Emerald | Pigment & Resin Technology | Table of Contents http://www.emeraldinsight.com/0369-9420.htm Table of contents from the most recently published issue of Pigment & Resin Technology Journal en-gb Tue, 01 Jul 2014 00:00:00 +0100 2013 Emerald Group Publishing Limited editorial@emeraldinsight.com support@emeraldinsight.com 60 Emerald | Pigment & Resin Technology | Table of Contents http://www.emeraldinsight.com/common_assets/img/covers_journal/prtcover.gif http://www.emeraldinsight.com/0369-9420.htm 120 157 Curing behaviour and mechanical properties of pigmented UV-curable epoxy acrylate coatings http://www.emeraldinsight.com/journals.htm?issn=0369-9420&volume=43&issue=4&articleid=17112371&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The purpose of this work was to study the effect of chemical structure of reactive diluents on the curing behaviour and physical-mechanical properties of a titanium dioxide pigmented UV curable epoxy acrylate system.<B>Design/methodology/approach</B> - Two different tri-functional and two different tetra-functional acrylate monomers were used as reactive diluents in the formulations. The curing behaviour of the formulations was studied by using photo-DSC analysis. The rate of curing, conversion at maximum rate and ultimate conversion for different formulations were calculated. In addition, the physical and mechanical characteristics of the cured films including glass transition temperature and modulus were measured by using a dynamic mechanical analysis (DMA) technique. <B>Findings</B> - The results showed that the ultimate conversion for non-pigmented pentaerythritol triacrylate (PETA) and trimethylol propane triacrylate (TMPTA) formulations were almost similar but the interference effect of titanium dioxide particles on the curing of the PETA formulations was found to be more considerable in comparison to the TMPTA formulations. The extent of reaction for tetra-functional acrylate monomers was considerably less than those for tri-functional acrylate monomers. The Tg and storage modulus of non-pigmented PETA, TMPTA and pentaerythritol tetraacrylate (PE4TA) formulations were almost the same and higher than that for ditrimethylol propane tetraacrylate (DiTMP4TA) formulations. However, Tg and storage modulus of pigmented tetra-functional acrylate monomer formulations were higher than those for tri-acrylate monomer formulations. <B>Research limitations/implications</B> - The curing conditions (temperature and UV intensity) can affect on the network formation and consequently will affect on the properties of the cured films. <B>Practical implications</B> - The pigmented UV curable coatings are interested for many industries such as wood and automotive industries. The reported data can be used by the formulators working in the R&D departments. In addition, the results obtained can be used by the researchers who are active in the field of structure-property relationship for UV curable coatings. <B>Originality/value</B> - The photopolymerisation of pigmented coatings is a great challenge and hardly investigated in the literature. Therefore, in this research, the effect of chemical structure and functionality of different multifunctional acrylate monomers on the curing behaviour of pigmented formulations was investigated. Article literatinetwork@emeraldinsight.com (Pooneh Kardar, Morteza Ebrahimi, Saeed Bastani) Tue, 01 Jul 2014 00:00:00 +0100 Resistance to weathering of wood-polypropylene and wood-wollastonite-polypropylene composites made with and without carbon black http://www.emeraldinsight.com/journals.htm?issn=0369-9420&volume=43&issue=4&articleid=17112397&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The purpose of this paper to study natural and accelerated weathering of wood-polypropylene and wood-wollastonite-polypropylene composites made with and without carbon black.<B>Design/methodology/approach</B> - Natural weathering was conducted in Ruokolahti, Finland in the time of year when solar radiation was maximal. The accelerated weathering tests included exposure to a xenon-arc source with and without spray, and a cyclic test consisting of water immersion-freeze-thaw stages. <B>Findings</B> - Both the type of weathering and the formulation of the composite determined the degree of change in their properties. Weathering, including xenon-arc exposure with spray resulted in much higher changes of colour of non-pigmented composites compared to natural weathering or xenon-arc weathering without spray. Both UV irradiation and moisture had an adverse effect on the Charpy impact strength of non-pigmented composites. Carbon black containing composites performed better than non-pigmented composites.