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Water Resistance (water + resistance)
Selected AbstractsProcessing of urea-formaldehyde-based particleboard from hazelnut shell and improvement of its fire and water resistanceFIRE AND MATERIALS, Issue 8 2009M. Gürü Abstract The purpose of this study was to manufacture urea-formaldehyde-based particleboard from hazelnut shell and eliminate its disadvantages such as flammability, water absorption, swelling thickness by using fly ash and phenol-formaldehyde. Synthesized urea-formaldehyde and grained hazelnut shells were blended at different ratios ranging from 0.8 to 3.2 hazelnut shell/urea-formaldehyde and dried at 70°C in an oven until constant weight was reached. In addition, other parameters affecting polymer composite particleboard from hazelnut shell and urea-formaldehyde were investigated to be the amount of fly ash, amount of phenol formaldehyde and the effects of these parameters on bending stress, limit oxygen index, water absorption capacity and swelling in the thickness. The optimization results showed that the maximum bending strength was 4.1N/mm2, at urea-formaldehyde ratio of 1.0, reaction temperature of 70°C, reaction time of 25,min, hazelnut shell/urea-formaldehyde resin of 2.4 and mean particle size of 0.1,mm. Although the limited oxygen index and smoke density of composite particleboard without fly ash has 22.3 and 1.62, with fly ash of 16% (w/w) according to the filler has 38.2 and 1.47, respectively. Water absorption and increase in the swelling thickness exponentially decreased with increasing phenol formaldehyde. Copyright © 2009 John Wiley & Sons, Ltd. [source] A Simple, One-Step Approach to Durable and Robust Superhydrophobic Textiles,ADVANCED FUNCTIONAL MATERIALS, Issue 22 2008Jan Zimmermann Abstract Superhydrophobic textile fabrics are prepared by a simple, one-step gas phase coating procedure by which a layer of polymethylsilsesquioxane nanofilaments is grown onto the individual textile fibers. A total of 11 textile fabrics made from natural and man made fibers are successfully coated and their superhydrophobic properties evaluated by the water shedding angle technique. A thorough investigation of the commercially relevant poly(ethylene terephthalate) fabric reveals an unparalleled long-term water resistance and stability of the superhydrophobic effect. Because of the special surface geometry generated by the nanoscopic, fibrous coating on the microscopic, fibrous textiles, the coated fabric remains completely dry even after two months of full immersion in water and stays superhydrophobic even after continuous rubbing with a skin simulating friction partner under significant load. Furthermore, important textile parameters such as tensile strength, color, and haptics are unaffected by the silicone nanofilament coating. For the first time, an in-depth characterization of the wetting properties, beyond simple contact angle measurements, as well as a thorough evaluation of the most important textile parameters is performed on a superhydrophobic fabric, which reveals a true potential for application. [source] Creating Hierarchical Structures in Renewable Composites by Attaching Bacterial Cellulose onto Sisal Fibers,ADVANCED MATERIALS, Issue 16 2008Julasak Juntaro The growth of bacterial-cellulose nanofibrils on the surfaces of micrometer-scale natural fibers provides a route to a new class of hierarchical, renewable, degradable composites. The nanofibrils improve the interaction between the primary fibers and the matrix, leading to improved mechanical properties and water resistance. [source] Microencapsulation of hydrophilic solid powder as fire retardant agent with epoxy resin by droplet coalescence methodJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Masanori Takahashi Abstract To give water resistance to Bistetrazol,diammonium (BHT,2NH3) as a fire retardant agent, microencapsulation with epoxy resin was tried by the droplet coalescence method. In this method, two kinds of epoxy resin droplets were prepared; one is the larger epoxy resin droplet containing BHT,2NH3 as a core material and the other the smaller droplets containing Imidazole as a gelation agent. The larger epoxy resin droplets were made to coalesce with the many smaller droplets during the microencapsulation process to prepare microcapsules. In the experiment, the agitation velocities for preparation of the droplets and for coalescence were mainly changed. With increase in the impeller speed, the content of core material increased, became maximum because of increase in the coalescence frequency, and then decreased because of breakup of droplets. With increase in the impeller speed, the leakage ratio of core material decreased, became minimum, and then increased. