Method of forming a cellulose nanocrystalline film

Patent metadata

Field	Value
Publication number	US-2016176075-A1
Application number	US-201615045802-A
Country	US
Kind code	A1
Filing date	Feb 17, 2016
Priority date	Oct 13, 2010
Publication date	Jun 23, 2016
Grant date	—

Abstract

A method is provided for forming a substantially uniaxially-oriented, high content cellulose nanocrystal film. The method includes providing a plant-biomass-based suspension of cellulose nanocrystals and altering the pH of the cellulose nanocrystals to a substantially neutral pH. The suspension is sheared at a shearing rate. The method further includes orienting the cellulose nanocrystals in a substantially axial direction and removing water from the sheared cellulose nanocrystal suspension. As a result, a substantially uniaxially-oriented cellulose nanocrystal film is formed.

First claim

1 . A method of forming a substantially uniaxially-oriented, high content cellulose nanocrystal film for a commercial application, comprising:
providing a cellulose nanocrystal suspension derived from plant-biomass-based material, where a concentration of the suspension is above a lyotropic limit; adjusting the pH of the suspension to a substantially neutral pH; shearing the neutralized suspension at a defined shearing rate using a doctor blade; removing water from the sheared cellulose nanocrystal suspension; and forming a cellulose nanocrystal film having a substantially uniaxial orientation in the axial direction.

2 . The method of claim 1 , further comprising adding a hydrophobic agent to the suspension.

3 . The method of claim 2 , wherein the hydrophobic agent comprises an epoxydyzed soybean oil or elastomer material.

4 . The method of claim 1 , further comprising controlling the viscosity of the suspension by providing the suspension with a concentration between about 3 wt. % and 15 wt. %.

5 . The method of claim 1 , wherein the adjusting step comprises adding a base material to the suspension.

6 . The method of claim 5 , wherein the base material comprises sodium hydroxide, potassium hydroxide, or ammonium hydroxide.

7 . The method of claim 1 , wherein the removing step comprises:
cooling the sheared cellulose nanocrystal suspension to a temperature at or above its freezing point; and applying a vacuum to the cooled suspension for a period of time; wherein, the period of time is minimized to maintain orientation of the cellulose nanocrystals in the formed film.

8 . The method of claim 1 , wherein the shearing rate is between about 100·s −1 and 10·s −1 .

9 . The method of claim 1 , wherein the Herman's order parameter of the formed cellulose nanocrystal film is about 0.5 or greater.

10 . The method of claim 1 , wherein the formed cellulose nanocrystal film comprises a tensile strength between about 250-350 MPa.

11 . The method of claim 1 , wherein the formed cellulose nanocrystal film comprises an elastic modulus between about 30-60 GPa.

12 . The method of claim 1 , the formed cellulose nanocrystal film comprises a strain-to-failure yield of approximately 10 times greater than that of glass.

13 . The method of claim 1 , wherein the suspension is provided in a liquid crystalline form.

14 . The method of claim 1 , wherein the forming step comprises forming a substantially flat and continuous film.

Assignees

• Purdue Research Foundation

Inventors

• Youngblood Jeffrey P
• Moon Robert J
• Reising Alex

Classifications

• B29C41/24 Primary

  for making articles of indefinite length · CPC title

• B29K2001/00

  Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material · CPC title

• B29C55/00

  Shaping by stretching, e.g. drawing through a die; Apparatus therefor (B29C61/08 takes precedence) · CPC title

• B29K2105/162

  Nanoparticles · CPC title

• C08B15/08

  Fractionation of cellulose, e.g. separation of cellulose crystallites · CPC title