Chemical Resistance Tests Research Articles

Moisture absorption and Chemical resistance studies on Pineapple fiber reinforced Vinyl ester Composite

This research discusses the moisture absorption and chemical resistance studies on pineapple fiber reinforced Vinyl ester composite. A composite material was developed with pineapple fiber as reinforcement in the Vinyl ester matrix. Pineapple fiber of three different weight percentages 30%, 40% and 50% wt as well as fiber length of 30mm, 40mm and 50mm respectively taken for the study. The moisture absorption and the chemical resistance property of the composite were investigated as per the ASTM standard. Five different chemicals were used to investigate the chemical resistance behavior of the composite. The initial and final weight loss of the composites was calculated to find the moisture resistance property. The chemical resistance property was increased with the addition of treated jute fiber. All the tested composites exhibited positive results on the chemical resistance test.

A comparative study of ultraviolet and electron beam irradiation on acrylate coatings

Radiation curing is the polymerization of a chemical system which is initiated by ultraviolet (UV) or electron beam (EB) irradiation. The curing, the transformation from a liquid into a non-tacky solid, is very fast and occurs in less than one second. In this work, the optimum irradiation time on curing urethane acrylate coating by using UV and the best cured dose by using EB irradiation was studied. Coating formulations were prepared by physical mixing of aliphatic urethane acrylate (AUA) and tripropylene glycol diacrylate (TPGDA) at different ratio (60:40), (70:30), and (80:20) to choose the optimum concentration. Cured coating films were characterized by Fourier transform spectroscopy (FTIR), and swelling properties. The wood surface that cured by UV or EB were tested for their end use performance properties like pencil hardness, adhesion, bending, chemical resistance, steam resistance, stain resistance, and cigarette burn resistance test. superior results and excellent mechanical performance of acrylate films on the surface of wood induced by EB were found compared with those induced by UV irradiation.

New series of brilliant yellow colorants in rare earth doped scheelite type oxides, (LiRE)1/2WO4- BiVO4 for cool roof applications

New series of brilliant yellow colorants with high NIR reflectance in rare earth doped scheelite type oxides, [(LiRE)0.125Bi0.75][W0·25V0.75]O4 (RE = La–Yb) and [(LiLa)x/2Bi1-x][WxV1-x]O4 (x = 0–0.3) were developed by the ceramic route. Different advanced techniques were used to examine the structural, morphological and optical properties of the synthesized colorants. The pigment series [(LiLa)x/2Bi1-x][WxV1-x]O4 undergoes a structural transformation from a monoclinic to a tetragonal scheelite phase and the second pigment series with various rare earth substitutions crystallize with a tetragonal phase. Strong absorption in the ultraviolet and blue region is observed for all the samples leading to brilliant yellow colorants with high solar reflectance. The band gap variation associated with the introduction of different energy levels between valance band and conduction band defines the various yellow shades of the pigments. Classically [(LiGd)0.125Bi0.75][W0·25V0.75]O4 pigment showed intense yellow color (b* 84.62) having NIR reflectance of 94% that has improved values than the commercially available Sicopal yellow. The probable applicability studies of [(LiLa)0·125Bi0.75][W0·25V0.75]O4 pigment as cool pigment was also exemplified on a concrete cement block and on a metal sheet. Chemical resistance tests are a sign of their permanence in the severe weathering conditions. These pigments are found to be promising ones for exterior coating energy saving applications.

