Production and analysis of electrospun PA 6,6 and PVA nanofibrous surfaces for filtration

Electrospun nanofibrous surfaces were produced by using two different polymers (PA 6,6 and PVA) at three different levels of polymer feeding rate (0.2, 0.6 and 1.0 ml/h, respectively) and three different levels of production time in electrospinning (5, 10 and 15 minutes, respectively) and the effect of polymer type, polymer feeding rate and production time was determined by analyzing unit weight and thickness of the nanofibrous membranes as well as fibre fineness and pore size distributions. The results showed that much finer fibres were produced by PA 6,6 polymer compare to PVA. The minimum average fibre fineness was 150.96 nm (by PA 6,6 polymer; 0.2 ml/h; 5 min.) while maximum fibre fineness was 243.43 nm (by PVA polymer; 0.6 ml/h; 15 min.). Similarly, the pore sizes of nanofibrous surfaces produced by PA 6,6 were smaller compare to the ones produced by PVA polymer. The results also indicated that coarser fibres were produced as the polymer feed rate and electrospinning time increased. In the second part of the work, composite structures were obtained by combining nanofibrous surfaces with PP non-woven material and their air permeability and filtration efficiency by using an aerosol having 0.2–0.33 mm diameter range were analyzed. The air permeability of PA 6,6 nanofibrous surfaces were much higher compare to the ones produced by PVA and quite high filtration efficiency (99.901 %) was obtained with PA 6,6 nanofibrous surfaces. Also, potential of these nanofibrous surfaces was evaluated by analysing chemical groups eliminated following their exposure to cigarette smoke which was chosen as a specific case study.

Thermal comfort properties of cool-touch nylon and common nylon knitted fabrics with different fibre fineness and cross-section

Cool-touch nylon multi-filament yarns with good heat transfer performance are widely used in the development of knitted fabrics for summer and sports clothing. However, the physical properties of cool-touch nylon fibres, and the effect of fineness and cross-section on comfort-related properties of their knitted fabrics are still not well understood. In this study, the physical properties of cool-touch nylon fibres and common nylon fibres, and comfort properties of knitted fabrics from both fibre types were measured and compared. It was found that cool-touch nylon fibres have better moisture absorption, but slightly lower crystallinity than common nylon fibres. Regarding the fibre fineness and cross-section of cool-touch nylon and common nylon, knitted fabrics showed a similar dependence on thermal comfort properties. Cool-touch nylon fabrics had increased wicking capacity, thermal transfer, and cooling properties, but poorer drying performance and moisture permeability compared to common nylon fabrics. It was concluded that using nylon multi-filament yarns made up of finer filaments and cool touch filaments is an effective way to develop thermal-wet comfort knitted fabrics for summer and sports clothing applications.

Influence of Needle-punching Parameters for the Preparation of Polypyrrole-coated Non-woven Composites for Heat Generation

This work deals with the preparation and characterization of electrically conductive needle-punched non-wo¬ven composites for heat generation. Electro-conductive non-woven composites were prepared through the in situ chemical polymerization of pyrrole with FeCl3 (oxidant) and p-toluene sulfonic acid (dopant). A two-stage double-bath process was adopted for the in situ chemical polymerization of pyrrole. The effect of parameters such as fibre fineness, needle-punching density and depth of needle punching on a polypyrrole add-on, and surface resistivity were studied by employing the Box-Behnken response surface design. It was observed that fibre fineness was the most influential parameter of the polypyrrole add-on. The lowest surface resistivity of the polypyrrole coated sample (200 g/m2, prepared with a punch density of 200 punch/cm2, a punching depth of 6 mm and fibre fineness of 2.78 dtex) was found to be 9.32 kΩ/ with a polypyrrole add-on of 47.93%. This non-woven composite demonstrated good electrical conductivity and exhibited Joule’s effect of heat gener¬ation. Due to the application of a 30 V DC power supply, the surface temperature of the non-woven composite rose to 55 °C from a room temperature of 37 °C. Optical and electron microscopy images of the non-woven composites showed that PPy molecules formed a uniform coating on the non-woven surface. FTIR studies evi¬denced the coating of PPy on a polyester surface. These coated non-woven composites were highly electrically conductive and practically useful for the fabrication of heating pads for therapeutic use.

