Statistical Experimental Design for Obtaining Nanocellulose from Curaua Fiber

Abstract

This study focuses on the methodology to obtain nanocellulose from vegetal fibers. An experimental planning was carried out for the treatment of curaua fibers and parameters were estimated, having the concentration of H 2 SO 4 , hydrolysis time, reaction temperature and time of applied sonication as independent variables for further statistical analysis. According to the estimated parameters, the statistically significant effects were determined for the process of obtaining nanocellulose. With the results obtained from the thermogravimetric analysis (TGA) it was observed that certain conditions led to cellulose with degradation temperatures near or even above that of the untreated cellulose fibers. The crystallinity index (I C ) obtained after fiber treatment (by X-ray diffraction technique) was higher than that of the pure fiber. Treatments with high acid concentrations led to higher IC. After the statistical experimental design, mixtures of polypropylene with fibers prepared after different treatments were performed in a mini-extruder. It was possible to observe a sharp increase in the mechanical properties through the dynamic mechanical thermal analysis (DMTA).

Thermal and Mechanical Properties of Sustainable Composites Reinforced with Natural Fibers

“…Then the fibers were repeatedly washed with deionized water until the pH of washings reached neutrality. The material was dried under vacuum until constant weight [20].…”

“…However, this process is quite expensive and harmful for the environment. In a previous study [20], we evaluated the treatment of curauá fiber with sulfuric acid at different conditions (concentration, time, and temperature) and observed that treatment with low concentration of the acid may weaken the fiber surface, allowing fibrillation during processing in an extruder under conditions of shear at elevated temperature.…”

Mechanical and Morphological Evaluation of the Reinforcement of Polycaprolactone With Different Cellulose Fibers

“…The fibers were extensively washed with water and then they were slightly hydrolyzed with a solution of sulfuric acid (10 wt%) at 40 °C for 240 min under continuous stirring. This process is described in detail elsewhere …”

Composites of Polycaprolactone with Cellulose Fibers: Morphological and Mechanical Evaluation

“…This improvement in compatibility generates better interfacial interaction, which enhances the composite's mechanical performance . Lunz et al conducted an experiment to assess the best conditions to remove the amorphous fractions in curauá fibers, finding an increase in the fiber crystallinity degree. The authors also treated curauá fibers with sulfuric acid under different conditions (concentration, time and temperature) and observed that treatment with low acid concentration can weaken the fiber surface, allowing fibrillation during processing in an extruder under conditions of shear at high temperature.…”

“…In the present work, we investigated jute fibers, chemically treated in the same conditions as a previous work with curauá, and compared both jute and curauá fibers with other sources of cellulose (commercial Arbocel ® and amorphized cellulose using ball milling), for potential use as reinforcing filler in polycaprolactone matrices, by evaluating the performance of the resulting composites. The innovation of this work is the assessment of using chemically treated natural fibers to promote an increase in PCL mechanical properties without affecting its thermal resistance, broadening the range of uses in other packaging and medical areas.…”