Showing papers on "Chemical resistance published in 2010"

Sisal/Carbon Fibre Reinforced Hybrid Composites: Tensile, Flexural and Chemical Resistance Properties

Abstract: The variation of mechanical properties such as tensile and flexural properties of randomly oriented unsaturated polyester based sisal/carbon fibre reinforced hybrid composites with different fibre weight ratios have been studied. The chemical resistance test of these hybrid composites to various solvents, acids and alkalies were studied. The effect of NaOH treatment of sisal fibres on the tensile, flexural and chemical resistance properties of these sisal/carbon hybrid composites has also been studied. The hybrid composites showed an increase in tensile and flexural properties with increase in the carbon fibre loading. The tensile properties and flexural properties of these hybrid composites have been found to be higher than that of the matrix. Significant improvement in tensile properties and flexural properties of the sisal/carbon hybrid composites has been observed by alkali treatment. The chemical resistance test results showed that these untreated and alkali treated hybrid composites are resistance to all chemicals except carbon tetra chloride. Hand lay-up technique was used for making the composites and tests are carried out by using ASTM methods.

Frictional Coefficient, Hardness, Impact Strength, and Chemical Resistance of Reinforced Sisal-Glass Fiber Epoxy Hybrid Composites

Abstract: In this article, the epoxy-based hybrid composites were developed by combining the sisal and glass fibers into epoxy matrix. Hardness, impact strength, frictional coefficient, and chemical resistance of hybrid composites with and without alkali treatments were studied. Variation of the aforementioned mechanical proper- ties and chemical resistance was studied with different fiber lengths such as 1, 2, and 3 cm. A 9 vol.% of the sisal and glass fibers was reinforced into the epoxy matrix. The aforementioned mechanical properties were optimally improved at 2-cm fiber length when compared with 1 and 3 cm fiber lengths. Chemical resistance was also significantly improved for all chemicals except sodium carbonates and toluene.

Chemical Resistance Studies of Silk/Sisal Fiber-Reinforced Unsaturated Polyester-Based Hybrid Composites

Abstract: The natural fiber environmental friendly composites of untreated and alkali treated silk-sisal unsaturated polyester-based hybrid composites were prepared by using hand lay-up technique. The fiber length was taken as 2 cm and the sisal fibers were treated with 2% NaOH. The chemical resistance of the treated and untreated silk/sisal hybrid composites to various acids, alkalis, and solvents was studied. The chemical resistance tests of these hybrid composites were performed in order to find out whether these composites can be used for manufacturing products that are resistant to chemicals.

Chemical Resistance and Tensile Properties of Glass and Bamboo Fibers Reinforced Polyester Hybrid Composites

Abstract: The chemical resistance of the glass/bamboo fibers reinforced polyester composites to acetic acid, sodium hydroxide, ammonium hydroxide, sodium carbonates, benzene, toluene, carbon tetrachloride, and water was studied. The hybrid fiber composites showed better resistance to these chemicals. Besides this, the tensile properties of glass/bamboo fibers reinforced polyester hybrid composites were studied. The effect of alkali treatment of the bamboo fibers on these properties was also studied. It was observed that tensile properties of the hybrid composites increased with glass fiber content. These properties were found to be higher when alkali treated bamboo fibers were used in the hybrid composites. The elimination of amorphous hemi-cellulose with alkali treatment leading to higher crystallinity of the bamboo fibers may be responsible for these observations.

