Diglycidyl Ether Of Bisphenol A Resin Research Articles

Mechanical and electrical performance of glass fiber reinforced plastic insulation for cryogenic application in fusion magnet irradiated in fast breeder reactor

In a superconducting (SC) magnet fusion reactor, the insulation material used has to withstand significant fluxes of neutrons and neutron-induced gamma radiation. Epoxy-based glass fiber-reinforced plastic (GFRP) composites are the insulation system for fusion magnets and are highly demanding. This insulation system requires excellent mechanical and electrical performance under mixed neutron and gamma radiation at cryogenic temperatures. The insulation material developed consists of boron-free S-glass fiber impregnated with a two-component modified Diglycidyl ether of Bisphenol-A (DGEBA) epoxy resin. An anhydride-cured DGEBA resin system is not suitable for cryogenic temperatures. Therefore, to overcome this thermal stress issue in cryogenic components of SC magnets, a high-toughness, flexible, aromatic amine-cured epoxy resin system was developed for the insulation system. In order to assess the radiation resistance for mechanical and electrical properties, the composite samples were irradiated in the fast breeder test reactor (FBTR) at IGCAR, Kalpakkam, India. The irradiation experiment was carried out for a neutron fluence of 1.0E+21 n/m2 and a gamma dose of 0.4 MGy at a full reactor power of 32 MWt. The tensile strength, interlaminar shear strength, and breakdown strength measurements were investigated before and after irradiation at room temperature and 77 K. The test results indicate that no significant degradation was observed in the properties of the irradiated samples up to the above-mentioned radiation doses.

Acetylated lignin as a biocomponent for epoxy coating — Anticorrosive performance analysis by accelerated corrosion tests

Carbon steel is one of the main metallic materials used in the manufacture of products in various sectors of society. The high susceptibility of this material to the corrosive process makes it necessary to use mechanisms to protect it from corrosion, with the use of epoxy coatings being one of the main methods. However, in harsh environments, the anticorrosive ability of epoxy coatings weakens. Therefore, there is a growing number of studies of compounds to be used as additives in the development of anticorrosive coatings. This work uses Kraft lignin, a waste from the pulp and paper industry, as a bio-additive for epoxy resins to be used in the corrosion protection of carbon steel when exposed to severe corrosion environments. For this, accelerated corrosion tests of salt spray, ultraviolet weathering, and saturated humidity were carried out. The epoxy-lignin coatings were obtained by incorporating acetylated lignin (AKL) in the diglycidyl ether of bisphenol-A resin (DGEBA). The curing agent for the coatings was isophorone diamine (IPDA). Two types of epoxy-lignin coatings were prepared, namely: DGEBA/7.5% AKL, and DGEBA/15%AKL. The structural characterization of the coatings was evaluated by Fourier transform infrared spectroscopy (FTIR). The physicochemical properties of the coatings were analyzed by testing contact angle, gel content, water vapor transmission, and ion permeation. The anticorrosive properties of the coatings were evaluated by electrochemical impedance spectroscopy (EIS). The performance of coatings with acetylated lignin was compared with the epoxy coating without acetylated lignin and the corrosion protection mechanism of epoxy-lignin coatings was proposed. The results indicate that the addition of acetylated lignin improves the resistance of the coatings against corrosion, as demonstrated by higher impedance values and capacitive behavior in the accelerated corrosion tests. Additionally, the coatings with acetylated lignin exhibit better performance in blocking the migration of Na+ and Cl− ions, further slowing down the corrosion process.

Experimental evaluation on the synergistic effect of PC/ABS/DGEBA blend in fracture toughness enhancement of CFRP composites at cryogenic temperatures

AbstractThe current study confirms that modified carbon fiber reinforced polymer (CFRP) composites have higher fracture toughness than unmodified CFRP composites achieved by exploiting the synergistic effect of a polycarbonate (PC)/acrylonitrile butadiene styrene (ABS) blend in toughening the diglycidyl ether of bisphenol A (DGEBA) epoxy resin. The CFRP composite specimens are tested at near cryogenic temperatures using TMA, DMA, and microcrack analysis to determine the best‐suited concentration of ABS in the PC/ABS blend. TMA and DMA results, as well as microcrack analysis at cryogenic temperatures (CT), confirm that the blend 90/10 is effective in reducing the brittle nature of DGEBA resin and increasing bond strength, resulting in the fracture toughness enhancement of CFRP specimens at CT. Further investigation of 90/10 modified CFRP (90/10 m‐CFRP) and unmodified CFRP specimens using Mode II fracture using ENF test and SEM analysis reveal significant reduction in brittle characteristics of matrix with increase in elongation at failure and fracture surface morphologies confirm nano web‐like structures bridging the CF layers, proving to improve fiber/matrix bond strength. This study concludes the effectiveness of hybrid PC/ABS blend in synergistically‐modifying DGEBA resin for improved fracture toughness of CFRP laminates across a wide temperature range (−150°C to 150°C).

