Synthesis and Characterization of Amino Acid Based Chemically Cross-linked Polymer Gels Using Multifunctional Cross-linker

Vaish, Avichal (2014) Synthesis and Characterization of Amino Acid Based Chemically Cross-linked Polymer Gels Using Multifunctional Cross-linker. Masters thesis, Indian Institute of Science Education and Research Kolkata.

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Abstract

This work reports the design and synthesis of side-chain amino acid containing cross-linked polymer gels with high mechanical strength. The Boc-leucine methacryloyloxyethyl ester (Boc-Leu-HEMA) has been polymerized by reversible addition-fragmentation chain transfer (RAFT) polymerization to obtain corresponding polymer, P(Boc-Leu-HEMA). After Boc group deprotection under acidic condition and pH neutralization amino groups remain in the polymer side chain, which were reacted with tetrakis(hydroxymethyl) phosphonium chloride (THPC) to obtain chemically cross-linked gels. The mechanical properties of gels has been studied by rheological measurements, which reveal that mechanical strength increases as weight % of polymer in solution, cross-linker density and polarity of solvents increases, and decreases as molecular weight of polymers increased. A plateau of storage modulus (G) over a wide range of angular frequency demonstrates that viscoelastic property of gels is independent of angular frequency. Field emission scanning electron microscopy (FE-SEM) studies of cross-sectioned gels validate rheological observation that as the G values of gel increases, porosity of gel decreases.

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