A fully biobased benzoxazine monomer, V-fa (using vanillin and furfurylamine) was grafted onto chitosan (CS) at different weight ratios (CXVY) using “grafting to” benign Schiff base chemistry. Incorporation of V-fa onto CS increased the tensile strength and improved chemical resistance of the CS-graft-V-fa films. Reversible labile linkages, expansion of CS galleries and leaching out of phenolic species from biobased polymer films led to an improved antibacterial activity against Staphylococcus aureus, which is ∼125 times higher than the bare CS film, V-fa and oligomeric V-fa. The leached out species from films were analyzed extensively by NMR, FTIR, GPC, ABTS and HRMS analysis. Oxidative-stress seems to be responsible for antibacterial activity. Current work illustrates an attractive synthetic approach and the improved antibacterial performance of biobased CS-graft-poly(V-fa) films which may hold as a potential alternative for wound-healing and implant applications in future. © 2020 Elsevier Ltd

Richa Priyadarshini

Life Sciences

(SoNS) School of Natural Sciences

Bimlesh Lochab

Chemistry

Yadav N.

Monisha M.

Niranjan R.

Dubey A.

Patil S.

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Shiv Nadar University

Carbohydrate Polymers

Polybenzoxazines (PBzs) are emerging as a highly promising and superior class of thermoset polymers for a variety of applications. However, it remains a significant challenge to substantially lower the ring-opening polymerization (ROP) temperature with an ease in processability. On the other hand, biomacromolecule chitosan (CS) is explored extensively, but its practical applications have been precluded by poor thermal and mechanical properties. Here, we developed a fully biobased copolymer of vanillin benzoxazine (V-fa) monomer with CS, which is effective in providing mutual benefits, effective lowering in ROP temperature of benzoxazine (70 °C), and an enhanced thermal stability of CS (by 85 °C, and with char yield of â32\%). To understand this unusual lowering in ROP temperature, we investigated the structural interaction mechanism between solvated CS and V-fa using in situ NMR studies. The analysis of fully intercalated co-structure demonstrated that there is a strong preference for ROP over Schiff base reaction. It is anticipated that benzoxazine molecules move within the interplanar distance of CS as supported by powder X-ray diffraction studies. An increase in V-fa content in feed ratio led to a placement of V-fa units from random to a systematic and hierarchical arrangement within the CS framework followed by its subsequent polymerization. The synergistic interactions were further supported by Fourier transform infrared, differential scanning calorimetry, scanning electron micrsocopy, thermogravimetric analysis, and tensile studies. Current work represents preparation of CS benzoxazine copolymers using a low-cost, efficient, and sustainable approach to assist metal-free ROP reaction of Bz to afford low curable temperature processable films. A new strategy is devised for the utility of CS-PBzs copolymers, enabling their extension to innovative applications in cross-domains. © 2019 American Chemical Society.

ACS Sustainable Chemistry and Engineering

Sustainable Framework of Chitosan-Benzoxazine with Mutual Benefits: Low Curing Temperature and Improved Thermal and Mechanical Properties

Polymers

Preparation of the Hybrids of Hydrotalcites and Chitosan by Urea Method and Their Antimicrobial Activities

ACS Applied Materials & Interfaces

Porous Chitosan Films Support Stem Cells and Facilitate Sutureless Tissue Repair

Journal of Materials Science

Carbon microtubes derived from self-rolled chitosan acetate films and graphitized by joule heating

Frontiers in Microbiology

Optimisation of the Protocol for the LIVE/DEAD® BacLightTM Bacterial Viability Kit for Rapid Determination of Bacterial Load

Antibacterial performance of fully biobased chitosan-grafted-polybenzoxazine films: Elaboration and properties of released material