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

Ling Zhou; Hui He; Mei-Chun Li; Siwei Huang; Changtong Mei; Qinglin Wu

doi:10.1016/j.carbpol.2018.02.039

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

Carbohydr Polym. 2018 Jun 1:189:331-341. doi: 10.1016/j.carbpol.2018.02.039. Epub 2018 Feb 21.

Authors

Ling Zhou¹, Hui He², Mei-Chun Li³, Siwei Huang⁴, Changtong Mei⁵, Qinglin Wu⁶

Affiliations

¹ School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China; School of Renewable Natural Resources, Louisiana State University AgCenter, Baton Rouge, LA, 70803, USA; College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, China.
² School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China. Electronic address: pshuihe@scut.edu.cn.
³ School of Renewable Natural Resources, Louisiana State University AgCenter, Baton Rouge, LA, 70803, USA.
⁴ College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, China; College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, 210037, China.
⁵ College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, 210037, China.
⁶ School of Renewable Natural Resources, Louisiana State University AgCenter, Baton Rouge, LA, 70803, USA. Electronic address: wuqing@lsu.edu.

PMID: 29580417
DOI: 10.1016/j.carbpol.2018.02.039

Abstract

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.

Keywords: Cellulose nanocrystals; Click chemistry; Hydrophobic; Polycarpolactone; Thermal properties.