Novel natural rubber-based epoxy coating

The use of renewable resources in development of polymeric products is becoming more relevant in the current times, braced by the scarcity of fossil resources and threat from global warming. The manuscript describes the preparation of epoxy resin from epoxidized natural rubber (ENR) via ultraviolet (UV) treatment, followed by investigation on the film properties of the coating produced by blending the natural rubber-based epoxy resin with pentaerythritol tetrakis(3-mercaptopropionate), PETMP as the hardener. The UV treatment involved is responsible to break down the natural rubber into smaller molecular weight fractions so that it becomes more compatible with common solvents and chemicals, and at the same time improves the solubility and viscosity of the resin. The results obtained are very encouraging, with significant reduction in the molecular weight of the rubber observed after 6 hours of UV treatment, and spectroscopic characterization suggests that substantial amount of epoxide group in the ENR was effectively preserved during the treatment for subsequent reaction with PETMP. The epoxide group in the UV-degraded ENR was found to react with the –SH group of PETMP after the two were blended, applied into film, and heated at 80 °C. The properties of the coatings produced were investigated via pencil hardness test, crosshatch adhesion tape test, thermal stability test, water, and chemical resistance test. Most of the coating formulations produced film with excellent hardness, adhesion and chemical resistance. Coating B and C are among the best coating formulations, with both recorded pencil hardness grade ≥ 4H, zero film removal in the adhesion test, no film defect observed during saltwater, acid and alkaline resistance test, and reasonably good thermal stability with onset of degradation above 200 °C.

수분산 폴리우레탄 코팅의 미세상분리와 물성에 Isosorbide가 미치는 영향

Series of waterborne polyurethanes (WPUs) containing poly(tetra methylene glycol) (PTMG), 4,4-dicyclohexylmethane diisocyanate (HMDI), 2,2-dimethylolpropionic acid (DMPA), 2,2,4-trimethyl-1,3-pentanediol (TMPD), isosorbide (ISO) and ethylenediamine (EDA) were synthesized. The effects of ISO on the structure and properties of WPUs were studied by gel permeation chromatography (GPC), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analyzer (DMTA), X-ray diffraction (XRD), thermogravimetry (TG), mechanical test, chemical resistance and hardness test. The deconvolution analysis of FTIR of WPUs revealed that the hydrogen bond interaction in the WPUs increased with the increase of ISO content. Furthermore, the degree of microphase separation was increased with the increase of hydrogen bond interaction, which was confirmed by DSC, XRD and DMTA test. The results demonstrated that the addition of ISO can increase the hydrogen bond interaction between the hard and hard segments in WPUs, which improved the mechanical properties of the WPU films. The highest tensile strength was obtained of 59.67 MPa when the content of isosorbide was 10.35 wt%. Moreover, the ISO was helpful to improve the chemical resistance and hardness of the coatings by the comprehensive performance analysis.

The Development of a Surface Finisher of Car Park Slab Using Waterborne Silicon Acrylic with Polyamide [Part II: Safety Tests

Due to the environmental concerns of solventborne coating systems, environmental directives have recently been promulgated in many countries. Additionally, integrated environmental policies have been pushed in many fields to minimise influences on the environment. Waterborne silicon acrylic finishers have gained much interest to replace the traditional finishing system. To satisfy the requirements, a waterborne finisher with polyamide was previously developed and its performance was determined. For further safety assessment, various tests were conducted, such as gas toxicity, heavy metals tests, chemical resistance test and chloride migration test, followed by equivalent standards. In the cases of gas toxicity and heavy metals evaluations, both results were acceptable considering their corresponding standards, e.g. KS F 2271, KS F 3888-2 and BS EN 71-3. Based on the evaluation, silicon acrylic with 30% mix ratio of polyamide resin (SA+PR30%) could be implemented as an environmentally friendly finisher for various applications. In the chemical resistance and chloride migration test results, the developed finisher showed a barrier effect in the chemical environment. Thus, the developed finisher could be an alternative finisher applicable for slabs in chemical industrial areas.

