A comparison of cellulose nanofibrils produced from Cladophora glomerata algae and bleached eucalyptus pulp

Cladophora, a fresh-water green macroalgae, has unique cellulose properties and thus may be promising for production of cellulose nanofibrils (CNFs). Cellulose was extracted from Cladophora glomerata and subjected to microfluidization with or without enzymatic hydrolysis pretreatment to produce CNFs. Increasing microfluidization passes produced smaller algal CNFs with more uniform sizes and lower crystallinity. Combining microfluidization with an enzymatic hydrolysis pretreatment, the algal CNFs’ crystallinity decreased further, but the diameter distribution showed little change. The algal CNFs were compared to CNFs produced from bleached eucalyptus pulp (BEP), with the algal CNFs having significantly higher crystallinity, smaller diameter and better thermal stability. The XRD spectra of algal and BEP CNFs were simulated by Mercury 3.0 software. The results indicated that BEP CNFs are mainly cellulose Iβ with a random orientation, while algal CNFs are likely a hybrid of cellulose Iα with preferred orientations along the [100] and [010] axes with a March–Dollase factor of 0.65.