Novel bio-based epoxy resins from eugenol derived copolymers as an alternative to DGEBA resin

A novel vinyl ether monomer from eugenol, 2-eugenoloxyvinyl ether (EEVE), was synthesized and copolymerized with cyclohexyl vinyl ether (CHVE) at three different weight ratios (25, 50 and 75 wt%) via carbocationic polymerization. Polymerization occurred exclusively through the vinyl ether groups leaving the allylic functionality of eugenol moieties available for epoxidation. Epoxidation of the copolymers resulted in epoxy resins with varying amounts of epoxy contents. Cured coatings and free films were produced from the epoxidized copolymers and from diglycidyl ether of bisphenol-A (DGEBA) resin as a reference via reacting with two amine curatives at elevated temperatures. The glass transition temperature of the networks derived from the Epoly(75EEVE-co-25CHVE) resin with 25 wt% CHVE monomer was lower (about 66 °C) than the networks from DGEBA resin (>120 °C), however, Epoly(75EEVE-co-25CHVE) networks showed better mechanical properties (modulus, elongation). The results showed that coatings derived from Epoly(EEVE-co-CHVE) copolymers are comparable in terms of hardness to DGEBA coatings. However, compared to DGEBA coatings which show very poor flexibility (0 % mandrel band), Epoly(75EEVE-co-25CHVE) showed excellent flexibility (32 % mandrel band) and higher base resistance (>3 months). These partially biobased epoxy resins derived from eugenol have the potential to be competitive with petroleum-based DGEBA resins in coatings applications.

Novel bio-based epoxy resins from eugenol as an alternative to BPA epoxy and high throughput screening of the cured coatings

A novel vinyl ether monomer from eugenol, 2-eugenoloxyvinyl ether (EEVE), was synthesized and used as a building block for polymeric epoxy resins. The EEVE monomer was polymerized via cationic polymerization of the vinyl ether group leaving the allylic functionality of eugenol available for further epoxidation. Epoxidized poly(EEVE) resins varying in levels of epoxidation (epoxy equivalent weights from 360 to 870 g/eq) were produced and cured with twelve amine curatives at ambient and elevated temperatures for different time intervals to evaluate and optimize the curing regime. The cured coatings were screened with high throughput dye extraction and “conventional” coating testing methods and compared to coatings produced from diglycidyl ether of bisphenol-A (DGEBA). Results showed that coatings derived from epoxidized poly(EEVE) [Epoly(EEVE)] can be tuned from soft and elastic with hardness <50 GPa and glass transition temperatures (Tgs) < 20 °C to hard and brittle with hardness >500 GPa and Tgs > 60 °C by varying the extent of epoxidation and the nature of curative, whereas DGEBA resulted in hard and brittle coatings irrespective of the type of curative used in the study. Compared to DGEBA resin, coatings with similar or higher crosslink densities and hardness were obtained from Epoly(EEVE) resins with >50% epoxidation of EEVE moieties using the same curative and curing regime. These partially biobased epoxy compounds derived from eugenol have the potential to be competitive with petroleum-based DGEBA resins in coatings applications.

Effect of sulfur in different valence on flame retardance of epoxy resin for light emitting diode

AbstractA novel phosphorus/nitrogen‐containing flame retardant (DOPO‐AM) was synthesized by 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and acrylamide (AM) and its chemical structure was characterized. DOPO‐AM was added into diglycidyl ether of bisphenol‐A (DGEBA) with curing agent m‐xylylenediamine (MXDA)to prepare flame retarded epoxy resin to reduce the possibility of fire. The compounds with different valences sulfur respectively replace partial DGEBA resin to study the effects of sulfur valences on the flame retardance of epoxy resins. The results indicated that DOPO‐AM had excellent flame retardance for epoxy resin. When phosphorus content was only 0.75%, DGEBS resin containing DOPO‐AM achieved the limiting oxygen index value of 34.55% and vertical burning test (UL‐94) V‐0 rating. Although sulfur element is help for refractive index of epoxy resin, sulfur element in three kinds of valences all weaken the flame retardant of epoxy resin. Improving phosphorus content is help for the synergistic effect of PN and PNS. Moreover, the flame retardance is not proportional to sulfur valence, sulfide with +2 valence had the best flame retardance. However, +6 valence sulfonic with strong oxidation effect worsen the flame retardant. Simultaneous thermal analysis of thermogravimetric analyzer and differential scanning calorimeter and scanning electronic microscopy photographs verified the above conclusion.

