of the composites increased significantly with the increase of the fibers volume fraction in agreement with the Counto model. The effect of water immersion time was also analysed. Immersion in water promotes a marked decrease in mechanical properties in the early seven-ten days, and afterwards tends to stabilize. Water causes a decrease of the relative strength which increases with fiber volume fraction and reaches about 29 % and 32 % for 20 % of 4.5 mm fiber length and for 25 % of 12 mm fiber length respectively, after 28 days immersion in water. Fracture toughness increases with fiber volume fraction and is always higher for 12 mm fiber length composites than for 4.5 mm fiber length composites.     

Coating superfine down powder on polypropylene for the production of dyeable fibers

To develop dyeable isotactic polypropylene (iPP) fibers, superfine down powder (SDP) was coated on the surface of iPP fibers post melt-spinning. Optical micrographs showed that the surface of powder-coated iPP fibers was roughness, and the amount and dispersion of coated SDP were found entirely dependent on melt-spinning temperature. With the increase in coated SDP content, the moisture and water absorption of powder-coated iPP fibers increased. Powder-coated iPP fibers could be, respectively, dyed by reactive red dye and acid red dye, and the observed enhancement of color strength (K/S) and red value (a*) of powder-coated iPP fibers could be attributed to SDP coated on iPP fibers. It was worth noting that the removal of coated SDP affected the wet-washing fastness of powder-coated iPP fibers largely. In addition, the powder-coated iPP fibers were produced in a few minutes with lower cost and could have potential applications in textile industry.     

Studies on melt spinning of sea-island fibers. I. morphology evolution of polypropylene/polystyrene blend fibers

Isotactic polypropylene/atactic polystyrene (iPP/aPS) immiscible polymer blends are prepared and are melt-spun to prepare blend fibers with matrix-fibril morphologies. The running fibers are captured at different positions of the spinning line, and the morphologies including dispersions of aPS droplets in iPP matrix fibers, droplets diameter and their distributions, as well as the radial gradients on counts and diameter of droplets are analyzed. The effect of take-up velocity on the morphology of take-up fibers is discussed by comparing with that of extrudate fibers. At low take-up velocities, the enhanced radial gradients are attributed to shrinking of matrix fibers on the elongation of spinning stress. While the effects of non-uniform deformation, coalescence and migration of droplets play a role to resist the effects of shrinking of matrix fibers at high take-up velocities. Based on morphology analysis, the mechanisms of compression from the shrinking of matrix fibers, non-uniform deformation, coalescence and migration of droplets are presented to explain why and how the radial gradients form.     

Modification of polypropylene fibers by electron beam irradiation. I. Evaluation of dyeing properties using cationic dyes

The dyeing properties of hydrophobic polypropylene fibers using cationic dyes were investigated to improve dyeability by electron beam irradiation and sulfonic acid incorporation. The color strength of polypropylene fibers after irradiation was examined according to the dyeing conditions including the pH of the dyebath, absorbed doses, and the introduction of a functional group to the fiber substrate. The best dyeing result was obtained when polypropylene fibers incorporated by sulfonic acid group after electron beam irradiation were dyed with cationic dyes at alkaline conditions and 30∼75 kGy irradiation ranges.