Grafting polymerization of 2‐[3‐(2h‐benzotriazol‐2‐yl)‐4‐hydroxyphenyl]ethyl methacrylate on vinyltriethoxysilane‐treated cotton for the preparation of ultraviolet‐protective fabrics

Vinyltriethoxysilane was used to modify the surface of cotton to provide polymerizable vinyl groups on the fiber surface. An ultraviolet‐absorbing monomer, 2‐[3‐(2H‐benzotriazol‐2‐yl)‐4‐hydroxyphenyl]ethyl methacrylate, was polymerized on the vinyltriethoxysilane‐treated fabric to prepare ultraviolet‐protective cotton. The effects of the amounts of the solvent, silane coupling agent, and 2‐[3‐(2H‐benzotriazol‐2‐yl)‐4‐hydroxyphenyl]ethyl methacrylate on the surface morphology and ultraviolet‐protection factor of the treated cotton fabric were investigated. With a suitable process, poly{2‐[3‐(2H‐benzotriazol‐2‐yl)‐4‐hydroxyphenyl]ethyl methacrylate} was successfully coated onto the fabric, and it significantly reduced ultraviolet transmission through the fabric, resulting in a cotton fabric with excellent ultraviolet‐protection properties. The use of a silane coupling agent helped to ensure a polymer coating with good uniformity and good resistance to washing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Enhanced triolein removal using microemulsions formulated with mixed surfactants

In previous work, a microemulsion-based formulation approach yielded excellent laundry detergency with hydrophobic oily soils hexadecane and motor oil. In this work, the same approach is used in detergency of triolein, which is a model triglyceride, some of the most difficult oils to be removed from fabric. The linker concept was applied in formulation of the microemulsion system. Three different surfactants were used: (i) dihexyl sulfosuccinate, an ionic surfactant with a moderate hydrophile-lipophile balance (HLB); (ii) secondary alcohol ethoxylate, a lipophilic nonionic surfactant with a very low HLB; and (iii) alkyl diphenyl oxide disulfonate (ADPODS), a hydrophilic anionic surfactant with a very high HLB. The phase behavior and interfacial tension (IFT) of the surfactant systems were determined with different concentrations of ADPODS. The results indicate that as the HLB of the system increases, a higher salinity is required to shift the phase transition from Winsor Type I to Type III to Type II. The three formulations at different salinities were used in detergency experiments to remove triolein from polyester/cotton sample fabric. The results showed that there were two peaks of maximum detergency in the range of salinity from 0.1% to 10% NaCl. The higher the hydrophilicity of the system, the higher the salinity required for maximum detergency. The results of the dynamic IFT and the detergency performance from two rinsing methods lead to the hypothesis that one of these maxima in detergency results from a spreading or wetting effect. The other maximum in detergency is believed to be related to ultralow IFT associated with oil/water middle-phase microemulsion formation. Triolein removal exceeding 80% was attained, validating the microemulsion approach to detergency.     

Effect of fiber surface modification on the mechanical properties of sisal fiber‐reinforced benzoxazine/epoxy composites based on aliphatic diamine benzoxazine

Sisal fibers were incorporated into a mixture of benzoxazine and bisphenol A type epoxy resins to form a unidirectionally reinforced composite. Surface modifications of the sisal fibers were carried out with sodium hydroxide, γ‐aminopropyltrimethoxysilane, and γ‐glycidoxypropyltrimethoxysilane. The surface treatments led to changes in the morphology, chemical groups, and hydrophilicity of the fibers. The effect of the fiber surface treatments on the fiber–matrix interfacial adhesion and mechanical properties of the composites were also studied. The results showed that surface treatments with sodium hydroxide and a silane coupling agent led to improved fiber–matrix adhesion; this could be seen in the scanning electron micrographs of the fractured surfaces from mechanical testing and the reduction in the impact strength of the composites made from treated fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Resistivity of conductive polymer–coated fabric

Preparation of conductive polymer–coated fabrics was carried out by admicellar polymerization. By this method, a thin layer of conductive polymers (polypyrrole, polyaniline, and polythiophene) was formed on cotton and polyester fabrics by a surfactant template. The effects of monomer concentration, oxidant to monomer ratio, and addition of salt on the resistivity of the resulting fabrics were studied. The results showed that the apparent surface and volume resistivity decreased with an increase in monomer concentration in the range 5–15 mM, but was not strongly dependent on the oxidant to monomer ratio over the range of 1 : 1 to 2 : 1. Addition of 0.5M salt was found to reduce the resistivity significantly. The lowest resistivity obtained was with polypyrrole‐coated fabric, with resistivity around 10⁶ ohm. SEM micrographs of the treated fabric surface showed a filmlike polymer coating, confirming that the fabrics were successfully coated by admicellar polymerization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2629–2636, 2004     

Improvement in the flame retardancy of cotton fabric by admicellar polymerization of 2‐acryloyloxyethyl diethyl phosphate using an anionic surfactant

The phosphorus‐containing acrylate monomer, 2‐acryloyloxyethyl diethyl phosphate (ADEP), was synthesized and applied to cotton fabric by using admicellar polymerization. Sodium dodecylbenzene sulfonate was used as the anionic surfactant. The film of polymerized monomer (PADEP) formed on the cotton surface was characterized by FTIR‐ATR spectroscopy and SEM. Thermal and flame retardant properties of PADEP‐coated cotton were investigated by TGA and flammability tests. Results showed that PADEP polymer film was successfully formed on the cotton fabric. The TGA and DTG analyses showed that the phosphorus‐containing PADEP lowered the decomposition temperature of the treated fabric resulting in a higher char yield than in the case of untreated cotton. The flammability tests showed that the treated cotton had much improved flame retardancy property after the treatment. The treated fabric also retained its good pliability and soft touch with good air permeability. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Resin transfer molding of natural fiber reinforced polybenzoxazine composities

