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Purpose: The silicone modifications of two-component epoxy resin coatings are commonly built on epoxy resins rather than on epoxy curing agents. The silicone-modified epoxy curing agent system is rarely reported yet. This study aims to prepare the polysiloxane (PS)-modified waterborne epoxy coatings based on aqueous curing agents technology. Design/methodology/approach: Waterborne epoxy curing agents with different contents of terminal epoxy PS were synthesized by reacting with triethylenetetramine, followed by incorporating of epoxy resin (NPEL-128) and polyethylene glycol diglycidyl ether. The waterborne epoxy coatings were prepared with the above curing agents, and their performance was investigated through thermogravimetric analysis, scanning electron microscopy, mechanical characterization, gloss measurement, chemical resistance test and ultraviolet (UV) aging experiment. Findings: The results showed that the epoxy coating prepared by silicon-modified curing agent has higher gloss, better chemical resistance and UV resistance than the coating from unmodified curing agent with terminal epoxy PS and commercially available waterborne epoxy curing agent (Aradur 3986), as well as the competitive mechanical properties and heat resistance. Reduced water absorption on fibrous paper was also obtained with the help of silicon-modified curing agent. Originality/value: These findings will be valuable for resin researchers in addressing the modification issues about waterborne epoxy resin and curing agent. [ABSTRACT FROM AUTHOR]

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3D printing technology is widely used in the manufacturing of fine ceramic fields due to its simple operation, rapid molding, and applications in preparation of complex structures. In this paper, the characteristics of different 3D printing technologies in ceramic preparation were reviewed based on the material morphology of 3D printing ceramics. The application and mechanism of binder and dispersant applied in direct ink writing, stereolithography and inkjet printing 3D printing technology of ceramics were introduced, and these additive components of water based and non-water based were summarized and discussed, aiming to provide reference for the preparation of high-performance ceramic samples via 3D printing technology. [ABSTRACT FROM AUTHOR]

In this study the influence of boron acrylates as functional monomer on adhesive and cohesive performance of water-borne pressure-sensitive adhesives coated on bi-orientated polypropylene (BOPP) has been investigated. A series of pressure-sensitive adhesives with different monomer composition was prepared using emulsion polymerization. The monomers were butyl acrylate; methyl methacrylate; acrylic acid; boron acrylate; and multi-acrylate functional boron methacrylate. The adhesive performance was studied at 0, 1.3 and 3.9% of boron acrylate monomer content based on total monomer composition and 1% of multi-acrylate functional boron methacrylate. The adhesives obtained with constant thickness were coated onto a BOPP and evaluated for the performance by measuring the tackiness, peel strength and shear strength on several surfaces including stainless steel, glass, aluminum (Al) and low density polyethylene. Results showed that addition of boron acrylate was slightly increasing the adhesion and cohesion performance on non-polar surfaces. While it did not show any dramatic decrease in the adhesive performance for different surfaces, the decomposition temperature showed increase in TGA analysis. [ABSTRACT FROM AUTHOR]

1,5-Pentamethylene diisocyanate, a novel aliphatic diisocyanate formed from bio-based 1,5-pentamethylenediamine, has been used as a hard segmented material to synthesize polyurethane. In this study, several waterborne polyurethane (WPU) dispersions have been successfully prepared by a prepolymer process from 1,5- pentamethylene diisocyanate poly(polyether) with different NCO/OH ratios and 1,6-hexanediol (HDO)/dimethylol propionic acid (DMPA) molar ratios. The Fourier transform infrared (FTIR) spectra, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, and a mechanical tensile test were used to investigate the structures, thermal stability, phase separation, crystallinity, mechanical properties, and adhesive performance of the WPU dispersions. The FTIR results indicate that the degree of hydrogen bonding and the numbers of urea groups increase as the NCO/OH ratio and HDO/DMPA molar ratio increase. Furthermore, the phase separation increases and the thermal stability decreases as the NCO/OH ratio increases or the HDO/DMPA molar ratio decreases. Finally, WPU3.0-2.4 (NCO/OH = 3, HDO/DMPA = 2.4) exhibits a maximum tensile strength and shear strength, pointing to its possible use as an adhesive. These results could provide a very valuable reference for industrial applications of WPU. [ABSTRACT FROM AUTHOR]