Studies on Influence of the Size of Waterborne Polyurethane Nanoparticles on Coating Performance

Abstract Waterborne polyurethanes are extensively utilized as in coatings and adhesive applications because of their outstanding performance as solventless system. To achieve such a product with almost no or minimum volatile organic compounds, water is the best choice to utilize as a solvent medium in coating formulations to eliminate organic solvents from the final products. During the synthesis of the waterborne polyurethanes, the particle size of final dispersion products depends on many factors like NCO:OH content, the concentration of acid, synthesis conditions, chain extension process etc. In this research work using the prepolymer mixing process and changing NCO:OH content, flame retardant waterborne polyurethane dispersions (FWBPUD) were prepared from phosphorous containing polyester polyol and isophorone diisocyanate (IPDI). These prepolymers were neutralized by triethylamine followed by the addition of predefined quantity of water. Diethylenetriamine was used as a chain extender. These FWBPUs were further coated on various substrates. Characterization was done using Fourier transform infrared and Nuclear magnetic resonance spectroscopy. The average particle size of the dispersions was characterized by Microtrac-analyser. An influence of the size of waterborne polyurethane nanoparticles on the coating performance was described by scratch resistance, pencil hardness, adhesion (cross-hatch), flexibility 1/4“ mandrel test, chemical resistance and solvent resistance test. Due to the presence of phosphorous moiety, these FWBPUs also show flame retardancy which was investigated by limiting oxygen index (LOI) and UL-94 test methods. The FWBPU dispersions were stable for 8 months.

Utilization of Waste Packaging Glass as Progressive Filler in Polymer Anchor Material Based on Epoxy Resin

The work deals with the use of waste glass to the polymer anchor material based on epoxy resin, primarily for anchoring to a high strength concrete (HSC). The main aim was to use the largest possible amount of the waste packaging glass by reducing the amount of epoxy resin, which is an expensive material and its production has a negative impact on the environment. Within the experimental verification, the influence of waste packaging glass fraction 0–0.63 mm on the final properties of the polymer anchoring material was observed. To determine the optimal formulation compressive strength, flexural strength, chemical resistance, shrinkage and pull-out test were performed. Based on the evaluation of the results the optimal percentage of filling was determined, when the polymer anchor material showed high strengths, minimal shrinkage, good chemical resistance, optimal consistency for anchoring into the HSC and high anchor bolt pull-out strength.

Modified cellulose membrane with good durability for effective oil-in-water emulsion treatment

Industrial spilled oil and oily wastewater have caused serious environmental pollution and energy dissipation. Hence, a robust cellulose-based filter paper-polyvinyl alcohol (cellulose-PVA) membrane for efficient oil-in-water emulsion separation was fabricated by a universal method of hydroxyl oxidation for any substrate containing hydroxyl groups that was cost-effective and easy to scale up. The resulting membrane exhibited superhydrophilicity, superoleophilicity in air, and stable superoleophobicity under various pH value solutions with contact angles exceeding 150°. The cellulose-PVA membrane can dispose of many types of surfactant-stabilized and different oil droplet sized oil-in-water emulsions with 98.75 % efficiency driven only by gravity without consideration the secondary processing problem. Furthermore, sand paper abrasion tests, tape peeling tests and chemical corrosion resistance tests were executed, indicating the excellent mechanical stability and superior durability of the cellulose-PVA membrane. These results suggest that it is a prospective and competitive candidate for industrial oil-in-water emulsion treatment.

Gradient structure based dual-robust superhydrophobic surfaces with high-adhesive force

Dual-robust (mechanical and chemical robust) superhydrophobic surfaces with a high adhesive state have aroused lots of attention for their potential application in liquid transportation, biochemical separation and in situ detection devices. Herein, we design a gradient structure based multi-scale micro- and nano-structures (inorganic-organic interpenetrating structures, self-similar sacrificial structures and micro-nano structures) to realize dual robust superhydrophobic surfaces by spraying method. Upon changing the fabrication process, three kinds of superhydrophobic surfaces were made based on benzoxazine, mesoporous SiO2 and imidazole. A rigorous sandpaper abrasion test, chemical resistance test (pH = 1–14, 12 h) and anticorrosion test were carried out to exhibit the environmental stability of the system. High adhesive properties of surfaces were demonstrated by adhering water test. The clear multi-scale structures are showed and its relationship with properties is built. Scanning electron microscope was used to examine different structures and the gradient structure in system. The gradient structure based dual-robust superhydrophobic surfaces give a promising prospect for water transportation application in their large-scale and low-cost fabrication method and super mechanical and chemical robust.

