Add-on Levels Research Articles

Permanent P/N-rich polymeric coating capable of extinguishing flame on cotton fabrics

Although polyphosphazenes having attracted attention for use as flame-retardant coatings for textiles, nonetheless their add-on level is still far from ideal with regard to high-efficiency flame-retardant properties, wearing comfort and durability. Herein, for the first time, a cross-linkable phosphorus and nitrogen-rich polyphosphazene, poly(methoxy/allylphenoxy)phosphazene (PMAP), with mainly methoxy groups and an appropriate amount of unsaturated chemical bonds containing allylphenoxy side groups (ca. 8 %) was synthesized. Subsequently, the noncombustible, transparent, elastic crosslinked PMAP coating was coated on cotton fabrics through dipping and photoinduced cross-linking processes. The PMAP-coated cotton showed high-efficiency flame-retardant properties along with remarkably high durability. The intrinsic properties of cotton fabric, such as whiteness, gas permeability and bending rigidity, were highly reserved after being coated with PMAP. Interestingly, the flame-retardant properties of the 4.9 wt%-coated cotton increased, and the coated cotton obtained a self-extinguishing property and maintained >95 % of its initial mass after 60 rigorous laundry cycles. Moreover, the PMAP-coated cotton exhibited enhanced carbonization ability at lower temperatures, which was the key to the flame-retardant properties of cotton fabric. The PMAP-coated cotton also showed a lower peak heat release rate and total heat release values than the control cotton during combustion. Therefore, the comprehensive highly favorable properties of the PMAP coating make it a cutting-edge material for flame-retardant cotton fabrics and greatly expand its potential in practical applications.

One Pot Facile Synthesis of Self-extinguishable Metal Based Flame Retardant for Cotton Fabric

ABSTRACT An efficient metal-based flame-retardant was prepared for cotton fabric (CF) by a convenient pad-dry-cure method, which involves the consecutive deposition of intumescent containing different combination of ammonium polyphosphate, melamine, pentaerythritol with Copper and Zinc metal ions. We studied different properties like thermal, mechanical, flammability, and laundering durability of treated CF samples. The intumescent-coated CF shows remarkable high-efficiency flame-retardant properties: (1) a self-extinguishing property (5 s) without lateral spreading of flame during the vertical flame test with a lower smoke release character; (2) the limiting oxygen index (LOI) values of coated CF are improved with increasing add-on level. The Zn-based samples exhibited a high limiting oxygen index value of 36%. Consequently, the resultant fabrics were observed to show great flame retardancy with high thermal stability as 35% of char yield at 600°C. The durability of modified cotton was tested after five laundering cycles, which showed that the coating maintains 84% of its initial mass. It is reported that in addition to durable flame retardancy, the mechanical properties of cotton were also enhanced. The present work provides eco-friendly one pot facile synthesis of intumescent-based flame retardant for CF which may be used in numerous applications. Abbreviations: ammonium polyphosphate; PER: pentaerythritol; MEL: melamine; LOI: limiting oxygen index; TGA: thermogravimetric analysis; DTG: derivative thermogravimetry; GSM: gram per square meter; FR: flame retardant; CP: plain cotton fabric; CT: twill cotton fabric; CF: cotton fabric; Int: intumescent; FTIR: Fourier Transformation Infrared; BEL: burn entire length; DNI: did not ignite; SE: self-extinguish; HGMs: hollow glass microspheres; CH/PA/Ba/PA: Chitosan/ Phytic Acid/Barium/Phytic Acid; DPPMA: diphenylphosphinic acid with melamine; PBS/30PA-GU: poly(butylene succinate/30 phytic acid-guanosine; PET: polyethyleneimine; Tri-HTAC: 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride; TA/B@PDA: tannic acid/Borax@polydopamine; P10H5: 5wt% HCCP(Hexachlorocyclotriphosphazene). ammonium polyphosphate; PER: pentaerythritol; MEL: melamine; LOI: limiting oxygen index; TGA: thermogravimetric analysis; DTG: derivative thermogravimetry; GSM: gram per square meter; FR: flame retardant; CP: plain cotton fabric; CT: twill cotton fabric; CF: cotton fabric; Int: intumescent; FTIR: Fourier Transformation Infrared; BEL: burn entire length; DNI: did not ignite; SE: self-extinguish; HGMs: hollow glass microspheres; CH/PA/Ba/PA: Chitosan/ Phytic Acid/Barium/Phytic Acid; DPPMA: diphenylphosphinic acid with melamine; PBS/30PA-GU: poly(butylene succinate/30 phytic acid-guanosine; PET: polyethyleneimine; Tri-HTAC: 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride; TA/B@PDA: tannic acid/Borax@polydopamine; P10H5: 5wt% HCCP(Hexachlorocyclotriphosphazene).