The stability of polyacrylate and polyester based aqueous dispersions designed for ultrathin coating of extruded plastic films, especially bi-axially oriented polyethylene terephthalate (BOPET), was studied. Also, the effect of the gemini surfactant based defoaming/wetting agent on the properties of the dispersions was examined. The addition of the defoaming/wetting agent resulted in reducing the surface free tension of the polyacrylate and polyester dispersion by 15% and 20%, respectively and the initial foam height by 60% and 15%, respectively. At the same time, the agent addition did not compromise the temperature and pH stability of the dispersions. Such modified dispersion can be utilized for ultrathin coating of plastic film used for packaging, to improve their processability, printability, and metallization. [ABSTRACT FROM AUTHOR]

Purpose This paper aims to synthesise block copolymers (PPy-b-ENP) of pyrrole (Py) and ethoxylated nonyl phenols (ENP) via redox systems in presence of ceric ammonium nitrate (CAN) at room temperature. The initiating radical was formed on reducing organic compound which in turn initiated polymerisation to give diblock copolymers containing chain ends of ENPs and polypyrrole (Ppy). The effects of the concentration of Ce+4 salt, ENPs and Py on both the yield and electrical conductivities of corresponding polymers were studied.Design/methodology/approach In total, 0.1 M stock solution of CAN:100 ml 1 M HNO3 was prepared freshly (7 ml HNO3 dissolved in 100 ml water) and used in 50 ml of 0.1 M CAN solution (2.7438 g CAN dissolved in 50 ml nitric acid solution). The reducing compound (Py) was dissolved in water. Py and ENP were added slowly to the flask with vigorous stirring. The content of the flask was flushed with oxygen-free nitrogen. The resulting copolymers were characterised with spectroscopic methods like Fourier transform infrared spectroscopy and scanning electron microscope.Findings In this study, DMSO-slightly soluble Py copolymers were produced with ENPs. The conductivities of copolymers were found to be in the range of 10-1 to 10-4 S/cm. Soluble and processable conductive polymers were developed.Research limitations/implications In this study, the water solubility of ENPs diminishes the conductivity of copolymer because of its surfactant structure. When the CAN/Py ratio was increased, PPys and copolymers with both higher yield and lower conductivity values were obtained. The results indicated that solubilities and the yield of the polymers synthesised in the presence of ENP have increased considerably. ENP caused degradative chain transfer reaction to become significant compared with bimolecular termination, so the yield decreased with increasing ENP concentration about 20 g/l. Results showed that yield of the copolymers strongly depends on Ce+4 concentrations while of copolymers were measured to be 10-3 S/cm.Practical implications PPy-b-ENP diblock copolymers were prepared with Ce+4 as an oxidation agent in a single step.Social implications These slightly soluble and conductive copolymers may overcome difficulties in the applications of PPy homopolymers and open new application areas.Originality/value PPy-b-ENPs of lightly soluble (in DMSO) and conductive (10-2 S/cm) copolymers have been synthesised in one step. The results indicate that the surface of the copolymer is composed of well-distributed nanospheres with an average particle diameter of 35-400 nm. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to evaluate the role of encapsulation temperature on the preparation of silica-encapsulated waterborne aluminium pigments.Design/methodology/approach The waterborne aluminium pigments were prepared with H2O2 as anchoring agent and siloxane used as precursors in pH = 9.0 medium at different temperatures. The anchorage and compactness of silicon which on aluminium surface were characterized by optical microscopy, scanning electron microscopy and N2 adsorption-desorption. The anticorrosion property was characterized by the volume of produced hydrogen as a function of time.Findings The effect of encapsulation temperature on anticorrosion property of aluminium pigments is reflected from the anchorage and the compactness of silica on aluminium surface. Furthermore, when encapsulation temperature is 45-50°C, the silica platelets uniformly anchored on the aluminium surface as a dense film, which show the best anticorrosion property. Lower and higher encapsulation temperatures cause the silica platelets to agglomerate rather than anchor on the aluminium surface, which is unfavourable for the anchorage and the formation of compact silica film. The use of product in waterborne coatings gives a higher glossiness than that of raw material.Research limitations/implications Only pH = 9.0 medium was explored, and the other pH medium could result in different optimum temperatures.Practical implications The investigation results provide theoretical basis for obtaining excellent waterborne aluminium pigments.Originality/value The method of investigating corrosion resistance mechanism of aluminium pigments based on anchorage and compactness is novel. [ABSTRACT FROM AUTHOR]