Luminescent anti-reflection coatings based on Er3+ doped forsterite for commercial silicon solar cells applications

Efficiency of solar devices is affected by several factors such as, devices surface reflection and the energy emitted in the ultraviolet and infrared regions, which are not harnessed by the cell, are among the main causes. To reduce these losses, we propose the use of rare-earth doped anti-reflection coatings. Erbium doped forsterite (Mg2SiO4:Er3+) thin films were synthesized in order to bind the anti-reflective property of forsterite films with the upconversion property of erbium ion. For the first time in literature, Mg2SiO4:Er3+ optical activity in the visible range with excitation at 1470 nm is presented. Single and double layers anti-reflective coating models, with forsterite as coating material, were simulated. The single layer model was compared to experimental data presenting elevated accordance. The coating application on silicon wafer leaded to a light absorption enhancement over 80% in the visible spectrum. The dopant influence on the films optical behavior was also studied indicating that despite the presence of erbium, the fosterite films preserved their anti-reflectivity. Moreover, the coatings were analyzed through chemical and mechanical resistance tests, indicating elevated scratch resistance (over 500 mN) and chemical stability at high humidity and corrosive environments. Mg2SiO4:Er3+ films revealed to be a promising anti-reflection coating for increasing commercial silicon-based solar cells efficiency.

Colored Poly(vinyl chloride) by Femtosecond Laser Machining

Colored poly(vinyl chloride) (PVC) was fabricated by femtosecond laser micromachining without the addition of chemical colorants, eliminating the concern of leaching dyes and pigments. We determined that the changes in surface chemistry and surface topography both contribute to the observed yellow, brown, and black color formation. X-ray photoelectron spectroscopy (XPS) on the machined samples showed that conjugated double bonds are liable for the yellow and brown colors, whereas the presence of oxidized carbon and surface topography contribute to the black color. Fourier transform infrared spectroscopy (FTIR) indicated that laser irradiation altered the material’s properties only near the surface, which left the bulk properties unaltered. Furthermore, chemical resistance tests showed that some of the samples were able to withstand the influence of aggressive chemicals and their color did not fade. Finally, we showed that the fabrication of colored PVC highly depends on its ablation energy threshold which is affected by the laser pulse duration and wavelength.

Curing mechanism, heat resistance, and anticorrosion properties of a furan/methyl phenyl silicone coating

A coating composed by methyl phenyl silicone resin (PSi) and furan resin (FR) was prepared, and its curing mechanism, heat resistance, and anticorrosion properties were investigated by Fourier transform infrared spectroscopy, thermogravimetric analysis, electrochemical test, and chemical resistance test. Aldol condensation reaction between FR and PSi occurred at below 200°C, and PSi underwent self‐multidehydrogenation at above 200°C. These curing reactions gave excellent thermal stability and anticorrosion properties. Compared with pure PSi, the blended containing lower than 20 wt% FR had better thermal properties, manifested as over 390°C of 5 wt% weight loss temperature and over 40% of char yield at 800°C. The adhesion property of cured blended system on the metal surface reached the first level which exceeded that of pure PSi coating (the third level). Furthermore, the corrosion resistances of coating in acid, alkali, and salt environments were all improved compared with those of monomeric polymer coating. The impedance of blended coating in 3.5% NaCl solution decreased with increasing FR content, which was 1.8 × 106 Ω cm2 when the FR content was 40%, being higher than that of pure PSi coating (7.12 × 105 Ω cm2). This was mainly due to the formation of a cross‐linked network structure based on Si―O―C bond and the enhanced adhesion of cured blended coating. In addition, the surface roughness of cured blended coating was below 2.0 μm, which may have a positive effect on drag reduction in real applications.

