Mechanical performance tailoring of tough ultra-high porosity foams prepared from cellulose I nanofiber suspensions

• Low-density structures of mechanical function in plants, arthropods and other organisms, are often based on high- strength cellulose or chitin nanofibers and show an interesting combination of flexibility and toughness. Here, a series of plant-inspired tough and mechanically very robust cellular biopolymer foams with porosities as high as 99.5% (porosity range 93.1-99.5%) were therefore prepared by solvent-free freeze-drying from cellulose I wood nanofiber water suspensions. A wide range of mechanical properties was obtained by controlling density and nanofiber interaction in the foams, and density property relationships were modeled and compared with those for inorganic aerogels. Inspired by cellulose-xyloglucan (XG) interaction in plant cell walls, XG was added during preparation of the toughest foams. For the cellulose-XG nanocomposite foams in particular, the mechanical properties at comparable densities were superior to those reported in the literature for clay aerogel/cellulose whisker nanocomposites, epoxy/clay aerogels, polymer/clay/nanotube aerogels, and polymer/silica aerogels. The foam structure was characterized by high-resolution field-emission scanning electron microscopy and the specific surface area was measured by nitrogen physisorption. Dynamic mechanical thermal analysis and uniaxial compression tests were performed. The foam was thermally stable up to 275 degrees C where cellulose started to degrade.

Subject headings

NATURVETENSKAP  -- Kemi -- Polymerkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Polymer Chemistry (hsv//eng)

Keyword

Density structures

Dynamic mechanical thermal analysis

Field emission scanning electron microscopy

Foam structure

High resolution

High-strength

In-plants

Mechanical functions

Mechanical performance

Nanocomposite foams

Solvent free

Thermally stable

Ultra-high

Uniaxial compression tests

Water suspensions

Xyloglucans

Aerogels

Cellulose

Ceramic materials

Compression testing

Density (specific gravity)

Dynamic mechanical analysis

Foams

High resolution electron microscopy

Nanocomposites

Nanofibers

Physisorption

Plant cell culture

Porosity

Scanning electron microscopy

Thermoanalysis

Polymer chemistry

Polymerkemi

Publication and Content Type

ref (subject category)

art (subject category)