Producing Cellulose Microfibrils at a High Solid Content with and without Mechanical or Enzymatic Pretreatment

Area of Science:

• Materials Science
• Biotechnology
• Chemical Engineering

Background:

• Cellulose microfibrils (CMF) are advanced biomaterials with diverse applications.
• Efficient production of CMF at high solid content is crucial for industrial scalability.
• Current literature lacks comprehensive data on high-solid CMF production methods.

Purpose of the Study:

• To evaluate the feasibility of producing CMF from hardwood pulp at high solid contents (17-28%).
• To investigate the impact of enzymatic and mechanical pretreatments on CMF production.
• To elucidate the mechanisms governing fiber fibrillation during high-solid milling.

Main Methods:

• Planetary ball milling of kraft-bleached hardwood pulp at various solid contents (1-28%).
• Application of endoglucanase pretreatment and mechanical refining (PFI mill) prior to milling.
• Analysis of CMF morphology, water retention value (WRV), and sedimentation behavior.

Main Results:

• High solid content (up to 28%) planetary ball milling is feasible for CMF production.
• Endoglucanase pretreatment yielded short, pulverized-like CMF; mechanical refining accelerated fibrillation.
• Two fibrillation mechanisms were identified: primary (ball-fiber interaction) and secondary (interfiber friction/tension).

Conclusions:

• High-solid CMF production is achievable and influenced by fiber dispersion and milling parameters.
• Pretreatments offer distinct advantages: enzymatic for short fibrils, mechanical for faster fibrillation.
• Study provides commercially relevant insights into scalable CMF production processes.