Abstract
Two sets of four cellulose acetate (degree of substitution = 2.2) were incorporated with lignin extracted from the macaúba endocarp, before and after being chemically modified to sodium carboxymethyl-lignin and aluminum carboxymethyl-lignin, respectively. The eight membranes were prepared by the casting method after dissolution in acetone and embedded with lignins (0.1% w/w), one without modification (CAc-Lig) and two chemically modified (CAc-CMLNa) and (CAc-CMLAl), compared to membranes of pure acetate (CAc). In group II, in the four membranes prepared, glycerol was added (10% w/w) as a plasticizer. The membranes were characterized by a number of techniques: thermal (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)), morphological (scanning electron microscope (SEM) and atomic force microscopy (AFM)), structural (X-ray powder diffraction (XRD)), hydrophobic (contact angle and water vapor permeability), and thermomechanical (dynamic thermal mechanical analysis and tensile tests). The results show that despite some incompatibility with the cellulose acetate, the incorporation of the lignin in a concentration of 0.1% w/w acts as a reinforcement in the membrane, greatly increasing the tension rupture of the material. The presence of glycerol in a concentration of 10% w/w also acts as a reinforcement in all membranes, in addition to increasing the tension rupture. In this study, glycerol and acetate both increased the compatibility of the membranes.
Highlights
Until recently, human activity on the planet spared no effort in the search for products and materials that facilitated our existence and improved the quality of human life
Group II represents the four membranes embedded with glycerol at 10% w/w (GCAc, GCAc-Lig, GCAc-CMLNa and GCAc-CMLAl)
The results of determination of the Tg by measures of tan delta (Figure 8), we note a better compatibility of the added components, due to the presence of glycerol. This can be checked by the proximity of the Tg results between −10 and 40 ◦C for all samples of group II, compared with the samples of group I. These results show reinforcement in the membranes caused by the presence of 10% glycerol, with positive Tg values from 15 to 24 ◦C
Summary
Human activity on the planet spared no effort in the search for products and materials that facilitated our existence and improved the quality of human life. The important actions used to achieve this aim are numerous, but the emergence of green chemistry, the search for sources of alternative energy (non-fossil fuel), the use of biomass in energy production, and new materials are important research objectives With these objectives in mind, we constructed membranes or films that can be used in diverse applications, such as packaging (food films), barriers in periodontal reconstitutions [1] and so on. Asymmetric membranes are often produced by phase inversion with partial solvent evaporation and immersion in a non-solvent These membranes present a superficial film, which is responsible for the separation, and a porous sub-layer, which usually works as a mechanical support. As well as its use in the native form, may provide inexpensive and environmentally-friendly applications of the macromolecule, for example, etherification of lignin and incorporation of different metals in the macromolecule, as alternatives for capturing pollutants from water [22,23]
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