Impact of Butyl Glycidyl Ether Comonomer on Poly(glycerol–succinate) Architecture and Dynamics for Multifunctional Hyperbranched Polymer Design

An original strategy is proposed to easily design functional materials from poly­(glycerol–succinate) (PGS). This approach consists in the introduction of an epoxidized functional agent during the polyesterification between the glycerol and succinic acid. In order to model the effect of this epoxide group on the polymerization process and its resulting hyperbranched architecture, the butyl glycidyl ether (BGE) has been selected as comonomer agent. The theoretical potential reactions have been confronted with the topological units revealed by 2D NMR correlations. The regioselectivity against the primary alcohol and the stoichiometric balance of the system have been modified <i>in situ</i> by the kinetic control of parallel reactions. This had the effect to delay the gelation and increase the polyesterification conversion. The resulting hyperbranched polymers (HBPs) obtained just after gelation exhibit a temperature of glass transition (<i>T</i>_g) of −3.9 °C for PGS and −16.1 °C for poly­(glycerol–succinate-<i>co</i>-butyl glycidyl ether) (PGS-<i>co</i>-BGE). This difference was explained by the BGE butyl tails effect which plays the role of dynamic spacer between the polymer chains during the relaxation process. The relaxation processes were investigated by the computation of the effective activation energy (<i>E</i>_α) through the <i>T</i>_g using the advanced isoconversional method and by the estimation of the β-relaxation activation energy (<i>E</i>_β) by means of annealing experiments. The variation of <i>E</i>_α and <i>E</i>_β values was discussed in terms of competition between the cooperative/noncooperative segment motions and the hindrance effect of the hydrogen-bonded network. The dynamic behavior of this system can be potentially generalizable to all the plastic glass containing a critical amount of secondary interactions

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