Epoxy Novolac

It is commonly acknowledged that polymer composites in service are often subjected to not only intricate mechanical loads but also harsh environmental conditions. The mechanical and thermal properties of five particular composites are explored here. The composites are composed of laminates of glass cloth type "E" sheet infilled with a duroplastic matrix. This is a thermoset polymer-epoxy resin with different molecular weights. The composites were fabricated by IZOERG company, which is based in Poland. The final articles were 1...

The surface properties of epoxy resin coatings influence their function as substrates for subsequent coats. Variation in ambient cure conditions (temperature and relative humidity, RH), stoichiometry (ratio of epoxy: amine) and delay time between epoxy component mixing and film casting ("induction time") significantly altered the surface properties of ambient cured epoxy resin coatings (Dow Epoxy Novolac D.E.N. 431, resorcinol diglycidyl ether and 4,4-diaminodicyclohexylmethane). Gravimetric analysis showed that increasing induction time significantly reduced surface layer formation (carbamation) of cured epoxy resin coatings at 80% RH but had no measurable effect at 40% RH and below...

A series of modified epoxy novolac resins (ENRs) were prepared by incorporating dodecyl chain surfactants with polar groups such as amine, carboxylic acid, phenol, resorcinol and benzene sulfonic acid. Except for the case of benzene sulfonic acid, no macrophase separation is seen in any of the modified ENRs. The addition of these dodecyl surfactants to ENR hinders the cross-linking reaction as revealed from their dynamic and isothermal DSC curing measurements and reduced glass transition temperatures ( T g )...

A better understanding of the chemical reaction between epoxy and amine compounds at a solid interface is crucial for the design and fabrication of materials with appropriate adhesive strength. Here, we examined the curing reaction kinetics of epoxy phenol novolac and 4,4'-diaminodiphenyl sulfone at the outermost interface using sum-frequency generation spectroscopy, and X-ray and neutron reflectivity in conjunction with a full atomistic molecular dynamics simulation. The reaction rate constant was much larger at the quartz interface than in the bulk...

Investigating Epoxy/hardener ratio and adsorption rate in epoxy/graphene oxide nanocomposites is of great importance, since these values can affect on the mechanical properties of the nanocomposite. In this study, molecular dynamics simulation was used to investigate and compare the mechanical properties of epoxy/graphene and graphene oxide nanocomposites (EPON 828, EPON 862, Epoxy Novolac, and Cycloaliphatic Epoxy with GNs and GO). Also, the effect of different weight percentages of graphene oxide (0,1,3 and 5 wt %), different weight percentages of epoxy compared to hardener, adsorption rate, and different temperatures were studied...

A core-shell magnetic sulfonatocalix[6]arene covalently cross-linked polymer was proposed as a magnetic adsorbent, combined with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) for the enrichment and determination of epoxy derivatives in canned foods. The adsorbent has high density of host-guest recognition functional groups, abundant binding sites and suitable cavity size, showing good extraction performance for epoxy derivatives. Quantum chemical simulation calculations provedmultiple interaction forces in the adsorption process...

Clarification of adhesive interactions in semiconductor packages can improve reliability of power electronics. In this study, the adhesion interfaces between the epoxy molding compound and Cu-based lead frames were analyzed using the density functional theory. A resin fragment was prepared based on the polymer framework formed in the curing reaction of epoxy cresol novolac (ECN) and phenol novolac (PN), which are typical molding materials. The resin fragment was optimized on the surfaces of Cu and Cu2 O. We calculated the charge density differences for adhesion structures and discussed the origin of adhesive interactions...

In transport sectors such as aviation, automotive and railway, materials combining a high lightweight potential with high flame retardant properties are in demand. Polymeric foams are suitable materials as they are lightweight, but often have high flammability. This study focuses on the influence of different flame retardants on the burning behavior of Novolac based epoxy foams using Isophorone Diamine carbamate (B-IPDA) as dual functional curing and blowing agent. The flame retardant properties and possible modifications of these foams are systematically investigated...

The need for renewable polymers capable of replacing their petrochemical counterparts continues to grow as sustainability concerns rise. Bisguaiacol (BG), a bioinspired alternative to bisphenol-A (BPA), has been synthesized using vanillyl alcohol and guaiacol via an electrophilic aromatic condensation. Purification provides both BG and an oligomeric coproduct with a consistent number average molecular weight and dispersity of ∼650 Da and ∼1.00, respectively. This coproduct has been well characterized as a low-molecular-weight novolac averaging five hydroxyls per molecule and was transformed into an epoxy resin suitable for use in thermosetting resins...

Up to now, various approaches have been used to fabricate lignin-based epoxy thermosets by utilizing lignin or lignin-derivatives, but there is still lack of a simple, effective and environmental-friendly pathway for producing lignin-based epoxy resins from industrial lignin. In this work, a novel strategy - one-pot to synthesize phenolated lignin incorporated novolac epoxy networks (PLIENs) was proposed. As expected, PLIENs obtained from the novel route exhibited preferable mechanical and thermal properties compared with the epoxy resins which obtained from common route...

