Preparation and mechanical properties of modified nanocellulose/PLA composites from cassava residue

Lijie Huang,Chunying Li,Shuxiang An,Yinghan Shi,Chongxing Huang,Mingzi Xu,Shuangfei Wang,Xiaoxiao Zhang,Jie Chen

doi:10.1063/1.5023278

Lijie Huang, Chunying Li + Show 7 more

Open Access

https://doi.org/10.1063/1.5023278

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Journal: AIP Advances	Publication Date: Feb 1, 2018
Citations: 23	License type: cc-by

Affiliation: Guangxi University, Qilu University of Technology

Abstract

Nanocellulose was prepared by a mechanochemical method using cassava residue as a raw material and phosphoric acid as the auxiliary agent. The prepared nanocellulose was hydrophobically modified with stearic acid to improve its dispersibility. This modified nanocellulose was added to polylactic acid (PLA) film-forming liquids at concentrations of 0%, 0.5%, 1.0%, 1.5% and 2.0%, and the effect of modified nanocellulose on the mechanical properties of polylactic acid (PLA) films were investigated. When at least 0.5% modified nanocellulose is added, more active groups of modified nanocellulose are adsorbed onto the PLA molecular chain. Although the tensile strength of the film is only improved by 13.59%, the flexibility of the film decreases, and the elastic modulus decreases by 28.91%. When 1% modified nanocellulose is added, the modified nanocellulose and PLA are tangled together through molecular chains and they co-crystallize to form a stable network structure. The tensile strength of the nanocomposite films is enhanced by 40.03%, the elastic modulus is enhanced by 55.65%, and the flexibility of the film decreases.

Highlights

Nanocellulose is broadly defined as cellulose where at least one dimension is 1–100 nm in size
Raque et al.[5] found that nanocellulose modified with meth-acryloyloxy groups could enhance the performance of polylactic acid (PLA) films compared to the case without nanofibers
The cellulose in cassava residue was used as a raw material in this study to generate nanocellulose with improved dispersibility, which was used during the preparation of PLA films, and its effects on the mechanical properties of the PLA films were investigated

Summary

INTRODUCTION

Nanocellulose is broadly defined as cellulose where at least one dimension is 1–100 nm in size It has a good affinity with biomass composites and can form self-adaptive structures where the interface local stress is weakened and the destruction of composite materials is impeded. Nanocellulose is hydrophilic like cellulose, and the surface area becomes larger to expose more strongly-polar hydroxyl groups, which produces weak border effects and results in interface defects; it cannot be well-dispersed in water and most non-polar solutions.[6] Cassava residue is a good source of cellulose, but the treatment costs of cassava residue are high.

Experimental materials and equipment

Preparation of nanocellulose

Modification of nanocellulose with stearic acid

SEM of cassava residue fiber and nanocellulose fiber

Effect of nanocellulose addition on tensile strengths of composites

CONCLUSIONS