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Reports results from studies conducted on a polyfunctional amine adduct epoxy curing agent (EPI‐CURE DPC‐3293) as a means to design low temperature cure coatings. Through the judicious choice of epoxide resins and amine‐functional curing agents, relatively fast reaction rates and resistance to moisture and humidity are maintained under low‐temperature cure conditions, and that is evidenced by a good balance of performance properties of coating films. We have used differential scanning calorimetry (DSC) to study the extent of reaction as well as the glass transition temperatures (T_g). Electrochemical impedance spectroscopy (EIS) has been used to predict the barrier properties of coating films. These results are compared with epoxide resins cured with a phenalkamine curing agent to illustrate some of the unique advantages of using multifunctional amine adduct curing agents for the curing of epoxide resins under sub‐ambient cure conditions for a multitude of end‐use applications.

The purpose of this paper is to investigate the effect of the replacement of natural coarse aggregate (NCA) with different percentages of recycled coarse aggregate (RCA) on properties of low calcium fly ash (FA)-based geopolymer concrete (GPC) cured at oven temperature. Further, this paper aims to study the effect of partial replacement of FA by ground granulated blast slag (GGBS) in GPC made with both NCA and RCA cured under ambient temperature curing.

M25 grade of ordinary Portland cement (OPC) concrete was designed according to IS: 10262-2019 with 100% NCA as control concrete. Since no standard guidelines are available in the literature for GPC, the same mix proportion was adopted for the GPC by replacing the OPC with 100% FA and W/C ratio by alkalinity/binder ratio. All FA-based GPC mixes were prepared with 12 M of sodium hydroxide (NaOH) and an alkalinity ratio, i.e. sodium hydroxide to sodium silicate (NaOH:Na₂SiO₃) of 1:1.5, subjected to 90^°C temperature for 48 h of curing. The NCA were replaced with 50% and 100% RCA in both OPC and GPC mixes. Further, FA was partially replaced with 15% GGBS in GPC made with the above percentages of NCA and RCA, and they were given ambient temperature curing with the same molarity of NaOH and alkalinity ratio.

The workability, compressive strength, split tensile strength, flexural strength, water absorption, density, volume of voids and rebound hammer value of all the mixes were studied. Further, the relationship between compressive strength and other mechanical properties of GPC mixes were established and compared with the well-established relationships available for conventional concrete. From the experimental results, it is found that the compressive strength of GPC under ambient curing condition at 28 days with 100% NCA, 50% RCA and 100% RCA were, respectively, 14.8%, 12.85% and 17.76% higher than those of OPC concrete. Further, it is found that 85% FA and 15% GGBS-based GPC with RCA under ambient curing shown superior performance than OPC concrete and FA-based GPC cured under oven curing.

The scope of the present paper is limited to replace the FA by 15% GGBS. Further, only 50% and 100% RCA are used in place of natural aggregate. However, in future study, the replacement of FA by different amounts of GGBS (20%, 25%, 30% and 35%) may be tried to decide the optimum utilisation of GGBS so that the applications of GPC can be widely used in cast in situ applications, i.e. under ambient curing condition. Further, in the present study, the natural aggregate is replaced with only 50% and 100% RCA in GPC. However, further investigations may be carried out by considering different percentages between 50 and 100 with the optimum compositions of FA and GGBS to enhance the use of RCA in GPC applications. The present study is further limited to only the mechanical properties and a few other properties of GPC. For wider use of GPC under ambient curing conditions, the structural performance of GPC needs to be understood. Therefore, the structural performance of GPC subjected to different loadings under ambient curing with RCA to be investigated in future study.

The replacement percentage of natural aggregate by RCA may be further enhanced to 50% in GPC under ambient curing condition without compromising on the mechanical properties of concrete. This may be a good alternative for OPC and natural aggregate to reduce pollution and leads sustainability in the construction.

The performance of epoxy coating on metal substrate at low temperature and high humidity application has adverse effect on cure rate, film properties and adhesion. In recent years, several advanced amine cross-linking agents having superior curing ability at low temperature application environment have been introduced. The aim of this paper is to study the properties of epoxy-based coating cured with different cross-linking agents designed for low temperature application at different environmental conditions.

Series of cross linking agents such as modified cycloaliphatic amine (H1), polyamine adduct (H2), modified aliphatic ketamine (H3), phenalkamine (H4) and phenalkamide (H5) have been studied to evaluate their performance in epoxy compositions when cured at four environmental conditions, i.e. at ambient and sub-ambient temperatures with 60 and 90 per cent relative humidity, respectively. The effect of curing conditions was investigated by evaluating different physico-mechanical properties. Dynamic mechanical analyser technique was used to determine glass transition temperature (T_g) and cross-link density (ρ) of coatings. Anticorrosive properties of coatings also have been studied by electrochemical impedance spectroscopy.