High-Efficiency Flame Retardants of a P-N-Rich Polyphosphazene Elastomer Nanocoating on Cotton Fabric.

Modification by intumescent flame retardants is an effective way to impart antiflame properties to fabric materials. Polyphosphazene elastomers contain all three elements required by intumescent flame retardants: an acid source, a gas source, and a carbon source, making them all-in-one integrated intumescent flame retardants. In this work, halogen-free poly(dimethoxy)phosphazene (PDMP) loaded with 29.0 wt % phosphorus and 13.1 wt % nitrogen is shown to be an ideal flame retardant for fabric materials. For the first time, transparent and elastic PDMP was applied as an intumescent flame retardant for cotton fabric. The PDMP-coated cotton shows remarkable high-efficiency flame-retardant properties: (1) a self-extinguishing property during the vertical flame test is obtained when the add-on level reaches 5.3 wt %, with a lower smoke release character; (2) the limiting oxygen index (LOI) values of coated cotton are improved with increasing add-on level, and the thickness of the coating is measured to be at the nanolevel, 2540 nm when 10.9 wt % PDMP is coated. The coated cotton shows enhanced carbonization ability at lower temperatures, which is the key to imparting flame-retardant properties to cotton, and the PDMP-coated cotton shows remarkably lower peak heat release rate and total heat release compared to the control cotton during combustion. The durability of modified cotton was tested after 50 laundering cycles, which showed that the coating maintains 80% of its initial mass, and the after-laundering sample preserves the characteristics of self-extinguishing and a high LOI. Thus, the PDMP nanocoating-modified flame-retardant cotton fabric is sufficiently durable for practical application.

Effect of Sawdust Extract, Wetting and Drying Cycles on of Aggregates Soil Stability and Saturated Hydraulic Conductivity

A laboratory experiment was conducted, in the laboratories of the College of Agriculture-University of Anbar, for disturbed soil samples taken from one of the fields in the previous College of Agriculture, Baghdad University, latitude 33.2 south, and longitude 44.24 east. Wooden sawdust extract (WSE) was added to soil in 5, 10, and 15% levels in an equivalent proportion of soil organic matter (SOM) content for nine cycles of wetting-drying (WDC). A factorial three replications experimental design was statistically analyzed. A significant increase was noticed in the mean weighted diameter (MWD) of soil at fast wetting, where it raised for 5, 10, and 15% WDS levels. The interaction was significant in the second WDC for the same WSE levels in comparison with zero addition treatment where they were 123.62 and 173 % respectively, meanwhile 10 and 15 % WSE levels significantly superior to 5% level by 38 and 69 %. Whereas slow wetting MWD gradually to be 37 and 86% starting from third till ninth WDC successively compared to second WDC. The effect of WDCs on the saturated hydraulic conductivity (ks) of aggregates greater than 9.5mm was significant in this trait, as it increased by 13, 8, 13, 19, 18, and 18% for the 2ed, 4th, 6th, 7th, 8th, and last WDC, respectively. It also found a clear effect of the add-on levels in the saturated water conductivity (SWC) within 9.5 – 4 mm aggregates. There was a significant increase in equivalent add-on levels of 5, 10, and 15% with 8.4, 32.9, and 74.2% successively. There was a significant increase of 5, 10, and 15% equivalent addition levels of 8.4, 32.9, and 74.2% respectively compared to the level of non-addition of WSE extract. Soil samples tested with an electron scanning microscope, the samples to which WSE were added became granular and aggregated surfaces, while the untreated samples were smooth, with no granular surfaces and sharp edges.