<B>Research limitations/implications</B> - This study is a part of an ongoing research on the development of wood-polymer composites suitable for outdoor applications in Finnish climatic conditions. Outdoor weathering limited to 1000 h cannot be used for the prediction of the service life of composites and was used here solely for comparative purposes.<B>Originality/value</B> - This paper will help to understand the effect of different weathering factors on the behaviour of wood-polypropylene and wood-wollastonite-polypropylene composites made with and without carbon black (as UV stabilizer). The study demonstrated that while accelerated weathering tests provided useful information on the resistance of wood-polypropylene composites to different weathering factors, they cannot be used alone to predict the behaviour of wood-polymer composites meant for outdoor application. Article literatinetwork@emeraldinsight.com (Svetlana Butylina, Timo Kärki) Tue, 01 Jul 2014 00:00:00 +0100 New thermal deblocking characterization method of aqueous blocked Polyurethane http://www.emeraldinsight.com/journals.htm?issn=0369-9420&volume=43&issue=4&articleid=17112413&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The mechanisms of the deblocking reaction of the polyurethane with blocking agent were investigated in detail relatively using TGA, FTIR and XPS. This kind of method for polyurethane as the application of wood adhesives can provide the conditions of application and the main theoretical basis.<B>Design/methodology/approach</B> - The blocking rate and latex particle size distribution were determined using the titrimetric analysis and the laser particle analysis, respectively. Thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC) were used to investigate the deblocking temperature and time of the blocked isocyanate in detail.<B>Findings</B> - The results indicated that the blocking rate was approximately 97% and the average particle size was 360 nm. The results of laser particle analysis have confirmed that the dispersivity of the blocked polyurethane emulsion was good. XPS results showed that the amount of -O=C-N- benzyl groups increased with an increasing deblocking temperature and subsequently reached equilibrium. In summary, the blocked isocyanate was deblocked at temperatures ranging from 50 to 90 °C.<B>Research limitations/implications</B> - An important approach in future wood adhesive work would be to gain access to man-made board application data.<B>Practical implications</B> - The paper provided some useful information about deblocking mechanisms of blocked polyurethane that would be helpful to guide applied practical applications as wood adhesive.<B>Originality/value</B> - The paper is the first to use the XPS characterisation method to characterise deblocking polyurethane solution. Article literatinetwork@emeraldinsight.com (Yanhua Zhang, Jun Cao, Haiyan Tan, Jiyou Gu) Tue, 01 Jul 2014 00:00:00 +0100 Employment of new modified ferrite pigments in anticorrosive alkyd-based paints http://www.emeraldinsight.com/journals.htm?issn=0369-9420&volume=43&issue=4&articleid=17112365&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - Silica fume is a byproduct of the smelting process in the ferrosilicon industry. The reduction of high-purity quartz to silicon at temperatures up to 2000°C produces SiO2 vapors which then oxidise and condense at low temperature zones to tonnage amounts of tiny particles consisting of non-crystalline silica that is collected and sold rather than being land-filled, because nowadays there is increasing environmental concern with regard to excessive volumes of solid waste hazards accumulation. Silica has no direct effect in protecting metals from corrosion, but on precipitating an effective anticorrosive pigment like ferrite on its surface with low concentrations, this can bring out new core-shell pigment with good anticorrosive performance and low cost. The new pigments will be constructed on a waste silica fume core comprising 80-85% of its chemical structure and the ferrite shell that will be only about 20-15%.These pigments are represented as efficient, economically feasible and eco-friendly.<B>Design/methodology/approach</B> - The different ferrites and ferrites/SiO2 pigments were characterized using different analytical and spectro-photometric techniques, such as X-ray diffraction (XRD), scanning electron microscopy/Energy dispersive X-ray (SEM/EDX) and transmission electron microscopy (TEM). Evaluation of these pigments was done using international standard testing methods (ASTM). After evaluation the pigments were incorporated in solvent-based paint formulations based on medium oil-modified soya-bean dehydrated castor oil alkyd resin. The physico-mechanical properties of dry films and their corrosion properties using accelerated laboratory test in 3.5% NaCl for 28 days were determined.