Purpose This paper aims to evaluate the effect of precursors on the anticorrosion property of silica encapsulated waterborne aluminium pigments (WBAPs).Design/methodology/approach The silica encapsulated WBAPs were prepared using different siloxanes as precursors. The anchorage and compactness of silica films on aluminium flakes were characterized by optical microscopy, scanning electron microscopy and N2 adsorption-desorption. The anticorrosion property and glossiness of WBAPs were evaluated.Findings The effect of precursors on anticorrosion property of silica encapsulated WBAPs is reflected from the anchorage and the compactness of silica on aluminium flakes surface. Furthermore, the structure of γ-aminopropyl triethoxysilane benefits the anchorage and the compatibility between pigment and acrylic resin. Neither high nor low ratio of tetraethoxysilane/γ-aminopropyl triethoxysilane is favourable to the anchorage and formation of dense silica film on the aluminium flakes surface. To obtain perfect WBAP, the precursors of silica must be carefully selected.Research limitations/implications Only four kinds of precursors were used in this work; other precursors could also be studied.Practical implications The investigation results provide theoretical basis to obtain excellent WBAPs.Originality/value The method to investigate anticorrosion property of WBAPs that is based on the effect of precursors on the performance of silica was novel. [ABSTRACT FROM AUTHOR]

Swelling elastomers are special polymers that increase in volume when exposed to water or oil. They have been successfully deployed in oil and gas wells for isolation of water-producing zones, partial replacement of cementing, slimming down of wells, and so on. Performance appraisal and design modifications cannot be attempted without knowledge of material response under specific field conditions. Results from an experimental investigation are presented here about the behavior of two commercial elastomers, one water swelling and one oil swelling. Of the one-month total testing time, one set of samples (for each elastomer type) was tested under acid for one day, and the other set without any acid exposure. Readings were taken at different stages of swelling to record the variation in volume, thickness, and hardness of elastomer samples. Test parameters were set to match existing conditions in a regional oil well. These results can be used to assess performance of elastomers under given well conditions and for modeling and simulation of seal behavior. [ABSTRACT FROM AUTHOR]

Acid-converted maize starch (ACS) was quaterized and then sulfosuccinylated in aqueous dispersion of starch to introduce 3-(trimethylammonium chloride)-2-hydroxypropyl (TACHP) and sulfosuccinate (SS) onto its backbones. A series of quaterized and sulfosuccinylated maize starch (QSS) samples with different zeta potentials were derived by altering the molar ratio of TACHP to SS substituents for exploring the influences of TACHP and SS substituents on the adhesion of QSS to viscose fibers and surveying the removability of QSS from sized viscose yarns. A desirable ratio of TACHP to SS was determined for alleviating the adverse impacts of (1) sulfosuccination on the adhesion and (2) quaterization on the removability. The adhesion was determined by a standard method (FZ/T 15001-2008), while the removability was assessed through an oxidant desizing under alkali conditions. It was found that this combined modification was able to alleviate the adverse impacts. The adhesion and removability of QSS were related to its zeta potential, depending on the ratio of TACHP to SS substituents. An increase in the potential favored adhesion, but disfavored removability. Electroneutral QSS had strong adhesion and good removability simultaneously, taking into account adhesion and removability. Furthermore, increasing the modification level at electroneutrality was helpful to the adhesion and removability. [ABSTRACT FROM AUTHOR]