Utilization of Waste Sorghum Grain for Producing Superabsorbent for Personal Care Products

Modification of useful starch extracted from waste sorghum grains was carried out for production of superabsorbent materials which can be used in personal care products. Starch was extracted using alkali steeping method. It was characterized for swelling power, percentage transmittance and iodine binding values. The extracted starch was modified via graft copolymerization of acrylic acid and acrylamide onto starch to produce biodegradable absorbent material. The changes in modified starch structure were assessed using TGA, FTIR and SEM. The evaluation of enhancement in the properties was done by performing absorption tests. The reaction parameters were optimized to achieve higher graft add-on level and water absorption capacity. The absorbent product was further subjected to saponification for further enhancing its water absorption capacity (368.8 g/g). The product prepared by using optimized parameters of reaction was made highly porous by introducing sodium bicarbonate during the reaction. It showed a significant increase in the rate of water absorption and enhancement in water absorption capacity (380.9 g/g).The modified product showed 101.1 and 77.0 g/g absorption of artificial blood and artificial urine, respectively. This modified product was infused in commercially available sanitary napkin and baby diaper. Further, it was tested for fluid absorption and centrifuge retention capacity and it performed distinctly better than the commercial products. This superabsorbent material showed 12% weight loss after 28 days when biodegradability test by soil burial method was carried out.

New Development in Flame Retardant Finishing of Cotton Blend Fabrics

Blending cotton with synthetic fibers drastically improved durability for use in protective clothing. Developing new flame retardant finishing technology for cotton blends was critical for producing low cost, durable and high performance fire resistance military protective clothing. In this paper, we discussed the flame retardant finishing of the Nomex/cotton (65/35) blend fabric using a hydroxy-functional organophosphorus oligomer (HFPO) in combination with 1,2,3,4-butane-tetracarboxylic acid (BTCA) as a bonding agent and triethanolamine (TEA) as a reactive co-additive. Because cotton was a highly flammable fiber, the Nomex/cotton blend fabric containing more than 20% cotton required flame-retardant finishing treatment. BTCA reacted with HFPO, cotton and TEA to form BTCA/HFPO/TEA/cotton crosslinked polymeric network, which improved the hydrolysis resistance of HFPO, whereas TEA provided synergistic nitrogen to enhance the performance of HFPO. The Nomex/cotton blend treated with the HFPO/BTCA/TEA system shows high flame retardant performance and excellent laundering durability at relatively low add-on levels. We also discussed the flame retardant finishing of the 50/50 nylon/cotton blend military fabrics using the combination of HFPO and dimethyloldihydroxyethyleneurea (DMDHEU), which formed HFPO/DMDHEU crosslinked networks on both cotton and nylon in the blends. The treated blend fabric passed the vertical burning test after 40-50 launderings cycles with negligible fabric strength loss. The heat release rate data indicated that the nylon and cotton fibers interacted with each other during their thermal decomposition on the blend fabric treated with the HFPO/DMDHEU system.

Fire Self-Extinguishing Cotton Fabric: Development of Piperazine Derivatives Containing Phosphorous-Sulfur-Nitrogen and Their Flame Retardant and Thermal Behaviors

