Bio-Based Furan-Polyesters/Graphene Nanocomposites Prepared by In Situ Polymerization

In situ intercalative polymerization has been investigated as a strategic way to obtain poly(propylene 2,5-furandicarboxylate) (PPF) and poly(hexamethylene 2,5-furandicarboxylate) (PHF) nanocomposites with different graphene types and amounts. Graphene (G) has been dispersed in surfactant stabilized water suspensions. The loading range in composites was 0.25–0.75 wt %. For the highest composition, a different type of graphene (XT500) dispersed in 1,3 propanediol, containing a 6% of oxidized graphene and without surfactant has been also tested. The results showed that the amorphous PPF is able to crystallize during heating scan in DSC and graphene seems to affect such capability: G hinders the polymer chains in reaching an ordered state, showing even more depressed cold crystallization and melting. On the contrary, such hindering effect is absent with XT500, which rather induces the opposite. Concerning the thermal stability, no improvement has been induced by graphene, even if the onset degradation temperatures remain high for all the materials. A moderate enhancement in mechanical properties is observed in PPF composite with XT500, and especially in PHF composite, where a significative increase of 10–20% in storage modulus E’ is maintained in almost all the temperature range. Such an increase is also reflected in a slightly higher heat distortion temperature. These preliminary results can be useful in order to further address the field of application of furan-based polyesters; in particular, they could be promising as packaging materials.

Preparation and Characterization of Polymer-Grafted Montmorillonite-Lignocellulose Nanocomposites by In Situ Intercalative Polymerization

Lignocellulose-clay nanocomposites were synthesized using an in situ intercalative polymerization method at 60°C and a pressure of 1 atm. The ratio of the montmorillonite clay to the lignocellulose ranged from 1 : 9 to 1 : 1 (MMT clay to lignocelluloses, wt%). The adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). FTIR results showed that the polymers were covalently attached to the nanoclay and the lignocellulose in the nanocomposites. Both TEM and XRD analysis showed that the morphology of the materials ranged from phase-separated to intercalated nanocomposite adsorbents. Improved thermal stability, attributable to the presence of nanoclay, was observed for all the nanocomposites. The nanocomposite materials prepared can potentially be used as adsorbents for the removal of pollutants in water treatment and purification.

Structure and swelling of polymer-clay composites

<p>Composition gels on the basis of bentonite clay of Manrak deposit (East-Kazakhstan region) and nonionogenic polymers - poly-2-hydroxyethyl-acrylate and polyacrylamide were synthesized by radical intercalative polymerization in situ with various content o f cross-linking agent N,N-methylene-bisacrylamide and with time of intercalation about 8 hours. The morphological structure, the nature of interaction of components and the swelling ability of composition gels were studied by scanner electron microscopy, equilibrium swelling and IR- spectroscopy methods. By studying of morphological structure it was determined, that the polymer-clay composition gels, synthesized by intercalative polymerization, are most homogenous and interconsistency in case of “acrylamide-clay” composition in contrast with “2-hydroxyethylacrylate-clay” composition. For “acrylamide-clay” gels the swelling degree of gels was stated to decrease with the increase in the content of cross-linking agent and ionic strength, but “2-hydroxyethylacrylate -clay” compositions have the extremely character of swelling, where maximum degree of swelling account for gel with content of cross-linking agent 1*10^-2М. Interaction of composition components was realized on account of hydrogen bonds with formation of chemically cross-linked complex polymer-clay. Decrease of swelling degree of compositions in physiological solution points to acquisition of polyelectrolyte nature of composition gels on account of combination of nonionogenic macromolecules of polymers with negatively charged particles of bentonite clay. For intercalated samples of polymer-clay compositions, the degree of swelling at all degrees of cross-linking is between those for pure polymers and pure clay, that in turn, agrees with the conclusion on the great composition homogeneity of samples with preliminary intercalation. As of results of holding investigation fit is safe to say, that obtained polymer-clay composition gels are potential sorbents and prolongated carriers of medicine</p>

Understanding the effects of carboxylated groups of functionalized graphene oxide on the curing behavior and intermolecular interactions of benzoxazine nanocomposites

Novel benzoxazine (BOZ)/carboxylated graphene oxide (GO-COOH) composites were prepared via in situ intercalative polymerization.