From biopaste to bioplastic

Date:
August 21, 2020
Source:
University of Freiburg
Summary:
Forest scientists develop innovative wood-based materials for
3D printing.



FULL STORY ==========================================================================
A viscous biopaste that is easy to process, solidifies quickly
and is suitable for producing even complex structures using the 3D
printing process has been developed by a research team headed by
Prof. Dr. Marie-Pierre Laborie from the Chair of Forest Biomaterials
at the University of Freiburg. The wood-based biodegradable synthetic
could potentially be used in lightweight construction, amongst other
things. The scientists have published their initial results in the
journals Applied Bio Materials and Biomacromolecules.


========================================================================== Lignin strengthens the cell walls of plants and causes them to turn woody (lignify) -- a mechanism that helps plants to protect themselves against
wind or pests. It is a waste product from paper manufacture and largely incinerated to produce bioenergy. "This is why we're researching into alternative possibilities for making better use of this raw material
in future," says Laborie. As a result the team started to reexamine a combination of materials which was already investigated in the 1980s
by an American research team. In this system, liquid crystals based on cellulose, the main component of plant cell walls, ensure not only the
strength but also the good flow properties of the biopaste. The other component, lignin, can 'stick together' the microstructure in the
process of creating the biosynthetic, as Robert Gleuwitz discovered
in his doctoral thesis. Its orientation subsequently determines the characteristics of the biosynthetic: for instance, it can respond more
rigidly or more flexibly, depending on the direction from which the
force comes.

Further research work will however be necessary until industrial
application is possible, for example as a composite in lightweight construction. Until now the team has used exceptionally pure lignin
which is produced in a pilot biorefinery at the Fraunhofer Center for Chemical-Biotechnological Processes (CBP) in Leuna -- whether the waste
product from the paper industry can also be directly processed still
has to be researched. As Lisa Ebers shows in her doctoral thesis, the characteristics of the biosynthetic can also be varied in many ways,
for instance by chemically processing or varying the components: Trials
to date have used lignin from beech trees -- if it is obtained from
other plants it will have slightly different material characteristics
such as different liquid crystals, even though they are all based on
cellulose. The optimal quantity ratios also differ depending on the
planned application. In addition, the researchers will soon be testing
an entirely different possible use: the quality of soil can be analyzed
with the help of the bio-based material. This takes place by studying
the degradability of lignin and cellulose in various types of soil.

The results arose from a research project by the Sustainability Center
Freiburg and the Fraunhofer Society. The research and 3D printing trials
took place in cooperation with Prof. Dr. Dr. Christian Friedrich and
Dr. Gopakumar Sivasankarapillai at the Freiburg Materials Research Center
(FMF) of the University of Freiburg and with Dr. Gilberto Siqueira in
the Swiss Federal Laboratories for Materials Testing and Research (EMPA)
in Du"bendorf, Switzerland.


========================================================================== Story Source: Materials provided by University_of_Freiburg. Note:
Content may be edited for style and length.


========================================================================== Journal References:
1. F. Robert Gleuwitz, Gopakumar Sivasankarapillai, Gilberto Siqueira,
Christian Friedrich, Marie-Pierre G. Laborie. Lignin in
Bio-Based Liquid Crystalline Network Material with Potential
for Direct Ink Writing. ACS Applied Bio Materials, 2020; DOI:
10.1021/acsabm.0c00661
2. F. Robert Gleuwitz, Gopakumar Sivasankarapillai, Yian Chen,
Christian
Friedrich, Marie-Pierre G. Laborie. Lignin-Assisted Stabilization
of an Oriented Liquid Crystalline Cellulosic Mesophase, Part B:
Toward the Molecular Origin and Mechanism. Biomacromolecules,
2020; 21 (6): 2276 DOI: 10.1021/acs.biomac.0c00220
3. F. Robert Gleuwitz, Christian Friedrich, Marie-Pierre
G. Laborie. Lignin-
Assisted Stabilization of an Oriented Liquid Crystalline Cellulosic
Mesophase, Part A: Observation of Microstructural and Mechanical
Behavior. Biomacromolecules, 2020; 21 (3): 1069 DOI: 10.1021/
acs.biomac.9b01352 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200821094820.htm

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