An Effective, Economical and Ultra-Fast Method for Hydrophobic Modification of NCC Using Poly(Methylhydrogen)Siloxane.

Xueqing You,Wenbin Yang,Hanxian Chen,Xinxiang Zhang,Qingjian Hu,Xiaoyong Hu

doi:10.3390/polym11060963

Xueqing You, Wenbin Yang + Show 4 more

Open Access

https://doi.org/10.3390/polym11060963

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Journal: Polymers	Publication Date: Jun 3, 2019
Citations: 7	License type: CC BY 4.0

Affiliation: Fujian Agriculture and Forestry University

Abstract

Poor compatibility between nanocellulose crystals (NCCs) and major polymers has limited the application of NCC as bio-reinforcements. In this work, an effective and ultra-fast method was investigated to significantly improve the hydrophobicity of NCC by using poly(methylhydrogen)siloxane (PMHS) as modifier. PMHS possessed amounts of reactive –Si–H groups and hydrophobic –CH3 groups. The former groups were reactive with the hydroxyl groups of NCC, while the latter groups afforded NCC very low surface energy. As the weight ratio of PMHS to NCC was only 0.0005%, the hydrophobicity of NCC was significantly improved by increasing the water contact angle of NCC from 0° to 134°. The effect of weight ratio of PMHS to NCC and the hydrogen content of –Si–H in PMHS on the hydrophobicity and thermal stability was investigated in detail by Fourier transform infrared spectroscopy (FTIR), (X-ray Diffraction) XRD and (thermogravimetric analysis) TGA. The results indicated that PMHS chains were covalently grafted onto NCC and PMHS modification improved the thermal stability of NCC.

Highlights

Nanocellulose crystals (NCCs), extracted from hierarchical structure of cellulose, demonstrate a number of advantages, such as exceptional mechanical properties, high aspect ratio, low density and availability [1,2,3,4]
We describe an effective, economical and ultra-fast approach for hydrophobic modification of NCC by using PMHS as modifier
For unmodified NCC, the water drop was adsorbed by NCC immediately within 40 ms

Summary

Introduction

Nanocellulose crystals (NCCs), extracted from hierarchical structure of cellulose, demonstrate a number of advantages, such as exceptional mechanical properties, high aspect ratio, low density and availability [1,2,3,4]. They have been widely used as the reinforcements in bionanocomposites. The methods for chemical modification of NCC include isocyanation [6], esterification [6], silanation [7,8,9,10], oxidation [11,12], and acylation [13,14,15]. Lin et al [10] realized very hydrophobic NCC by a two-step silanation method by using KH560 (γ-(2,3-epoxyproxy) propytrimethoxysilane) as a linker and dodecyltrimethoxysilane (DTMOS) as hydrophobic modifier

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Conclusion