Mesoporous guar galactomannan based biocomposite aerogels through enzymatic crosslinking

Published Date
Composites Part A: Applied Science and Manufacturing
March 2017, Vol.94:93–103, doi:10.1016/j.compositesa.2016.12.013

• Author 

• Abdul Ghafar ^a,,
• Pavel Gurikov ^b
• Raman Subrahmanyam ^b
• Kirsti Parikka ^a
• Maija Tenkanen^a
• Irina Smirnova ^b
• Kirsi S. Mikkonen ^a

• aDepartment of Food and Environmental Sciences, P.O. Box 27 (Latokartanonkaari 11), FI-00014 University of Helsinki, Finland
• bInstitute for Thermal Separation Process, Eiβendorfer Str. 38, 21073, Hamburg University of Technology (TUHH), Germany

Received 4 October 2016. Revised 9 December 2016. Accepted 10 December 2016. Available online 15 December 2016. 

Abstract

Guar galactomannan (GM) was crosslinked using a sustainable enzymatic oxidation approach to form hydrogels. Nanofibrillated cellulose was used as reinforcement prior to crosslinking. Thirteen solvents were tested for replacing water in the gels, and the volumetric yields of hydrogels are discussed in relation to the solvents’ Hansen solubility parameters. Ethanol and dimethyl sulfoxide (DMSO) were selected for further stepwise solvent exchange, to characterize the hydrogels’ shrinkage in response to solvents at each step. DMSO displayed a good compatibility with GM-based hydrogels as compared to ethanol during stepwise solvent exchange, and the overall shrinkage value was similar with those two solvents after supercritical CO₂drying. The obtained aerogel exhibited highly porous composite structures with a large surface area (up to 333 m²/g) and good mechanical stiffness. Negligible ethanol residue was detected, which makes the aerogels safe materials for food and other life science applications.

Keywords

A. Biocomposite

A. Cellulose

B. Microstructures

D. Mechanical testing

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• ⁎ 
  Corresponding author.

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