Quaternization/maleation of cornstarch to improve its adhesion and film properties for warp sizing

The aims of this work were to examine the influences of starch quaternization/maleation on the film properties and adhesion-to-fibers of starch, and also to reveal if the quaternization/maleation could improve the adhesion-to-fibers and film properties of starch. A series of quaternized and maleated cornstarch (QMS) with the total degree of substitution (DS) values of 0.02-0.061 were prepared via a quaternization of acid-thinned cornstarch with N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride for introducing 3-(trimethylammonium chloride)-2-hydroxypropyl (TACHP) substituents onto the backbones of starch, and a further maleation with maleic anhydride for the introduction of maleate substituents. The effects of starch quaternization/maleation on paste viscosity, paste stability, adhesion strengths to both cotton and viscose fibers, and film properties of starch were investigated. The degree of crystallinity of starch film was quantitatively obtained from X-ray diffraction analysis. It was found that the quaternization/maleation was able to stabilize the viscosity, increase adhesion strengths of starch to both cotton and viscose fibers, enhance breaking elongation, moisture regain, and bending endurance of starch film, and decrease tensile strength and degree of crystallinity of starch film, thereby improving the adhesion and displaying toughening effect to the film. Increasing the level of starch quaternization/maleation was capable of gradually increasing adhesion and toughness of the film. The quaternization/maleation with the DS values of 0.04-0.061 could be applied for the alleviation of the intrinsic drawbacks (insufficient adhesion and film brittleness) of cornstarch for warp sizing.     

Comparative study on sizing properties of amphoteric starch and phosphorylated starch for warp sizing

By varying the ratios of N-(3-chloro-2-hydroxypropl) trimethylammonium chloride and orthophosphate to starch, a series of amphoteric starch with different degree of substitution (DS) were prepared for evaluating sizing effect of amphoteric starch for cotton warps. The amphoteric starch contained quaternary ammonium and phosphate groups simultaneously, and was set to electric neutrality by varying relative quantity of anionic and cationic groups in order to prevent adverse effects of negative and positive charges. The influence of amphoteric modification of starch on the adhesion to cotton fibers was assessed by measuring tensile strength and work-to-break of slightly sized cotton roving and comparing the adhesion of amphoteric starch with those of phosphorylated one. Comparison on mechanical performances of amphoteric starch film over phosphorylated one was evaluated in terms of tensile strength, breaking extension and wear loss of starch film. The properties such as increase in tensile strength, loss in elasticity, abrasion resistance, and hairiness of cotton yarns sized with amphoteric starch were evaluated through control tests by the comparison with those of phosphorylated one. When zeta potential of amphoteric starch was set close to zero, the adhesion increased and the properties of sized yarns enhanced as the modification level increased. The amphoteric starch was evidently superior to phosphorylated one in improving the quality of sized cotton yarns. The amphoteric starch with neutral zeta potential and DS levels of 0.02–0.03 for quaternary ammonium groups and phosphate ones, respectively, could be applied to size cotton warp yarns for the improvement of yarn quality.     

Amphipathic Starch with Phosphate and Octenylsuccinate Substituents for Strong Adhesion to Cotton in Warp Sizing

The objectives of this work were to survey the effect of amphipathic modification of starch on the adhesion to cotton fibers for improving the adhesion of starch to cotton in warp sizing. The amphipathic starch (AS) with oleophilic octenylsuccinate and hydrophilic phosphate substituents was prepared by the phosphorylation with sodium tripolyphosphate (STP) followed by the octenylsuccinylation with 2-octenylsuccinic anhydride (OSA). Two series of AS samples with differential total degrees of substitution (DS_t) and substituent ratios of phosphates to octenylsuccinates were evaluated by fourier transform infrared (FTIR) analysis, degree of substitution, adhesion to cotton and surface tension. The adhesion of the starch to fibers was investigated using a legal method (FZ/T 15001-2008). The FTIR spectra revealed that octenylsuccinates and phosphates have been attached to the backbones of the starch. The amphipathic modification of starch with STP and OSA was an effective method to enhance the adhesion of corn starch to cotton. The strong adhesion of the AS to cotton was attributed to the reduced surface tension arisen from oleophilic octenylsuccinate and hydrophilic phosphate substituents and increased steric hindrance of the substituents introduced onto starch. The investigation showed that the improvement in the adhesion of the starch after amphipathic modification could be buttressed by the tensile strength of cotton yarns sized with AS. It was found that the AS was desizable and showed satisfactory desizing efficiency in oxidant desizing. Based on the adhesion, reaction efficiencies, and desizability, the AS with a total DS_t of 0.033 and a substituent ratio of DS_p0.014/DS_o0.032 showed potential for use in warp sizing.     

