The cover photo of July 2019 issue is dedicated to the 41st anniversary of the first reported synthetic approach of dendritic hyperbranched structure. The cover photo adopted from the Valer et al., where they reported the preparation of dendritic hyperbranched copolymers based on bis(hydroxyl methyl) propionic acid polyester and studied the architecture - behavior - properties relationship. Dendritic structures are known for their perfect chemical definition, highly dense structure, and a well-defined number of surface functionalities. The soft multifunctional modifications could be compliant to valuable flexibility for embedding different chemical moieties on the surface either within the structure or at the core.
Optimization of acid hydrolysis process for the preparation cellulose nanofibrils
Melina E. Bracone, Leandro N. Luduena*, Vera A. Alvarez
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA), Grupo de Materiales Compuestos Termoplásticos (CoMP) Facultad de Ingeniería, Universidad Nacional de Mar del Plata, Av. Colón 10850 (B7606BVZ), Mar del Plata, Argentina
Adv. Mater. Lett., 2019, 10 (7), pp 499-507
Publication Date (Web): Jan 14, 2019
Copyright © 2019 VBRI Press
Cellulose nanofibrils can be obtained from microcrystalline cellulose by acid hydrolysis processes. Under optimum hydrolysis conditions is possible to obtain cellulose nanofibers with high surface/volume ratio, high aspect ratio (length to diameter), high crystallinity and improved thermal stability. All these parameters then determine their effectiveness as reinforcement in a polymer matrix. In this work, cellulose nanofibrils were obtained from commercial microcellulose supplied by Aldrich. The acid hydrolysis synthesis was optimized studying the effect of reaction time and temperature and acid solution concentration. The optimized parameters were selected so as to obtain fibers with high crystallinity, high aspect ratio with diameter in nanoscale and high thermal stability. The morphology and size (length and diameter) of the fibers was analyzed by Field Emission Scanning Electron Microscopy (FESEM), the chemical structure by Fourier Transform Infrared Spectroscopy (FTIR), thermal stability by Thermogravimetric Analysis (TGA) and crystallinity by X-ray Diffraction (XRD). © VBRI Press.
Cellulose, nanofibrils, optimization, acid hydrolysis, characterization.