Topological Manipulation of Fully Biobased Poly(epoxy imine): From Thermoplastic Elastomers to Covalent Adaptable Networks and Permanently Cross-Linked Networks

Abstract

Tunable properties arising from variable topologies make polymers versatile and irreplaceable in modern society. However, manipulating the topology of a specific polymer with a determined composition remains a big challenge. This study aimed to propose a facile approach to manipulate the topology of fully biobased poly(epoxy imine)s (PEIs), which were synthesized from the reaction between epoxy-derived trialdehyde precursors (ETPs) and decamethylene diamine (DDA). PEIs with topologies varying from branched structures to covalent adaptable networks (CANs) and permanently cross-linked networks (PCNs) were easily obtained by simply adjusting the reaction temperature. At a low temperature (T = 120 °C), partial aldehyde-amine condensation between ETP and DDA gave rise to a branched thermoplastic; at medium temperature (120 °C < T ≤ 160 °C), enhanced extent of aldehyde-amine condensation led to a CAN cross-linked by imine bonds; at a high temperature (T > 160 °C), self-cross-linking of imine bonds occurred to result in a PCN. With different topologies, fully biobased PEIs showed different mechanical, physical, and chemical properties and thus great potential as alternatives to fossilderived polymers in various applications.

High-Performance Poly(imide-imine) Vitrimers Derived from Semiaromatic Bisimide Diamines

“…To make this conversion visible, TGA-DSC synchronous thermal analysis has been performed on the resulting PIIH films from room temperature to 800 °C in nitrogen, during which the heat flow resulting from the imine self-cross-linking was monitored by the DSC accessory. As shown in Figures S27–S31 (Supporting Information), an evident exothermic peak can be observed at around 230–350 °C along with the insignificant weight loss for all PIIH samples from their DSC and TGA curves, possibly resulting from the self-cross-linking reaction between aromatic imine linkages to form cyclic dimer or trimer in nitrogen flow (Figure S32, Supporting Information), which have been confirmed in several reported investigations. ,– Additionally, the enthalpy (Δ H ) for imine cross-linking varies from 168.7 to 187.9 J·g –1 upon varying the quantity and substitution position of the substituents, suggesting that the imine cross-linking behavior is substituent dependent. The TGA and corresponding derivative thermogravimetry (DTG) curves obtained from TGA-DSC measurements are also given in Figures S27–S31.…”

“…It has been reported by Zeng and Yu et al ,– that aromatic imine linkages are prone to self-cross-linking when thermally treated at the temperature of above 200 °C, accompanied by –CN– (imine linkage) converting to −C–N– (aminal linkage). To make this conversion visible, TGA-DSC synchronous thermal analysis has been performed on the resulting PIIH films from room temperature to 800 °C in nitrogen, during which the heat flow resulting from the imine self-cross-linking was monitored by the DSC accessory.…”

Bio-based hyperbranched epoxy resins: synthesis and recycling

“…Many researchers have conducted extensive studies on the HERs containing imine bonds. For example, Zeng 203 designed a fully bio-based poly(epoxyimine) (PEI) using glycerol triglycidyl ether with vanillin epoxy-derived trialdehyde precursors (ETPs) and decamethylene diamine (DDA). By varying the reaction temperature, PEIs with different structures, including branched structures (BTP), covalent adaptive networks (CAN), and permanently crosslinked networks (PCN) can be obtained, respectively (Fig.…”

Fully Biobased and Mechanically Robust Elastomeric Vitrimer based on Epoxidized Natural Rubber and Dynamic Imine Bonds

“…Dynamic imine bonds have garnered significant attention in the development of recyclable thermosets due to their ability to undergo three types of exchange reactions: imine metathesis, transamination, and imine condensation/hydrolysis. , These reactions offer numerous advantages and functionalities to thermosets, including reprocessability, weldability, self-healing performance, thermal recyclability, and chemical closed-loop recycling. ,, Additionally, imine bonds can be easily synthesized from commercially available low-cost amines and aldehydes, making them suitable for incorporation into various thermoset systems to achieve customizable physical properties and functionalities. ,,− Despite these merits, the exploration of incorporating dynamic imine bonds into ENR to fabricate elastomeric vitrimers has yet to be undertaken.…”