Compatibilization and toughness modification of linear aliphatic epoxy compound on paving epoxy asphalt

Epoxy asphalt (EA), which is usually prepared by diglycidyl ether of bisphenol A (DGEBA), curing agent and asphalt, is a kind of high-performance pavement material in highway construction. However, because of rigid molecular structure of DGEBA, poor compatibility with asphalt and high cross-linking density of three-dimensional network, cured EA usually has high strength but poor toughness especially at low temperature. In order to solve the problem of insufficient toughness of EA below glass-transition temperature (Tg) and eliminate the potential brittle fracture of EA mixture, linear aliphatic epoxy compounds, which have low viscosity, good molecular flexibility, similar solubility parameter and polarity with asphalt or DGEBA resin, can be used as phase structure controller and toughner to modify EA. By introducing a little of linear aliphatic epoxy compound, such as 1, 4-butanediol diglycidyl ether (BDDGE) or 1, 6-hexanediol diglycidyl ether (HDDGE), not only the viscosity of EA could be significantly decreased during the curing process, but also the phase compatibility of EA could be improved. An obvious reduction in storage modulus (E′) at low temperature and decreased Tg also prove that BDDGE or HDDGE modified EA have better toughness than neat EA at low temperature. The optimum amount of linear aliphatic epoxy compound based on its mixture with DGEBA should be 10–15 wt%.

One-Step Preparation of Hyperbranched Polyether Functionalized Graphene Oxide for Improved Corrosion Resistance of Epoxy Coatings

In this paper, hyperbranched polyether functionalized graphene oxide (EHBPE-GO) was prepared by a facile one-step method. Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), thermogravimetric analyzer (TGA), and trans-mission electron microscopy (TEM) results confirmed the formation of EHBPE-GO. Then, EHBPE-GO was cured with phenolic amides at room temperature to prepare epoxy coatings. The corrosion resistance of epoxy coatings was investigated systematically by using electrochemical and traditional immersion methods. Results show that a small amount of EHBPE-GO (8 wt % of Diglycidyl ether of bisphenol A (DGEBA)) in epoxy coating achieves 50% higher improvement in acid-resistance than unmodified neat DGEBA resin. For the nanocomposite epoxy coating, the superior acid-resistance is attributed to the increased crosslink density and the impermeable 2D structure of EHBPE-GO. This work provides a facile strategy to develop the effective improved corrosion resistance nanofiller for epoxy coating.

PEG-based epoxy and epoxy/silica networks: Thermal, mechanical, and thermo-mechanical investigations

A diglycidyl ether resin and an amine hardener, both based on polyethylene glycol (PEG) were synthesized and utilized for preparing new epoxy thermosetting materials. Two popular monomers, i.e. diglycidyl ether of bisphenol A (DGEBA) and/or isophorone diamine (IPDA) were also utilized. Three transparent and rubber-like films were fabricated through one combinational and two non-combinational manners. In the combinational manner, diglycidyl ether of PEG (DGEPEG) and DGEBA with equal moles were cured with equal moles of amine-functionalized PEG (APEG) and IPDA. In the non-combinational manners, at one time, the PEG-based resin was cured with IPDA hardener, and at the other time, DGEBA resin was cured with PEG-based amine hardener. Stoichiometric amounts of epoxy resin and amine hardener were used in all of the curing processes. Three epoxy/silica nanocomposites with silica-loading of 5.0 wt%, and with the same epoxy matrices were also synthesized similarly. Silica nanoparticles were organically modified and amine-functionalized prior to use. The neat epoxy networks and their silica-loaded nanocomposites were characterized by FT-IR, and FE-SEM techniques. The structure and composition of the six networks obtained significantly affect their thermal, mechanical, and thermo-mechanical behaviors. These influencing factors were fully investigated by thermogravimetric analysis, tensile testing, and dynamic mechanical analysis.