Physico-chemical and mechanical characterization of natural fibre reinforced polymer composites

Abstract: Polymer biocomposites based on resorcinol-formaldehyde resin matrix, reinforced with pine needles were fabricated by compression moulding technique and further developed in our laboratory. Mechanical properties such as flexural strength, tensile strength, compressive strength and wear resistance of pine needlesreinforced phenolic resin matrix based composites were evaluated to assess the prospect of using the lignocellulosic fibres as a new environmental friendly material in engineering applications. The addition of pine needles into the polymeric matrix promotes a significant improvement in the composite properties. Effect of fibre dimension on mechanical properties was evaluated. It has been observed that polymer composites obtained by particle reinforcement exhibit better mechanical properties as compared to short and long fibre reinforcement. Morphological and thermal properties of the polymer matrix and fibre reinforced green composites have also been studied. In case of morphological features, the results clearly show that when polymer resin matrix is reinforced with fibres of different dimensions, morphological changes take place depending on the fibres' dimension. In case of thermal behaviour, the results obtained clearly indicate that the presence of lignocellulosic pine needles affects the thermal stability of polymer matrix. The values of initial decomposition temperature and final decomposition temperature for polymer composite have been found to be in between those of matrix and the fibre which indicate that the composite is slightly less stable thermally as compared to resin matrix. These composites were further subjected to identical characterization tests such as swelling under different solvents, moisture absorption and chemical resistance analysis, etc. It has been observed that particle reinforced composites exhibit higher resistance to swelling, moisture absorption and chemical resistance behaviour.

Characterization of polydimethylsiloxane–polyurethanes synthesized by graft or block copolymerizations

Abstract: We synthesized polydimethylsiloxane–polyurethane dispersions modified with graft copolymerization (PDMS-G-PUDs) and polydimethylsiloxane–polyurethane dispersions modified with block copolymerization (PDMS-B-PUDs). We systematically investigated the effects of PDMS’s structure, content, and molecular weight on properties of copolymer including viscosity, particle size, and stability of dispersions as well as the properties of the film formed by dispersions including gloss, contact angle, water resistance, oil resistance, and mechanical properties. The results demonstrated that the viscosity, particle size, water resistance increased but gloss decreased with the increase of PDMS content and molecular weight. In addition, we compared the properties of PDMS-B-PUD films and PDMS-G-PUD films with the same amount of PDMS and similar molecular weight. PDMS-G-PUD films showed higher water and oil resistance, but lower gloss and poorer mechanical properties. Scanning electron microscopy–energy dispersive spectroscopy analysis (SEM–EDS) indicated that the films of PDMS-G-PUD had better microphase separation and PDMS surface enrichment.

Halogen-free flame resistance resin composite and prepreg, laminate and laminate for printed circuit prepared from same

Abstract: The invention provides a halogen-free flame resistance resin composite and a prepreg, a laminate and a laminate for printed circuits prepared from same. The halogen-free flame resistance resin composite comprises the following components in parts by weight: 40-80 parts of a mixture (A) which contains phenoxyphosphazene compound (A1) and compound (A2) containing dihydrobenzoxazine in a weight ratioof 1:10-1:2, 15-45 parts of polyepoxy compound (B), 5-25 parts of phenolic resin curing agent (C) and 0.1-1 part of imidazole compound used as curing accelerator. The prepreg, the laminate and the laminate for printed circuits prepared from he halogen-free flame resistance resin composite provided by the invention have excellent flame resistance, high glass-transition temperature Tg, heat resistance, bending strength and reliability, low dielectric loss, hygroscopicity and C.T.E and good chemical resistance and mechanical processing performance.

Development of a high performance hybrid epoxy silicone resin for coatings

Abstract: Purpose – The purpose of this paper is to develop a novel organic‐inorganic (epoxy‐silicone) hybrid resin for application in heat resistant surface coatings.Design/methodology/approach – Thermally stable aminosilicone resin was prepared by using diethoxydimethyl silane and γ‐aminopropyldiethoxy methyl silane.Findings – The hybrid epoxy silicone resin shows significant properties such as toughness, chemical resistance and thermal stability.Research limitations/implications – The prepared amino siloxane was cured by commercially available epoxy resin PG 100 and toluene diisocyanate in different ratios at high as well as at room temperature to develop high‐temperature vulcanisation and room temperature vulcanisation resin systems.Practical implications – The hybrid epoxy silicone resin may be used as heat resistant coatings due to their low shrinkage and lesser internal stress.Originality/value – The developed hybrid epoxy silicone resin was novel for application in thermally stable coatings.

