Thermally-induced cellulose nanofibril films with near-complete ultraviolet-blocking and improved water resistance

Weisheng Yang; Ying Gao; Chu Zuo; Yulin Deng; Hongqi Dai

doi:10.1016/j.carbpol.2019.115050

Thermally-induced cellulose nanofibril films with near-complete ultraviolet-blocking and improved water resistance

Carbohydr Polym. 2019 Nov 1:223:115050. doi: 10.1016/j.carbpol.2019.115050. Epub 2019 Jul 8.

Authors

Weisheng Yang¹, Ying Gao², Chu Zuo², Yulin Deng³, Hongqi Dai⁴

Affiliations

¹ Jiangsu Co-innovation Center for Efficient Processing and Utilization of Forestry Resources, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China; School of Chemical & Biomolecular Engineering and Renewable Bioproducts Institute, Georgia Institute of Technology, Atlanta, GA, 30318, USA.
² Jiangsu Co-innovation Center for Efficient Processing and Utilization of Forestry Resources, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China.
³ School of Chemical & Biomolecular Engineering and Renewable Bioproducts Institute, Georgia Institute of Technology, Atlanta, GA, 30318, USA. Electronic address: yulin.deng@rbi.gatech.edu.
⁴ Jiangsu Co-innovation Center for Efficient Processing and Utilization of Forestry Resources, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China. Electronic address: hgdhq@njfu.edu.cn.

PMID: 31426951
DOI: 10.1016/j.carbpol.2019.115050

Abstract

In recent years, ultraviolet (UV) protection films made from cellulose nanofibril (CNF) have drawn significant attention, owing to its high transparency, high mechanical strength and relatively high thermostability. Generally, CNF films had poor UV-shielding performance, and required UV absorbent to enhance their UV-shielding ability. Herein, a simple thermal treatment is proposed to directly improve the UV blocking properties of CNF films without incorporating UV absorbent. After thermal treatment at 160 °C, the CNF films exhibited a near-complete UV blocking ability. In particular, they exhibited full absorption of ultraviolet A (UVA) and ultraviolet B (UVB), and also showed a high visible light transmittance of 72%. In addition, the UV-shielding films performed stable UV-blocking when exposed to UV irradiation. Simultaneously, the hornification induced by thermal treatment endowed an improved hydrophobicity for CNF films. However, the tensile strength of the CNF films decreased from 133 MPa to 81 MPa after thermal treatment at 160 °C.

Keywords: Cellulose nanofibril films; Thermal treatment; Transparency; UV protection; Water resistance.