Thermal degradation mechanism and flame retardancy of epoxy systems containing tris(3-nitrophenyl) phosphine

The aim of this work was to study the effect of tris(3-nitrophenyl) phosphine (NPPh3), which showed a good thermal stability and carbon-forming ability, on the flame retardancy and thermal degradation mechanism of epoxy resins. A series of diglycidyl ether of bisphenol A (DGEBA) loaded with tris(3-nitrophenyl) phosphine (NPPh3) were prepared. It was found that NPPh3 can effectively improve the flame retardancy and thermal stability of the composites. When the loading amount of NPPh3 was 14%, the LOI value of the DGEBA composites was 29.2% (about 1.53 times the corresponding value of the original DGEBA resin). Thermal stability was studied by thermogravimetric analysis, and the results showed that the addition of NPPh3 can improve char formation of this system both in nitrogen and in air atmosphere. Specifically, its combustion residue at 800 °C in nitrogen atmosphere was about 4.26 times of the original resin. Differential scanning calorimetry indicated that NPPh3 slightly decreased the glass transition temperature of epoxy resins. Additionally, the gaseous degradation products were analyzed by thermogravimetric analysis/infrared spectrometry, providing insight into the thermal degradation mechanism. Scanning electron microscopy and Fourier transform infrared were brought together to evaluate the morphology and structure of the residual char obtained after combustion.

Fracture toughness and ductile characteristics of diglycidyl ether of bisphenol-A resins modified with biodegradable epoxidized linseed oil

Abstract Epoxidized linseed oil (ELO) was synthesized to improve the biodegradability and fracture toughness of the diglycidyl ether of bisphenol-A (DGEBA). The ELO was characterized using Fourier transform infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC), and epoxy equivalent weight (EEW) tests. DGEBA was blended with ELO contents from 10 to 40 wt% to obtain a modified network. DGEBA and the DGEBA/ELO blends were characterized by their biodegradability, thermal properties, and fracture toughness. The thermal properties of the DGEBA/ELO blends were investigated using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The fracture toughness of the DGEBA/ELO blends was studied by measuring the Izod impact strength and the critical stress intensity factor (KIC). The morphologies were observed by scanning electron microscopy (SEM). In the biodegradability results, the DGEBA/ELO blends degraded 5% of the initial weight. The thermal property results confirmed that the crosslinking density of the epoxy networks decreased. The impact strength of the DGEBA/ELO blends was significantly improved with the addition of ELO owing to the reduced cross-linking density of the epoxy network.

Occupational allergic contact dermatitis caused by epoxy chemicals: occupations, sensitizing products, and diagnosis.

Epoxy products are among the most common causes of occupational allergic contact dermatitis. Diglycidyl ether of bisphenol A resin (DGEBA-R) is the most important sensitizer in epoxy systems. To describe patients with occupational allergic contact dermatitis caused by epoxy products. Patients with allergic reactions to epoxy chemicals were chosen from test files (January 1991 to June 2014). Only patients with occupational contact allergy to some component of epoxy resin systems were included. We analysed patch test results, occupation, symptoms, and exposure data. We found a total of 209 cases with occupational contact allergy to epoxy chemicals. The largest occupational groups were painters (n = 41), floor layers (n = 19), electrical industry workers (n = 19), tile setters (n = 16), and aircraft industry workers (n = 15). A total of 82% of the patients reacted to DGEBA-R. Diagnosis of the DGEBA-R-negative patients required testing with m-xylylenediamine, N,N'-tetraglycidyl-4,4'-methylenedianiline, 1,4-butanediol diglycidyl ether, 2,4,6-tris-(dimethylaminomethyl)phenol, diglycidyl ether of bisphenol F resin, N,N'-diglycidyl-4-glycidyloxyaniline, isophoronediamine, 4,4'-diaminodiphenylmethane, diethylenetriamine, and cresyl glycidyl ether. The hands/upper extremities were most commonly affected (69%), but facial symptoms were also frequent (60%). Allergic contact dermatitis caused by to epoxy products cannot always be diagnosed by the use of commercial test substances. Workplace products need to be tested.