Performance of cotton fabric treated with an amino-terminated hyperbranched polymer

An amino-terminated hyperbranched polymer (HBP-NH₂), synthesized from methyl acrylate and diethylene tri-amine by polycondensation, was applied to treat cotton samples by a pad-dry-cure method. Physical properties, salt-free dye-ability, antimicrobial activity, and antiultraviolet property of the treated cotton samples were tested. The crystallinity and mechanical properties, including breaking strength, breaking elongation, and Young’s modulus of the treated cotton fibers, increased slightly in comparison with those of the untreated cotton fibers. The thermal stability and the moisture regain were also improved slightly. Dyed with direct dyes and reactive dyes in the absence of the electrolytes, the treated cotton fabric showed similar or higher color strength compared with the untreated cotton fabric in conventional dyeing. The treated cotton fabric can also be dyed with acid dyes effectively. In addition, the treated cotton fabric showed good antimicrobial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The study of the antiultraviolet properties of the treated cotton fabric indicated that the HBP-NH₂ contributed to the reduction of UV transmission and the increase of UPF.     

Environment-friendly crosslinking of cornstarch by pentanedioic acid for stabilizing the viscosity of starch paste during warp sizing

Acid-thinned cornstarch was crosslinked with pentanedioic acid to different degrees to enhance viscosity stability of cooked starch paste for replacing the currently used toxic crosslinking agents such as formaldehyde and epichlorohydrin in the preparation of starch sizing agents. The degree of crosslinking was determined according to the stability, adhesion-to-fibers, film properties, desizability, and aerobic biodegradation of crosslinked starch. The degree of crosslinking showed significant effects on the stability, adhesion, desizability, and film properties, but was less sensitive to the biodegradation and wear loss of starch film. Suitable degree of crosslinking resulted in stable viscosity, good adhesion to fibers, strong and bending resistant film, and better desizability. Low degree of crosslinking could be utilized to increase the stability and improve usability of the starch used as warp sizing agent. The degree of crosslinking range (902-477 anhydroglucose units per crosslink) was recommended to stabilize the viscosity of cooked starch paste and improve the sizing properties of starch sizing agents.     

Electroneutral cornstarch by quaternization and sulfosuccinylation to improve the adhesion of cold starch paste to raw cotton for low-temperature sizing

The objective of this research was to survey the effects of starch quaternization and sulfosuccinylation on the adhesion of cold starch paste to raw cotton fibers for cotton warp sizing at low temperature. Acid-thinned cornstarch (ATS) was quaternized and then sulfosuccinylated to introduce 3-(trimethylammonium chloride)-2-hydroxypropyl and sulfosuccinate substituents onto its backbones. The electroneutrality of starch samples prepared was achieved by maintaining a constant mole ratio (5.3:1) of the two substituents. A series of electroneutral cornstarch (ECS) samples with different levels of the substituents were derived by altering the feed ratio of the modifying reagents to starch for determining desirable level of starch modification. Adverse influences of cotton wax and starch retrogradation on the adhesion of cold starch paste to raw cotton fibers were evaluated to illustrate the effectiveness of starch quaternization and sulfosuccinylation. It was found that the modification was able to alleviate the adverse influence of starch retrogradation and ameliorate the adhesion to the fibers at low temperature. Higher level of the modification led to less retrogradation and resulted in strong adhesion. Furthermore, the adverse influence of cotton wax on the adhesion could be eliminated after a pre-wetting treatment of raw cotton warps with hot water. The adhesion of ECS paste to raw cotton at 60 °C was statically the same as that of ATS at 95 °C when total DS of ECS was 0.0443 or higher.     

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.     

