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Cellulose tosylates with different degree of substitution (DS) were prepared by reacting cellulose in DMAc/LiCl with p‐tosyl chloride at 8 °C in the presence of triethylamine. The effects of number of mole of tosyl chloride (A), number of mole of base (triethylamine) (B) and reaction time (C) on DS were studied by Response Surface Methodology (RSM) known as Box‐Behnken Design (BBD). It was found that A is the main factor influencing DS and the interaction between B and C is negligible. An optimal DS value of 2.79 was obtained with A=6.96 and B=2.99 mol eq. at a reaction time C=24 h. The synthetic polymers were characterized by elemental analyses, FT‐IR, NMR and SEM spectroscopy. The results indicated that the cellulose was successfully tosylated with various DS. Cellulose tosylate with DS=0.5 and DS=2 were subjected to thermo‐gravimetric analysis under inert atmosphere. The kinetic parameters were determined by Coats‐Redfern method. Thermal analyses and kinetics indicates that the lower DS of tosyl group the higher thermal stability is. Thus, cellulose lose its stability after esterification with p‐tosyl chloride.

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This study intends to synthesis chitosan‐aromatic aldehyde Schiff bases (ChSB) to investigate their thermal stability and kinetics degradation. All samples were characterized by FTIR, XRD and SEM techniques. Chitosan and chitosan derivatives were subjected to thermo‐gravimetric analysis, at four multiple heating rates 5, 10, 15 and 20 °C.min−1. Calculations using two isoconversional integral methods, Flynn Wall Ozawa and Kissinger were performed. The changes in Entropy, Enthalpy, Gibbs free energy, and lifetime have been estimated. Thus, chitosan modification with aromatic aldehydes would have an accelerating effect on thermal decomposition. In addition, chitosan p‐chlorobenzaldehyde were found to have the relative highest activation energy and the highest lifetime to thermally decompose amongst the other examined biopolymers. The kinetic process for the degradation of pure chitosan, chitosan‐N,N‐dimethylaminobenzaldehyde and chitosan‐p‐chlorobenzaldehyde was most probably described by an exponential function E1.While for chitosan‐p‐methoxybenzoaldehyde the function D12 corresponding to a mechanism coupling “transfer and diffusion” seems to describe the degradation.

The present study deals with the homogeneous acylation of cellulose withp-nitrobenzoyl chloride in a reaction medium composed of a mixture of 1-butylpyridinium chloride and dimethylsulfoxide (BPyCl/DMSO), in the presence of different bases and under mild conditions. The preparation of cellulosep-nitrobenzoate depending on the reaction conditions, the influences of reaction parameters such as the base type, and the types of cellulose (kraft and microcrystalline) on the products were investigated. Cellulosep-nitrobenzoate with a degree of substitution (DS) in the range from 0.12 to 1.5 was accessible, with a low excess of reagent and for a short reaction time. The cellulose esters were characterized by1H-NMR,13C NMR, and FT-IR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and solubility tests.

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