Peculiarities in the structure – Properties relationship of epoxy-silica hybrids with highly organic siloxane domains

Epoxy-silica hybrids were produced from a diglycidyl ether of bisphenol-A resin using Jeffamine 230 hardener with a two-step in situ generation of siloxane domains. The siloxane component was obtained by hydrolysis and condensation of a mixture of γ-glycidoxypropyl-trimethoxysilane and tetraethoxysilane, which was added to the epoxy resin after removal of the formed alcohols and water. The morphological structure of the hybrids was examined by TEM, SAXS and WAXS analysis, and confirmation of the identified co-continuity of the constitutive phases for nominal silica contents greater than 18%wt was obtained by TGA and DMA analysis. While the loss modulus was found to increase monotonically over the entire range of siloxane content, the glass transition temperature exhibited a stepwise increase upon reaching the conditions for phase co-continuity. Molecular dynamics simulations were used to produce model structures for silsequioxanes cage-like structures, as main constituents of the siloxane phase. The predicted interdomain distance between the silsequioxane structures was in agreement with the SAXS experimental data.

Contact allergy to reactive diluents and related aliphatic epoxy resins.

Diglycidyl ether of bisphenol A resin (DGEBA-R) is the most common sensitizer in epoxy systems, but a minority of patients also develop contact allergy to reactive diluents. To analyse the frequency and clinical relevance of allergic reactions to different epoxy reactive diluents and related aliphatic epoxy resins. Test files (January 1991 to June 2014) were screened, and the clinical records of patients with allergic reactions were analysed for occupation, concomitant allergic reactions, and exposure. A total of 67 patients reacted to at least one of the compounds. The largest numbers of allergic reactions were to phenyl glycidyl ether (PGE; n = 41), 1,4-butanediol diglycidyl ether (BDDGE; n = 34), and p-tert-butylphenyl glycidyl ether (PTBPGE; n = 19). Ten of the patients did not have contact allergy to DGEBA-R. The reactions of 5 of these were related to the use of BDDGE-containing products. We found no significant exposure to PGE or PTBPGE in patients sensitized to them, but some of the patients had used cresyl glycidyl ether-containing products. Allergic reactions to reactive diluents and related aliphatic epoxy resins usually occurred together with reactions to DGEBA-R. BDDGE was the clinically most significant compound, and was the sole cause of occupational allergic contact dermatitis in 3 patients.

Novel nanocomposites based on epoxy resin/epoxy-functionalized polydimethylsiloxane reinforced with POSS

The purpose of the present study is to develop novel nanocomposites based on diglycidylether of bisphenol A (DGEBA) combined with diglycidylether-terminated polydimethylsiloxane (DG-PDMS), reinforced with 10 wt.% (mono-/octa) epoxy POSS nanocages (MEP or OEP-POSS). DG-PDMS and POSS compounds were covalently incorporated into DGEBA resin via copolymerization of epoxy groups. The effect of both DG-PDMS and POSS nanoparticles on the curing reaction, glass transition temperature (Tg), thermal stability, hardness and morphology of DGEBA/DG-PDMS ± POSS nanocomposites were studied by DSC, FTIR, DMA, TGA, SEM/EDX, AFM and contact angle measurements. SEM/EDX and AFM results prove that OEP-POSS is well dispersed within DGEBA/DG-PDMS polymer matrix, while MEP-POSS forms large POSS aggregates. The thermo-mechanical properties of POSS based nanocomposites are also in good correlation with morphology features. MEP-POSS based nanocomposite with heterogeneous dispersion of POSS aggregates exhibits lower Tg value and thermal stability in comparison with OEP-POSS nanocomposite which exhibits a nanoscale dispersion of the POSS cages. The obtained Tg of OEP-POSS based nanocomposite increases with 31 °C in comparison with the unreinforced matrix. Moreover, this nanocomposite shows the highest storage modulus (E′) and hardness.

Curing study and evaluation of epoxy resin with amine functional chloroaniline acetaldehyde condensate

Purpose – 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. Design/methodology/approach – 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. Findings – 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. Research limitations/implications – 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. Originality/value – 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 investigation of methyl phenyl silicone resin/epoxy resin using epoxy-polysiloxane as compatibilizer

A novel polysiloxane (HPS) with epoxy and phenyl groups was synthesized by controlled hydrolysis and condensation of γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH560) and diphenyl silanediol. Besides, HPS was used as the compatibilizer of the miscible diglycidyl ether of bisphenol A (DGEBA)/methyl phenyl silicone resin (Si603) blend. The structure and effect of HPS were characterized by Fourier transform infrared spectra, nuclear magnetic resonance (1H-NMR), differential scanning calorimetry, and scanning electron microscopy (SEM). The results showed that HPS could significantly improve the compatibility between epoxy resin (EP) and Si603 resin. In addition, the glass transition temperature (T g) of the blend increases with increasing amount of Si603 from 129 to 151 °C. The thermal stability of blending system was studied by thermogravimetric analysis, derivative thermogravimetric analysis and SEM. The results showed that the incorporation of Si603 into DGEBA resin not only obviously increased the thermal resistance, but also remarkably improved the flame retardancy. The high limiting oxygen index of the HPS/EP/Si603/DDM system at 31 is considered as excellent flame retardancy in the epoxy system.