Chromate-free black coated metal plate

Abstract: An inexpensive chromate-free black metal sheet not containing the high environmental load hexavalent chromium and extremely excellent in finish (coloring power and concealing power including worked parts), moisture resistance, corrosion resistance, formability, scratch resistance, chemical resistance, etc. The present invention is a chromate-free black-coated metal plate characterized by comprising a metal sheet on at least one surface of which is formed a black coating (α), containing a polyester resin (A1) containing sulfonic acid groups cured by a curing agent (B) and carbon black (C), of a thickness of 2 to 10 μm.

Influence of artificial body fluids and medical sterilization procedures on chemical stability of Parylene C

Abstract: Among materials suitable for flexible encapsulation poly-para-xylylene (Parylene C), often chosen as protective coating for biomedical devices and variety of anticorrosion applications due to its favorable chemical and biological resistance, high thermal stability, low water vapor absorption, permeability, high biocompatibility as well as excellent dielectric and mechanical properties, is one of the most promising. In spite of a wide use only few systematic studies on biological and chemical stability of Parylene C have been carried out. In this work the influence of autoclave, electron beam (e-beam), gamma, ethylene oxide (EtO) and H 2 O 2 -plasma sterilization procedures as well as influence of in-vitro dynamic loading with artificial blood plasma (ABP) and cerebrospinal fluid (ASCF) and 0.9 % NaCl on chemical resistance and crystallinity of Parylene C were studied by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The samples, treated with e-beam sterilization, show substantial changes in their chemical content comparing to the untreated state. The XPS-analysis revealed the intrusion of CH- and CN-groups into the polymer structure and formation of inorganic chlorides on the surface of Parylene C. The second effect was also present in the samples after EtO-treatment. No detectable changes in chemical content of polymer films were observed after gamma, plasma and autoclave procedures. The reduction of Cl-concentration in Parylene C, resulted from damaging of its structure, was found in all the samples loaded with fluids. Additionally, after the fluid influence, the already mentioned implantation of nitrogen and formation of inorganic chlorides have been observed. According to the XRD-results, the autoclave sterilization and fluidic treatments caused the significant ride of Parylene C crystallinity grade. Low crystallinity increase was detected after EtO and plasma procedures, while the both irradiation treatments leads to stronger marked amorphism of the studied structures.

Epoxy terrace material and preparation method thereof

Abstract: The invention discloses an epoxy terrace materials consisting of a polyurethane leather layer, a fibre glass cloth layer which is mutually bonded with the polyurethane leather layer, and a terrace coating layer formed by coating and distributing the terrace paint on the surface of the fibre glass cloth layer. The terrace material not only inherits the excellent physicochemical properties of epoxy resin, such as wear resistance, scouring resistance, oil stain resistance, aging resistance, strong chemical resistance, extremely strong adhesive force and other characteristics. By adopting fibre glass as the material skeleton, the epoxy terrace material further strengthens the impact resistance and tensile strength, and belongs to the high-strength composite material; and compared with the traditional coating materials, the epoxy terrace material is more durable, has longer service life, and easier installation and construction.

Polyurethane-acrylic ester composite emulsion and preparation method thereof

Abstract: The present invention provides one kind of polyurethane-acrylate composite emulsion and its preparation process. The preparation process includes preparing water soluble polyurethane seed emulsion, and adding methacrylate and cross-linking agent to the seed emulsion to prepare interpenetrating polymer network polyurethane-acrylate composite emulsion. The polyurethane-acrylate composite emulsion contains solid material in 20-60 wt%, and has particle diameter of 10-100 nm. The preparation process is simple, and the prepared polyurethane-acrylate composite emulsion has high quality, especially excellent water resistance, heat resistance, chemical resistance and wear resistance, and wide application range.

