Effects of Incorporation of Organically Modified Montmorillonite on the Reaction Mechanism of Epoxy/Amine Cure

The aim of this study is to understand the effect of nonmodified or different organically modified montmorillonites on the reaction mechanism of epoxy/amine cure. The reference material consists of diglycidyl ether of bisphenol A (DGEBA) and 1,3-phenylene diamine (<i>m</i>PDA) in stoichiometric proportions. The reaction with various organically modified montmorillonites (I28E, I34TCN, and MMTm) is compared to highlight the catalytic effect of MMT water content and of the alkylammonium cations on the epoxy/amine reaction mechanism. In the absence of <i>m</i>PDA curing agent, DGEBA develops homopolymerization reactions with I28E, I34TCN, and MMTm. Chemorheological kinetics and advanced isoconversional analysis of epoxy cure are studied by rheometrical measurements and differential scanning calorimetry (DSC). Molecular mobility of the system under curing is modified in the presence of montmorillonites. Finally, the study underlines the role of montmorillonites and the influence of the change in reaction mechanisms on glass transition of the nanocomposites

Valorization of Biorefinery Side-Stream Products: Combination of Humins with Polyfurfuryl Alcohol for Composite Elaboration

A challenge of today’s industry is to transform low-value side products into more value-added materials. Humins, a byproduct derived from sugar conversion processes, can be transformed into high value-added products. Thermosetting furanic composites were elaborated with cellulose filters. Large quantities of humins were included into a polyfuranic thermosetting network. Comparisons were made with composites generated with polyfurfuryl alcohol (PFA) and with PFA/lignin. It was concluded that new chemical interactions were created between the side-chain oxygen groups of the humins and the PFA network. Analysis of the fracture surface of the composites containing humins lead to the conclusion that higher interfacial bonding and more efficient stress transfer between the matrix and the fibers is present. The higher ductility of the humins-based matrix allows for a two-fold higher tensile strength in comparison with other composites tested. Incorporation of humins decreases the brittleness of the furanic composites, which is one major drawback of the pure PFA composites