Feasibility of Producing Glass-Ceramics from a Mixture of Glass Cullet-Eggshell and Perlite

Feasibility of producing glass-ceramics from cullet, eggshell and perlite was investigated. In this study, a nucleating agent was synthesized from calcined eggshell and expanded perlite prior to blend with soda-lime waste glass, and then sintered at temperatures ranging from 850 to 1050°C at a heating rate of 10°C/min for 30 - 180 minutes. The crystallization behavior of glass-ceramics was investigated by means of X-ray diffraction analysis and surface morphology, and the chemical compositions were evaluated by scanning electron microscopy and energy dispersive X-ray spectroscopy. Results showed that crystalline phase embedded in the glass phase were needle-like crystal of wollastonite, cristobalite and quartz. According to the chemical resistance test, the obtained glass-ceramics showed acceptable corrosion resistance particularly in acidic environment. The weight loss for glass-ceramics immersed in 1wt% of sodium hydroxide solution was 0.28 - 0.50 wt%, while weight loss due to 1vol% of sulfuric acid solution was 0.04 - 0.16 wt%.

Castor oil based hyperbranched urethane acrylates and their performance as UV-curable coatings

ABSTRACTCastor oil (CO) based hyperbranched urethane acrylates (HBUAs), namely C10-IH and C20-IH, were synthesized by modifying the hydroxyl groups of first (C10)- and second (C20)-generation of CO-based hyperbranched polyesters with isocyanate-bearing semi-adducts (IPDI-HEA). Herein, the C10 and C20 polyesters were prepared using the renewable CO as a B3 core molecule and dimethylolpropionic acid as an AB2 monomer via a pseudo-one-pot condensation procedure. For comparison, a CO-based urethane acrylate (CO-IH) was synthesized by directly modifying the hydroxyl groups of CO with IPDI-HEA. The structure-property relationship of the UV-cured films was investigated in detail. Consequently, the number of terminal urethane acrylates greatly influenced their final properties. The tensile strength of the C20-IH based UV-cured sample could be improved by 129% in comparison with the CO-IH based sample, and its pencil hardness reached up to 7H. Furthermore, the chemical resistance tests and the morphology study proved that the C20-IH based UV-cured coatings exhibited excellent chemical stability and superb microstructure. These improvements can be attributed to the unique oligomer architecture that combined the structural features of hyperbranching, castor oil chains and multiple urethane acrylates.

Lead extraction and glass-ceramics synthesis from waste cathode ray tube funnel glass through cooperative smelting process with coal fly ash

In this study, a novel process was developed for extracting lead from the hazardous waste cathode ray tube (CRT) funnel glass and simultaneously producing glass-ceramics. CRT funnel glass was mixed with coal fly ash and subjected to carbon thermal reduction with the addition of CaO. The homogeneous glass melt and reduced metallic lead were quenched in water. Glass-ceramics were produced from the parent glass through an appropriate heat treatment. The optimum carbon loading amount (calculated as the molar ratio of C/PbO), CaO/SiO2 ratio, smelting temperature and holding time for lead recovery were 1.0, 0.3–0.6, 1450 °C and 2 h, respectively. Under these conditions, more than 95% of lead can be extracted from the funnel glass and a low lead content of the resultant parent glass below 0.6 wt% was successfully achieved. CaO behaved as a network modifier to reduce the viscosity of the glass and also acted as a substitution to release lead oxide from the silicate network structure, resulting in a high lead separation efficiency. X-ray diffraction (XRD) analysis revealed that the main crystalline phase was gehlenite when 50–70 wt% funnel glass was added. Scanning electron microscopy (SEM) observation showed that well-crystallized crystals occurred in the specimens with 50–70 wt% funnel glass additions, whereas the specimens with 40 wt% and 80 wt% glass additions exhibited a relative low crystallization degree. Furthermore, property measurements, chemical resistance tests and leaching characteristics of heavy metals confirmed the possibility of engineering and construction applications of the superior glass-ceramic products. Overall results indicate that the process proposed in this paper is an effective and promising approach for reutilization of obsolete CRT funnel glass.

