Search Results (3)

The condensation reactions of 4,4′-(ethane-1,2-diylbis (oxy)) bis(3-methoxybenzaldehyde) (VV) with cystamine, 1,6-hexamenthylene diamine, and a dimer diamine (Priamine^TM 1075) produced three types of vanillin-derived imine-and disulfide-containing diamines (VC, VH, and VD, respectively). Thermal curing reactions of polyglycerol polyglycidyl ether with VD and mixtures of VC/VD and VH/VD produced bio-based epoxy vitrimers (BEV-VD, BEV-VC/VD, and BEV-VH/VD, respectively). The degree of swelling and gel fraction tests revealed the formation of a network structure, and the crosslinking density increased with a decreasing VD fraction. The glass transition temperature, tensile strength, and tensile modulus of the cured films increased as the VD fraction decreased. In contrast, the thermal degradation temperature of the cured films increased as the VD fraction increased. All the cured films were healed by hot pressing at 120 °C for 2 h under 1 MPa at least three times. The healing efficiencies, based on tensile strength after the first healing treatment, were 75–78%, which gradually decreased as the healing cycle was repeated. When imine-and disulfide-containing BEV-VC/VD and imine-containing BEV-VH/VD with the same VC/VD and VH/VD ratios were used, the former exhibited a slightly higher healing efficiency. Full article

Non-isocyanate polyurethanes (NIPUs) based on biobased polyamines and polycarbonates are a sustainable alternative to conventional polyurethanes (PU). This article discloses a novel method to control the crosslinking density of fully biobased isocyanate-free polyurethanes, synthesized from triglycerides carbonated previously in scCO₂ and different diamines, such as ethylenediamine (EDA), hexamethylenediamine (HMDA) and Priamine^TM-1075 (derived from a dimerized fatty acid). As capping substances, water or bioalcohols are used in such a way that the crosslinking density can be adjusted to suit the requirements of the intended application. An optimization of the NIPU synthesis procedure is firstly carried out, establishing the polymerization kinetics and proposing optimal conditions set for the synthesis of the NIPUs. Then, the influence of the partial blocking of the active polymerization sites of the carbonated soybean oil (CSBO), using monofunctional amines, on the physical properties of the NIPUS is explored. Finally, the synthesis of fully biobased NIPUs with a targeted crosslinking density is achieved using hybrid NIPUs, employing partially carbonated oil and H₂O or ethanol as blockers to achieve the desired physical properties in a very precise manner. Full article

Renewable polymers with self-healing ability, excellent elongation, hydrophobicity, and selective oil absorption attributes are of interest for an extensive range of applications, such as e-skin, soft robots, wearable devices, and cleaning up oil spills. Herein, two fully renewable eco-friendly polyamide (PA)-based self-healing elastomers (namely, PA36,IA, and PA36,36) were prepared by a facile and green one-pot melt polycondensation of itaconic acid (IA), Pripol^TM 1009, and Priamine^TM 1075 monomers. The molecular structures of these PAs were analyzed by FITR, ¹H NMR, and ¹³C NMR. The distinct structure of these PAs shows superior strain values (above 2300%) and high ambient temperature autonomous self-healing ability. Interestingly, the synthesized renewable PA36,36 showed zero water absorption values and hydrophobic properties with a contact angle of θ = 91° compared to the synthesized PA36,IA and other previously reported PAs. These excellent attributes are due to the low concentration of amide groups, the highly entangled main chains, the intermolecular diffusion, the manifold dangling chains, and the numerous reversible physical bonds within the renewable PAs. Furthermore, the hydrophobic properties may aid in the selective oil absorption of the PA36,36-based foam, for which PA36,36 foam is produced by the green supercritical carbon dioxide (scCO₂) batch foaming process. The PA36,36 foam with a microporous cellular structure showed better absorption capacity and high stability in repeated use. Due to these advantages, these bio-based PAs have potential for the production of eco-friendly self-healing materials, superabsorbent foams, and other polymeric materials. Full article