Nouvelles re ́sines vinylesters sans styre ̀ne—2. proprie ́te ́s me ́caniques et thermiques et comportement au vieillissement hydrothermique

Becart, D.; Mariette, B.; Hoarau, P. A.; Guerin, et Ph.

doi:10.1016/s0014-3057(97)00188-2

Cited by 2 publications

(1 citation statement)

References 5 publications

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“…Characteristic ester absorption bands are located at 1730 and 1296 cm −1 . The peaks at 700 and 1510 cm −1 were chosen as reference peaks (carbon–carbon vibrations in aromatic rings) 25, 26. The 1296 cm −1 peak normalized with respect to the 700 cm −1 peak was found to be the most suitable indicator of the presence of ester groups.…”

Section: Resultsmentioning

confidence: 99%

Short‐term and long‐term performance of thermosets exposed to water at elevated temperatures

Römhild

Bergman

Hedenqvist

2009

J of Applied Polymer Sci

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The water-transport, mechanical, and chemical-structure changes in various vinyl ester, novolac, and urethane-modified vinyl ester thermosets exposed to water at 50 to 95 C for times up to 1000 days have been studied within the framework of a larger study of osmotic blistering in fiber reinforced plastics (FRP) process components. The water sorption saturation concentration did not reach a steady-state value but gradually increased in many cases upon long-term exposure. The diffusion coefficient was not significantly affected. Infrared spectroscopy and gas chromatography-mass spectrometry indicated that the net mass loss from the thermosets on immersion in water was due to the leaching of non-reacted styrene, monomer, and addi-tives. It is suggested that this, together with polymer relaxation processes (as measured on specimens under tension in water at 80 C), is the primary reason for the time-dependent increase in the water saturation concentration. Infrared spectroscopy indicated that, even at the highest temperatures, hydrolysis of the polymer ester groups was small. Correlations were found between the styrene content in the uncured thermosets, the estimated solubility parameters, and the sorption and diffusion coefficients.

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Section: Resultsmentioning

confidence: 99%

Short‐term and long‐term performance of thermosets exposed to water at elevated temperatures

Römhild

Bergman

Hedenqvist

2009

J of Applied Polymer Sci

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Influence of glass transition temperature of crosslinked unsaturated polyester resin/styrene formulations on the final conversion after an isothermal curing at 100°C

Delaite

Bistac

Dreyer

et al. 2020

Polymers for Advanced Techs

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SMC (sheet molding compound) is a composite based on fibers‐reinforced unsaturated polyester (UP) resin molded usually at 140°C to 170°C under a pressure of 60 to 100 bars. In order to develop new SMC formulations that can be molded at lower temperature (100°C) for economic and environmental reasons, the formulation of the composite had to be completely modified, both to allow a rapid reaction at 100°C, but also to avoid a vitrification phenomenon due to the fact that the glass transition temperature (Tg) of the SMC parts becomes, during the molding process, higher than the mold temperature. In this paper, the relation between the molding temperature, the glass transition temperature, and the final conversion of UP resin/styrene formulations has been underlined. The Tg of the cured resin was decreased by two different ways. The first way involved the reduction of the crosslinking density of the UP resin by using a blend of two resins, a pure maleic and a more flexible one. This blend allows to adjust the Tg over a temperature range from 197°C (Tg of the pure UP resin) to 75°C (Tg of the pure flexible resin). The second way consisted in the addition of butyl methacrylate (BuMA), a reactive plasticizer, to the formulation, allowing a decrease of the final material's Tg from 197°C to 130°C by replacing 35 wt% of styrene by BuMA. These two methods allow to obtain a final conversion of 99% after 8 minutes of molding at 100°C.

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Nouvelles re ́sines vinylesters sans styre ̀ne—2. proprie ́te ́s me ́caniques et thermiques et comportement au vieillissement hydrothermique

Cited by 2 publications

References 5 publications

Short‐term and long‐term performance of thermosets exposed to water at elevated temperatures

Short‐term and long‐term performance of thermosets exposed to water at elevated temperatures

Influence of glass transition temperature of crosslinked unsaturated polyester resin/styrene formulations on the final conversion after an isothermal curing at 100°C

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