Crosslinking of mixtures of diglycidylether of bisphenol‐A with 1,6‐dioxaspiro[4.4] nonan‐2,7‐dione initiated by tertiary amines: III. Effect of hydroxyl groups on network formation

Progress in Organic Coatings

Flor

et al. 2015

Self Cite

New dendritic modifiers have been synthesized by amidation of hyperbranched poly(ethylenimine) (PEIs) with 10-undecenoic acid to obtain hyperbranched polymers (HBPs) with different degree of modification. These HBPs have been used as toughness modifiers in a proportion of 10 and 20% in reference to the epoxy resin in diglycidyl ether of Bisphenol A (DGEBA) / methyltetrahydrophthalic anhydride (MTHPA) formulations. The curing process has been studied by dynamic scanning calorimetry and by rheometry, which allow the kinetic constants and the gel and vitrification times to be evaluated. The materials obtained have been thermally characterized and their mechanical properties have been evaluated. An increase in impact resistance has been achieved and the Tg of all thermosets prepared was higher than 100ºC in spite of the flexible structure of the PEI modifiers. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 We thank the reviewers for their task and I would like to tell that we have corrected all the failures detailed by the reviewer 2. ProfWe have also improved a little the grammar and we have shortened some sentences to make them more understandable. Response to ReviewersGraphical Abstract (for review) Highlights 10-unedecenoyl derivative of polyethyleneimine was obtained.  This polymer was used as modifier in epoxy/anhydride formulations.  The final materials were characterized thermally and mechanically.  Impact strength was notably increased in the modified materials. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 formulations. The curing process has been studied by dynamic scanning calorimetry and by rheometry, which allow the kinetic constants and the gel and vitrification times to be evaluated. The materials obtained have been thermally characterized and their mechanical properties have been evaluated. An increase in impact resistance has been achieved and the T g of all thermosets prepared was higher than 100ºC in spite of the flexible structure of the PEI modifiers. Research Highlights

Section: Effect Of the 10-undecenoyl Modified Pei On The Curing Kineticssupporting

confidence: 58%

Section: Rheological Studies Of the Curing Of The Formulationsmentioning

confidence: 99%

New anhydride/epoxy thermosets based on diglycidyl ether of bisphenol A and 10-undecenoyl modified poly(ethyleneimine) with improved impact resistance

Acebo

Progress in Organic Coatings

Flor

et al. 2015

Self Cite

“…A thermomechanical analyser (Mettler TMA SDTA840) was used to determine the conversion at the gel point following a procedure previously discussed . A silanized glass fibre disc, ca 5 mm in diameter, was impregnated with the liquid formulation and sandwiched between two thin aluminium discs.…”

Section: Methodsmentioning

confidence: 99%

Sequential heat release: an innovative approach for the control of curing profiles during composite processing based on dual‐curing systems

Romero

Ramis

2018

Polymer International

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The sequential heat release (SHR) taking place in dual‐curing systems can facilitate thermal management and control of conversion and temperature gradients during processing of thick composite parts, hence reducing the appearance of internal stresses that compromise the quality of processed parts. This concept is demonstrated in this work by means of numerical simulation of conversion and temperature profiles during processing of an off‐stoichiometric thiol–epoxy dual‐curable system. The simulated processing scenario is the curing stage during resin transfer moulding processing (i.e. after injection or infusion), assuming one‐dimensional heat transfer across the thickness of the composite part. The kinetics of both polymerization stages of the dual‐curing system and thermophysical properties needed for the simulations have been determined using thermal analysis techniques and suitable phenomenological models. The simulations show that SHR makes it possible to reach a stable and uniform intermediate material after completion of the first polymerization process, and enables a better control of the subsequent crosslinking taking place during the second polymerization process due to the lower remaining exothermicity. A simple optimization of curing cycles for composite parts of different thickness has been performed on the basis of quality–time criteria, producing results that are very close to the Pareto‐optimal front obtained by genetic algorithm optimization procedures. © 2018 Society of Chemical Industry

“…The experimental time was corrected taking into account the time of sample preparation. The gelation time was determined as the tan δ crossover of the different harmonics , . The complex viscosity of the uncured formulations was measured isothermally using a frequency sweep from 0.1 to 100 rad s −1 and a 50% strain at different temperatures.…”

Section: Methodsmentioning

confidence: 99%

Modification of epoxy–anhydride thermosets using a hyperbranched poly(ester‐amide): I. Kinetic study

Rybak

Sekuła

et al. 2012

Polymer International

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An epoxy‐anhydride formulation used for the coating of electrical devices was modified with a commercially available hyperbranched poly(ester‐amide), Hybrane™ S2200, in order to improve the thermal degradability of the resulting thermoset and thus facilitate the recovery of substrate materials after use of the component. The curing kinetics of the unmodified and modified formulations were studied in detail with differential scanning calorimetry, Fourier transform infrared spectroscopy and rheology. The results suggest that S2200 gets incorporated into the network structure and the curing kinetics are accelerated by the presence of hydroxyl groups from S2200. Copyright © 2012 Society of Chemical Industry