1.1 Societal needs
This proposal addresses the substitution of mineral
fillers and fibers presently used in automotive parts made with organic matrices, by
annually renewable natural fibers (NF) based polymeric matrix composites (NFC). This
substitution will allow the production of vehicle components with potentially complete
recyclability (zero waste at the end of the life cycle). Moreover, the attainable lower
weight due to the low density of the NF will allow a lowering of gas emission in vehicles
enhancing the quality of life.
Besides, the lower abrasiveness and friendly handling of
natural fibers as reinforcing agents with respect to those presently used (glass fibers)
will supply more safety during fiber managing and it will permit a longer life for
processing tools. The reduction of glass fibers in waste disposal will also have positive
health effects.
Complementarily, the use of European natural fibers extracted
from related-plants becomes a very interesting alternative for the agriculture sector in
which an increasing of economic activities and employment could be expected when these NFC
materials will be applied in mass production sectors like the processing of vehicle
components.
Weight lowering together with the possibility of cost
decreasing in vehicle parts as a consequence of introducing renewable natural fibers based
composites will allow to increase the efficiency of cars, and also to reduce the carbon
dioxide emissions because plants absorption of this gas during their growth is
approximately the same to that they remove in their decomposition processes.
Simultaneously, using of these natural fibers will lead to the increase of production in
the European agricultural area.
Indeed some applications of natural fibers are already
present in limited quantity in some vehicle components and most of fibers used are from
non-European origin determining a poor quality constancy. Then these projects intends to
address a common problem to two Community sectors: In fact one of the objectives of the
project is addressed to obtain standard quality criteria which will allow a higher
competitivity of European fibers and will improve the reliability of the technologies and
products in mass production sectors like the automotive industry. Other mass production
sectors could also benefit from the results of this project.
Finally, it should be stresses the European dimension of the
production of vehicle parts with renewable/recyclable natural fiber-based composites,
included as one of the main keys of the European Community since fully (95%) recyclable
products are to be demanded for the 2015 year.
This proposal is included in the Competitive and
Sustainable Growth Specific Programme in 1999 Call (16th March). The Key Action 1,
Innovative Products, Processes and Organisation, is specifically addressed by this project
and the referred Generic Activities are Cleaner processes products and eco-efficient
technologies, moreover the following thematic are also addressed: The integrated
production and exploitation of biological materials for non-food users, Eco-efficient
design of products and processes, and Product recovery and waste recycling. This is a RTD
project. A short time period is expected for the exploitation of the results.
1.4 Technical and Scientific
Objectives and Innovative Aspects
Two main technical and scientific orientations are defined in this proposal. Firstly, the proposal intends to develop innovative production technologies for vehicle parts based on renewable natural fiber composites. The objectives related to this orientation are:
. Standardisation of fibers properties to guarantee
quality constancy and product reliability
. Assurance of a good fiber/matrix compatibility
. Optimisation of the composite durability
. Obtainig a good finishing in vehicle parts made with
these materials.
Secondly, the proposal intends to approach the adequation and optimisation of the manufacturing technologies used with these materials in order to obtain large series parts in a sector which demands constant quality products. Therefore, at short term the objective is the using of technologies which allow to attain high quality/low cost parts made with NFC materials. The following technologies have been envisaged as those with higher potential for the objectives proposed:
-The development of the coinjection technology for
thermoplastic matrices
-For structural parts the development of thermosetting
matrices reinforced with long natural fibers which are presently being developed in the
market. The processing of these materials will require the adequation of technologies as
RTM for manufacturing of NFC-based components. (and also NMT for TPs)
- Also compression technologies for the processing of
structural parts with thermoplastic matrices and natural fibers (NMT) will be analyzed in
analogy with GMT processes for glass fiber composites.
Concerning the innovations related to the proposal, total
recyclability, weight reduction, mass production technologies, possibility for lower
costs, performing of decorative finishing, development of structural components based on
natural fibers, have to be outlined as main objectives of this project.
