Issue 01/2017

10
Years ago
From Science & Research
Controlled (soil) biodegradation
Published in
bioplastics MAGAZINE
In Jan 2017, Kate Parker (Zealafoam) says:
“The ten years since first introducing our PLA foaming
technology have been an exciting and busy period for the
Biopolymer Network Limited (BPN) team from New Zealand.
Over that time BPN has continued working on their patented
process for making Zealafoam ® , a PLA based alternative to
expanded polystyrene (EPS), which uses CO 2
as a green blowing
agent to produce low density particle PLA foam. Advances
have been made in base material with work focussed
on optimisation of PLA grades, blends and additives
(bM 01/13). Cost-effective biomass fillers have shown
excellent results in producing novel foams. A focus on
commercialisation has led to a multitude of industry
trials worldwide (bM 01/11) allowing us to prove our
technology on a range of existing foaming and moulding
machines. This has enabled us to address issues around
commercial production. It has also led to foams of lower density
with moulded products under 20 g/l being achieved. Applications
today include products ranging from loose bead (used in furniture
and loose fill packaging), to fish boxes and cycle helmets. The next
stages for the research team include leveraging this technology for
other product lines including foamed cups and thin, lightweight
labelling film (bM 01/16).”
Advancing Bioplastics from Down-Under:
CO 2 production in bioplastic-additive degradation trials
mmol CO 2
8.00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
Fig 1
Impact Resistance (kJ/m 2 )
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
PLA
Fig 2
Bioplastic with
various additives
Bioplastic only
www.scionresearch.com
PLA 1
PLA 2
New Developments in Environmentally Intelligent
Bioplastic Additives & Compounds
Advancing Bioplastics from Down-Under:
Time (days)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Impact strength PLA compounds
Article contributed by
Dr. Alan Fernyhough, Unit Manager of the Bioplastics
Engineering Group, Scion, Rotorua, New Zealand
PLA 3
Scion, based in Rotorua, New Zealand, is a research organisation
with approx. 390 employees firmly focused on a biomaterials
future and has been working with bioplastics for about
10 years.
Scion recognised at an early stage that bioplastics represented
a huge opportunity for New Zealand, with its traditional
strengths in all aspects of the agriculture, horticulture, and
forestry industries’ value chains. Each year large volumes of a
wide range of biomasses are processed for an increasing range
of end uses in New Zealand. Such resources, and the residues
from the harvesting and downstream processing, represent valuable
sources of fibres, fillers, polymers and functional chemical
additives for use in industrial biopolymer products, such as
bioplastics.
The core focus of Scion has been on additives and compounding
formulations for enhanced performance in commercial bioplastics.
One of the early areas of research was the compatibilised
combination of wood and other natural fibres with a range
of commercial bioplastics such as MaterBi, Solanyl, Biopol
(PHA), PLA and others. Scion then developed a novel technology
for wood-fibre (as opposed to wood flour) pellet manufacture for
bioplastics compounding and moulding- showing markedly superior
performance to wood flour and to agri-fibre reinforced bioplastics.
A database of properties and formulations for a wide
range of biobased additives, fillers/fibres, compatibilisers etc
was established with data on mechanical properties, processability,
water and biodegradation responses, durability/weathering
(UV/humidity) and other properties such as flame retardancy.
Now the database comprises in excess of 300 formulations
with such data, using major commercial bioplastics, variously
compounded with novel (biobased) additives, or combinations of
additives, sourced primarily from readily available biomasses.
With moulders and compounders Scion is developing several
applications in New Zealand, ranging from controllably degradable
plant pots, erosion control products, underground temporary
fixtures, office furniture and stationery products. The
knowhow in enhancing bioplastics performance, together with
an ability to control the degradation (accelerate or decelerate)
profiles of commercial bioplastics, in soil and aqueous media, is
now being applied to such product developments. Most interest
has been for injection moulding, but there is increasing interest
in extrusions and thermoforming. Examples of some of Scion’s
developments are:
Controlled Degradation Compounds
The biodegradation of PLA and other bioplastics in soil
media can be controlled by (biobased) additive technologies,
while maintaining processability and mechanical integrity. For
example Figure 1 shows examples of different biodegradation
profiles, in soil, of PLA compounds with the addition of biomass
additive systems, selected from the database.
High Impact PLA
Another outcome from Scions screening work has been
clues to improving the impact resistance of brittle bioplastics,
such as PLA. While it is relatively straightforward to improve
stiffness and strength in PLA, for example by compatibilised
addition of natural fibres or fillers, it is less easy to improve
impact strength at the same time. However, researchers at
Scion have identified some approaches which can do this.
Figure 2 shows example data on impact strength for some
injection moulded PLA formulations.
Visualising Biopolymers in Natural Fibres
A unique approach to ‘track’ biopolymers in moulded compounds
has been developed by Dr Grigsby and Armin Thumm.
Natural fibres differ from glass and carbon fibres in that they
are permeable, and have cell walls and hollow centres of
various dimensions (lumen). Confocal microscopy has been
applied (Figure 3) to visualise differences in interfacial behaviours,
at a fibre cell wall level. Use of selected flow modifiers,
and/or certain processing conditions can lead to lower
instances of voids between the biopolymer and fibre, and, can
promote (or reduce) lumen filling. The implications of such
differences on properties are being evaluated.
New Functional Additives for Bioplastics
Scion continues to screen biomass streams for functional
Biofoam Developments
Work on biofoams has focused on a new PLA foaming technology
which uses carbon dioxide as blowing agent. Dr Witt
has led this work and developed novel routes to the manufacture
of very low density moulded blocks (~20g/l; Figure 4). Scion
also works with a major foam moulder in New Zealand to
further develop their bioplastic foaming technology for packaging
products. Much of this is undertaken within Biopolymer
Network Ltd, a JV between Scion and two other NZ research
institutes, AgResearch and Crop & Food Research.
About Scion
Scion was established in 1947 as the New Zealand Forest
Research Institute. From its forestry science roots, the government-owned
Institute branched out into other areas of
research: exploring the potential of trees, and other plants,
crops and biomass residues to produce new bio-based materials.
To mark this shift in emphasis, the organisation changed
its trading name to “Scion”, which refers to a piece of plant
material that is grafted onto an established rootstock. This
new name symbolises the growth of research towards a future
world where bio-based materials are required to replace
non-renewable synthetics.
This article could only give a condensed and incomplete
overview of Scions activities. In future issues bioplastics MAG-
AZINE will address one or the other activity in more detail.
Fig 3 all pictures: Scion
Fig 4
additives of potential use in bioplastics. Scion has developed
34 bioplastics MAGAZINE [01/07] Vol. 2
extractions, fractionations and derivatisations of such extracts
and has developed novel ways of using them. For example,
they can be used as components in high performance
adhesive formulations and as functional additives for bioplastic
compounds.
bioplastics MAGAZINE [01/07] Vol. 2 35
tinyurl.com/foam2007
40 bioplastics MAGAZINE [01/17] Vol. 12