Abstract Blends of polystyrene (PS) with an epoxy monomer (DGEBA) and a tertiary amine (BDMA), were initially miscible at 120°C but phase‐separated very low conversions in the course polymerization. Although there was significant difference between refractive indices DGEBA/BDMA solution, index network increased polymerization, attaining value close to that PS complete conversion. A sharp decrease light transmittance observed cloud‐point, conversions. However, continuous increase phase...

Abstract The cure reaction of a commercial epoxidized novolac with 4,4' diaminodiphenylsulfone (DDS) was studied at constant temperatures in the range 120–270°C, as well heating rates (differential scanning calorimetry, DSC). Stoichiometric formulations did not attain complete conversion due to presence topological restrictions. limiting x max = 0.8. Samples containing an amine excess (≥ 20%) could be completely reacted, whereas this possible for epoxy excess. 20% showed maximum value glass...

A bisphenol A-based epoxy resin (DGEBA) was modified with 15 weight percent polysulphone (PSU) and thermally cured using 4-4′diaminodiphenylsulphone (DDS). Starting from a homogeneous DGEBA/DDS/PSU mixture, the system developed two-phase morphology upon network formation. Dynamic mechanical analysis (DMA), transmission optical microscopy (TOM) scanning electron (SEM) studies showed that co-continuous consisting of two distinct domains. One domains an rich matrix containing PSU particles...

Polymer-dispersed liquid crystals (PDLCs), consisting of a dispersion LC-rich domains in polymer matrix, are used different types electrooptical devices. Their efficiency can principle be increased if the LC exhibit uniform characteristic size range wavelength visible light. In an attempt to generate this type morphology, model PDLC system based on 50 wt % solution N-4-ethoxybenzylidene-4'-n-butylaniline (EBBA) epoxy monomer (diglycidyl ether bisphenol A, DGEBA) was analyzed. The...

Abstract Summary: Reactions taking place in a homogeneous solution of an epoxy monomer based on the diglycidyl ether bisphenol A (DGEBA) and palmitic acid (PA), presence benzyldimethylamine (BDMA), were investigated using Fourier‐transformed infrared spectroscopy (FTIR) size exclusion chromatography (SEC). In stoichiometric formulations prepared with equal molar ratios (E) to carboxyl groups, E/PA = 1, main reaction was addition giving β ‐hydroxy ester. This followed by transesterification...

Thermally reversible light scattering (TRLS) films were synthesized by the reaction-induced phase separation of solutions N-4-ethoxybenzylidene-4'-n-butylaniline (EBBA; 20−50 wt %) and polystyrene (PS; 1−5 in diglycidyl ether bisphenol A (DGEBA), using benzyldimethylamine (BDMA) (0.06 mol with respect to epoxy groups), initiate polymerization. The material obtained after complete reaction consisted a dispersion EBBA/PS droplets network partially swollen EBBA. fractionation EBBA between both...

Abstract An azo prepolymer (TAZ) was synthesized by reaction between Disperse Orange‐3 (DO3) and diglycidyl ether of bisphenol A (DGEBA). Selected amounts TAZ were blended with DGEBA cured an aliphatic diamine, either meta ‐xilylenediamine (MXDA) or polyetheramines (Jeffamine D series). The photoinduced anisotropy optical storage properties in two series crosslinked epoxy‐based polymers different architectures chromophore contents (from 3 to 24 weight) have been investigated. Measurements...

Abstract Ternary mixtures based on stoichiometric of the diglycidyl ether bisphenol‐A (DGEBA) and 4,4′‐diaminodiphenyl sulfone (DDS) two miscible thermoplastics, poly(methyl methacrylate) (PMMA) poly(hydroxy bisphenol‐A) (phenoxy), were investigated by optical microscopy (OM), atomic force (AFM) dynamic mechanical analysis (DMA). Mechanical testing was used to study ultimate behavior. All modified epoxy heterogeneous. DMA has been shown be an excellent technique for detecting morphologies...

Abstract Epoxy–aromatic diamine formulations are simultaneously modified with two immiscible thermoplastics (TPs), poly(ether imide) (PEI) and polysulfone (PSF). The epoxy monomer is based on diglycidyl ether of bisphenol A the aromatic diamines (ADs) either 4,4′‐diaminodiphenylsulfone or 4,4′‐methylenebis(3‐chloro 2,6‐diethylaniline). influence TPs epoxy–amine kinetics investigated. It found that PSF can act as a catalyst. presence TP provokes an increase gel times. Cloud‐point curves...

Poly(methyl methacrylate) (PMMA, Mn = 232 000) was used to modify a stoichiometric epoxy (diglycidyl ether of bisphenol A; DGEBA)–anhydride (methyl tetrahydrophthalic anhydride; MTHPA) thermoset. PMMA concentrations in the range 3–7 wt% led morphologies consisting continuous PMMA-rich region that appeared rough and striated scanning electron micrographs large domains thermoset exhibiting dispersion particles micrometre range. These are result critical point location, estimated at 2.1 as high...

An epoxy-diamine system was simultaneously modified with two immiscible thermoplastic polymers, polysulfone (PSF) and poly (ether imide) (PEI), to develop tough materials without adding high quantities of modifiers, in order avoid the processibility problems caused by initial viscosity mixtures. The mechanical behavior blends containing 10 15 wt% total analyzed compared generated morphologies. scanning electron micrographs (SEM) broken surfaces showed that when a small part PEI is replaced...

Abstract As an example of thermoplastic/liquid crystal blends that do not exhibit a liquid‐liquid immiscibility region in their phase diagrams, polystyrene (PS)/ N ‐4‐ethoxybenzylidene‐4′‐butylaniline (EBBA) blend was analyzed. The complete diagram built up using thermal transitions determined by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). boundary the nematic + isotropic fitted with Flory‐Huggins‐Maier‐Saupe model, extended to consider polydispersity PS....

Abstract New photosensitive materials containing photochromic azobenzene moieties were synthesized. For this purpose, an epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) was reacted with chromophore (disperse orange 3, AZ) to satisfactorily synthesize azo‐modified prepolymer, which then used generate series epoxy‐based polymers azo groups. Three different amines as hardeners, the aim obtaining chemical structures. Understanding polymerization kinetics is essential for intelligent...