This work deals with the study of the rheological behavior of an epoxy system subjected to three cooling processes referred to as the normal, air-, and watercooling processes. The system was set up by a difunctional epoxy resin (DGEBA) mixed with a tetrafunctional diamine (mPDA) in stoichiometric proportions. Different samples of (1) neat and cured polymers and (2) alumina-epoxy composites were prepared. The first part of this work was devoted to optimizing the cure cycle of the neat samples using differential scanning calorimetry and rheometry. The best cure cycle is based on a first heat step at 110°C during 10 min followed by a crosslinking stage of 75 min at 180°C. In the second part of the study the influence of the cooling cycle on the thermomechanical behavior of polymer and composite samples was investigated. Measurement of loss modulus, GЉ, and loss factor, tan ␦, versus temperature showed that an intermediate relaxation ␣Ј peak arose between the main and secondary relaxations (resp. ␣ and ␤). The position and amplitude of the ␣Ј peak increased with the cooling rate. This rheological phenomenon is related to the presence of nonequilibrium stresses frozen in the sample during cooling. The effect of thermal aging on the ␣Ј peak also is reported. Our work also showed the presence of an ␣Ј peak for the composites. However, the amplitude of this peak was more pronounced in the composites because of additional stresses induced by the difference between the resin and the ceramic in thermal expansion coefficients. We showed that a calculation based on a thermoelastic model was useful for qualitative comparison of rheological data on the influence of the cooling process.

a b s t r a c tIn this work, we aimed to characterize the energy of adherence of nanoscale structured epoxy adhesives Diglycidyl ether of bisphenol-A/Methylene-diethylaniline (DGEBA/MDEA) induced by phase separation triblock copolymers Poly (Methacrylate de Methyl)-b-Poly (Butyl Acrylate)-b-Poly (Methyl Methacrylate) (PMMA-b-PBA-b-PMMA) at gel state by a probe tack test, which is an original use of this kind of test for thermoset adhesives. For a set of mechanical parameters (probe's roughness, contact time, contact pressure and debonding velocity), we measured the energy of adherence for both neat and filled adhesives. The probe tack test was performed at different steps of gelation. We compared the behavior of the adhesives and evaluated the dissipation contribution to the energy of adherence of the adhesives during the test. We finally discussed the nanoparticles' influence on the competition between cavitation and fibrillation. We report that the addition of nanoparticles leads to an overall improvement of the energy of adherence, with a significant increase of the dissipation contribution to the energy measured.

The hygrothermal ageing of epoxy resins and epoxy matrix composite materials has been studied many times in the literature. Models have been developed to represent the diffusion behaviour of the materials. For reversible diffusions, Fick, Dual–Fick and Carter and Kibler models are widely used. Many parameters, correlated or not, have been identified. The objectives of this review by statistical analysis are to confirm or infirm these correlations, to highlight other correlations if they exist, and to establish which are the most important to study. This study focuses on the parameters of the Fick, Dual–Fick and Carter and Kibler models. For this purpose, statistical analyses are performed on data extracted and calculated from individuals described in the literature. Box plot and PCA analyses were chosen. Differences are then noticeable according to the different qualitative parameters chosen in the study. Moreover, correlations, already observed in the literature for quantitative variables, are confirmed. On the other hand, differences appear which may suggest that the models used are inappropriate for certain materials.