Chemical modification of waste paper: An optimization towards hydroxypropyl cellulose synthesis.

Chemical modification of waste paper offers a good prospective for environment protection through minimizing the waste density. The study develops a new opportunity for recycling of waste paper through hydroxypropyl cellulose (HPC) synthesis. Waste paper cellulose was hydroxypropylated by alkalization and etherification process. The hydroxypropylation reaction conditions were optimized for reactant concentrations, reaction time and temperature. Maximum DS (1.15) was achieved at 1.5 M/anhydro glucose unit (AGU) NaOH concentration, 40 °C alkalization temperature, 2.5 h alkalization time, 27.82 M/AGU propylene oxide concentration, 3.5 h reaction time for hydroxypropylation and 55 °C hydroxypropylation reaction temperature. HPC sample (DSmax. = 1.15) was examined for rheological behaviour and characterized by using FTIR spectroscopy, 1H NMR spectroscopy, XRD, HPLC and SEM techniques. This environment friendly approach explored an alternative new route for waste paper recycling and substantiated waste paper as a promising feedstock for HPC synthesis. The study further forms a real stepping stone towards resource conservation and recycling.

Synthesis and characterization of carboxymethyl cellulose from office waste paper: a greener approach towards waste management.

In the present study, functionalization of mixed office waste (MOW) paper has been carried out to synthesize carboxymethyl cellulose, a most widely used product for various applications. MOW was pulped and deinked prior to carboxymethylation. The deinked pulp yield was 80.62 ± 2.0% with 72.30 ± 1.50% deinkability factor. The deinked pulp was converted to CMC by alkalization followed by etherification using NaOH and ClCH2COONa respectively, in an alcoholic medium. Maximum degree of substitution (DS) (1.07) of prepared CMC was achieved at 50 °C with 0.094 M and 0.108 M concentrations of NaOH and ClCH2COONa respectively for 3h reaction time. The rheological characteristics of 1-3% aqueous solution of optimized CMC product showed the non-Newtonian pseudoplastic behavior. Fourier transform infra red (FTIR), nuclear magnetic resonance (NMR) and scanning electron microscope (SEM) study were used to characterize the CMC product.

Polymorphic transformation of cellulose I to cellulose II by alkali pretreatment and urea as an additive.

The effect on crystalline structure transformation from cellulose I to cellulose II polymorph was studied of the cotton linter treated with NaOH with and without urea as an additive, analyzed by wide-angle X-ray diffraction analysis. Cotton linter treated with increasing NaOH concentration showed at 15 wt% sudden transformation from cellulose I to cellulose II polymorph. But when urea 5 wt% was used as additive along with 15 wt% NaOH concentration the magnitude of the transformation reduced largely. The crystallinity index showed a gradual decrease with increasing concentration of NaOH. The crystallinity index showed a gradual decrease with increasing concentration of NaOH with or without addition of urea, nevertheless with addition of urea a further slight more transformation was also observed.