100% Bio-Based Polyamide with Temperature/Ultrasound Dually Triggered Reversible Cross-Linking

Abstract

Bio-based polyamides (100%) with responsive functionality were designed and synthesized by using biorenewable diamine and dicarboxylate. 1,5-Pentanediamine and dimethyl furan-2,5-dicarboxylate were chosen not only because of the biomass feedstock but also because of the reactivity of the furan rings. Enzymatic process enhanced the sustainability of these 100% bio-based furan-containing polyamides (PA5F). By regulating the temperature, PA5F was cross-linked at a low temperature via the Diels−Alder (DA) reaction and then was de-cross-linked at a high temperature. Alternatively, ultrasound exhibited a better performance in triggering the transformation of cross-linked polymers back to the original ones. The DA linkage could also be solidified by aromatization. The thermal properties were well controlled by reversible cross-linking. These 100% bio-based polyamides would open the window for the development of smart sustainable polymers with broad applications.

Structure, thermal and mechanical properties of copoly(ester amide)s based on 2,5‐furandicarboxylic acid

“…The enzymatic polymerization, due to the milder reaction conditions (lower temperature and pressure), appeared to be a promising method, but even in its case, the reaction efficiency did not exceed 50% [34]. Some other researchers also described enzymatic polymerization using the same enzyme, to obtain furan-based polyamides [35]. To overcome the low molecular weight problems, it seemed promising to synthesize copolyamides and copoly(ester amide)s (PEAs) based on FDCA [36][37][38][39].…”

Fully Bio-Based High-Performance Thermosets with Closed-Loop Recyclability

“…32 Besides aldehydes, the counterpart monomers, diamines, were carefully screened to be bio-based as well. BDA, 38 PDA, 39 HDA, and NDA 40 can be obtained from biomass succinic acid, lysine, adipodinitrile, and azelaic acid, respectively. By changing the types of the diamines and the molar ratio of dimethoxyisophthalaldehyde (DA) to TFMP, a series of fully bio-based PV thermosets (PV-M-C) with different cross-linking densities were prepared, where M stands for the type of the diamines and C represents the proportion of the aldehyde groups of TFMP to the total aldehyde groups.…”

Synthesis and Characterization of Low-Melting-Point Polyamides with Trace Thermoreversible Cross-Linked Networks

“…The random molecular structure of the terpolyamide realized low-temperature blending conditions; T m was about 145 °C. Inspired by the previous report, 19 FDCA was used to design the trace cross-linked LMPAs with DA adducts in our work. LMPA materials with DA adducts were synthesized by loading 6F salt into the aforementioned PA6/66/612-based terpolyamide as a DA unit.…”

“…Generally, the reversible process of DA can be controlled by adjusting the reaction temperature; a forward DA reaction often occurs at low temperatures ( T < 70 °C), while the debonding state of a retro-DA reaction often occurs at high temperatures ( T > 120 °C) . In previous reports, polyurethane and polyester materials with Diels–Alder adducts have been much studied. ,− In contrast, polyamide materials with Diels–Alder adducts have received much less attention and are very limited in the research of traditional polyamide materials. − This is related to the limitations of high processing temperatures and the poor solvent solubility of conventional polyamides. In this aspect, low processing temperatures and the dissolvable possibility of LMPAs expand the possibility of blending with other materials with lower processing temperatures, which means that introducing thermally reversible DA adducts in the polyamide system is possible.…”