Efficacy of Defoliants on Yield and Fibre Quality of American Cotton in Semi-Arid Conditions

The study was conducted for exploring the effect of Dropp ultra and Ethrel, their application rates and time of application on two American cotton cultivars. The experiment was carried out at Regional Agricultural Research Station, Nandyal with cultivars NH615 and Sivanandi for two consecutive seasons from 2015-2017 in split plot design with three replications. Application of defoliants like Dropp ultra SC (Thidiazuron 360 + Diuron 180) 200 and 250 ml/ha, Ethrel 1500, 2000 and 3000 ppm were carried at 120 and 140 days after sowing respectively. The results of the study indicated that defoliation with Dropp ultra 250 ml/ha recorded higher percentage of defoliation (92.3) and higher seed cotton yield (2207 kg/ha). Application of defoliants at 140 days after sowing significantly recorded higher yields. There was no difference between the treatments in terms of fibre length and fibre strength. However fibre fineness and uniformity ratio were significantly affected by application of defoliants.

Heat insulation characteristics of multi-layer nonwovens

Purpose This paper aims to deal with the thermal resistance of multilayer nonwovens. The effect of fibre denier, cross-sectional shape and positioning within the layers were analysed with respect to the thermal resistance. Moreover, effect of compression on thermal resistance of the multilayer nonwoven structure have also be studied. Design/methodology/approach The study involves multiple layering of thermal bonded nonwoven webs and the effect of fibre denier and positioning of different nonwovens from the hot plate. To avoid the increase in thermal resistance because of the air gaps between layers, the nonwovens were enclosed within an acrylic frame to compress them to a thickness of 12 mm. Compressional behaviour of the nonwovens were tested at a rate of 5 mm/min with peak compressive load of 50 N. Multilayer nonwoven assemblies were tested for thermal resistance with compressive pressure of 3.5 gf/cm2 and compared with that tested at zero pressure. Findings In the study, three-layered nonwoven structure, provided better thermal resistance than their single component counterparts. The structural characteristic of the multilayer nonwovens affected the conductive, convective and the radiative heat transfer. In a multi-layer nonwoven, the top most layer should have the finest fibre as possible. Second preference may be given to the middle and followed by bottom layers in terms of fibre fineness. However, fine solid fibres performed poorly in terms of compression and recovery resulting in poor thermal resistance under compressive load. Originality/value The experimental approach of controlling thickness while evaluating the thermal resistance will help in nullify the effect of air gaps between the layer interface, thus focussing on the effect of fibre denier and the positioning of nonwovens. This paper also discusses the unique properties of fine solid fibre and hollow fibres and their role in providing better thermal insulation for extreme cold weather applications.

Development of polyester needle-punched nonwoven fabrics for filter press applications

This paper reports the development of nonwoven fabric by needle-punching technique for filter press application in textile effluent treatment plant. For filter press development, the nonwoven fabric was reinforced with the nylon scrim as the central layer in order to withstand the filtration pressure. The nonwoven fabrics were developed using different denier polyester fibres and changing punch density. The influence of fibre fineness and punch density on the properties of nonwovens was investigated. The filtration parameters such as filtration efficiency, dewatering efficiency, blinding tendency and cake discharge properties of the developed nonwoven filter fabrics filter fabrics were evaluated and compared with existing woven fabric filter media. The influence of calendering on the filtration properties of the nonwovens was also studied. The results showed that bursting strength of the developed nonwovens increased with increase in fibre fineness and decrease in punch density. It was also found that the air permeability of the developed nonwovens varied inversely in relation to punch density and the proportion of fine fibres. It was observed that developed nonwovens had 8% higher filtration efficiency and 6% higher dewatering efficiency compared to the existing woven fabric filter media. The blinding resistance and cake discharge properties were slightly lower than that of woven fabric filter. It was found that calendering improves filtration properties of the developed nonwoven fabrics.