Chemical Resistance of Glass Composite Materials Made From Incinerated Scheduled Waste Slag and SLS Waste Glass

Incineration of scheduled waste and landfilling of the incineration residue (Bottom Slag) is extensively practised in Malaysia as a treatment method for scheduled waste. Land site disposal of Bottom Slag (BS) may lead to environmental health issues and reduces the availability of land to sustain the nation’s development. This research aims in producing Glass Composite Material (GCM) incorporating BS and Soda Lime Silicate (SLS) waste glass as an alternative method for land site disposal and as an effort for recycling SLS waste glass. SLS waste glass originates from the urban waste has been a waste stream in most of the nation whereby the necessity for recycling is in high priority. Batches of powder mixture is formulated with 30 wt. % to 70 wt. % of BS powder and SLS waste glass powder for GCM sintering. The powder mixtures of BS and SLS waste glass is compacted by uniaxial pressing and sintered at 800°C with heating rate of 2°C/min and 1 hour soaking time into tiles of 18mm×18mm. The GCM porosity and water absorption increases as the BS waste loading increases. Meanwhile, its bulk density increases as the BS waste loading decreases. The GCM tiles made from BS 30 wt. % and 70 wt. % SLS waste glass are determined to have the lowest water absorption of 1.17 % and porosity percentage of 2.2 % with the highest bulk density of 1.88 g/cm3. It was also found is found that the chemical resistance of these GCM tiles is classified as ULA (No visible Effect) and UHA (No visible Effect) after 5 day immersions in low and high concentration of acid and alkali solution; respectively (determined using MS ISO10545-13:2001(Ceramic Tile: Determination of chemical resistance) test. However, the chemical resistance is weak upon increased duration of 12 immersion days where severe corrosion effects on both surface tiles in low and high concentration chemical solutions. The penetration of chemical in attacking the samples are related to the presence of pores. Hence, further work should have aimed to reduce the amount of porosity presence in the produced tiles.

Effects of perlite addition on the structure of hard porcelain glaze

This investigation is reported the effects of perlite addition on the properties of hard porcelain glazes. Five compositions were prepared containing 10, 25, 50, and 90% perlite addition. The glaze compositions were formulated using the Seger method and prepared by conventional porcelain processing. Chemical and microstructural characterization of materials prepared from representative samples were carried out using X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques, respectively. The melting test, color measurement test, thermal shock resistance test (Harkort test), autoclave test, and chemical resistance tests were done to all of the glazed samples. As a result of this study, it has been shown that addition of 10% perlite mineral can be utilized as an alternative fluxing raw material for production of the hard porcelain glaze.

Evaluation of Structures and Morphologies of Recycled PC/PET Blends Fabricated by High-Shear Kneading Processing

Abstract We fabricated polymer blends of recycled-PC (PC) and recycled-PET (PET) using high-shear processing technology. We also assessed its structure, morphology, and physical properties. Results of DSC measurements show that Tg of PC and Tc of PET shifted to higher temperatures by kneading under high-shear conditions. Results show further that the Tm of PET shifted to a lower temperature. Moreover, compatibilization progressed. TEM observations show that the PET domain was not confirmed completely under the kneading condition of 1 000 min−1/10 s or more. Compatibilization progressed. Tensile test results show that the PET ratio of 30 wt% (1 000 min−1/10 s) has higher breaking strain than neat PC does. Chemical resistance test results obtained by good solvent of PC demonstrated that blending of PET makes PC elution difficult.

Fingerprint resistant coatings for stainless steel substrates

Abstract In this paper, development of coatings with anti-finger print feature for stainless steel substrates is presented. Coatings with tailored surface roughness are demonstrated which provide these properties. Polyurethane coatings are produced by incorporation of matting agents with different particle size and surface chemistry. Depending on the amount of incorporated matting agents and their particle size, we were able to obtain anti-finger print coatings with the designed surface patterns. Chemical resistance tests of the coatings prove that they are chemically durable to be utilized in daily activities.