Effect of Cellulose Reducing Ends on the Reinforcing Capacity of Powdered Cellulose in Polypropylene Composites

Abstract

Powdered cellulose-reinforced (20 wt%) polypropylene composites were prepared by melt compounding and subsequent injection moldings. We assessed the effect of cellulose reducing ends on the capacity of powdered cellulose to reinforce polypropylene composites after seven days exposure to air circulation during the conditioning of samples. Tensile tests on the composites were performed at 5.08 mm/min. Fourier transform infrared spectroscopy revealed some changes that occurred within the composites by demonstrating a practical decrease in –C=O (1744 cm−1) absorption band intensity. A thermogravimetric analysis indicated differences within the thermal behavior of the prepared composites, showing a higher onset of degradation. Scanning electron microscopy of the fracture areas, together with load–extension curves, further characterized the development of interfacial cellulose/matrix adhesion as well as the brittle and ductile behavior of the composites. The results indicate that the thermal and tensile properties of powdered cellulose/polypropylene are improved by decreasing the amount of cellulose reducing ends in the system.

Surface Characterization of Powdered Cellulose Activated by Potassium Hydroxide in Dry Condition Through Ball Milling

“…The milling frequency throughout the experiment was 50 Hz, in single-direction mode and at a rotation speed of 550 rpm. The limited temperature increase resulting from this process was deemed to have a negligible influence on the powdered cellulose [20].…”

“…In cellulose, anomeric carbons (C-1) are tied up in the glycosidic bonds and thus they have no reducing properties. The breakage of cellulose chains during ball milling and mechanical cleavage of glycosidic bonds are correlated to the emergence of free reducing ends in powdered cellulose [19,20].…”