Cutinase treatment of cotton fabrics

Our study proposes an enzymatic scouring method for cotton fabrics using the enzyme cutinase. We established cutinase treatment conditions for cotton fabrics from their relative activity at different pH levels, temperatures, enzyme concentrations, and treatment times. Weight loss, moisture regain, K/S value, tensile strength, and SEM micrographs of cotton fabrics were analyzed. We determined the optimum cutinase treatment conditions to be as follows: pH of 9.0, temperature of 50°C, cutinase concentration of 100 %, and a treatment duration time of 60 min. We discovered that this cutinase treatment hydrolyzed the cuticle of cotton fabrics. The cutinase treatment did not decrease the moisture regain and the K/S value. The optimum concentrations of Triton X-100 and calcium chloride, which were used as auxiliaries for cutinase treatment, were found to be 0.5 % (v/v) and 70 mM, respectively. Some cracks were observed on the surface of the cotton fibers; however, the tensile strength did not decrease.     

天然竹纤维与竹浆粘胶纤维的结构性能比较

竹纤雏有以竹材为原料制成浆粕，经纺丝加工而成的竹浆粘胶纤维；也有从竹材中以物理化学方法直接提取出的天然竹纤维，两种纤维因来源不同，故性能差异很大。本文对两种竹纤维的结构与性能进行了较全面的比较研究。研究结果表明：天然竹纤维具有优异的抗茵性能，夏季干爽舒适性好，热稳定性好，结构上属结晶度高、大分子排列紧密的典型的纤维素Ⅰ型结晶。竹浆粘胶纤维则由于纺丝过程而在性能上受到很大损伤，强力低、结晶度低、大分子排列较稀疏，回潮率高，属于与普通粘胶纤维相似的再生纤维素纤维。     

Fabrication and characterization of dense Chitosan/polyvinyl-alcohol/poly-lactic-acid blend membranes

Dense membranes of Chitosan (CS)/Poly(vinyl alcohol) (PVA)/Poly(lactic acid) (PLA) blend were successfully fabricated using casting technique. The mechanical properties, moisture regain and water vapor permeability of polymer blend membranes were estimated by tensile test, moisture regain rate and dish method test respectively. The microstructures, morphology, chemical composition and thermal properties were also characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) respectively. Results indicated that there were interactions and good compatibility among CS, PLA and PVA. And the blend membranes have good breaking elongation and slightly decreased breaking strength, and show best moisture regain at the case of CS60 (the content of CS in the blends is 60 %). They also have excellent porous structure, which is beneficial to their air permeability and may also contribute to cell regeneration. With the adding of PVA content, the melting peaks of blend membranes reduce and gradually close to that of PVA, demonstrating that the regularity of CS molecular chain may be destroyed and hydrogen bonds of macromolecules in polymers were newly formed. As a result, solution blending of the three polymers could complement their disadvantages and significantly improve the membrane performance of a single polymer, thus promote the mechanical and biological properties of blend membrane.     

Mechanical characterization of flocked fabric for automobile seat cover

In this study, the tensile and tearing properties of substrate, substrate with adhesive and flocked fabric were studied with developed regression model which explains the relationships between fabric forms and tensile and tearing strength of the flocked fabrics. Warp and weft tensile strengths of wet flocked fabric are generally higher than the warp and weft tensile strengths of dry flocked fabric due to the high wet properties of cotton yarn. Weft tensile elongation of the flocked fabric is generally higher than warp tensile elongation due to the higher crimp ratio of the flocked fabric in the weft direction. Warp and weft tearing strengths of wet form substrate with adhesive and flocked fabric are higher than those of dry forms of substrate with adhesive and flocked fabric. One of the reasons could be the decrease of inter-yarn frictional forces due to the lubrication effect of the wet form of acrylic adhesive in substrate with adhesive fabric. Generally, tearing strength of flocked fabric is low compared with substrate. It was concluded that the regression model used in this study could be viable and reliable tools and flocked fabric could be considered as an alternative seat cover material to use in automotive industry.     

Study on the effects of single fiber tensile properties on bundle tensile properties through estimation of HVI bundle modulus and toughness

The HVI properties and Mantis® single fiber tensile properties were analyzed to evaluate the relationship between fiber and bundle tensile properties. For this study, a new method has been developed for estimating the modulus and toughness of cotton fiber bundles directly from the HVI tenacity-elongation curves. The single fiber tensile properties were shown to be translated well into the bundle tensile properties. The single fiber breaking elongation was found to be the most significant contributing factor to bundle tensile properties. The bundle breaking elongation and toughness were shown to increase as the single fiber breaking elongation increased. The bundle modulus increased as the single fiber breaking elongation and/or standard deviation of single fiber breaking elongation decreased.     

