Cellulose nanocrystal surface functionalization for the controlled sorption of water and organic vapours
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- 作者：Etzael Espino-Pérez ; Julien Bras ; Giana Almeida ; Perla Relkin ; Naceur Belgacem…
- 关键词：Cellulose nanowhiskers ; Chemical surface modification ; Water sorption ; Organic vapour sorption ; GAB model
- 刊名：Cellulose
- 出版年：2016
- 出版时间：October 2016
- 年：2016
- 卷：23
- 期：5
- 页码：2955-2970
- 全文大小：1,621 KB
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Chemistry
Bioorganic Chemistry
Physical Chemistry
Organic Chemistry
Polymer Sciences - 出版者：Springer Netherlands
- ISSN：1572-882X
- 卷排序：23
文摘
The surface grafting of cellulose nanocrystals (CNC) is a valuable tool to increase opportunities for their application. This work had several goals designed to improve CNC: reduction of hornification, increased re-dispersibility after CNC drying, and tuning of the surface graft to enhance the adsorption of particular molecules. To achieve this, the CNC surfaces were modified chemically with aromatic surface grafts using widely employed methods: the creation of urethane linkages, silylation and esterification. Even a low degree of grafting sufficed to increase water contact angles to as much as 96°. The analysis of water sorption isotherms showed that at high water activities, capillary condensation could be suppressed and hysteresis was decreased. This indicates that hornification was significantly suppressed. However, although the contact angles increased, the water sorption isotherms were changed only slightly because of reduced hysteresis. The grafts were not able to shield the surface from water vapour sorption. A comparison of the sorption isotherms of anisole and cyclohexane, sorbates with a similar surface area, showed that the sorption of anisole was three times higher than that of cyclohexane. The specific sorption of aromatic molecules was achieved and the most efficient methodology was the esterification of CNC with carboxylic acids containing a flexible linker between the aromatic moiety and ester bond.