Novel bio-based polymers highlighted in ScienceDirect

Mohammad Mahaninia Mohammad Mahaninia started his PhD study at the Department of Chemical Engineering & Applied Chemistry under the supervision of Professor Ning Yan in 2021. His research focuses on the synthesis of bio-based polymers. These types of polymers are anticipated to have considerable applications in many fields (e.g., environmental science, 3-D printing) due to their tunable and recyclable properties.

In November 2022, Mahaninia and Ning published, Catalyst-free pH-responsive chitosan-based dynamic covalent framework materials, in ScienceDirect. Their study, funded by an NSERC Discovery Grant, reports a first example of chitosan-based dynamic covalent framework materials successfully prepared through one-pot/ultrasonic-assisted amidation reaction via either citric acid (CA) or trimesic acid (TMA) as the linker unit under moderate conditions.

Chitosan-based framework materials with residual carboxylic acid functional groups were obtained by tripodal cross-linking reactions without the need of any catalyst. The obtained materials were capable of bond exchange via neighboring group participation (NGP) effect within their dynamic covalent networks. It was demonstrated that the chitosan-based framework materials could undergo a dynamic transamidation reaction to exhibit self-healing characteristics. The structural properties of the synthesized dynamic covalent framework materials were controlled by the type and composition of the tripodal cross-linkers.

Mahaninia and Ning’s paper showcase a novel and green approach to synthesize biodegradable, self-healing, pH-responsive, and selective mixed-dye adsorbent materials using chitosan as the building block. These types of materials are potentially able to solve the problems related to the non-recyclability of the thermoset plastics. The biodegradability and non-toxicity aspects of these polymers in comparison with synthetic polymers increases their use in medical devices and other applications. The use of these polymers can also help reduce the amount of hazardous substances that are released into the environment.