Effect of the epoxycyclohexyl polyhedral oligomeric silsesquioxane content on the dynamic fragility of an epoxy resin

Ornaghi, Heitor Luiz; Pistor, Vinícius; Zattera, Ademir J.

doi:10.1016/j.jnoncrysol.2011.10.014

Cited by 50 publications

(34 citation statements)

References 38 publications

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“…The soluble fractions were between *98.2 and 99.7 % for all the samples containing POSS. The gel content suggests that the cure and post-cure processes not only generate the complete reticulation of the process but also corroborate the fact that the reduction in E a is a consequence of the system increased free volume [31]. In addition, the changes in the ''degree of arrangement'' of the active complex formation are not dependent on the inhomogeneous reticulation of the DGEBA microstructure.…”

Section: Resultssupporting

confidence: 61%

“…In contrast, the reduction in E a can be consequent to the easier breaking of the bonds formed between the interfaces of the epoxy resin with the glycidyl groups present at the vertices of the inorganic cages. This assumption is based on recently published results, where it was demonstrated that POSS (epoxycyclohexyl-POSS) leads to reduction in glass transition for the DGEBA resin associated with flexibility in the region of the interface [30] and by the increased free volume in the resin [31]. The E a values were used to determine the kinetic mechanism of degradation, shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Effect of glycidylisobutyl–POSS on the thermal degradation of the epoxy resin

2015

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In this study, polyhedral oligomeric silsesquioxane glycidylisobutyl-POSS was dispersed in an epoxy resin (DGEBA) using ultrasound, and the thermal degradation was investigated by the Flynn-Wall-Ozawa and Criado methods using thermogravimetric analysis. The TEM analysis indicated higher polyhedral oligomeric silsesquioxane (POSS) dispersion in spherical shape. The POSS dispersion was associated with the formation of micelles as a result of their hybrid character. The addition of POSS did not change the degradation of the resin until *380°C, and above this temperature, increase in the thermal stability was observed. The kinetic results revealed that the addition of POSS decreased E a values primarily to 10 % POSS and did not affect the mechanism of degradation for all contents. The reduction in E a was associated with the easier breaking of bonds at the interface of the DGEBA/POSS nanocomposite. The thermodynamic parameters suggested an increased ''degree of arrangement'' for the formation of an active complex during the degradation process and corroborate the lower E a values. The results suggest that the addition of POSS is able to cause an effect of thermal barrier at higher temperatures without affecting the homogeneity of the microstructure of the cured resin.

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Section: Resultssupporting

confidence: 61%

Section: Resultsmentioning

confidence: 99%

Effect of glycidylisobutyl–POSS on the thermal degradation of the epoxy resin

2015

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“…addition of octafunctional POSS containing amine groups can modify the T g and the thermal stability [13][14][15] .…”

Section: -Influence Of the Polyhedral Oligomeric Silsesquioxane N-phementioning

confidence: 99%

“…The mechanism of diffusion was associated with the increase in the average distance between the chains. The increase in free volume promotes a reduction of the T g [14,15] . On the other hand, the addition of POSS can also promote an increase in T g [7] .…”

Section: Introductionmentioning

confidence: 99%

Influence of the Polyhedral Oligomeric Silsesquioxane n-Phenylaminopropyl - POSS in the Thermal Stability and the Glass Transition Temperature of Epoxy Resin

2013

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Abstract:In this study, epoxy nanocomposites containing different fractions of n-phenylaminopropyl (POSS) were prepared. The nanocomposites were studied by transmission electron microscopy (TEM), gel content, dynamicmechanical analysis (DMA) and thermogravimetric analysis (TGA). The parameters for Avrami's equation were calculated from the degradation curves. The dispersions used to form the nanocomposites were effective above 5 wt % of POSS, and the gel content increased with the addition of POSS. The DMA analysis exhibited an increase in the storage modulus (E') and a shifting of T g to higher temperatures upon POSS incorporation. The weight loss indicated that the POSS promoted an increase in thermal stability of the epoxy resin. The Avrami parameters demonstrated that the addition of POSS decreased the Avrami constant (k'), increased the half-life (t 1/2 ) of degradation and promoted changes in the Avrami exponent (n). These results suggest that the increase in the glass transition temperature and thermal stability depend on the reactive groups in the POSS nanoparticles.

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“…Because these materials combine typical qualities of traditional organic polymers with properties of inorganic compounds, their characteristics include enhanced thermal stability and reduced flammability, lower thermal conductivity and smaller heat emission during combustion. [19][20][21] This report presents results of a study on the use of silsesquioxane for modification of elastomer type epoxy resins. Diglycidyl ethers of 1,4-butanediol and 1,6-hexanediol cured with polyoxypropylenediamine Jeffamine D2000 were used as polymer matrices.…”

Section: Introductionmentioning

confidence: 99%

Epoxy Elastomers Modified with Silsesquioxane

Mossety‐Leszczak¹,

Ostyńska²,

Galina³

2015

Macromolecular Symposia

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Summary: This study aimed at investigating into possible applications of polyhedral oligomeric silsesquioxanes (POSS) as fillers of epoxy elastomers. Detailed studies were carried out for octakis [(3-glycidyloxypropyl) dimethylosiloxy] octasilsesquioxane (POSS-OG). The elastic epoxy materials consisted of diglycidyl ethers of 1,4-butanediol or 1,6-hexanediol, crosslinked with polyoxypropylenediamine Jeffamine D2000. The results obtained by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMA), and rheological measurements made it possible to establish the effect of POSS-OG modifier on the properties of the material. The silsesquioxane modifier was found to enhance the elasticity of the resulting polymers and reduced gelation time.

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Effect of the epoxycyclohexyl polyhedral oligomeric silsesquioxane content on the dynamic fragility of an epoxy resin

Cited by 50 publications

References 38 publications

Effect of glycidylisobutyl–POSS on the thermal degradation of the epoxy resin

Effect of glycidylisobutyl–POSS on the thermal degradation of the epoxy resin

Influence of the Polyhedral Oligomeric Silsesquioxane n-Phenylaminopropyl - POSS in the Thermal Stability and the Glass Transition Temperature of Epoxy Resin

Epoxy Elastomers Modified with Silsesquioxane

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