Crosslinking mechanism of an anhydride‐cured epoxy resin as studied by fourier transform infrared spectroscopy

Antoon, M. K.; Koenig, Jack L.

doi:10.1002/pol.1981.170190228

Cited by 109 publications

(88 citation statements)

References 43 publications

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“…The different fillers had a wide range of effects on the reaction rates of the resins studied. The reaction rates were found to increase, 13,15,16,20 decrease, 14,17,18,20 or remain the same 15 as that of the unfilled resins, depending on the fillers and resins studied. Therefore, there seems to be no general rule that can be applied to predict how particular fillers may affect the kinetics of a curing system.…”

Section: Introductionmentioning

confidence: 97%

“…For example, kinetic studies had been done on systems such as CaCO 3 in polyester resins, 13,14 SiO 2 in epoxy resins, [15][16][17][18] carbon black in epoxy resins, 18 and fiberglass in polyester resins. 15 Various techniques, such as differential scanning calorimetry, 18,19 FTIR spectroscopy, 20 rheology, 15 and a dynamic torsional vibration method, 16 have been employed to obtain reaction rates or cure profiles. The different fillers had a wide range of effects on the reaction rates of the resins studied.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Colloidal Fillers on the Cross-Linking of a UV-Curable Polymer: Gel Point Rheology and the Winter−Chambon Criterion

2001

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The effect of colloidal silica fillers on the cross-linking behavior of a model UV-curable polymer system (thiol-ene) is studied using in situ rheology and real-time FTIR spectroscopy. The validity of the Winter-Chambon criterion (convergence of the loss tangents at the gel point) is examined for the cross-linking of these filled polymers, some of which are strongly flocculated dispersions (physical gels) prior to chemical cross-linking. Two different types of colloidal silica particles are studied: one with octyl chains tethered to the surface and the other with methyl surface groups. The Winter-Chambon criterion is satisfied for all samples containing the methyl-terminated silica. However, the criterion breaks down for samples containing the octyl-modified silica, with the loss tangents not converging at any single point. This suggests the absence of a self-similar critical gel at the gel point in the latter case. Neither type of silica particles alters the mechanism of the cross-linking reaction, as revealed by FTIR spectroscopy, but they do retard the cross-linking kinetics. An alternate method is suggested for determining the chemical gel point of filled systems that fail to obey the Winter-Chambon criterion. This method involves monitoring the critical strain (limit of the linear viscoelastic region) at various UV exposure times. A dramatic increase is observed in the critical strain at the gel point, indicating a transition from weak, physical bonds to strong, covalent cross-links.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Effect of Colloidal Fillers on the Cross-Linking of a UV-Curable Polymer: Gel Point Rheology and the Winter−Chambon Criterion

2001

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“…The polymerization conversion is determined by the change of the absorbed peak in FTIR characterization. 17,18 The conversion of the respective time is given by…”

Section: Up/pu Network Formationmentioning

confidence: 99%

Effect of reactive polyurethane on toughness of unsaturated polyester resin

Min

Hwang

Choi

et al. 2002

J of Applied Polymer Sci

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Unsaturated polyester (UP) resin is one of the major thermosetting resins and is very useful as a matrix resin of composite material for its processibility. UP resin, however, has several shortcomings: it is weak in alkalis, volume shrinkage occurs during the crosslinking reaction of the oligomeric UP resin with a styrene monomer, and it is also brittle. The mechanical properties of UP resin can be enhanced by blending it with various materials. In this study, polyurethane (PU) was used as a modifier to improve the toughness of the UP resin. The effect of the polyol molecular weight as a PU soft segment and the PU contents on the toughness of PU-modified UP resins were studied. A UP/PU polymer network may occur through a reaction between an isocyanate group in the methyl diisocyanate (MDI) and a hydroxyl one in the UP molecules. The maximum toughness was observed at approximately 2 wt % of the PU content. These results can be rationalized by the incorporation of a rubbery PU segment into a brittle UP resin.

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“…At higher conversions, reaction rates, change for example, due to vitrification 19 and to changing dielectric constants. 20 Finally, chemical equilibrium was addressed. Physical operating conditions can affect observations.…”

Section: End-group Analysismentioning

confidence: 99%

Z‐protected glutamic acid‐based biodegradable thermoplastic and thermosetting polyesters: Synthesis and characterization

Tadros

Noureddini

Timm

1999

J. Appl. Polym. Sci.

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Biodegradable polymers were formed from N-benzyloxycarbonyl-L-glutamic acid with the comonomers ethylene glycol, diglycidyl ether of 1,4-butanediol, and diglycidyl ether of bisphenol A. The three polymers were a linear and a crosslinked heterochain polyester and a crosslinked polyester that contained aromatic units within its network chains. The thermoplastic resin and the soluble fractions for the thermosetting resins were characterized by gel permeation chromatography. Conversions for carboxylic acid were determined by titrations. A quality, 22,000 molecular weight thermoplastic resin was formed. The two thermosets were cured past their gel points. Gelation analysis revealed that the relative rate constants for the sequential oxirane/ acid and alcohol/acid reactions were distinct. With diglycidyl ether of 1,4-butanediol, the ratio of the respective rate constants was 3; with diglycidyl ether of bisphenol A, the ratio approached 200. The resins hydrolyzed to monomers in the presence of lipase, but in the presence of a mixed microbial culture, only the first two resins decayed to biomass, respiratory gases, and water. The third resin was inert during the period of observation.

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Crosslinking mechanism of an anhydride‐cured epoxy resin as studied by fourier transform infrared spectroscopy

Cited by 109 publications

References 43 publications

Effect of Colloidal Fillers on the Cross-Linking of a UV-Curable Polymer: Gel Point Rheology and the Winter−Chambon Criterion

Effect of Colloidal Fillers on the Cross-Linking of a UV-Curable Polymer: Gel Point Rheology and the Winter−Chambon Criterion

Effect of reactive polyurethane on toughness of unsaturated polyester resin

Z‐protected glutamic acid‐based biodegradable thermoplastic and thermosetting polyesters: Synthesis and characterization

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