Grafting polycaprolactone diol onto cellulose nanocrystals via click chemistry: Enhancing thermal stability and hydrophobic property

• Published in: Carbohydrate polymers 2018-06, Vol.189, p.331-341
• Main Authors: Zhou, Ling, He, Hui, Li, Mei-Chun, Huang, Siwei, Mei, Changtong, Wu, Qinglin
• Format: Article
• Language: English
• Subjects: Cellulose nanocrystals; Click chemistry; Hydrophobic; Polycarpolactone; Thermal properties
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2018.02.039

[Display omitted] •PCL diol grafted onto cellulose nanocrystal (CNC) via click chemistry.•Azide and alkyne modification for CNC and PCL diol.•Sequent copper (I)-catalyzed cycloaddition reaction.•Hydrophobicity and thermal stability of CNCs greatly improved by PCL-grafting.•Click chemistry as an attractive modification tool for CNCs with polyester chains. Hydrophobic and thermally-stable cellulose nanocrystals (CNCs) were synthesized by polycarpolactone diol (PCL diol) grafting via click chemistry strategy. The synthesis was designed as a three-step procedure containing azide-modification of CNCs, alkyne-modification of PCL diol and sequent copper(I)-catalyzed azide–alkyne cycloaddition reaction. The structure of azide-modified CNCs and alkyne-modified PCL diol, the structure, hydrophobic ability and thermal stability of click products CNC-PCL were characterized. FTIR, XPS and H1 NMR results indicated a successful grafting of the N3 groups onto the CNCs, synthesis of PCL diol-CCH, and formation of the CNC-PCL material. CNC-PCL had enhanced dispersion in the non-polar solvent chloroform owing to the well-maintained microscale size and PCL-induced hydrophobic surface. The thermal stability of CNC-PCL was largely increased due to the grafting of thermally-stable PCL. This work demonstrates that click chemistry is an attractive modification strategy to graft CNCs with polyester chains for further potential application in polymer composites.