Integration of biobased functionalized feedstock and plastisol in epoxy resin matrix toward developing structural jute biocomposites with enhanced impact strength and moisture resistance properties

Epoxy resin matrix based on diglycidyl ether of bisphenol A (DGEBA) was modified with addition of epoxidized soybean oil (ESBO). Structural jute composites prepared with ESBO modified DGEBA resin showed a decrease in tensile strengths, owing to reduced cross linking density. Percentage elongation of the samples increased with addition of ESBO. An optimized composition was identified, at which the composite showed increase in tensile strength, modulus and elongation. Interestingly, impact strengths increased initially with incorporation of ESBO, but with further increase in ESBO, impact strengths decreased. Structural Jute composites were also prepared by incorporating polyvinyl (chloride) (PVC) plastisol into the modified matrix which showed an increase in both tensile and impact strengths. Fourier transform infrared spectroscopy (FT‐IR) analysis indicated the curing state of the composites. The spectrum peaks became increasingly stronger in the OH band with increasing ESBO quantities. This could be attributed to the hydrophilic nature of ESBO, a result that was well supported by the moisture absorption test. Although, water uptake capacity of ESBO/DGEBA modified matrix composites recorded increasing trend with increased ESBO content, with inclusion of plastisol, the water uptake values dropped. Composite with DGEBA/ESBO/plastisol modified matrix actually recorded water uptake capacity comparable to composite with neat DGEBA, possibly owing to improved interfacial adhesion and hydrophobic nature of PVC plastisol. POLYM. COMPOS., 37:391–397, 2016. © 2014 Society of Plastics Engineers

Screening occupational contact allergy to bisphenol F epoxy resin

Epoxy resins based on diglycidyl ether of bisphenol F (DGEBF) are widely used as such in applications requiring chemical resistance, and also together with diglycidyl ether of bisphenol A resin (DGEBA-R). Concomitant patch test reactions to DGEBA-R and DGEBF resin (DGEBF-R) are common. Previous studies have yielded conflicting results on the frequency of independent DGEBF-R contact allergies. To report the results of over 11 years of screening with DGEBF-R. An in-house test substance of DGEBF-R (Epikote 862) was tested in the baseline patch test series, first at 1% and later at 0.25%. Test files were screened for allergic reactions to DGEBF-R and DGEBA-R, and the clinical records of positively reacting patients were analysed for occupation and exposure. Among 1972 patients, 66 (3.3%) reacted to DGEBF-R and 96 (4.9%) to DGEBA-R. Independent DGEBF-R allergies were seen in 5 patients only, and independent DGEBA-R allergies in 35. Specific exposure to DGEBF-R was found in 26 patients. The main occupational fields were the aircraft industry, the electrical and sports equipment industry, boat building, painting/floor coating, tile setting, and pipe relining. Independent contact allergies to DGEBF-R were rare, and screening with it was not found to be useful.

High performance modification of hyperbranched polyborate on diglycidyl ether of bisphenol‐a resin

High performance epoxy resin was obtained by introducing hyperbranched polyborate (HBPB) into diglycidyl ether of bisphenol A (DGEBA) resin to overcome the defects such as low char yield and poor toughness of DGEBA resin. By virtue of the massive functional end groups, hyperbranched and rigid boron‐containing structures of HBPB, the thermal resistance of DGEBA resin cured with diamino diphenyl sulfone (DDS) can be greatly improved. Moreover, with the toughening effect of hyperbranched structures of HBPB, the mechanical properties such as flexural strength and interlaminar shear strength of the carbon fiber reinforced DGEBA‐DDS composite could be greatly increased by HBPB without a decrease on modulus and glass transition temperature of DGEBA‐DDS resin. POLYM. COMPOS. 36:424–432, 2015. © 2014 Society of Plastics Engineers