Synthesis and characterisation of poly(acryalamide) grafted carboxymethyl xanthan gum copolymer

•An unreported graft copolymer CMXG-g-PAAm has been synthesised.•An acrylamide grafting improves the thermal stability of carboxymethyl xanthan gum.•A wrinkled and nodular morphology distorted to flattened flaky thin sheet structure.•Grafting of AAm onto CMXG leads to disruption of partial crystallinilty.•CMXG-g-PAAm might be well exploited globally as a potential drug delivery carrier.

In the present work, an unreported graft copolymer of carboxymethyl xanthan gum and acrylamide has been synthesised by free radical polymerisation in a nitrogen atmosphere using ammonium persulphate as an initiator. The optimum reaction conditions adopted for affording maximum percentage of grafting including its grafting efficiency were obtained by varying the concentration of carboxymethyl xanthan gum from 4 to 24 g dm−3; ammonium persulphate from 5 × 10−4 to 30 × 10−4 mol dm−3; acrylamide from 0.4 to 1.2 mol dm−3; reaction temperature from 55 to 75 °C and reaction time from 30 to 90 min. The synthesised graft copolymer has been characterised by 1H NMR, FTIR spectroscopy, X-ray diffraction measurement, thermal analysis, viscosity measurement and scanning electron microscopy. However, grafting of acrylamide onto carboxymethyl xanthan gum backbone enhanced its thermal stability. This graft copolymer might be well exploited globally as a potential carrier for drug delivery system.

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