Search results for "Thermosetting polymer"
showing 10 items of 29 documents
Properties of radiation-modified blends of polyethylene with elastomers and liquid crystalline copolyester
2001
The results are given on the effect of γ-irradiation on properties of blends of high and low-density polyethylene (HDPE, LDPE) with elastomers -ethylene/propylene/diene rubber (EPDM) and chlorinated polyethylene (CPE), and thermotropic liquid crystalline polymer (LCP). The morphological, thermal, mechanical properties (including thermosetting properties) and adhesion properties of blended composites were investigated. A special attention was paid to the applicability of the blends as thermosetting materials (TSM). The LCP used was a copolyester of poly(ethylene terephthalate) with p-(hydroxybenzoic acid) in the ratio 40: 60. It was found that addition of LCP essentially influenced the therm…
Curing of an epoxy resin modified with nanoclay monitored by dielectric spectroscopy and rheological measurements
2006
Dielectric and rheological measurements have been performed in “real-time” to follow curing reaction on blends of a diglycidyl ether of bisphenol-A epoxy resin with 4,4-methylene bis(2,6-diethylaniline) hardener and different amounts of organically modified nanoclay (Nanofil 919) as modifier. The effect of the modifier and its amount on the curing reaction, as well as that of the curing temperature has been studied. Changes in molecular mobility in the reaction mixture have been investigated by dielectric relaxation spectroscopy. Evolutions of ionic conductivity and main relaxation have been analyzed and vitrification times have been obtained and compared with those obtained by rheological …
The effect of a liquid CTBN rubber modifier on the thermo-kinetic parameters of an epoxy resin during a pultrusion process
2003
Abstract Rheo-kinetic behaviour of an epoxy resin, coupled with an anhydride hardener, with different CTBN liquid rubber concentration (0–15 phr), used in fibre reinforced plastics, was analysed comparing experimental data with theoretical models. The modelling of technological pultrusion process for thermoset matrix composites, developed through a numerical code realised with MATLAB, is reported, too. The model includes conduction and cure heat, degree of cure and viscosity evolution during the curing within the die. Considerable differences in process condition, using different rubber amount, are obtained. The numerical modelling of process conditions shows that the CTBN rubber presence i…
Thermomechanical properties of radiation-modified blends of polyethylene with liquid crystalline copolyester
1999
The results of investigation of gamma irradiated blends of high-density polyethylene (PE) with thermotropic polymer liquid crystal (PLC) are presented. The PLC used was a copolyester of 40% poly(ethylene terephthalate) with 60% p-(hydroxy-benzoic acid). The PLC content in the blends was 0, 5, and 10 wt%. The constituents were blended with the use of a single screw extruder. The specimens were prepared by compression molding. The irradiation of the samples was performed by a Co 60 γ-radiation source in inert atmosphere (argon) up to absorbed relatively low doses (up to 200 kGy: 1 Mrad = 10 kGy). The morphological, thermal, and mechanical properties were investigated for irradiated and unirra…
Study and comparison of interaction parameters and phase behavior of epoxy/polystyrene and epoxies copolymer polystyrene-b-poly(methyl methacrylate) …
2008
Thermodynamic studies in terms of phase separation behavior and interaction parameters, in mixtures of epoxy resins (thermoset materials) with thermoplastic additives, consisting of polystyrene (PS) or polystyrene-b-poly(methyl methacrylate) P(S-MMA) (with small proportion of MMA), have been carried out. It can be confirmed that the solubility of P(S-MMA) is an improvement on that of PS, with the prepolymer epoxy resins. Moreover, the interaction parameters are positive at temperatures in which phase separation is observed, but negative at temperatures in which the phase separation window disappears, in the corresponding phase diagram. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engine…
Thermosetting composites based on bronze particles for archaeological and artistic metal heritage cloning
2018
peer-reviewed Artificial Metals are polymeric semi-metallic composites obtained by combining thermosetting resins with atomized metal powders in order to achieve composite materials capable of reproducing metals, even in a rusty or corroded condition. These composites provide a solution for the reproduction of archaeological artefacts, sculptures, and ornaments for the purpose of conservation. This work explores mechanical properties of three different resins bronze composites loaded with two different proportions of metal filler. The degree of conversion of the samples was measured by differential scanning calorimetry (DSC) and flexural tests were carried out to determine their mechanical …
Toward high performance renewable agave reinforced biocomposites: Optimization of fiber performance and fiber-matrix adhesion analysis
2017
Abstract The increasing sensitivity toward the environmental pollution and the recent laws on the environmental protection, have led to an increasing attention to the so called biocomposites, i.e. to ecofriendly or renewable composite materials, obtained from biopolymers reinforced by natural fibers. Although the contribution of various works reported in literature, focused on biocomposites reinforced by agave fibers, such materials are still exclusively used in the automotive industry for non-structural applications, and the implementation of high performance biocomposites for semi-structural and structural applications, is an expected, but not yet reached objective. Therefore, the present…
Noninvasive monitoring of polymer curing reactions by dielectrometry
2011
A microwave sensor system for the noninvasive monitoring of the curing process of a thermoset material placed inside a metallic mold is described. The microwave sensor is designed as an open-ended coaxial resonator with a curved surface adapted to the mold inner shape. The analysis of the microwave resonator comprises a recently developed method for deembedding the effect of coupling network in overcoupled resonators, so the range of permitted measurements encompass both low and high dielectric losses of polymeric materials. Results show that noninvasive, continuous monitoring of the microwave dielectric properties of the thermoset material can be performed in real time, allowing one to che…
Leach-Proof Sol–Gel Microcapsules as Curing Agents for One-Pot Thermosetting Resins
2013
The sol-gel microencapsulation of free-radical initiator benzoyl peroxide in sol-gel methyl-modified silica microcapsules of core/shell geometry allows curing of acrylate-based polyurethane and polyester resin formulations sprayed from a pressurized can without the need to compartmentalize reactants from the initiator to cross-link. These results open the route to widespread application of sol-gel microcapsules to efficiently cure polymer and composite mixtures that are widely used as functional coatings, molding compounds, adhesives, and sealants.
Morphology and thermal behavior of dicyanate ester-polyetherimide semi-IPNS cured at different conditions
2000
A high-temperature thermosetting bisphenol-A dicyanate, BADCy was modified with polyetherimide, PEI, at various compositions. Phase separation and rheokinetics through curing were studied by optical microscopy, dynamic and isothermal differential scanning calorimetry, and rheological measurements. The PEI phase separated at the early stages of curing, well before gelation, and did not affect the polycyclotrimerization kinetics. The phase structure and thermal properties of the final network were investigated as a function of the PEI content and cure temperature. For this purpose, dynamic mechanical analysis, scanning electron microscopy studies, and thermogravimetrical analysis were carried…