Cellulose Nanofibrils Dewatered with Poly(Lactic Acid) for Improved Bio-Polymer Nanocomposite Processing.

Area of Science:

• Materials Science
• Polymer Science
• Biocomposites

Background:

• Cellulose nanofibrils (CNFs) offer ideal properties for bio-based composites.
• Water binding and drying-induced agglomeration hinder CNF incorporation into polymers.
• Previous contact dewatering methods used wood flour (WF) with some success.

Purpose of the Study:

• To evaluate the viability of contact dewatering using poly(lactic) acid (PLA) powder for PLA/CNF composites.
• To assess energy efficiency, CNF morphology preservation, and mechanical property enhancement.
• To compare performance against existing methods like spray-drying.

Main Methods:

• Mixing wet CNFs with pulverized PLA at various loading levels.
• Mechanical water removal via cold pressing (contact dewatering).
• Composite fabrication through compression molding and shear mixing.

Main Results:

• Preservation of micron-to-nanoscale CNF fibers with high aspect ratios within PLA.
• Achieved 1.7% increase in strength and 4.2% increase in modulus compared to neat PLA.
• Demonstrated equivalent or superior properties to spray-dried nanocellulose composites.
• Reported an 11-194x reduction in drying energy compared to spray-drying CNFs.

Conclusions:

• Contact dewatering with PLA powder is a viable and energy-efficient method for producing PLA/CNF biocomposites.
• The method effectively preserves CNF nanoscale morphology and enhances composite mechanical properties.
• This approach offers a promising alternative to conventional drying techniques for nanocellulose processing.