Recyclable and Mechanically Robust Palm Oil-Derived Epoxy Resins with Reconfigurable Shape-Memory Properties

Abstract

The development of sustainable epoxy resins from renewable biomass is gaining more and more attention. In most cases, chemically cross-linked biomass-derived epoxy resins are nonrecyclable. Here, mechanically strong and recyclable epoxy resins from palm oil that possess reconfigurable shape memory properties are developed. By converting palm oil-based methyl methacrylate monomers into epoxy monomers, high molecular weight palm oil-based epoxy polymers (EP) are prepared with high conversion. After being cured with citric acid (CA) without using any catalyst, palm oil-based epoxy resins (EP-CA) cross-linked with β-hydroxyl ester groups are obtained. The EP-CA can rearrange the chemical network topology through transesterification reactions, which endows the materials with the ability to be recycled and reshaped. The EP-CA prepared via the epoxy polymer approach contains a well-defined network structure, resulting in remarkable mechanical properties. Moreover, the dynamic network structure allows the EP-CA samples to possess reconfigurable shape memory properties.

Reprocessable, Self-Adhesive, and Recyclable Carbon Fiber-Reinforced Composites Using a Catalyst-Free Self-Healing Bio-Based Vitrimer Matrix

“…Generally, the gel content is proportional to the cross-link density of the network. , As the ratio increases from 0.6 to 1.0, the gel content increases from 94.1 ± 0.9 to 99.4 ± 0.2%, which also confirms an increase in the cross-link density. The T g of the TOTGE–MDA vitrimers can be obtained from the tan δ curves. − As can be seen in Figure b, the T g of the TOTGE–MDA vitrimers increases from 60.5 °C (TOTGE–MDA 0.6 ) to 82.6 °C (TOTGE–MDA 1.0 ) because the number of active amino hydrogen atoms increases rapidly as the stoichiometric ratio increases, and these hydrogen atoms form bonds with the epoxy groups, thereby forming a highly cross-linked structure. Meanwhile, the rigid MDA structure restricts the flow of molecular chain segments, thereby increasing the cross-link density and T g of the TOTGE–MDA vitrimers.…”

Development and Mechanism of High-Performance Fully Biobased Shape Memory Benzoxazine Resins with a Green Strategy

“…Summarizing T g and T di values of fully and partially biobased SMPs reported in literature so far (Figure b, Table S1), − ,,− it is interesting to conclude that poly­(IE-dea) and poly­(G-dea) have superiorly high, and in fact the highest, thermal resistance among all available fully biobased SMPs reported so far.…”

Degradation of Thermal-Mechanically Stable Epoxy Thermosets, Recycling of Carbon Fiber, and Reapplication of the Degraded Products

“…To achieve environmental sustainability, the used polymers or electronic wastes should be recyclable as much as possible. − Recently, thermosets with dynamic bond-exchange reactions, ,− known as vitrimers, have been developed for reprocessability and recyclability. Qi et al degraded carbon fiber composites based on fatty acid-cured epoxy vitrimers by ethylene glycol .…”