The rapid progress in silicon carbide (SiC)-based technology for high-power applications expects an increasing operation temperature (up to 250 °C) and awaits reliable packaging materials to unleash their full power. Epoxy-based encapsulant materials failed to provide satisfactory protection under such high temperatures due to the intrinsic weakness of epoxy resins, despite their unmatched good adhesion and processability. Herein, we report a series of copolymers made by melt blending novolac cyanate ester and tetramethylbiphenyl epoxy (NCE/EP) that have demonstrated much superior high-temperature stability over current epoxies...

Composite materials that consisted of a polymer resin as matrix (PMCs), filled using construction and demolition (C&D) wastes powder of different grain sizing in micro-scale were manufactured and studied. Three different kinds of resins were used as the matrix for the purposes of this study. More specifically, composites made of epoxy and unsaturated polyester resins purchased from the market and phenolic resin (novolac) laboratory synthesized, were produced. The morphological and elemental analysis of these materials was performed through scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD)...

A simple and novel method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated to determine the levels of 10 compounds (bisphenol A diglycidyl ether (BADGE), novolac-glycidyl ethers (NOGEs), and their related compounds) migrated from food and beverage cans into food simulants. Method validation showed acceptable linearity, precision, and accuracy. The detection limits ranged from 0.28 to 14.8 μg L-1 , and the quantification limits ranged from 0.94 to 49.3 μg L-1 ...

During this paper, we improved the compressive strength of cementitious matrix based on ion exchanging resin (IER) at 12% and formulated by the modified novolac epoxy polymer surfactant (NEPS) at various percentages (0, 1, 2, 3, 4 and 5%). The results show that the introduction of 1% and 2% of NEPS in the cementitious matrix with 12% of IER increases the compressive strength compared to that of the basic matrix (from 7 to 90 days). However, the formulations 3, 4 and 5% show the compressive strength is less than that of the basic matrix (from 28 to 90 days)...

The aim of the present study was to establish a standard methodology for the extraction of epoxy resin precursors from several types of food packages (cans, multi-layered composite material, and cups) with selected simulation media (distilled water, 5% ethanol, 3% dimethyl sulfoxide, 5% acetic acid, artificial saliva) at different extraction times and temperatures (factors). Biological analyses were conducted to determine the acute toxicity levels of the extracts (with Vibrio fischeri bacteria) and their endocrine potential (with Saccharomyces cerevisiae yeasts)...

In this study, DICY (dicyandiamide)-containing novolac (NN) was first prepared, and then DOPO (9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) was introduced to react with the unsaturated bonds from DICY to obtain a novel phosphorus-nitrogen-containing novolac resin (PNN), which was used as a curing agent for epoxy resins. The curing condition was confirmed by a non-isothermal curing kinetics study. The thermal stability and flame retardancy of the cured epoxy resin system were studied by thermogravimetric analysis (TGA), limited oxygen index (LOI) measurement, UL-94 test and cone calorimeter...

The aim of this work is to develop a biobased functional reactive diluent for thermosetting epoxy resins suitable for high-performance applications. An advanced organosilicon-grafted cardanol novolac epoxy resin (SCNER) was synthesized from cardanol novolac epoxy resin and heptamethyltrisiloxane. After the chemical structure of SCNER was identified by Fourier transform infrared, 1 H NMR, and 13 C NMR, it was used to modify the diglycidyl ether of the bisphenol A (DGEBA)/methylhexahydrophthalic anhydride system...

In this study, the flame-retardant, thermal and mechanical properties of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and nano-SiO2 modified epoxy novolac resin is evaluated, and the combinational effects of both additives are verified. As a hardener, an isophorone diamine (IPDA) and polyetheramine blend is stoichiometrically added to obtain a low viscous epoxy resin system, suitable for resin injection and infusion techniques. The glass transition temperature (Tg) and the silica dispersion quality is affected by the DOPO modification and the nano silica particles...

The present study focuses on the processing and properties of epoxy foams by the use of CO2 blocked hardener N-aminoethylpiperazine (B-AEP) and different resins. Although some studies described the foaming with carbamates, little attention has been given to the interaction of resin properties (such as viscosity) on the foaming performance. Therefore, two resins, diglycidyl ether of bisphenol-A (DGEBA) and epoxy novolac (EN), as well as their 50:50 blend, were foamed with B-AEP and unblocked/blocked AEP hardener mixtures in a batch foaming process...

Conventional shape memory polymers (SMPs) can memorize their permanent shapes. However, these SMPs cannot reconfigure their original shape to obtain a desirable geometry owing to permanent chemically or physically crosslinked networks. To overcome this limitation, novel SMPs that can be reconfigured via bond exchange reactions (BERs) have been developed. In this study, polymer composites consisting of epoxy phenolic novolac (EPN) and bio-based cashew nut shell liquid (CNSL) reinforced by multi-walled carbon nanotubes (CNTs) were prepared...