The effects of stoichiometry and structure on the dynamic torsional properties of a cured epoxy resin system

Gupta, V. B.; Drzal, L. T.; Lee, C. Y-C.; Rich, Michael J.

doi:10.1080/00222348408219470

Cited by 41 publications

(11 citation statements)

References 18 publications

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“…Ghosh et al [28] reported similar effects in the case of jute fiber reinforced composites. They explained that the organosilane coating used for commercial fibers, with unreactive organic groups led to an interface with many unrestrained or free end groups which resulted in reduction in the crosslink density of the polymer network in the interface region, and thereby caused a reduction in relaxation temperature [29]. In our experiments, we used the macromolecular coupling agents synthesized by ourselves, but not the commercial organosilane coating, the similar effects were also obtained.…”

Section: Loss Factor Tan$! Of "-Relaxationmentioning

confidence: 73%

“…Furthermore, for the CF0 composite, the presence of uncoated fibers can affect the initial stoichiometry of the epoxy-amine network due to the higher affinity of the carbon surface for one of the monomers. The generation of a non-stoichiometric interphase is possibly the reason of the decrease of T g [29]. For the CF-GMA, CF-DI130 and CF-DI220 composites, some epoxy groups in PGMA block react with amine hardener during the curing process; the others unreacted are free or unrestrained and have a plasticization effect on the zone next to the interface, explaining the decrease in T g of the composites.…”

Section: Loss Factor Tan$! Of "-Relaxationmentioning

confidence: 99%

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Interfacial toughening and consequent improvement in fracture toughness of carbon fiber reinforced epoxy resin composites: induced by diblock copolymers

Deng¹,

Zhou²,

Zhu³

et al. 2013

Express Polym. Lett.

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Abstract. Carbon fibers chemically grafted with hydroxyl-terminated diblock copolymer poly (n-butylacrylate)-b-poly (glycidyl methacrylate) (OH-PnBA-b-PGMA), were used as the reinforcement for epoxy composites. The multi-filament composite specimens were prepared and measured by dynamic mechanical analysis (DMA), to study the interfacial toughness of carbon fiber reinforced epoxy composites with the diblock copolymers. The loss modulus and loss factor peaks of !-relaxation indicated that composites with diblock copolymers could dissipate more energy at small strain and possess better interfacial toughness, whereas composites without the ductile block PnBA having the worse interfacial toughness. The glass transition temperature and the apparent activation energy calculated from the glass transition showed that the strong interfacial adhesion existed in the composites with diblock copolymers, corresponding with the value of interfacial shear strength. Therefore, a strengthening and toughening interfacial structure in carbon fiber/epoxy composites was achieved by introducing the diblock copolymer OH-PnBA-b-PGMA. The resulting impact toughness, characterized with an Izod impact tester, was better than that of composite without the ductile block PnBA.

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Section: Loss Factor Tan$! Of "-Relaxationmentioning

confidence: 73%

Section: Loss Factor Tan$! Of "-Relaxationmentioning

confidence: 99%

Interfacial toughening and consequent improvement in fracture toughness of carbon fiber reinforced epoxy resin composites: induced by diblock copolymers

Deng¹,

Zhou²,

Zhu³

et al. 2013

Express Polym. Lett.

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show abstract

“…It has been proposed that this occurs as a consequence of limited packing efficiency around crosslink sites [66,67]. An alternative explanation lies in the raised T g of more highly cross-linked samples, meaning that these are farther from their equilibrium conformation when the structure is frozen on cooling [68,69]. Both entail greater amounts of frozen free volume for more highly cross-linked samples.…”

Section: Discussionmentioning

confidence: 96%

Water transport in an epoxy–phenolic coating

Morsch

Lyon

Greensmith

et al. 2015

Progress in Organic Coatings

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a b s t r a c tThermoset coatings commonly rely on high cross-linking density to provide enhanced barrier properties. Hence it is surprising that for the industrial epoxy-phenolic network investigated, equilibrium moisture uptake is found to increase with respect to cure time, i.e., with greater cross-linking. Molecular interactions between absorbed water and the resin are characterised using infrared spectroscopy, and water uptake is correlated to network polymer features such as polarity and free volume.

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“…The organosilane group with unreactive organic groups leads to an interface with many unrestrained or free end-groups which result in reduction in the crosslink density of the polymer network in the interface region. 20 The plasticized region then yields decreased internal friction and thereby causes a reduction of relaxation temperature.…”

Section: Resultsmentioning

confidence: 99%

Dynamic mechanical analysis of fibre-reinforced plastic composites based on carboxyl terminated poly(ethylene glycol) adipate modified epoxy and E glass fibre

Ratna¹,

Chongdar²,

Chakraborty³

2000

Polym. Int.

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The effects of stoichiometry and structure on the dynamic torsional properties of a cured epoxy resin system

Cited by 41 publications

References 18 publications

Interfacial toughening and consequent improvement in fracture toughness of carbon fiber reinforced epoxy resin composites: induced by diblock copolymers

Interfacial toughening and consequent improvement in fracture toughness of carbon fiber reinforced epoxy resin composites: induced by diblock copolymers

Water transport in an epoxy–phenolic coating

Dynamic mechanical analysis of fibre-reinforced plastic composites based on carboxyl terminated poly(ethylene glycol) adipate modified epoxy and E glass fibre

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