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1 – 10 of 164Pundalik Pandharinath Mali, Nilesh S. Pawar, Narendra S. Sonawane, Vikas Patil and Rahul Patil
The purpose of this work was to develop a new trispiperazido phosphate-based reactive diluent (diphosphate-piperazine hydroxyl acrylate [DPHA]) and used as a flame retardant with…
Abstract
Purpose
The purpose of this work was to develop a new trispiperazido phosphate-based reactive diluent (diphosphate-piperazine hydroxyl acrylate [DPHA]) and used as a flame retardant with an epoxy acrylate (EA) in ultraviolet (UV)-curable wood coating.
Design/methodology/approach
The concentration of reactive diluent was varied from 0% to 20% in the UV-curable formulation with constant photoinitiator concentration. The effect of DPHA concentration on film properties was studied by differential scanning calorimetry and thermogravimetric analysis, gel content, water absorption and limiting oxygen index.
Findings
The results showed that the viscosity of the prepared formulation decreased by increasing reactive diluent (DPHA) concentration which leads to improving the coating efficiency. A high concentration of reactive diluent (DPHA) of the cured films shows good resistance against stain, mechanical and thermal properties, which results in an increased glass transition temperature (Tg) and cross-linking density of the films.
Originality/value
The new trispiperazido phosphate-based reactive diluent was used in wood coating formulation, which resulted in excellent flame-retardant properties with higher cross-linked density with good stain resistance. This material can provide a wide range of application for coating industries to produce a glossy finish.
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A. Srivastava, D. Agarwal, S. Mistry and J. Singh
The purpose of this paper is to synthesise environment friendly UV curable polyurethane acrylate resins for various industrial applications and study the performance properties of…
Abstract
Purpose
The purpose of this paper is to synthesise environment friendly UV curable polyurethane acrylate resins for various industrial applications and study the performance properties of the cured coating films applied over metal surfaces.
Design/methodology/approach
The polyurethane acrylate resin was synthesised using polyester polyol (synthesised using ethylene glycol, adipic acid and 1,6 hexane diol), isophorone diisocynate (IPDI) and 2‐hydroxy ethyl methacrylate (HEMA). The different formulations were developed using various reactive diluents viz. monofunctional, difunctional, trifunctional and tetrafunctional (ethoxylated phenol monoacrylate, 1, 6 hexane diol di acrylate, dipropylene glycol di acrylate, trimethylol propane triacrylate, propoxylated trimethylol propane triacrylate, pentaerythrol triacrylate – PETA). These samples were cured under UV radiation. For effective curing, various compositions of oligomers, photoinitiator and reactive diluents were used. The mechanical, optical, rheological, chemical and stain resistance properties were evaluated.
Findings
The designed polyurethane acrylate gave good performance properties when used with reactive diluents having different functionality in different ratios for application over metal surfaces as protective coatings for various industrial applications. While using reactive diluents, the coating compositions showed significant enhancement of mechanical, physical and chemical resistance properties. Owing to different functionality of reactive diluents used, highly cross‐linked structures are formed, which lead to excellent mechanical and chemical properties. The optimum results were obtained with PETA as reactive diluent.
Research limitations/implications
The polyurethane resin has been synthesised from polyester polyol (made up of ethylene glycol, adipic acid and 1, 6 hexane diol), IPDI, 2‐HEMA. Besides, this, it can be synthesised from some other polyester polyol or polyether polyol. In addition to this, some other isocyanates such as TDI, MDI, HDI, HMDI, etc. may be used.
Practical implications
The study has provided a better solution for developing low volatile organic compound (VOC) products by using UV radiations, which can be cured within a minimum period of time and can save significant application curing time for the end‐users. The developed product is also an environmentally friendly product.
Originality/value
Metallic surfaces are widely used in packaging industry in rigid and semi‐rigid forms. One of the prime requirements of the surface is an attractive printing on it. Conventionally used coating system on metallic surfaces are not holding or retaining their decorative effect/gloss level to a large extent. For this purpose, an overprint varnish is normally used which is mostly solvent based. This paper has been able to suggest very good formulations for printing of metallic surfaces for packaging and for overprinting in particular, which is radiation curable and environment friendly.
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This study aims to focus on how reactive diluents with mono- and di-functionalities affect the properties of resin formulation developed from bioderived precursors. A hydroxyethyl…
Abstract
Purpose
This study aims to focus on how reactive diluents with mono- and di-functionalities affect the properties of resin formulation developed from bioderived precursors. A hydroxyethyl methacrylate (HEMA) terminated urethane acrylate oligomer was synthesized and characterized to study its application in stereolithography 3D printing with different ratios of isobornyl acrylate and hexanediol diacrylate.
Design/methodology/approach
Polyester polyol was synthesized from suberic acid and butanediol. Additionally, isophorone diisocyanate, polyester polyol and HEMA were used to create urethane acrylate oligomer. Fourier transform infrared spectroscopy and 1H NMR were used to characterize the polyester polyol and oligomer. Various formulations were created by combining oligomer with reactive diluents in concentrations ranging from 0% to 30% by weight and curing with ultraviolet (UV) radiation. The cured coatings and 3D printed specimens were then evaluated for their properties.