Crosslinked polyurethane–epoxy hybrid emulsion with core–shell structure

Abstract: An epoxy resin was used to prepare crosslinked polyurethane hybrid emulsion through the blocked NCO prepolymer mixing process. Due to their hydrophobicity, the amine chain extender, blocked –NCO, and epoxy are located inside the emulsion particles. Thus, the crosslinking reaction occurs mostly in the interior of the particles. In this way, the crosslinking density of the resin is increased without the use of solidifying agents or heating during film formation, and the stability of the emulsions remains uninfluenced. The effects of the type of amine chain extender and the type, dosage, and addition mode of the epoxy resin were studied in terms of mechanical properties and swelling properties in water and toluene of the cast films. Additionally, the stability of the single-pack hybrid emulsion was studied. The results showed that the sample prepared with diethylene triamine had good stability, chemical resistance, and high mechanical strength. The modulus and water resistance of the films increased with the epoxy resin content, which could reach 20 wt%. The type of amine chain extender affected the stability of the emulsions significantly. The molar ratio of NH/NCO at 1:1 led to the best film performance. The optimal temperature of the chain-extension reaction was approximately 80°C. The hybrid emulsions could be stored for at least 6 months without apparent performance changes.

Development of Anticorrosive Poly(Ether-Urethane) Amide Coatings from Linseed Oil: A Sustainable Resource

Abstract: Polyetheramide(PEtA) resin was synthesized by the condensation polymerization of N,N-bis(2-hydroxy ethyl) linseed oil fatty amide diol (HELA) with resorcinol. It was further treated with different percentage of toluylene 2-4-diisocyanate (TDI) to obtain the urethane modified polyetheramide resins (UPEtA). The structural elucidation of PEtA and urethane modified polyetheramide(UPEtA) were carried out by FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. These analyses confirm the formation of PEtA and UPEtA. Physico-chemical and physico-mechanical analysis were performed by standard laboratory methods. The resin composition UPEtA-24 showed best physico-mechanical properties with scratch hardness 2.0 kg, impact resistance 150 lb/in. and good bending ability. The thermal stability and curing behavior of polymers were respectively studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal analysis shows that these coatings can be used safely upto 190 °C. The coatings of UPEtA resins were prepared on mild steel strips. The anticorrosive behavior of UPEtA coatings were investigated in acid, alkali, water and xylene. All the coatings exhibit good chemical resistance performance in acid, alkali, saline and organic solvents, while the resin UPEtA-24 shows the best performance.

Urethane modified polyimide based flame retardant resin composition

Abstract: Disclosed is a urethane modified polyimide based flame retardant resin composition having excellent solubility in non-nitrogenous solvents, varnish stability, low temperature drying / curing, low warpage, flexibility, printability, and flame resistance, and also having excellent heat resistance, chemical resistance, electrical properties, and operability, and is low-cost. The urethane modified polyimide based flame retardant resin composition is characterized by containing: (A) a urethane modified polyimide based resin having urethane bonds and generated having as essential components (a) trivalent and/or 4-valent polycarboxylic acid derivatives having an acid anhydride group, (b) diol compounds, and (c) aliphatic polyamine residue derivatives and/or aromatic polyamine residue derivatives; (B) an epoxy resin having two or more epoxy groups per molecule; (C) an organic or inorganic filler; and, (D) a non-halogen-based flame retardant, wherein the non-halogen-based flame retardant (D) contains two essential components (D-1 and D-2), wherein, in an air atmosphere at 350°C, the rate of weight reduction of one component (D-1) is greater than or equal to 50% and less than or equal to 90%, and that of the other component (D-2) is greater than or equal to 0% and less than or equal to 20%.