The outcome of this study is expected to generate new insight into the curing behaviour of epoxy coating using different cross-linking agents which are recommended for low temperature application. Optimum physico-mechanical and corrosion resistance properties have been obtained by phenalkamine curing agent at low temperature and high humidity condition.

This study is an experimental approach to select the better cross-linking agent for low temperature application. Different test conditions were measured for understanding the performance of epoxy coating cured at different environmental condition.

The understanding reaction mechanism of the epoxy resin with cross-linking agent at different environmental condition is the great challenge and is hardly investigated in the literature. Therefore, in this research, the influence of climatic conditions and type of cross-linking agents on curing behaviour of epoxy-based coating was investigated.

The purpose of this paper is to find a new curing agent for diglycidyl ether of bisphenol A (DGEBA) resin and to check effectiveness of this new curing agent to obtain toughness and chemical resistance of cured epoxy.

For this purpose, an investigation was carried out to synthesise, characterise and to study curing reaction of amine functional aniline acetaldehyde condensate (AFAAC) with DGEBA resin. AFAAC was first synthesised from the reaction of aniline and acetaldehyde in acid medium and characterised by FT‐IR, ¹H‐NMR spectroscopic analyses, elemental analysis, concentration of primary and secondary amine analysis. Then equimolecular mixture of AFAAC and DGEBA was subjected to curing reaction and the reaction was followed by differential scanning calorimetry (DSC) analysis. The kinetic studies of this curing reaction, mechanical properties, dynamic mechanical analysis and thermogravimetric analysis (TGA) of cured epoxy were also reported.

The DSC analysis showed the complete exotherms of effective curing reaction indicating the efficiency of AFAAC as curing agent for DGEBA resin. The kinetic studies revealed that the curing reaction was first order. Mechanical properties reflect the better fracture properties of cured matrix and TGA showed that the cured matrixes were stable up to around 238°C.

The curing agent AFAAC has been synthesised by using aniline and acetaldehyde. By changing amine and aldehyde, other curing agents could be synthesised and the curing efficiency of these for epoxy resin could also be studied.

The method for curing study of epoxy resin (DGEBA) is novel and relevant as the cured products have high‐performance applications in protective coatings, adhesives for most substrates.

Microwave curing (MC) can facilitate rapid concrete repair in cold climates without using conventional accelerated curing technologies which are environmentally unsustainable. Accelerated curing of concrete under MC can contribute to the decarbonisation of the environment and provide economies in construction in several ways such as reducing construction time, energy efficiency, lower cement content, lower carbonation risk and reducing emissions from equipment.

The paper investigates moisture loss and pore properties of six cement-based proprietary concrete repair materials subjected to MC. The impact of MC on these properties is critically important for its successful implementation in practice and current literature lacks this information. Specimens were microwave cured for 40–45 min to surface temperatures between 39.9 and 44.1 °C. The fast-setting repair material was microwave cured for 15 min to 40.7 °C. MC causes a higher water loss which shows the importance of preventing drying during MC and the following 24 h.

Portland cement-based normal density repair mortars, including materials incorporating pfa and polymer latex, benefit from the thermal effect of MC on hydration, resulting in up to 24% reduction in porosity relative to normal curing. Low density and flowing repair materials suffer an increase in porosity up to 16% due to MC. The moisture loss at the end of MC and after 24h is related to the mix water content and porosity, respectively.

The research on the application of MC for rapid repair of concrete is original. The research was funded by the European commission following a very rigorous and competitive review process which ensured its originality. Original data on the parameters of porosity and moisture loss under MC are provided for different generic cementitious repair materials which have not been studied before. Application of MC to concrete construction especially in cold climates will provide environmental, economic and energy benefits.

The purpose of this paper is to study the curing mechanisms, anticorrosive properties and protective mechanisms of three kinds of amine curing agents applied in a new kind of light colored water‐borne epoxy antistatic anticorrosive paint.

Using light color‐conductive mica, titanium oxides and environmentally‐friendly anticorrosive pigments in the two‐component water‐borne epoxy system, the light colored water‐borne antistatic anticorrosive paint was prepared. The molecular structure and curing mechanisms of the curing agents was analyzed by Fourier transform infra‐red spectroscopy, and the influence of the curing agents on anticorrosive properties and protective mechanisms was studied by electrochemical impedance spectroscopy.

The paints cured by the modified amine curing agent possessed optimal integrated properties with a coating surface resistivity of 10⁶ Ω and the best anticorrosive performance.

A novel light colored water‐borne epoxy antistatic anticorrosive paint cured by the optimal curing agent could be used in corrosion protection for oil tanks to replace the traditional oil‐based antistatic anticorrosive paints.

