Modification and fluorescence monitoring of cellulose phosphate for Intumescent Flame Retardant applications in Poly Lactic Acid

Abstract

This thesis focuses on the synthesis of Intumescent Flame Retardant (IFR) from a sustainable resource that is abundant, environmentally less toxic than standard IFRs, biodegradable and economical. For this purpose Nano Fibrillated Cellulose (NFC) was used as a carbon/char producing source. Modification by phosphorous and nitrogen compounds as acid and gas producing agents resulted in the synthesis of IFR. Fourier Transform Infrared Spectroscopy (FTIR) was used to confirm the modification of the cellulose. Thermo Gravimetric Analysis (TGA) was performed to check the thermal stability of modified cellulose. Estimation of cellulose phosphate was measured by Potentiometry. The modified cellulose composites with Poly Lactic Acid (PLA) were obtained by using a melt blending technique. The composites were analyzed for viscoelastic/stiffness properties using Dynamic mechanical analyzer (DMA). The composites were found to exhibit horizontal burn (HB) flammability ratings. Additionally, to study the interfacial and dispersion properties of nano fibrillated cellulose in PLA two thermally stable fluorescent tagged celluloses with amino-methyl Coumarin and Fluoresceinamine (FA) dyes in PLA were synthesized. The Amino methyl Coumarin tagged cellulose showed good thermal stability even after blending with PLA and showed absorbance in UV-Visible Spectrophotometer; the FA tagged cellulose was thermally stable before blending with PLA but showed reduced quantum yield once it was blended in PLA.