Grafting of methyl methacrylate (MMA) and styrene (St) onto polychloroprene latex (CRL) was carried out successfully using emulsion polymerization. The chemical structure of the grafted copolymer was characterized using Fourier transform infrared spectroscopy. The compatibilizing effects of the grafted polymer CRL-g-(MMA-co-St) on the CRL/styrene-acrylate emulsion (SAE) blend were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and mechanical testing. The results showed that the mechanical properties of the contained CRL-g-(MMA-co-St) blend improved significantly in comparison to those of the simple CRL/SAE blend. For the contained CRL-g-(MMA-co-St) blend, the maximum tensile strength (6.72 MPa) and the maximum elongation at break (1142.6%) were obtained when the content of SAE was 60% (occupied by the total dry weight). At the same content of SAE, the T-peel and lap shear strengths of the contact adhesive derived from the contained CRL-g-(MMA-co-St) blend were 5.3 N/mm (canvas to canvas) and 1.8 MPa (plywood to plywood), respectively. The grafted copolymer CRL-g-(MMA-co-St) showed a remarkable compatibilizing effect on the CRL/SAE blends by drastically improving their mechanical properties. [ABSTRACT FROM PUBLISHER]

Water borne polyurethane dispersions synthesized using poly caprolactone-isophorone diisocyanate combination and caprolactone-metatetramethyl xylene diisocyanate combination. Thermal stability of the polyurethane dispersions was studied using thermogravimetric technique. The activation energy of decomposition of these polyurethane dispersions was determined by applying classical kinetic models and isoconversional method. Though the classical kinetic models assume constant activation energy for any reaction, the activation energy determined is in good agreement with that obtained via isoconversional analysis. However, the advantage of isoconversional analysis is highlighted compared to classical kinetic models based on the mechanism delineating capacity of isoconversional analysis. The present work compares the thermal stability of the aqueous polyurethane dispersion formed from poly caprolactone-isophorone diisocyanate with caprolactone-metatetramethyl xylene diisocyanate. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to investigate the effects of the components of whey-protein based aqueous polymer-isocyanate (API) adhesives on the bond strength. Design/methodology/approach – The bond test (according to the JIS K6806-2003 standard), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterise the whey-protein based API adhesives with various formulations and processing technologies. Findings – The good bond strength of the optimised whey-protein based API adhesive was attributed to the formation of strong chemical bonds in the bondline and to the additions of polyisocyanate, polyvinyl alcohol (PVA) and nano-CaCO3 powder that improved adhesive cohesive strength by either chemical crosslinks or mechanical interlocking. The blending procedures of whey protein, PVA, polyvinyl acetate (PVAc) and p-p-MDI had great impacts on the performances of the whey-protein based API adhesives. Research limitations/implications – SEM micrographs showed that the effects of blending processes on the bond strength, pot life and colour might be attributed to the particle size of hydrophobic p-MDI droplet and p-MDI distribution in the protein-PVA matrix. Practical implications – The study lays the foundations of the formulation design and the processing technology for preparing whey-protein based API adhesives. Originality/value – The effects of the components of whey-protein based API adhesives and the effects of blending processes on the bond strength were investigated by means bond strength evaluation, FTIR and SEM analyses; whey protein is utilised successfully to prepare novel API adhesives for structural uses. [ABSTRACT FROM AUTHOR]

Health and safety legislation has forced changes in the type of anticorrosive pigments used in paint formulations, mainly focused on their substitution with different phosphates. The zinc phosphate pigment used with different types of binders has provided contradictory experimental results. In this paper, waterborne anticorrosive paints pigmented with zinc phosphates were studied. The main variables considered were PVC and the anticorrosive pigment content. Accelerated tests (salt spray, humidity chamber, and electrochemical tests) were performed to evaluate the paints' anticorrosive performance. Good correlation was found using salt spray and impedance tests. From analysis of the time dependence of all the experimental results it was concluded that an efficient steel protection could be obtained using a waterborne epoxy primer pigmented with zinc phosphate. Such protection is attained through the barrier effect afforded by the paint film as well as the precipitation of a pretty stable ferric phosphate layer under the intact and damaged coating areas. [ABSTRACT FROM AUTHOR]

Changes in regulations aiming at reducing the impact that technologies such as coatings, adhesives, cleaners have on the environment is leading to large advances in these end-use technologies. In achieving the required quality of the end product, and irrespective of whether this is in areas such as high solids paints or water-based coatings, solvents keep on playing an important role. At the same time different requirements are set for the solvents employed. The changing role of solvents and the technological benefits solvents are bringing are discussed. It is shown that the computer programme BLENDPRO is an effective reformulation tool which assists in the efficient development of new formulations in these areas. [ABSTRACT FROM AUTHOR]