<B>Findings</B> - The results of this work revealed that, ferrite/SiO2 core-shell pigments were close in their performance to that of the ferrite pigments in protection of steel and at the same time, they verified good physico-mechanical properties.<B>Practical implications</B> - As silica fume has a large array of uses, these pigments can be applied in various industries such as painting, wooding coating, anti-corruption coating, powder coating, architectural paint and water-proof paints.<B>Originality/value</B> - Ferrite, ferrite/SiO2 are environmentally friendly pigments which can impart high anticorrosive behaviour to paint films with concomitant cost savings. Article literatinetwork@emeraldinsight.com (Nivin M. Ahmed, Walaa M. Abd El-Gawad, Elham Ahmed Youssef, Eglal M.R. Souaya) Tue, 01 Jul 2014 00:00:00 +0100 Optimizing the process for production of high performance bagasse-based composites from rice bran-UF adhesive system http://www.emeraldinsight.com/journals.htm?issn=0369-9420&volume=43&issue=4&articleid=17112425&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - Investigations have continued for production high performance agro-based composites using environmentally acceptable approaches. The possibility of preparing high performance agro-based composites, from non-toxic rice bran-urea formaldehyde (RB-UF) adhesive system is the main objective of this work. The utilisation of such system with the available used local agro-based wood products (sugar-cane bagasse; SCB), will add economic value, helps reduce the environmental impact of commercial urea-formaldehyde adhesive (UF) and most importantly provides a potentially inexpensive alternative to the existing commercial artificial wood-panel mills.<B>Design/methodology/approach</B> - Optimising the process for incorporating the rice bran in urea-formaldehyde, as wood adhesive for binding the bagasse fibres, was carried out, by partially replacing commercial UF by denaturalised RB in slurry (wet) and dry form, or through synthesis of urea-formaldehyde. The denaturalisation of RB was carried out at different pH's (10- 11), and temperature 60 °C for 2 h. The incorporation of the RB during synthesis of UF was carried out according to the method reported elsewhere. The formulation of adhesive components, pH-value of denaturalisation stage, and process of incorporating the RB were optimised. Assessment the role of RB adhesive was specified from its free-HCHO content, as well as the properties (mechanical and physical properties) of the produced composites of bagasse particle board type, in comparison with environmental impact commercial thermosetting resin (urea-formaldehyde).<B>Findings</B> - The promising adhesive system exhibits improvement in the environmental performance (as E1) over a commercially HCHO-based adhesive (UF), besides providing boards that fulfil the requirements of grade H-3 (According to particle board grade requirements from NPA; ANSI A208.1). This adhesive system resulted from replacing 30 % of UF by denaturalised RB (at pH 10), in slurry form. Where, its reduction in free-HCHO reached 53%, as well as MOR, MOE, IB and TS of the produced boards were ~24.2 N/mm2, ~3753 N/mm2, ~ 0.84 N/mm2 and ~11.4%, respectively.<B>Research limitations/implications</B> - The eco-adhesive with relatively high percentage of low cost commercial UF (70%) and 30% RB, as oil production by-product, in slurry form provides good board strength and environmentally friendly comparative SCB-based composite properties, with that produced from commercial UF. The mechanical (MOR, MOE and IB) and water resistance properties of the produced composite comply with the standard values.<B>Practical implications</B> - The approach provided low HCHO-free UF adhesive with good comparative board strength and water resistance, reasonable working life. Replacing 30% of UF by RB in slurry form, and denaturalised at pH 10 is considered a promising inexpensive alternate adhesive (as E1) in wood industry based on SCB wastes.