Functionalization of Cellulose Nanocrystals in Choline Lactate Ionic Liquid.

Sarah Montes,Germán Cabañero,Ibon Odriozola,Itxaso Azcune,Hans-Jürgen Grande,Jalel Labidi

doi:10.3390/ma9070499

Sarah Montes, Germán Cabañero + Show 4 more

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https://doi.org/10.3390/ma9070499

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Abstract

Cellulose nanocrystals (CNCs) are valuable nanomaterials obtained from renewable resources. Their properties make them suitable for a wide range of applications, including polymer reinforcement. However, due to their highly hydrophilic character, it is necessary to modify their surface with non-polar functional groups before their incorporation into a hydrophobic polymer matrix. In this work, cellulose nanocrystals were modified using a silane coupling agent and choline lactate, an ionic liquid derived from renewable resources, as a reaction medium. Modified cellulose nanocrystals were characterized by infrared spectroscopy, showing new peaks associated to the modification performed. X-ray diffraction was used to analyze the crystalline structure of functionalized cellulose nanocrystals and to optimize the amount of silane for functionalization. Poly(lactic acid) (PLA) nanocomposites containing 1 wt % of functionalized cellulose nanocrystals were prepared. They were characterized by field-emission scanning electron microscopy (FE-SEM) and mechanical tests. The use of choline lactate as reaction media has been shown to be an alternative method for the dispersion and silanization of the cellulose nanocrystals without the addition of an external catalyst.

Highlights

Cellulose, which is considered as the most abundant biopolymer on earth [1], is a promising feedstock from lignocellulosic biomass due to its availability and renewability
The hydrophilic character of cellulose nanocrystals was modified by a silanization process
This process was carried out using choline lactate, an ionic liquids (ILs) derived from renewable resources, as a reaction medium

Summary

Introduction

Cellulose, which is considered as the most abundant biopolymer on earth [1], is a promising feedstock from lignocellulosic biomass due to its availability and renewability. Cellulose nanocrystals (CNCs) are stiff rod-shaped particles with nanoscale dimensions. They consist of pure crystalline cellulose chain segments, which are usually isolated from cellulosic fibers through an acid treatment to remove amorphous domains [2]. These nanomaterials exhibit high specific strength and modulus, high surface area, and low density (~1.6 gcm ).

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