Findings
The findings revealed an improvement in thermal stability, contact angle value, tensile strength and surface properties of the product which indicated its suitability for use as a 3D printing material.
Originality/value
This study discusses how oligomers that have been cured by UV radiation with mono- and difunctional reactive diluents give excellent coating characteristics and demonstrate suitability and stability for 3D printing applications.
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There is a rising demand for high-performance 3D printed objects that have established potential applications in the sector of dental, automotive, electronics, aerospace, etc…
Abstract
Purpose
There is a rising demand for high-performance 3D printed objects that have established potential applications in the sector of dental, automotive, electronics, aerospace, etc. Thus, to meet the requirements of high-performance 3D printed objects, this study has synthesized, formulated and applied a resorcinol epoxy acrylate (REA) oligomer to a stereolithography (SLA) 3D printer.
Design/methodology/approach
Different formulations were developed by blending reactive diluents in the concentration of 10%, 15% and 20%, along with the fixed quantity of photo-initiators in the REA oligomer. The structure of synthesized REA oligomer was confirmed using 13 C nuclear magnetic resonance (NMR) and 1H NMR spectroscopy, and the rheological properties for prepared REA formulations were also evaluated. The ultraviolet (UV)-cured specimens of all REA formulations were thoroughly examined based on physical, chemical, optical, mechanical and thermal properties. The best suitable formulation was selected for SLA 3D printing.
Findings
As perceived, UV cured REA specimens exhibit superior mechanical, chemical and thermal properties, portraying the ability to use as a high-performance material. The increase in the concentration of reactive diluents indicated a significant improvement in the properties of REA resin. The 20% diluted formulation achieved excellent compatibility with a SLA 3D printer; thus, 3D objects are cast with good dimensional stability and printability.
Originality/value
Resorcinol-based resins have always been a key additive used to enhance properties in the coating and tire industry. In a new attempt UV, curable REA has been applied to a SLA 3D printer to cast high-performance 3D printed objects.
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Ghodsieh Mashouf, Morteza Ebrahimi and Saeed Bastani
The purpose of this work was to perform a systematic study on the effect of formulation on the physical and mechanical properties of ultaviolet (UV) curable urethane acrylate…
Abstract
Purpose
The purpose of this work was to perform a systematic study on the effect of formulation on the physical and mechanical properties of ultaviolet (UV) curable urethane acrylate resins. In addition, the authors wanted to derive mathematical formula for the prediction of physical and mechanical properties for the aforementioned system.
Design/methodology/approach
The experiments were carried out based on mixture experimental design to determine the effect of different multifunctional acrylates (i.e. 1,6-hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA), trimethyolpropane triactylate (TMPTA)) concentration on the physical and mechanical properties of a UV curable polyurethane acrylate system. The urethane oligomer was synthesized and characterized by the research team. Microhardness, adhesion strength and scratch resistance of the cured films were evaluated as the physical and mechanical properties.
Findings
The results revealed that the resin and TMPTA concentrations had the most significant effects on the microhardness property. Adhesion strength of the films showed a linear trend with respect to all variables. Moreover, all components also had a significant and complex influence on the scratch resistance of the cured systems. In addition, mathematical equations proposed by mixture experimental design were derived for all the mentioned properties.
Research limitations/implications
Other multifunctional acrylate monomers (i.e. more than three functional) can be used in the formulations. The kinetics of the curing can affect on the network formation and consequently on the properties of the cured films.
Practical implications
The obtained results can be used by the researchers who are active in the field of structure-property relationship of polymers and surface coatings. The reported data and the mathematical equations can also be used for the formulating of an appropriate formulation based on a specific application.
Originality/value
A systematic and statistical-based approach, i.e. mixture experimental design, was used to evaluate the effect of formulation on some of the properties of a UV curable polyurethane acrylate system. A urethane oligomer and three different multifunctional acrylate monomers as reactive diluents were used in the formulations. Noteworthy to mention that several mathematical models were derived by using analysis of variance for the prediction of the properties studied in this system.
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Pooneh Kardar, Morteza Ebrahimi and Saeed Bastani
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…
Abstract
Purpose
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.
Design/methodology/approach
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-differential scanning calorimetry analysis. The rate of curing, conversion at the 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 technique.
Findings
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.
Research limitations/implications
The curing conditions (temperature and UV intensity) can affect the network formation and consequently will affect on the properties of the cured films.
Practical implications
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.
Social implications
UV-curing systems are considered as one of the most environment-friendly coatings system. Therefore, the developing of its knowledge can help to extend its usage to different applications.
Originality/value
The photopolymerisation of pigmented coatings is a great challenge and is 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.
