issue 05/2021

Biocomposites
Automotive composites
from banana bast fibres
Sudents Deepak Sundar Saravana Kumar, Maryam
Sodagar and Balaji Subramanian, among others, of RWTH
Aachen University, joined forces in 2020 to create a novel
product from banana fibres. They founded team BioInterio,
a student initiative with the aim of producing fully biobased
and biodegradable composites for various applications.
After winning the G-BiB 2020/2021 competition on a
national level, team BioInterio successfully took part in
the international final at the beginning of 2021, competing
against teams from the United Kingdom and Finland. In
addition, they also won the Biobased Innovation Student
Challenge Europe on the National level and are part of
the Chemstars community as well as the RWTH Ideation
Program. Using feedback from these experiences, they
successfully applied for and were recently granted the NRW
Gründerstipendium, to take their ideas to the next level.
The product team BioInterio aims to produce is a
composite made from hybrid nonwovens, consisting of
banana fibres as well as biobased and biodegradable
polyesters. While polyester fibres are already used as
matrix polymers for composite applications, using banana
fibres as a reinforcing fibre is a novel approach. Other than
abacá, which also belongs to the plant family of banana
plants, the banana fibres which team BioInterio used were
not cultivated for their fibre content but as a food source.
As such, once bananas are harvested the plants serve no
further purpose. Current procedures to deal with what is
essentially considered a waste product, include producing
fishing nets and ship ropes due to high saltwater resistance,
or simply burning down the remaining stems of the plants
if the field space is needed. The latter has the advantage
of acting as soil fertilization, but emits carbon dioxide into
the atmosphere and burns valuable biomass that would not
need further water or maintenance to be harvestable. If the
stems are harvested the retting can be done by chemical
means or mechanical separation. The sale of banana fibres
also provides an additional source of income for local
farmers.
While abacá fibre from similar plants is gathered from
leaves, the banana fibres used by BioInterio were bast fibres
sourced from the stem of the plant. As such they possess
all the advantages of other common natural fibres such
as flax and hemp (renewable, biodegradable, high specific
strength and modulus, low density, excellent dampening
properties) and can be processed in a similar way. One
further advantage is a 1.5 times lower cost compared to
other fibres such as flax and hemp.
The students of team BioInterio sourced banana fibres
of varying hoarseness from Indian locals and processed
them at the Institut of Textile Technology of RWTH Aachen
University. While working at the institute, they had full
access to machinery and expertise in the nonwoven and
composite production as well as characterization of both.
Using these resources, hybrid nonwovens could be produced
on laboratory scale equipment (see Figure 1 for a process
scheme) and thermoformed into test specimens as well
as a prototype glove compartment lid for the automotive
industry, as depicted in Figure 2. Even without optimization,
the composite showed an even distribution of fibre and
matrix and a smooth surface quality.
The first characterization steps included an analysis of
Figure 1: Process chain for the production of banana bast fibre polyester composites at ITA
primary material
(banana fibre
& PLA filament)
hybrid nonwoven
production
mechanical bonding
of nonwovens
rough cut
component
consolidation
40 bioplastics MAGAZINE [05/21] Vol. 16