<B>Originality/value</B> - It provided a potential simple way to improve both the utilization of commercial UF and SCB as industrial substrates for particle-board production. This will benefit farmers, local wood mills in Upper Egypt, significantly. Meanwhile, incorporating low percentage of RB, as oil Mill by-products, is promising to partly replace urea formaldehyde resin in wood industry, minimising formaldehyde emission or toxic gasses during board formation. Article literatinetwork@emeraldinsight.com (Altaf A H Basta, houssni El-Saied, Emad M. Deffallah) Tue, 01 Jul 2014 00:00:00 +0100 Surface modification of iron oxide (Fe2O3) pigment particles with amino-functional polysiloxane for improved dispersion stability and hydrophobicity http://www.emeraldinsight.com/journals.htm?issn=0369-9420&volume=43&issue=4&articleid=17112424&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The purpose of the present study is to use an amino functional polysiloxane for the surface modification of red iron oxide pigment particles for their improved dispersion stability and hydrophobicity and to study the chemical interactions of polysiloxanes with the particle surface.<B>Design/methodology/approach</B> - Surface treated red iron oxide pigment particles were prepared by treatment of the particles with different quantities of the (aminopropylmethylsiloxane)-dimethylsiloxane copolymer in concentrated suspensions in water. The samples were analysed with different instrumental and spectroscopic techniques to study the interaction of the polysiloxane with the particle surface and the effect of the surface treatment of the particles on their dispersion stability and hydrophobicity.<B>Findings</B> - Chemisorption of the amino-polysiloxane onto the surface of iron oxide particles resulted in stable layers which turned out to be helpful in improving greatly the dispersion stability of the particles as shown by the Static Light Scattering and Dynamic Light Scattering results. Formation of a polysiloxane coating onto the surface of the pigment particles was confirmed by studying the interactions of the polymer molecules with iron oxide surfaces by FTIR and XPS techniques.<B>Practical implications</B> - The surface treated red iron oxide particles with improved dispersion stability can be important components of various formulations in applications such as the colouring of the cement or inorganic pigment based paint formulations.<B>Originality/value</B> - The study provides mechanistic insights about the interactions of amino-polysiloxane with the red iron oxide particles. The process of surface modification of red iron oxide particles with the amino-functional polysiloxane showed increased hydrophobicity and dispersion stability which is an important requirement of the of pigment based formulations in real applications. Article literatinetwork@emeraldinsight.com (Sushilkumar A. Jadhav, Roberta Bongiovanni, Daniele L. Marchisio, Daniela Fontana, Christian Egger) Tue, 01 Jul 2014 00:00:00 +0100 Physicochemical studies and rheological modelling of Albizia lebbeck (AL) gum exudates http://www.emeraldinsight.com/journals.htm?issn=0369-9420&volume=43&issue=4&articleid=17112419&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The purpose of this study is to determine the physicochemical and rheological parameters of Albizia lebbeck gum.<B>Design/methodology/approach</B> - Physicochemical analysis were carried out using recommended methods. GCMS and FTIR analysis were carried out using their respective spectrophotometer; Scanning electron microscopy was carried out using scanning electron microscope while rheological measurements were carried out using ubbelohde capillary viscometer, digital Brookfield DV 1 viscometer and a rheometer <B>Findings</B> - Albizia zygia gum is ionic gum with unique physical and chemical properties. Scanning electron micrograph revealed that the internal structure of the gum is porous with irregular molecular arrangement. Thermodynamic parameters of viscous flow indicated the existence of few inter and intra molecular interactions and the attainment of transition state was linked to bond breaking. Coil overlap transition studies revealed the existence of dilute and concentrated regimes. The viscosity of the gum was also found to decrease with decrease in the charge of cation (such that Al3+ >Ca2+>K) and with increase in ionic strength.<B>Research limitations/implications</B> - The paper provided information on physicochemical and rheological characteristics/behavior of Albizia zygia gum, of Nigerian origin. From this information, possible application of this gum in the food and pharmaceutical industries can be deduced. <B>Originality/value</B> - The paper is original since information concerning Albizia zygia gum of Nigerian origin are not well documented as established in the work. It also add values on the use of Albizia zygia gum, either on its own or in combination with other gums for industrial purpose. Article literatinetwork@emeraldinsight.com (NNABUK OKON EDDY, Inemesit Udofia, Adamu Uzairu) Tue, 01 Jul 2014 00:00:00 +0100