Aqueous paint for wooden wares

Abstract: The invention relates to an aqueous paint for wooden wares and a preparation method thereof. The paint of the invention is characterized by comprising acrylic acid modified aqueous polyurethane dispersion. The aqueous polyurethane has good low-temperature resistance, flexibility and wear resistant property, no environmental pollution, but poor water resistance. By compositely modifying the aqueous polyurethane, the property of the polyurethane can be improved, and the polyacrylate has better water resistance, chemical resistance and weather resistance. Thus, the water paint for wooden wares prepared by organically combining the polyurethane and polyacrylate not only has the original superior property of PU, but also has increased water resistance, ultraviolet light aging resistance, and the like.

Composition for coating

Abstract: The method consists of the formation of a layer over a stone substrate to increase its hardness, chemical resistance, wear and scratch resistance, comprising applying on the substrate a coating matrix incorporating an organic material and fillers including inorganic nanoparticles and/or microparticles; chemically binding said matrix to the substrate, by a self-assembly process and/or a binding process by covalent bonding, electrostatic bonding, van der Waals bonding or hydrogen bonds; and finally drying said matrix. The mentioned organic material is selected from organosilanes, organophosphates, polycarboxylic compounds, compounds based on triazine heterocycles and said nanoparticles are nanoparticles of oxides, carbides, borides, nitrides of metals or of semimetals.

Induction of the morphological changes in Hibiscus sabdariffa on graft copolymerization with acrylonitrile and co-vinyl monomers in binary mixture

Abstract: Hibiscus sabdariffa stem fiber existing as waste biomass, was graft copolymerized with acrylonitrile (AN) as principal monomer and in binary mixture with acrylic acid (AA) and 4-vinyl pyridine (4VP), using ceric ammonium nitrate (CAN) - nitric acid as initiator system, under optimized reaction conditions. Graft co-polymers thus obtained were subjected to characterization using X-ray powder diffraction (XRD), thermo-gravimetric-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and fourier transformer infra red spectroscopic (FTIR) techniques and compared with their percentage grafting. The fiber was found to have undergone morphological transformations on grafting that effected its properties. Graft copolymers were evaluated for physico-chemico-thermal changes like chemical resistance against 1N HCl and 1N NaOH and moisture absorbance at variable relative humidity. With increase in Pg, the percentage crystallinity, crystallinity index, moisture absorbance were found to decrease whereas there was an increase in chemical and thermal resistance of the graft copolymers.

Dispersion and aqueous coating composition comprising the dispersion

Abstract: The present invention relates to a dispersion comprising an acryl-modified cellulose ester derivative (D) dispersed in an aqueous medium, wherein a hydrophobic acrylic resin (B) and a hydrophilic acrylic resin (C) are grafted onto a cellulose ester derivative (A) in the acryl-modified cellulose ester derivative (D). The dispersion has excellent long-term storage stability, and aqueous coating compositions comprising the dispersion can form coating films with excellent coating workability, solvent resistance, chemical resistance, water resistance, and excellent curability.

Preparation and evaluation of epoxy methacrylate UV‐curable coatings containing phthalazinone

Abstract: Epoxy methacrylate resin (EMA) UV-curable coatings exhibit high reactivity, low viscosity and excellent chemical resistance in environmentally friendly coatings. A novel EMA containing phthalazinone moieties for high temperature resistant UV-curable coatings was synthesized. The formulations were cured with hexanediol diacrylate (HDDA) and trimethylol propane triacrylate (TMPTA) as reactive diluents promoted by a photoinitiator, and then interpenetrating polymer networks were generated. The mechanical, chemical and thermal properties of the clear coatings were characterized using Chinese National Standard methods (GB). EMA was used with UV radiation curing in combination with 6.7 wt% of HDDA and 13.4 wt% of TMPTA, and the properties of the cured films were as follows: pencil hardness of 5 H, 30% NaOH resistance for 30 days, 15% HCl resistance for 10 days, 3% NaCl resistance for 30 days and 5% weight loss temperature of 300.5 °C. EMA UV-curable coatings containing phthalazinone exhibit excellent chemical and thermal stability, and could be potential candidates for UV-curable zero volatile organic compound coatings applied in the fields of salt spray corrosion, strong radiation and high-temperature resistance. Copyright © 2009 Society of Chemical Industry

