Highly Hydrophobic Organosilane-Functionalized Cellulose: A Promising Filler for Thermoplastic Composites

• Published in: Materials Vol. 14; no. 8; p. 2005
• Main Authors: Cerny, Pavel, Bartos, Petr, Kriz, Pavel, Olsan, Pavel, Spatenka, Petr
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 16.04.2021; MDPI
• Subjects: Brand names; cellulose; Cellulose fibers; Chemical composition; Composite materials; Contact angle; Design optimization; Fillers; Functional groups; Hexamethyldisiloxane; Homogeneous mixtures; Hydrogen bonds; Hydrophobicity; Impact strength; Low pressure; Mechanical properties; Microwave plasmas; Moisture absorption; Morphology; Photoelectrons; Plasma; plasma functionalization; Plasma jets; Polypropylene; Scanning electron microscopy; Stainless steel; Thermoplastic composites; Wettability; X ray photoelectron spectroscopy; Czech Republic; hydrophobicity; plasma functionalization; cellulose; hexamethyldisiloxane; thermoplastic composites; agglomeration; polypropylene
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14082005

The aim of this work is to design and optimize the process of functionalization of cellulose fibers by organosilane functional groups using low-pressure microwave plasma discharge with hexamethyldisiloxane (HMDSO) precursor in order to prepare a compatible hydrophobic filler for composites with nonpolar thermoplastic matrices. Particular attention was paid to the study of agglomeration of cellulose fibers in the mixture with polypropylene. In our contribution, the dependence of the surface wettability on used process gas and treatment time was investigated. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses were applied to characterize the surface morphology and chemical composition of the cellulose fibers. It was observed that the plasma treatment in oxygen process gas led to the functionalization of cellulose fibers by organosilane functional groups without degradation. In addition, the treated cellulose was highly hydrophobic with water contact angle up to 143°. The use of treated cellulose allowed to obtain a homogeneous mixture with polypropylene powder due to the significantly lower tendency of the functionalized cellulose fibers to agglomerate.