Recent studies have shown interest in flame retardants containing phosphorus, nitrogen and sulfur a combination small molecule with a promising new approach in preparing an important class of flame retardant materials. Tetraethyl piperazine-1,4-diyldiphosphonate (TEPP) and O,O,O’,O’- tetramethyl piperazine-1,4-diyldiphosphonothioate (TMPT), based on Piperazine derivatives, were prepared successfully and their structures were proved by means of 1H, 13C and 31P NMR. Cotton twill fabric was treated with both compounds to provide different add-on levels. Thermogravimetric Analysis (TGA), microscale combustion calorimeter (MCC), vertical and 45° flame test and limiting oxygen index (LOI) were performed on the treated cotton fabrics and showed promising results. When the treated twill fabrics (5 wt% - 7 wt% add-ons) were tested using the vertical flammability test (ASTMD6413-11), we observed that the ignited fabrics self extinguished and left behind a streak of char. Limiting oxygen index (LOI, ASTM 2863-09) was utilized to determine the effectiveness of the flame retardant on the treated fabrics. LOI values increased from 18 vol% oxygen in nitrogen for untreated twill fabric to a maximum of 30 vol% for the highest add-on of twill. Furthermore, Scanning Electron Microscope (SEM), Attenuated Total Reflection-Infrared (ATR-IR), and Thermogravimetric Analysis-Fourier Transform Infrared (TGA-FTIR) spectroscopy were employed to characterize the chemical structure on the treated fabrics, as well as, the surface morphology of char areas of treated and untreated fabrics. Additionally, analysis of the release gas products by TGA-FTIR shows some distinctive detail in the degradation of the treated fabrics during the burning process.

3 Level Ventilation: the First Clinical Experience

Considering the issues of artificial ventilation (AV) in non-homogenous pathological lung processes (acute lung injury (ALI), acute respiratory distress syndrome (ARDS), pneumonia, etc.), the authors applied the three-level lung ventilation to a group of 12 patients with non-homogenous lung injury. Three-level ventilation was defined as a type (modification) of AV whose basic ventilation level was produced by the modes CMV, PCV or PS (ASB) and add-on level, the so-called background ventilation was generated by two levels of PEEP. PEEP (constant) and PEEPh (PEEP high) with varying frequency and duration of transition between the individual levels of PEEP. Objective: to elucidate whether in cases of considerably non-homogenous gas distribution in acute pathological disorders, three-level ventilation (3LV) can correct gas distribution into the so-called slow bronchoalveolar compartments, by decreasing the volume load of the so-called fast compartments and to improve lung gas exchange, by following the principles of safe ventilation. Results. 3LV was applied to 12 patients with severe non-homogenous lung injury/disorder (atypic pneumonia and ARDS/ALI) and low-success PCV ventilation after recruitment manoeuvre (PaO2 (kPA) /FiO2 = 5—6). There were pronounced positive changes in pulmonary gas exchange within 1—4 hours after initiation of 3LV at a fPCV of 26±4 breaths/min-1 and PEEPh at a fPEEPH of 7±2 breaths/min-1 with a minute ventilation of 12±4 l/min. 3LV reduced a intrapulmonary shunt fraction 50±5 to 30±5%, increased CO2 elimination, with PaCO2 falling to the values below 6±0.3 kPa, and PaO2 to 7.5±1.2 kPa, with FiO2 being decreased to 0.8—0.4. Lung recruitment also improved gas exchange: with PEEP=1.2±0.4 kPa, static tho-racopulmonary compliance (Cst) elevated from 0.18±0.02 l/kPa to 0.3±0.02 l/kPa and then to 0.38±0.05 l/kPa. Airways resistance (Raw) decreased by more than 30%. Improved lung aeration was also estimated as a manifestation of gas distribution with a long time constant. After 5±1-day 3LV, the patients were switched to PS ventilation; after gradually reduction of ventilation maintenance, they were disconnected from a ventilator and transferred to a specialized unit. Conclusion. The small study group made it impossible to statistically assess outcomes; the clinical results are not at least contrary to the results of theoretical mathematic simulation of 3LV in mathematical and physical models. 3LV as compared with PCV applied within the first 2—4 hours of AV improved lung gas exchange. It can be a promising mode of ventilation for the lungs afflicted by a diffusive non-homogenous pathological process. Key words: artificial ventilation, three-level ventilation, acute lung injury, acute respiratory distress syndrome.