Analysis and tensile characterization of air-entangled textured polyester woven fabrics depending on interlacement and yarn sets

The aim of this study was to understand the failure mechanism of two dimensional dry fabric structure considering yarn sets and interlacements. For this purpose, data generated on air-entangled textured polyester woven fabric under the simple tensile load and analyzed by developed regression model. The regression model showed that warp and weft directional tensile strengths of satin fabric were higher than those of plain and rib fabrics in unravel sample. This might be related to the number of interlacements of the fabrics. There was not a considerable difference between warp directional tensile strength of ravel and unravel satin fabrics, whereas weft directional tensile strength of ravel satin fabric decreased rapidly with respect to its unravel form. The satin fabric showed the highest warp directional tensile strength among the others. The lowest weft directional tensile strength was received from ribs fabric. In semi-ravel sample, all fabrics showed low warp and weft directional tensile strength values except in plain fabric. Warp directional tensile elongation of plain fabric was the highest in unravel sample. Satin fabric showed the highest warp directional tensile elongation in the ravel sample. Warp directional tensile elongations of all the fabrics in the semi-ravel sample became low. Weft directional tensile elongation of satin fabric was the highest in unravel sample. In addition, satin and plain fabrics showed the highest weft directional tensile elongations in the ravel sample. Weft directional tensile elongations of all the fabrics in the semi-ravel sample became low except in ribs fabric.     

Preparation and characterization of silk sericin/glycerol/graphene oxide nanocomposite film

Sericin (SS) is a protein that is secreted by silkworms, but it is usually discarded during the degumming process. To obtain and make use of the sericin, we prepared sericin/glycerol/graphene oxide nanocomposite film. The inherent brittleness of pure sericin film was improved by the addition of glycerol (Glc) as a plasticizer. To compensate for the reduced stiffness, we added graphene oxide (GO) into the SS/Glc film. At concentrations of up to 0.8 wt% relative to SS, GO dispersed evenly in the SS matrix without any agglomeration. The maximum tensile strength (9.5±0.7 MPa) and Young’s modulus (414.4±23.2 MPa) were obtained when the GO content was 0.8 wt% relative to SS. The elongation of SS/Glc/GO nanocomposite film also increased by approximately 40 % compared to SS/Glc film. The strong interfacial interaction between the SS and the GO was responsible for the increased stiffness. The increased elongation was due to the reduced crystallinity of the sericin matrix in the presence of GO.     

Sodium carboxylmethylate cellulose from date palm rachis as a sizing agent for cotton yarn

The chemical composition of date palm rachis wastes, which are widely available cellulosic biomass-based agricultural crops in Tunisia, were characterized to determine if they had the potential for use as a starting raw material to prepare cellulose derivatives. To accomplish this, several sodium cellulose carboxylmethylates (NaCMCs) were prepared and tested as sizing agents for coating yarn. The synthesis of NaCMC was conducted in n-butanol containing NaOH (40 %) as a solvent mixture and monochloroacetic acid (MAC) as the etherifying reagent. The NaCMC samples were characterized based on their degrees of substitution (DS) and polymerization (DP). The prepared NaCMC samples were then tested as sizing agents for cotton yarn in textile applications. Specifically, different NaCMC samples were used to prepare a coating bath, which was then applied to size a cotton yarn textile. The quality of the coated yarns was subsequently evaluated by determining three parameters, yarn hairiness, the load at break, and the elongation at break. The sizing performances of the NaCMCs prepared from date palm rachis wastes were then compared with those of commercial NaCMC. The values of hairiness, breaking load, and breaking elongation of some of the NaCMC-treated yarns were as high as those prepared using commercial additives as sizing agents. These findings indicate that the cellulose derivatives prepared in this study are good candidates for alternatives to currently available additives.     

Preparation and characterization of modified collagen/PAN blending fibers

Graft modification of collagen with acrylonitrile in concentrated aqueous solution of sodium thiocyanate (NaSCN) is developed in this paper. This modification can largely change it’s solubility in water and can be applied in fiber production. Grafting modified collagen is characterized by infrared spectrum and wide angle X-ray diffraction. Wet spinning of PAN fibers containing several content of modified collagen is performed. The tests about these fibers show that breaking strength and sonic orientation decrease as the amount of collagen is raised. The addition of collagen can largely improve the moisture regain of PAN fiber. Micro-appearance of fibers observed under scanning electron microscope (SEM) presents circular cross section and longitudinal grooves on surface, the depth of grooves increases with the increasing draw ratio.     

