Microstructural, thermal, crystallization, and water absorption properties of films prepared from never‐dried and freeze‐dried cellulose nanocrystals

DOI: 10.1002/mame.202000462

Authors: Kazi M. Zakir Hossain (University of Bath) , Vincenzo Calabrese (University of Bath) , Marcelo A. Da Silva (University of Bath) , Julien Schmitt (University of Bath) , Saffron J. Bryant (University of Bath) , Md Towhidul Islam (Noakhali Science and Technology University) , Reda M. Felfel (University of Nottingham; Mansoura University) , Janet L. Scott (University of Bath) , Karen Edler (University of Bath)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Macromolecular Materials And Engineering , VOL 10

State: Published (Approved)
Published: November 2020
Diamond Proposal Number(s): 20409

Abstract: In this paper, the microstructural, optical, thermal, crystallization, and water absorption properties of films prepared from never‐dried (ND) and freeze‐dried (FD) cellulose nanocrystals (CNCs) are reported. Morphology of the ND CNCs reveals a needle‐like structure, while after freeze‐drying, they show a flake‐like morphology. Microstructural analysis of ND and FD CNCs are further studied via small angle X‐ray scattering to probe interactions. ND CNCs yield a transparent film with a low surface roughness (14 ± 4 nm), while the FD CNC film evidence a significant reduction of their transparency due to their higher surface roughness (134 ± 20 nm). Although Fourier transform infrared spectroscopy and energy‐dispersive X‐ray spectroscopy analyses reveal no chemical change occurs during the freeze‐drying process, yet a more intense thermal degradation profile is observed for FD CNC film, probably due to the higher oxygen ingress within the gaps created between the stacked flakes. This, in turn, results in a greater loss of crystallinity at a higher temperature (300 °C) compared to the ND CNC film. A rapid decrease in water contact angle of the FD CNC film proves that the morphology of flakes and their orientation within the film has a strong influence in increasing water absorption capacity.

Journal Keywords: cellulose nanocrystals; crystallinity; freeze‐drying; thermal degradation; water absorption

Subject Areas: Biology and Bio-materials, Materials


Instruments: I22-Small angle scattering & Diffraction

Added On: 02/12/2020 10:31

Documents:
mame.202000462.pdf

Discipline Tags:

Biomaterials Physics Soft condensed matter physics Chemistry Materials Science Organic Chemistry

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)