Multilevel Ventilation: Theory and Simplified Mathematical Model

Considering the issues of artificial ventilation (AV) in non-homogenous pathological lung processes (acute lung injury, acute respiratory distress syndrome, pneumonia, etc.), the authors created a mathematical model of multicompartment non-homogenous injured lungs that were ventilated by a new mode of AV, the so-called three-level ventilation. Multilevel ventilation was defined a type (modification) of ALV whose basic ventilation level was produced by the modes CMV, PCV or PS (ASB) and add-on level, and the so-called background ventilation was generated by the levels of PEEP and high PEEP (PEEPh) with varying frequency and duration. Multi-level ventilation on 3 pressure levels was realized by the mathematical model as a combination of pressure-controlled ventilation (PCV) and two levels of PEEP and PEEPh. The objective was to prove that in cases of considerably non-homogenous gas distribution in acute pathological disorders of lungs, gas entry into the so-called slow bronchoalveolar compartments could be improved by multilevel AV, without substabtially changing the volume of so-called fast compartments. Material and Method. Multi-level ventilation at 3 pressure levels was realized by the mathematical model as a combination of PCV and two levels of PEEP and PEEPh. Results. By comparing the single-level AV in the PCV mode with the so-called three-level ventilation defined as a combination of PCV+PEEPh/PEEP, the authors have discovered that the loading of slow compartments in the model was considerably improved by 50—60% as compared with the baseline values. In absolute terms, this difference was as many as 2—10 times of the volume. Conclusion. The mathematical model may demonstrate that the application of the so-called three-level AV causes considerable changes in gas distribution in the lung parenchyma disordered by a non-homogenous pathological process. The authors state that the proposed mathematical model requires clinical verification in order to evaluate the efficiency of this modification of AV. Key words: artificial ventilation, multilevel artificial ventilation, acute lung injury, acute respiratory distress syndrome.

Nonformaldehyde Flame Retardant Finishing of the Nomex/Cotton Blend Fabric Using a Hydroxy-Functional Organophosphorus Oligomer

Multifunctional carboxylic acids, such as 1,2,3,4-butanetetracarboxylic acid (BTCA), have been used as durable press finishing agents to produce wrinkle-resistant cotton. In our previous research, we used BTCA as a nonformaldehyde bonding agent in the flame retardant finishing system based on a hydroxy-functional organophosphorus oligomer (HFPO) for cotton. In this research, we investigate the application of HFPO to the 65%/35% Nomex/cotton blend fabric using BTCA as a bonding agent and triethanolamine (TEA) as a co-reactant. We found that the addition of TEA in the flame retardant finishing system improves the hydrolysis resistance of the HFPO bound to the Nomex/ cotton blend and enhances the flame retardant performance of HFPO by means of phosphorus—nitrogen synergism. Moreover, TEA reduces the deposit of calcium salt on the treated fabric during laundering by esterifying the free carboxylic acid groups on cotton. The Nomex/cotton blend fabric treated with the HFPO/BTCA/TEA system shows high flame retardant performance at relatively low add-on levels. It is a completely nonformaldehyde flame retardant finishing system.

Influence of Frictional Characteristics of Core and Sheath on Twist Structure and Tensile Properties of DREF-3 Friction Spun Yarns: Part I: Filament-core DREF-3 Friction Spun Yarns

The influence of fibre friction on twist structure and tensile properties of filament-core DREF-3 friction spun yarns has been investigated. A 110/48 dtex polyester multi-filament in three different forms – namely, flat, twisted, and textured – was used for the core, and acrylic fibres of 38 mm and 1.65 dtex with three different add-on levels of polyethylene glycol 400 (PEG) finish were used for the sheath, to spin a set of nine yarns, each of 37 tex with a core: sheath ratio of 30:70. It was found that an increase in fibre-to-filament and fibre-to-fibre friction to a certain extent improves the twisting/wrapping of sheath fibres over the core in the yarn. The increased sheath fibre twist reinforces the yarn structure, resulting in increased yarn strength and enhanced sheath slipping resistance over the filament-core. The filament-core was found to exhibit twist in both Z and S directions. The sheath fibres were observed to he arranged in layers and to exhibit differential twist structure.