Thermoplastic resin composition having excellent electrical conductivity, mechanical strength and chemical resistance, and plastic article

Abstract: PURPOSE: A thermoplastic resin composition is provided to improve electric conductivity, mechanical strength and chemical resistance, and to apply to a manufacturing of vehicles, various kinds electronic device, and electronic assemblies. CONSTITUTION: A thermoplastic resin composition consists a polycarbonate resin 45~95wt%, an aromatic vinyl-based polymer resin 1~50wt%, and a carbon nanotube 0.01~10wt%. The polycarbonate resin has an average molecular weight of 10,000~500,000 g/mol. The aromatic vinyl-based polymer resin is a copolymer with an aromatic vinyl monomer 50~100wt% and unsaturated nitrile-based monomer 0~50wt%, and has an average molecular weight of 10,000~900,000 g/mol. The carbon nanotube is selected from the group consisting of a single wall carbon nanotube, a double-wall carbon nanotube, and a multi-wall carbon nanotube.

Novel Surface Coating System Based on Maleated Shellac

Abstract: Shellac a natural forest product was reacted with various proportion of maleic anhydride. The resulted maleated shellac samples were designated as (MS-1 to 3) and applied for the preparation of surface coating material. Thus various compositions of coating materials were prepared by varying the contents of MS and commercial grades of acrylic resins (AR). The coating materials were applied on substrates like plaster of paris, cement and limed surface. All the coating showed film performance with good adhesion finish, smoothness and lack of flaking on the surfaces. The results show that the coating showed good water and chemical resistance.

Thermal and Chemical Resistance Behavior of Cured Epoxy Based on Diglycidyl Ether of Bisphenol-A And Thiol Treated Liquid Polysulfide Blends

Abstract: In the present study five blends of Diglycidyl ether of bisphenol-A and thiol terminated liquid polysulfide with varying amount of polysulfide (i.e. 10 to 50 phr) were synthesized by physical mixing at 90 o C and synthesized blends were cured with phthalic anhydride. Interaction among epoxide group of DGEBA, -SH group of polysulfide and anhydride group of curing agent discussed through FT-IR analysis. The TGA studies revealed a decrease in thermal stability and activation energy (114.35 73.04 kJ/mole) with increase in polysulfide content. Volume resistivity decreases from 5.34 × 10 15 to 3.83 × 10 11 ohm-cm with increase in polysulfide content in the blends. The study of chemical resistance for various acids, alkalies to distilled water, sea water, xylene, ethanol, methyl ethyl ketone and acetone indicated that chemical resistance of blends decreased with increase in polysulfide content. Scanning electron microscopy (SEM) indicated the presence of two-phase morphology in the blends. Copyright © 2010 VBRI press.

Uv curable heat resistant epoxy acrylate coatings

Abstract: Polymeric materials are exposed to high temperatures that results in lowering of the film integrity. A blend of an epoxy resin with the silicone acrylate resin was developed to provide high heat resistance UV cured coatings. Earlier siliconized epoxy coatings had been developed by conventional curing. But due to environmental awareness, high productivity rate, low process costs and energy saving UV curable coatings are enjoying considerable growth. Thermally stable UV cured coatings used in the present study were developed from silicone acrylate and epoxy acrylate resin with different diluents and photoinitiator. Such coatings provide higher thermal stability (693 K) along with physical and chemical resistance. In addition, such coatings can also be obtained by using functional amino silanes. The resin developed provides a simple and practical solution to improve heat resistance along with physical and chemical resistance of the UV cured coatings. The purpose of this research paper is to develop UV curable heat resistant coatings by the combination of inorganic and organic polymer, taking epoxy acrylate as a base resin.