Kenaf fiber is incorporated in a polybenzoxazine (PBZX) resin matrix to form a unidirectionally reinforced composite containing 20 wt% fiber by a resin transfer molding technique. Two types of benzoxazine monomer are synthesized and used as resin mixtures: Benzozazines based on bisphenol‐A/aniline (BA‐a) and phenol/aniline (Ph‐a). The effects of varying BA‐a:Ph‐a ratio in the resin mixture and curing conditions on mechanical properties of pure PBZX resin and kenaf/PBZX composites are studies. The Flexural strength of the pure PBZX resin increases with increasing ratio of BA‐a:Ph‐a, curing temperature and curing time, but the impact strength increases only slightly. PBZX resin has lower water absorption and higher flexural modulus, when compared with unsaturated polyester (UPE) resin. PBZX composites with 20 wt% fiber content have lower flexural and impact strengths, but higher moduli compared with UPE composites with the same fiber content.     

Microemulsion formation and detergency with oily soils: III. Performance and mechanisms

The objective of this study was to investigate the correlation between oily soil removal efficiency and low oil-water interfacial tension (IFT) generated by microemulsion formation. A mixture of sodium dioctyl sulfosuccinate, alkyl diphenyl oxide disulfonate, and sorbitan monooleate was selected as a detergent formulation to evaluate detergency performance for two highly hydrophobic oils: hexadecane and motor oil. The maximum detergency corresponds to formation of a Winsor Type III microemulsion as well as to the supersolubilization region, which is a Winsor Type I microemulsion close to the Winsor Type III region. In addition, the oil removal in the rinse step is almost as high as that in the wash step for both regions. We propose the following mechanism to explain these results: During the wash step, the contact angle of the oil on the fabric surface is progressively increased, resulting in the detachment of the oil droplets. However, owing to the very low IFT, the spreading effect is dominant, thereby causing incomplete oil removal. During the subsequent rinse step, the IFT increases, passing through a composition at which the rollup mechanism causes additional oil removal. These results demonstrate that microemulsion formation and the resulting IFT reduction are important mechanisms in oily soil detergency.     

Mechanism of antifoam behavior of solutions of nonionic surfactants above the cloud point

Aqueous solutions of nonionic surfactants exhibit low foaming above their cloud point, a temperature above which the homogeneous solutions separates into two phases: a dilute phase containing a low surfactant concentration and coacervate phase containing a very high surfactant concentration (e.g., 20 wt% surfactant). In this work, foam formation was measured for the dilute phase, the coacervate, and the mixed solution using the Ross-Miles method for nonylphenol polyethoxylates with 8, 9, or 10 ethylene oxide moieties per molecule. The dilute phase showed no antifoam effect above the cloud point if the coacervate phase was not present, and the coacervate phase foamed little in the absence of the dilute phase. The coacervate phase acts as an oil droplet antifoam to the dilute phase. From surface and interfacial tension data, entering, spreading, and bridging coefficients for this system make it appear probable that the coacervate phase is forming bridges across the film lamellae of the dilute-phase foam and acting to suppress foam formation through the bridging mechanism.     

Effective surface treatments for enhancing the thermal conductivity of BN‐filled epoxy composite

To improve the thermal conductivity of BN‐filled epoxy composite, admicellar polymerization was used to coat polystyrene and polymethyl methacrylate on the BN surface to improve the interfacial adhesion in the composite. The treated surface was characterized by FTIR and contact angle measurements. The results show that the admicellar treatment led to improved wettability of epoxy resin on the treated surface. Thermal conductivity of the composite increased from 1.5 W/mK for untreated BN to 2.69 W/mK when the admicellar‐treated BN was used, indicating improvement in the interfacial adhesion between BN and epoxy resin in the composite. The mechanical properties of the composite also improved significantly. The surfactant : monomer molar ratio of 1 : 10 was found to be the optimum condition for the admicellar polymerization process. The solubility parameter concept was used to explain the difference in the effectiveness of polystyrene and polymethyl methacrylate. When compared to the more conventional silane treatment, admicellar treatment was found to be more effective in improving the interfacial adhesion between the BN particles and epoxy resin. SEM micrographs of the fractured surface of the composite further confirm the improvement in the interfacial adhesion after the admicellar treatment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical property improvement of unsaturated polyester composite reinforced with admicellar-treated sisal fibers

Sisal fiber was treated by admicellar polymerization with a poly(methyl methacrylate) film coating in order to enhance the interfacial adhesion of the fiber/polymer composite for mechanical property improvement. Properties of the admicellar-treated sisal fiber were investigated by measuring its moisture absorption and electrostatic charge. Thermal stability study by thermogravimetric analysis and film identification by FTIR was also carried out. The treatment was shown to improve the tensile and flexural properties, impact strength, and hardness of the composite. SEM micrographs of the tensile fracture surface of sisal/unsaturated polyester composites also show interfacial adhesion improvement of the composite prepared with admicellar-treated sisal.