Influence of Frictional Characteristics of Core and Sheath on Twist Structure and Tensile Properties of DREF-3 Friction Spun Yarns Part II: Staple-core DREF-3 Friction Spun Yarns

The influence of fibre-to-fibre friction on structure and tensile properties of staple-core DREF-3 friction spun yarns has been investigated. Acrylic fibres of 38 mm and 1.65 dtex with three different add-on levels of PEG400 finish were used to produce a set of nine yarns, each of 50 tex with a core:sheath ratio of 70:30. It was found that, to a certain extent, an increase in core- and/or sheath-fibre friction increased twist in both the core and the sheath fibres. The increased twist reinforced the yarn structure, resulting in higher yarn strength and initial modulus. The tenacity increased by about 18% for an approximately 10–14% increase in fibre-to-fibre friction. The core was found to exhibit twist in both the Z and S directions.

A study of the influence of structure on the effectiveness of chitosan as an anti-felting treatment for wool

The effect of chitosan on the resistance of wool fabric to felting on washing has been studied using nine structurally different samples of chitosan. Structural differences examined include molecular weight, level of N-acetylation, and the nature and concentration of homologous N-acyl groups. No strong dependency of shrinkage on molecular weight or level of N-acetylation has been found, but increasing the hydrophobic character of chitosan through the incorporation of a number of long-chain N-acyl groups gives improved antifelting behaviour, compared to chitosan itself, at the same level of add-on.

Evaluating a One-Bath Process for Imparting Antimicrobial Activity and Repellency to Nonwoven Surgical Gown Fabrics

A one-bath process to apply both antimicrobial and fluorochemical repellent finishes to nonwoven surgical gown fabrics is investigated in this study. The finishes are applied to two nonwovens: a polypropylene spunbonded/meltblown/spunbonded fabric and a wood pulp/polyester spunlaced fabric. Four different add-on levels of the finishes are applied to each fabric, resulting in sixteen finish combinations per fabric. Results show that both finishes are compatible for application in a one-bath process, and the antimicrobial and repellent properties are adequate with this process. Minimum chemical add-on levels of the antimicrobial and oil repellent finishes to achieve acceptable antimicrobial and repellent properties are determined for each fabric. The effectiveness of the antimicrobial finish is not affected by the repellent finish, but the effectiveness of the repellent finish varies with the add-on level of the antimicrobial finish.

Dye Molecules as Bridges for Functional Modifications of Nylon: Antimicrobial Functions

Dye molecules often contain reactive groups such as sulfonate, amino, and hydroxyl that serve as auxochromes in dyes, but are chemically reactive and potentially useful as linkers for attaching functional moieties to synthetic fibers. Using these reactive groups as a means of functionalizing textile materials is proposed and implemented in this study of modifying chemically stable polymers. As an example of this innovative finishing tech nology, acid dyed nylon 66 and nylon 6 fabrics are finished in a quaternary ammonium salt solution, and durable and refreshable antimicrobial functions are conferred on the fibers. Most acid dyes can be used with this method to incorporate quaternary ammonium salts into nylon fabrics. The add-on levels of the salts on the dyed and undyed fabrics are significantly different, evidence for the occurrence of interactions of dye molecules with salts. Quantitative antimicrobial evaluations of the treated fabrics reveal that there are significant reductions in bacterial populations up on surface contact with the finished fabrics. The bactericidal function of the fabrics survives through ten Launder-Ometer washes, according to AATCC test method 61-1994, equivalent to fifty machine washes.

Graft polymerization of methacrylamide onto wild silk fibers treated with an alkaline solution

Graft polymerization of methacrylamide was made on wild silk fibers (Chinese tussah silk fibers) and Indian muga silk fibers, and the level of polymer add-on was investigated. The polymer add-ons for these wild silk fibers were not as large as those obtained with commercial mulberry silk fibers. However, the level of polymer add-on for these wild silk fibers was increased by swelling treatment with a sodium hydroxide aqueous solution prior to the graft treatment.

