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 fossil-derived polymers in various applications.