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008. [source] Rheological and curing behavior of aqueous ambient self-crosslinkable polyacrylate emulsionJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Xiaohua Liu Abstract An aqueous ambient crosslinkable polymer acrylic (AACPA) emulsion was obtained by adding adipic acid dihydrazide (ADH) to the polyacrylate emulsion incorporating diacetone acrylamide (DAAM), and this emulsion was synthesized by two feeding materials methods. The AACPA emulsion and its paint film were characterized with rheological measurements, laser light scattering, Fourier transform infrared, torsional braid analysis (TBA), DTA, and so on. The results showed that AACPA emulsion was pseudoplastic fluid and pseudoplasticity increased with increasing of DAAM content. The results also showed that water resistance, solvent resistance, and thermotacky temperature of AACPA paint film increased with increasing of the content of DAAM. The results dealing with curing behavior of the paint film showed that adding organic swelling solvent and organic acid to the AACPA emulsion can accelerate the curing speed of the paint film. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Properties of Poly(lactide)-Coated Paperboard for the Use of 1-Way Paper CupJOURNAL OF FOOD SCIENCE, Issue 2 2009J.-W. Rhim ABSTRACT:, Poly(lactide)-coated paperboards were prepared by a solution coating method, and the effect of coating to improve properties of paperboard used for the manufacturing of 1-way paper cups was tested. Surface of PLA-coated paperboards was smooth and shiny like PE-coated paperboard, and the coating weight and thickness increased linearly with increasing PLA concentration of coating solution. Tensile strength (TS) and elongation at break (E) of the paperboard also increased after PLA coating. Water vapor barrier or water-resistant properties tested, such as water vapor permeability (WVP), water absorptiveness (WA), and contact angle (CA) of water drop, indicated that water resistance of the paperboard was improved through surface coating with PLA. The increase in water resistance of PLA-coated paperboards was mainly due to the hydrophobicity of PLA and the improvement of water barrier properties increased depending on the PLA concentration. In addition, PLA-coated paperboard showed strong heat sealing property when coated with more than 1 w/v% of PLA. Wet strength of PLA-coated (3, w/v%) paperboard was comparable to or greater than that of PE-coated paperboard. All the test results indicated that the PLA-coated paperboard can be exploited for the manufacturing of 1-way paper cups as an alternative to the PE-coated paperboard. [source] Water-resistant conducting hybrids from electrostatic interactionsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2007Jing Luo Abstract Conductive hybrids were prepared in a water/ethanol solution via the sol,gel process from an inorganic sol containing carboxyl groups and water-borne conductive polyaniline (cPANI). The inorganic sol was prepared by the hydrolysis and condensation of methyltriethoxysilane with the condensed product of maleic anhydride and aminopropyltriethoxysilane as a catalyst, for which the carboxyl counterion along the cPANI backbone acted as an electrostatic-interaction moiety. The existence of this electrostatic interaction could improve the compatibility of the two components and contribute to the homogeneous dispersion of cPANI in the silica phase. The electrostatic-interaction hybrids displayed a conductivity percolation threshold as low as 1.1 wt % polyaniline in an emeraldine base, showing 2 orders of magnitude higher electrical conductivity than that without electrostatic interactions. The electrostatic-interaction hybrids also showed good water resistance; the electrical conductivity with a cPANI loading of 16 wt % underwent a slight change after 14 days of soaking in water. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1424,1431, 2007 [source] Development of Gelatin Hydrogel Pads as Antibacterial Wound DressingsMACROMOLECULAR BIOSCIENCE, Issue 10 2009Vichayarat Rattanaruengsrikul Abstract Gelatin hydrogel pads have been prepared from a 10,wt.-% gelatin solution that contained 2.5,wt.