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C. Paul Sharma, K.L. Vadera and R.P. Agarwal
In the past, solvents containing impregnation systems were in vogue, e.g. phenoloic‐alkyd, isophthalic polyester, silicone, etc. for electrical machines. The disadvantages of…
Abstract
In the past, solvents containing impregnation systems were in vogue, e.g. phenoloic‐alkyd, isophthalic polyester, silicone, etc. for electrical machines. The disadvantages of solvent borne impregnants are a higher dissipation factor (at elevated temperatures) and water absorption, etc., due to the presence of air voids formed during the curing process. The phenomenon has been controlled with the present day use of solvent/ess systems, e.g. polyester, polyesterimide, epoxy and silicone resins. Solvent/ess polyester resins are now indigenously available along with their additives such as: inhibitor, catalyst and reactive diluent, etc. Modern methods of impregnation for electrical machines in BHEL include: (a) Dip impregnation by rotational method (b) V P I process The methods include storing the catalysed resin in cool storage, warming for impregnation, and final impregnation under vacuum and pressure, and curing in an oven. A monitoring system has also been standardised for the impregnation resin to keep its viscosity and gelling time within the specified tolerances by the addition of an appropriate amount of inhibitor and reactive diluent. Proper monitoring keeps the tank life of the system indefinitely long and its properties within limits.
M.A. Shenoy, A. Sabnis and D.J. D'Melo
To study the effect of addition of free diols and triols in the coating formulation on coating properties.
Abstract
Purpose
To study the effect of addition of free diols and triols in the coating formulation on coating properties.
Design/methodology/approach
Polyester resins were synthesised from maleic anhydride, dimerised fatty acid, neopentyl glycol and tris (2‐hydroxyethyl) isocyanurate (THEIC). Then, ethylene glycol, propylene glycol, glycerol, trimethylol propane and THEIC were added as reactive components to the coating formulation. These coatings were then analysed for various coating properties and compared with those obtained with the base resins.
Findings
The coatings obtained with the addition of these reactive components were found to have improved properties compared with those of the base resins except in cases where the reactive component itself contributed to a reduction in performance, e.g. reduced alkali resistance with the addition of THEIC.
Research limitations/implications
The addition of the free diols and triols required a corresponding increase in the amount of the curing agent to be added.
Practical implications
This process would allow for the tailoring of coatings to suit requirements to a certain extent without modifying the base resin. The addition of low molecular weight components in the coating formulation, which is then incorporated in coatings, could reduce the solvent requirement.
Originality/value
Although polyesters are an established polymeric system in coatings, the use of reactive diluents has not been investigated with the exception of unsaturated polyesters, whose curing chemistry is fundamentally different from that of polyesters focused on in this paper.
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Yuyue Guo and Shudong Lin
This paper aims to investigate the effects on material performance in the epoxy acrylate resin system owing to the existence of the different ring of the cyclic methacrylate. In…
Abstract
Purpose
This paper aims to investigate the effects on material performance in the epoxy acrylate resin system owing to the existence of the different ring of the cyclic methacrylate. In this paper, cyclic methacrylate as diluents was added into epoxy acrylate (EA) resin by ultraviolet (UV)-cured polymerization to investigate the effects on material performance owing to the existence of the different rings.
Design/methodology/approach
EA and 1-adamantyl methacrylate were synthesized by traditional methods according to previous papers, respectively. After adding different cyclic methacrylate as diluents to the EA oligomers, the system was exposed to the UV-light for polymerization.
Findings
The hydrophobic properties of the cured materials were increased slightly because of the alkyl groups from the methacrylate. The thermal stabilities and mechanical properties of the resins were enhanced by the cyclic diluents with the hard segments. Meanwhile, the crosslink density of the polymer decreased with the bulky group like adamantly owing to its huge structure.
Research limitations/implications
The cyclic methacrylates were introduced into EA oligomers for decreasing the viscosity and increasing the materials performances, which could be recognized as new diluents applied in UV-cued polymerization.
Originality/value
The results of this study will be conducive to fabricate EA resins possessed with high thermal stabilities and mechanical properties by convenient UV-cured polymerization.
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C. Hinczewski, S. Corbel and T. Chartier
Ceramic three‐dimensional parts can be produced by a stereolithography (SL) process using a ceramic suspension containing alumina powder, UV curable monomer, diluent…
Abstract
Ceramic three‐dimensional parts can be produced by a stereolithography (SL) process using a ceramic suspension containing alumina powder, UV curable monomer, diluent, photoinitiator and dispersant. The monomer reacts to UV radiation (argon ionized laser) and is transformed into a solid polymer which is then removed by thermal treatment (debinding). Subsequent sintering of green parts leads to dense ceramic parts. The effect of each component on the rheology of the alumina suspensions has been studied first. Both the addition of dispersant and diluent and the increase in temperature allow a significant decrease of the viscosity of the suspensions. The highly loaded (more than 55 vol. per cent), homogeneous and stable suspensions have a shear thinning behaviour which is favourable for casting the layers. Adequate cured depth (above 200μm) and satisfactory transversal resolution have been obtained and these allow the production of ceramic parts, which demonstrates the feasibility of the process. Sintering at 1,580°C leads to dense ceramic parts with homogeneous microstructure. The process still needs to be optimized to improve even more the mechanical properties.
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