Combining ability and heterosis analysis for fibre yield and quality parameters in roselle (Hibiscus sabdariffa L.)

Roselle (Hibiscus sabdariffa L.) is second important bast fibre crop after jute in India. With an aim to ex-ploit non-additive genetic variance present experiment was designed to identify good general combining parents and specific cross combination for fibre yield and fibre quality parameters (fibre fineness, fibre tenacity) in roselle. A total of 11 parents were crossed in complete diallel fashion which resulted 55 F1, 55 RF1 (reciprocal F1). Parents, F1s and RF1s were grown in randomized block design. Analysis of variance revealed significant differences (P< 0.01, P<0.05) among the parents and their hybrids. The parents AMV 1, AMV 5, GR 27 and AHS 160 were identified as good combiners since they recorded significant general combining ability (GCA) effects for fibre yield and quality parameters. Further, For fibre yield only three crosses (AMV 1 × AMV 4, AMV 1 × GR 27, HS 4288 × JRR 07) showed significant specific combining ability (SCA) effects from them hybrid AMV 1 × GR 27 (fibre yield=27.37g/ plant) exhibited positively significant best parent (Non bris 4, Mean fibre yield=21.16g/plant) heterosis (29.35%). Similarly, for fibre tenacity, hybrid GR 27 × JRR 07 (fibre tenacity=23.47g/tex) exhibited positively significant best parent (HS 4288; fibre tenacity=20.35g/tex) heterosis (15.30%).

The Effects of Organic Wastes on Soil and Cotton Quality with respect to the Risk of Boron and Heavy Metal Pollution

The effects on soil and cotton quality of organic wastes from medicinal and aromatic plant factories were investigated with regard to the risks of boron and heavy metal pollution. Oily cumin, oregano, oilless oregano wastes, and mineral fertilizers were applied to cotton in two field experiments performed in the years 2003 and 2006. The Pb content of the soil differed significantly in the 2003 experiment and oregano wastes had significantly decreasing effect. Boron of soil to which oily cumin wastes had been applied reached a toxic limit value in 2006. Boron in soil adversely affected long fibres; B in leaves had a positive effect on the fineness of fibres in 2006. Soil Ni adversely affected plant height in 2006 and seed cotton yield in 2003. Leaf Ni had an adverse effect on fibre elasticity in 2006. Soil Co increased ginning out-turn and Cr decreased the fibre fineness of cotton in 2003.

Zero tillage: A potential technology to improve cotton yield

Zero tillage technology revealed with no use of any soil inverting technique to grow crops. The crop plant seed is planted in the soil directly after irrigation to make the soil soft without any replenishing in soil layers. A study was conducted to evaluate cotton genotypes FH-114 and FH-142 for the consecutive three years of growing seasons from 2013-15. The seed of both genotypes was sown with two date of sowing, 1 March and 1 May of each three years of sowing under three tillage treatments (zero tillage, minimum tillage and conventional tillage) in triplicate completely randomized split-split plot design. It was found from results that significant differences were recorded for tillage treatments, date of sowing, genotypes and their interactions. Multivariate analysis was performed to evaluate the yield and it attributed traits for potential of FH-114 and FH-142 cotton genotypes. The genotype FH-142 was found with higher and batter performance as compared to FH-114 under zero tillage, minimum tillage and conventional tillage techniques. The traits bolls per plant, boll weight, fibre fineness, fibre strength, plant height, cotton yield per plant and sympodial branches per plant were found as most contributing traits towards cotton yield and production. It was also found that FH-142 gives higher output in terms of economic gain under zero tillage with 54% increase as compared to conventional tillage technique. It was suggested that zero tillage technology should be adopted to improve cotton yield and quality. It was also recommended that further study to evaluate zero tillage as potential technology should be performed with different regions, climate and timing throughout the world.