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Increasing ecological concerns have given rise to renewed interest in the use of natural materials, considering their renewability and possibility of disposal at the end of their life cycle without damage to the environment. In this study, we examined the isolation of cellulose from Esparto ' Stipa tenacissima' of Eastern Morocco by two different ways; the first one using an acetic acid solution catalyzed by nitric acid. The objective is to determine the optimum amount of this catalyst needed to the extraction. The second way consists to study the cellulose extraction with change of the alkaline solution concentration in order to choose the required value. The cellulosic samples were characterized by FT-IR spectroscopy and X-ray diffraction, the morphology of the isolated fibers was investigated by optical microscopy. Thermal analysis ( DT-TGA) were carried out to study the thermal behavior of the cellulose isolated compared with the control sample. The degree of polymerization (DP) of the samples extracted is estimated from the intrinsic viscosity value using the Mark-Houwink equation in two different solutions (DMAc/9%LiCl) and (6%NaOH/4%urea/90%H2O). We have demonstrated that the extraction using an acetic acid solution has been very successful by adding 2% in volume of nitric acid (HNO3). However, the extraction process using an alkaline solution (NaOH; 1M) is preferable because of the absence of acetylating reaction and the high purity and the nondegradation of the resulted fibers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Esparto 'Stipa tenacissima' cellulose esters derivatives: HECA-COOC4H8COOC2H5, HECA-COOC8H16COOC2H5, and HECA-COOC6H4COOC2H5 were successfully prepared in Tetrahydrofuran (THF)/triethylamine system with a degree of substitution (DS), respectively, DSAD-Et=0.32, DSSB-Et=0.22, and DSTRP-Et=0.50 using hydroxyethyl cellulose acetate (HECA; DSAC=0.50) as intermediate product, and we avoided the drawbacks of cellulose solubility. The structural modifications were investigated using Fourier transform infrared spectroscopy (FTIR), Proton nuclear magnetic resonance (1H-NMR), Carbon-13 nuclear magnetic resonance (13C-NMR), and Distortionless Enhancement by Polarization Transfer 135° (DEPT-135). The results from these analyses revealed the presence of the characteristic groups indicating that the grafting reaction was successful. The crystallinity and the structure order changes during the esterification reactions were recorded by X-ray diffraction (XRD), it is found that the crystallinity degree decrease from 63.1% for Esparto 'Stipa tenacissima' cellulose to 27.74% for HECA. The thermal stability of the esterified and unmodified cellulose samples was studied by thermogravimetric analysis (TGA)-differential thermal analysis (DTA); the modified HECA exhibits a decrease in thermal stability relatively to the unmodified HECA, and this may be related to the groups grafted. The resulted cellulose esters HECA-P x ( x = 1, 2, or 3) were soluble in THF and present an amorphous structure justified by XRD spectra. It was noted by TGA-DTA analysis that the cellulose esters with low melting range were proved as thermoplastic polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]