The purpose of this paper is to investigate the curing efficiency of amine functional aniline furfuraldehyde condensate (AFAFFC) for diglycidyl ether of bisphenol A (DGEBA) resin to achieve toughness, chemical resistance, etc.

To study curing reaction, the curing agent AFAFFC is synthesised first from the reaction of aniline and furfuraldehyde in acid medium and characterised by Fourier transform infrared spectroscopic analysis, elemental analysis, concentration of primary and secondary amine analysis. Then, equimolecular mixture of AFAFFC and DGEBA is subjected to curing reaction and the reaction is followed by differential scanning calorimetry (DSC) analysis. The kinetic studies of this curing reaction, mechanical properties, dynamic mechanical analysis and thermogravimetric analysis (TGA) of cured epoxy are also reported.

The DSC analysis shows the complete exotherms of effective curing reaction indicating the efficiency of AFAFFC as curing agent for DGEBA resin. The kinetic studies reveal that the curing reaction is first order. Mechanical properties reflect the brittleness of cured matrix and TGA shows that the cured matrixes are stable up to around 240°C.

The curing agent AFAFFC has been synthesised by using aniline and furfuraldehyde. By changing amine and aldehyde, other curing agents could be synthesised and the curing efficiency of these for epoxy resin could also be studied.

The method for curing study of epoxy resin (DGEBA) is novel and relevant as the cured products have high performance applications in protective coatings and adhesives for most substrates.

The purpose of this paper was to check effectiveness of amine functional chloroaniline acetaldehyde condensate (AFCAC) as a new curing agent for diglycidyl ether of bisphenol A (DGEBA) resin. For this purpose, first AFCAC was synthesised, characterised and then curing reaction was carried out.

Equimolecular mixture of AFCAC and DGEBA was subjected to curing reaction, and the reaction was followed by differential scanning calorimetry (DSC) analysis. The kinetic studies of this curing reaction were also carried out from those DSC exotherms. The mechanical properties, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) of cured epoxy were also reported.

DSC results reflected the effective first order curing reaction of AFCAC with epoxy resin. Mechanical properties reflected appreciable rigidity of AFCAC cured epoxy matrix and TGA showed that the cured epoxy networks were thermally stable up to around 297°C.

The curing agent AFCAC was synthesised by using chloroaniline and acetaldehyde in acid medium. There are some limitations for this procedure. The synthetic procedure is pH dependent. So reaction cannot be done at any pH value. The reaction must also be carried out at room temperature without any heating. To obtain low molecular weight curing agent, chloroaniline and acetaldehyde cannot be taken in equimolecular ratio because the equimolecular mixture of them produces high molecular weight condensate. This was shown in our previous publication. Some implications are also there. By changing amine and aldehyde other curing agents could be synthesised and the curing efficiency of those for epoxy resin could also be studied.

Experimental results revealed the greater suitability of AFCAC as curing agent for DGEBA resin and novelty of AFCAC cured matrix in the field of protective coating, casting, adhesives, etc.

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.

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.

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.

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.

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.

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.

Polymeric parts produced by 3D stereolithography (SL) process have poorer mechanical properties as compared to their counterparts fabricated via conventional methods, such as injection or compression molding. Adding nanofillers in the photopolymer resin for SL could help improve mechanical properties. This study aims to achieve enhancement in mechanical properties of parts fabricated by SL, for functional applications, by using well-dispersed nanofillers in the photopolymers, together with suitable post-processing.

Carbon nanotubes (CNTs) have high strength and Young’s modulus, making them attractive nanofillers. However, dispersion of CNTs in photopolymer is a critical challenge, as they tend to agglomerate easily. Achieving good dispersion is crucial to improve the mechanical properties; thus, suitable dispersion mechanisms and processes are examined. Solvent exchange process was found to improve the dispersion of multiwalled carbon nanotubes in the photopolymer. The UV-absorbing nature of CNTs was also discovered to affect the curing properties. With suitable post processing, coupled with thermal curing, the mechanical properties of SL parts made from CNTs-filled resin improved significantly.

With the addition of 0.25 wt.% CNTs into the photopolymer, tensile stress and elongation of the 3D printed parts increased by 70 and 46 per cent, respectively. With the significant improvement, the achieved tensile strength is comparable to parts manufactured by conventional methods.

This allows functional parts to be manufactured using SL.

In this paper, an improved procedure to incorporate CNTs into the photopolymer was developed. Furthermore, because of strong UV-absorption nature of CNTs, curing properties of photopolymer and SL parts with and without CNT fillers were studied. Optimized curing parameters were determined and additional post-processing step for thermal curing was discovered as an essential step in order to further enhance the mechanical properties of SL composite parts.