Improving the barrier and mechanical properties of corn starch-based edible films: Effect of citric acid and carboxymethyl cellulose

The films produced from pure starch are brittle and difficult to handle. Chemical modifications (e.g. cross-linking) and using a second biopolymer in the starch based composite have been studied as strategies to produce low water sensitive and relatively high strength starch based materials. A series of corn starch films with varying concentrations (0-20%, W/W) of citric acid (CA) and carboxymethyl cellulose (CMC) were produced by casting method. The effects of CA and CMC on the water vapor permeability (WVP), moisture absorption, solubility and tensile properties were investigated. The water vapor barrier property and the ultimate tensile strength (UTS) were improved significantly (p < 0.05) as the CA percentage increased from 0 to 10% (W/W). At the level of 15% (W/W) CMC, the starch films showed the lowest WVP values (2.34 × 10⁻⁷ g Pa⁻¹ h⁻¹ m⁻¹) and UTS increased from 6.57 MPa for the film without CMC to 16.11 MPa for that containing 20% CMC.     

Environmentally benign scouring of wool fibers using mesophile acidic lipase

Surfaces of raw wool fibers possess high amounts of greasy substances that need to be removed prior to further processing. Acidic lipases using Bacillus licheniformis (MTCC 2618) were produced with the optimum activity levels closer to the room temperature. Scouring of wool fibers using mesophile acidic lipase has been attempted, in the present work, as an alternative to the existing alkaline treatment and the samples were assessed in terms of weight loss, moisture regain, tenacity, elongation, surface appearance, and friction of the fibers. The lipase scoured wool fibers showed moisture regain and weight loss values comparable to that of alkaline treatment, with lower static and dynamic frictional coefficients. Higher tenacity and elongation values were observed in the lipase scoured fibers compared to the alkaline scoured samples and clear appearance of the surface, compared to the raw wool fibers, was also observed in the lipase scoured samples.     

Incorporation of aliphatic units into aromatic water-soluble polyesters to improve the performances for warp sizing

Aliphatic units (ethylene succinate) were incorporated into aromatic water-soluble polyesters (WSP) in order to improve their environmental protection and sizing performances. The environmental performance was measured in terms of biological oxygen demand for 5 days (BOD₅) and chemical oxygen demand (COD). Apparent and intrinsic viscosities, the adhesion to polyester fibers, glass transition temperature, and mechanical behavior of sizing films of WSP were evaluated for improving their sizing performance. The composition of copolymeric WSP was also investigated by ¹H-NMR. A series of copolymeric WSP with a variation in molar ratio of aliphatic monomer (dimethyl succinate) to aromatic monomer (dimethyl terephthalate) from 10:90 to 40:60 was synthesized through a two-step reaction, transesterification and polycondensation. It was found that, by incorporating aliphatic units into the macromolecular chain of aromatic WSP, the environmental performance, apparent and intrinsic viscosities, and the toughness of sizing film were enhanced obviously. The adhesion to polyester fibers showed no sensitivity to the molar ratio of dimethyl succinate to dimethyl terephthalate when the ratio ranged from 10:90 to 30:70. In view of overall performance of the aliphatic-containing WSP sizes, the molar ratio should be 30:70. Based on the ratio, the WSP prepared showed better environmental and sizing performances.     

Nano-TiO<Subscript>2</Subscript> based multilayer film deposition on cotton fabrics for UV-protection

Nano-TiO₂ based multilayer nanocomposite films were fabricated on cationically modified woven cotton fabrics by layer-by-layer molecular self-assembly technique. Cationization process was used to obtain cationic surface charge on cotton fabrics. Attenuated total reflectance Fourier transform infrared spectroscopy analyses were used to verify the presence of cationic surface charge and multilayer films deposited on the fabrics. Scanning electron microscope micrographs of poly(sodium 4-styrene sulfonate)/TiO₂, nano polyurethane/TiO₂, and TiO₂/poly(diallyldimethylammonium chloride) multilayer films deposited on cotton fabrics were taken. With nano-TiO₂ based multilayer film deposition, the protection of cotton fabrics against UV radiation is enhanced. The UV protection durability of the self-assembled multilayer films deposited on the cotton fabrics was analyzed after 10 and 20 washing cycles at 40 °C for 30 min. Air permeability and whiteness value analysis were performed on the untreated and multilayer film deposited cotton fabrics. The effect of layer-by-layer deposition process on tensile strength properties of the warp and weft yarns was determined.