Tensile Properties and Static Fatigue Behavior of Cotton Warp Yams

Warp yams under a state of dynamic loading on a loom have to withstand cumulative damage caused by tensile fatigue at relatively low loads coupled with the abrasive action of the machine parts. To evaluate the fatigue phenomenon of sized cotton yams and its correlation with performance on a loom, one must first understand basic mechanical properties of yams in terms of fiber properties and fiber length distribution. The first section of this paper reports on the effect of fiber length distribution on tensile properties of yams at various tensile strain rates, and the second section presents the . fatigue behavior of 100% cotton yams. Fiber length and its distribution in cotton yams seem to influence the tensile behavior of both sized and unsized yams at all strain rates, but strain rates do not play a significant role in determining the properties of sized yams. Adding size tends to mask the effect of fiber length variation, particularly at higher size loading. The tensile properties of sized cotton yams are also influenced by the size type, such as polyester, carboxymethyl cellulose, and polyvinyl alcohol, at all add-on levels. The fatigue behavior of 100% cotton unsized and sized yam is eval uated using a Sulzer-Ruti Webtester. The mechanism of yam failure due to fatigue/ abrasion for unsized yam is affected by short fiber content. The base tension has the largest overall effect. Unsized yam containing 10% comber noil has an optimum bal ance of short and long fibers, making the yam structure more resistant to fatigue / abrasion. In sized yam, the effect of short fibers is partly masked by the properties and compatibility of size materials with the substrate. Polyester size has poor com patibility with cotton fibers; carboxymethyl cellulose and partially hydrolyzed polyvinyl alcohol tend to produce very highly increased resistance to fatigue and abrasion. Rep resenting fatigue /abrasion data in terms of mean or average lifetimes is questionable due to contradictory evidence. Representing fatigue data in terms of a three-parameter Weibull distribution leads to realistic interpretations.

Ultraviolet‐radiation‐induced graft copolymerization of styrene and acrylonitrile onto cotton cellulose

AbstractPhotoinitiated graft copolymerization of the vinyl monomers, styrene and acrylonitrile, onto cotton cellulose was studied using uranyl nitrate and ceric ammonium nitrate as photoinitiators. Uranyl nitrate photoinitiation showed a higher level of grafting for styrene, whereas in the case of acrylonitrile ceric ammonium nitrate was found to be the better photoinitiator. Optimized conditions of grafting, when employed to cotton swollen with sodium hydroxide and zinc chloride, enhanced the graft levels for both monomers. Grafted samples were subjected to thermal analysis, as well as estimation of moisture regain and tenacity. Thermal stability increased, whereas, the moisture regain and tenacity decreased, with the increase in graft add‐on in the case of both monomers. Acrylonitrile‐grafted cotton showed dyeability with cationic dye that improved with the level of graft add‐on. Possible explanations have been given.

Reacting Cotton Cellulose with Lignin-Based Polyurethane

Chain-extended lignin was reacted with blocked isocyanate and the product, lignin polyurethane (LPU), was subsequently applied by padding to cotton print cloth at three add-on levels: 1.70, 3.45, and 4.30%. Product syntheses and reactivity were followed by FTIR spectroscopy. LPU as a formaldehyde-free finish improved durable press (DP) and dimensional stability of the unfinished cloth, but the improvement was less than conventional amino resin finishes. Unlike conventional resin finishes, LPU showed strength and abrasion resistance retention. Abrasion resistance improved at the 3.5% add-on level. Grafting LPU onto cotton cloth is a surface reaction, given the molecular size of the product and detection by specular reflectance infrared spectroscopy. Even with the limited accessibility of the reactant groups in the unswollen cloth, a sufficient number of carbamoyl linkages formed to improve properties. Although DP ratings were not high, LPUs tailored by alkyloxyhydroxide chain extensions are likely resins for films, nonwoven consolidants, and composite materials, providing receptivity of cellulose to materials for which it has little affinity.

Mechanical and thermal behavior of cotton cellulose grafted with hydroxyethyl methacrylate using photoinitiation

AbstractThe textile properties of tensile strength and thermal decomposition of cotton cellulose grafted by photoinitiation technique using 2‐hydroxyethyl methacrylate monomer were studied. The photoinitiators, namely, uranyl nitrate (UN) and ceric ammonium nitrate (CAN), were used during grafting of unswollen and swollen cotton samples. The tensile strength decreased with increase in graft add‐on, whereas, the thermal stability was imparted to the grafted cotton according to the level of graft add‐on.