Method for production of cellulose nanocrystals from Miscathus giganteus and composites therefrom

Patent metadata

Field	Value
Publication number	US-10000578-B2
Application number	US-201415105851-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 20, 2013
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

Methods for isolating cellulose nanocrystals (CNCs) from the plant Miscanthus Giganteus (MxG). Impressive yields are obtained through a combination of processing steps including base hydrolysis, bleaching and acid hydrolysis. MxG-CNCs are produced having high aspect ratios, are biorenewable and can be used for a wide range of applications such as nanofillers in composites. MxG-CNC-containing composites are also disclosed.

First claim

What is claimed is:

1. A process for isolating cellulose nanocrystals from Miscanthus Giganteus , comprising the steps of:
performing a base hydrolysis step on a quantity of Miscanthus Giganteus;
performing a bleaching step on a solid material recovered from the base hydrolysis step;
performing an acid hydrolysis step on a solid material recovered from the bleaching step; and
recovering cellulose nanocrystals from Miscanthus Giganteus after performing the acid hydrolysis step.

2. The process according to claim 1 , wherein prior to performing the base hydrolysis step a quantity of Miscanthus Giganteus is obtained and comminuted to a smaller average particle size.

3. The process according to claim 1 , wherein the base hydrolysis step includes contacting the Miscanthus Giganteus with a basic solution having a pH of about 13 to about 14, and wherein the base utilized has a formula of MOH, wherein M is a cationic counter ion.

4. The process according to claim 3 , wherein the bleaching step comprises contacting acetic acid and one or more of sodium chlorite or sodium hypochlorite with the solid material recovered from the base hydrolysis step, wherein the one or more of the sodium chlorite or sodium hypochlorite are present in a concentration between about 0.5 and about 4 weight percent and the concentration of acetic acid is between about 0.2 and about 9 weight percent.

5. The process according to claim 4 , wherein the bleaching step is performed for about 1 to about 3 hours at a temperature of about 50° C. to about 80° C., wherein mixing is performed during at least part of the time period.

6. The process according to claim 4 , wherein the acid hydrolysis step comprises contacting the solid material recovered from the bleaching step with an acid having a concentration ranging from 0.5 molar to about 18 molar.

7. The process according to claim 6 , wherein the acid is one or more of hydrobromic acid, phosphoric acid, sulfuric acid or hydrochloric acid.

8. The process according to claim 7 , wherein the acid hydrolysis step is performed for about 0.5 to about 24 hours.

9. The process according to claim 1 , further including the step of adding carboxyl functionality to the recovered cellulose nanocrystals.

Assignees

• Univ Case Western Reserve

Inventors

• Rowan Stuart
• Hunsen Mo
• Way Amanda

Classifications

• C08L71/02

  Polyalkylene oxides · CPC title

• D21C1/06

  with alkaline reacting compounds · CPC title

• C08L77/00

  Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain (of polyhydrazides C08L79/06; of polyamideimides or polyamide acids C08L79/08); Compositions of derivatives of such polymers · CPC title

• C08B5/14

  Cellulose sulfate · CPC title

• C08L1/04

  Oxycellulose; Hydrocellulose {, e.g. microcrystalline cellulose} · CPC title