-% AgNO3 in 70% v/v acetic acid by a solvent-casting technique. The AgNO3 -containing gelatin solution was aged under mechanical stirring for various time intervals to allow for the formation of silver nanoparticles (nAgs). The formation of nAgs was monitored by a UV-vis spectrophotometer. The morphology and size of the nAgs were characterized by transmission electron microscopy (TEM). To improve the water resistance of the hydrogels, various contents of glutaraldehyde (GTA) were added to the AgNO3 -containing gelatin solution to cross-link the obtained gelatin hydrogels. These hydrogels were tested for their water retention and weight loss behavior, release characteristics of the as-loaded silver, and antibacterial activity against Gram-negative Escherichiacoli and Gram-positive Staphylococcusaureus. The AgNO3 -containing gelatin solution that had been aged for 5 d showed the greatest number of nAgs formed. The size of these particles, based on TEM results, was 10,11,nm. With an increase in the GTA content used to cross-link the hydrogels, the water retention, the weight loss, and the cumulative amount of silver released were found to decrease. Finally, all of the nAg-loaded gelatin hydrogels could inhibit the growth of the tested pathogens, which confirmed their applicability as antibacterial wound dressings. [source] Core-Shell Nanoblends from Soy Protein/Polystyrene by Emulsion PolymerizationMACROMOLECULAR MATERIALS & ENGINEERING, Issue 8 2008Dagang Liu Abstract Novel soy protein/polystyrene nanoblends with core-shell structures were successfully prepared by introducing nano-sized PS into soy protein through emulsion polymerization. The nanoblends showed core-shell structures, with the core being of PS and the shell of sodium dodecane sulfonate and soy protein polypeptides, when investigated by electron microscopy. Nanoblends containing high levels of PS (>30%) exhibited characteristic infrared spectrum bands, X-ray diffraction peak, and glass transition, since PS microsphere aggregated to form independent PS domains. Mechanical strength and water resistance were effectively improved by introducing PS. An effective structure-performance relationship was thereby established to describe the nanoblends. [source] Properties and interfacial bonding for regenerated cellulose,polyurethane/amylose acetate sipn composite filmsPOLYMER COMPOSITES, Issue 6 2000Jiahui Yu Composite films were obtained by placing a polyurethane/amylose acetate semi-interpenetrating polymer network (SIPN) coating onto the surfaces of regenerated cellulose (RC) film. The properties of the composite film, such as tensile strength, 79.9 MPa (in dry state), 49.5 MPa (in wet state), water resistance (R), 0.62, dimensional stability (Sc), 3.0%, and water vapor permeability (P), 5.96 × 10,5 Kgm,2h,1, are better than those of the uncoated RC film or RC film with PU coating. The interfacial strength was characterized with infrared spectroscopy (IR), ultraviolet spectroscopy (UV), transmission electron microscopy (TEM), and electron probe microanalysis (EPMA). The results showed the existence of covalent and hydrogen bonds between the SIPN coat layer and the RC layer. It was also found that the PU prepolymer in the coating layer penetrated into the cellulose bulk, and reacted with the cellulose molecules, which formed another SIPN. [source] Study on flame retardance of co-microencapsulated ammonium polyphosphate and dipentaerythritol in polypropylenePOLYMER ENGINEERING & SCIENCE, Issue 12 2008Zhengzhou Wang Co-microencapsulated ammonium polyphosphate and dipentaerythritol [M(A&D)] was prepared using a melamine-formaldehyde (MF) resin by in situ polymerization method, and characterized by XPS. The co-microencapsulation of ammonium polyphosphate and dipentaerythritol (DPER) leads to a great improvement in water solubility of the additives. The flame retardant effect of M(A&D) in polypropylene (PP) is evaluated using limiting oxygen index (LOI) and UL 94 test, and the water resistance of the PP/M(A&D) composites is also studied. The flame retardant properties and water resistance of the PP/M(A&D) composites are much better than the ones of the PP/APP/DPER composites. Moreover, the thermal stability of the PP/M(A&D) composites is improved compared with the PP/APP/DPER composites. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] Effects of particle size of Al(OH)3 on electrical properties of EPDM compoundsPOLYMER ENGINEERING & SCIENCE, Issue 4 2000Cheol Ho Lee Effects of particle size of Al(OH)3 (ATH) filler on electrical properties of ethylene propylene diene terpolymer (EPDM)/ATH compounds were studied. It was found that tracking and erosion resistance of EPDM/ATH compounds decreased while dielectric properties and 90°C water resistance were improved with the increase of particle size. Homocharge accumulates in the compounds, which increases first and then decreases with the increase of particle size. This was explained by the change of particle-to-particle distance due to filler size. [source] Synthesis, characterization and properties of organoclay-modified polyurethane/epoxy interpenetrating polymer network nanocompositesPOLYMER INTERNATIONAL, Issue 3 2006Qingming Jia Abstract organoclay-modified polyurethane/epoxy interpenetrating network nanocomposites (oM-PU/EP nanocomposites) were prepared by adding organophilic montmorillonite (oMMT) to interpenetrating polymer networks (IPNs) of polyurethane and epoxy resin (PU/EP) which had been prepared by a sequential polymerization technique. Wide-angle X-ray diffraction (WAXD) and transmission electronic microscopy (TEM) analysis showed that the interpenetrating process of PU and EP improved the exfoliation and dispersion degree of oMMT. The effects of the NCO/OH ratio (isocyanate index), the weight ratio of PU/EP and oMMT content on the phase structure and the mechanical properties of the oM-PU/EP nanocomposites were studied by tensile testing and scanning electronic microscopy (SEM). Water absorption tests showed that the PU/EP interpenetrating networks and oMMT had synergistic effects on improvement in the water resistance of the oM-PU/EP nanocomposites. Differential scanning calorimetry (DSC) analysis showed that PU was compatible with EP and that the glass transition temperature (Tg) of the oM-PU/EP nanocomposites increased with the oMMT content up to 3 wt%, and then decreased with further increasing oMMT content. The thermal stability of these nanocomposites with various oMMT contents was studied by thermogravimetric analysis (TGA), and the mechanism of thermal stability improvement was discussed according to the experimental results. Copyright © 2005 Society of Chemical Industry [source] Microencapsulated ammonium polyphosphate with polyurethane shell: preparation, characterization, and its flame retardance in polyurethanePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2010Jianxiong Ni Abstract A series of polyurethane (PU) microencapsulated ammonium polyphosphate (MCAPP) were prepared by in situ polymerization from toluene-2,4-diisocyanate (TDI), polyethylene glycol (PEG), and pentaerythtritol (PER). And the structure was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Then it chose the optimal PEG constituent to design microcapsule from scanning electron microscopy (SEM) and water solubility test. The combustion and thermal degradation behaviors of PU blended APP or MCAPP were investigated by thermogravimetric analysis (TGA), UL-94 test, and microcombustion calorimetry. The results showed that the PU/MCAPP had better thermal stability and flame retardance, due to the stable char forming by APP and PU shell. Moreover, the water resistance of flame retarded PU composite was greatly improved. Copyright © 2009 John Wiley & Sons, Ltd. [source] A novel organic rectorite modified bismaleimide/diallylbisphenol A systemPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11 2009Li Yuan Abstract 4,4,-Bismaleimidodiphenylmethane (BMIPM)/O,O,-diallylbisphenol A (BA) system was modified by organic rectorite (OREC) to develop a novel BMI/BA/OREC nanocomposite. The effect of OREC on the viscosity and reactivity of BMIPM/BA system was investigated. The mechanical properties of BMIPM/BA/OREC composites such as the flexural and impact strength were evaluated. The morphology of cured BMIPM/BA/OREC systems was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The hot water resistance of BMIPM/BA/OREC systems was discussed. The thermal property of BMIPM/BA/OREC systems was investigated using thermogravimetric analysis (TGA). The dynamic mechanical properties of BMIPM/BA/OREC systems were also measured. Results show that the addition of OREC has a significant influence on the reactivity of the BMIPM/BA system. Proper content of OREC can improve the flexural strength, impact strength, and hot water resistance of a BMIPM/BA system. The addition of OREC cannot decrease the thermal degradation temperature of cured BMIPM/BA system with a slight sacrifice of the glass transition temperature (Tg). Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||