1.5 Scientific and Technical Workplan
To attain the main objective of the proposed project,
which consists on the development of natural fibre composites for automotive applications,
natural fibre reinforcements, polymeric thermoset and thermoplastic matrices and
compatibilizers will be identified and characterised (workpackages 3, 4 and 5) to fulfil
the imposed specifications of two prototypes defined by the end-user partners (WP 2)
according to the application they are aimed to. Moulding compounds will be obtained and
processed to obtain samples for material testing (WP6) while a specific task will address
the development of the optimised technologies for both, thermosetting and thermoplastic
natural fibre composites (WP 7). By complying with the specifications of the selected
prototypes (WP 2) and the data base of the different materials and processes (WP 5, 6 and
7) the appropriate prototype design (WP 8) will be defined. Once the prototypes and moulds
designs have been realised, the production step will start (WP 9) and the obtained
prototypes will be, technically and economically, evaluated by the end-users companies
involved in the project (WP 10). At the same time, the recycling possibilities (WP 11) of
the natural fibre reinforced composites will be studied by identification and evaluation
of the most suitable technologies. Moreover three tasks will accompany the project from
the beginning to coordinate the RTD strategy (WP12), to analyze the different
socio-economic aspects of the project (WP13) and to elaborate the exploitation plans (WP
14).
The partnership is highly complementary and has the
necessary skills and facilities to carry out the allocated workpackages. The partnership
is also vertically integrated as it contains raw material suppliers, technology
developers, automotive component manufacturers and automotive end-users. Moreover, the
Consortium is supported by highly specialised technical skills residing at the
universities and the research centres involved in the project. The partnership is
transnational with partners from 5 European countries. It is unlikely that a Consortium
with all necessary skills could have been formed within a single country. Being a
vertically integrated partnership it is envisaged that co-operation among members will
continue to interact both technically and commercially at the end of the proposed
programme.
A University group with extensive international research
and technology transfer activities, and vast experience in participation and coordination
of European projects, will act as project coordinator. This solution has been agreed by
the other partners to allow a better balance and management of the project results. A
Consortium Agreement will be signed between all the partners to establish a solid formal
commitment of all the partners for the realisation of the project and exploitation of the
results.
Each workpackage has appointed leaders who will co-ordinate
the work and ensure the delivery of the milestones. The Consortium will have, at least, a
regular meeting every six months of a steering committee with representatives of all
partners. This committee will make decision over all technical and financial aspects of
the project. Moreover specific meetings will be programmed to address RTD strategic plans
and activities and to define standardisation procedures to assure the consistency of
common test methods used in the project by different partners and the implementation of
the common test method.
A mid term meeting at the end of the second year will be
planned to allow a complete critical revision of project objectives, methodology and
strategy. Project results, project risks, European Community and partners priorities and
policies will be reviewed to produce a go-on or go-off decision with an eventual program
revised.
A specific workpackage WP1 has been designed for technical
and economic management of the project. Moreover three additional tasks have been
programmed to support coordination activities: While the technical management of the
project will be addressed from WP1, WP12 will address all the RTD strategy and plans of
the project regarding specific scientific questions which will support the technical
activities. The same task leader has been designed for these two management activities.
The socio-economic aspects of the project will be the objective of WP13 in terms of
monitoring the European Commission priorities and policies and their interaction with
partners priorities and policies. Finally the exploitation strategies and plans will be
managed from WP14.
1.8 Economic Development Perspectives
The proposed project aims to integrate the entire production chain from fibre cultivation, treatment, compounding, processing and end-product manufacturing in order to ensure the highest quality of the final product. The assessment of qualified products will assure economic benefits to companies involved in the project. In fact, the massive substitution of glass fibers in mass production sectors like the automotive industry, with clear economic benefits, other than social and environmental advantages, will produce clear benefits for the different sectors involved: European fiber producers, fiber processors, plastic compounders and transformers, end users. Other industrial end-users, other than the automotive, will also economically benefits from the results of this project.
1.9 European Technological Progress
Natural fibers already in use in some composite applications
are typically produced in non-European countries (Asia and Latin America) with a
dispersion of fiber quality and properties. Then, the development of a European RTD
project focused in the reliability of natural fiber composites, with European fiber
producers, transformers and consumers, will increase the competitiveness of the European
industry (raw materials suppliers, composite manufacturers, to end-users) in comparison
with EEUU or Japan, where similar activities are known to be in progress.
2 SCIENTIFIC/TECHNICAL OBJECTIVES AND
INNOVATION
2.1 International state-of-the-art
The collapse in prices for engineering and standard plastics, with the assumption of the future exhaustion of the crude reserves world-wide and the increasing environmental concerns is leading to consider, more and more insistently, the use of regenerable raw materials for the design and development of new vehicle components. The production of parts with low cost composites based on natural fibers (NF) will offer both technological, as referred to environmental impact and fuel economy and cost advantages in this extremely competitive market. The importance of natural fibers based composites (NFC) stands mainly in:
-Reduction of CO2 emission (because the amount of CO2
plants absorbs during their growth is approximately the same to that they remove in their
decomposition processes).
-Reduction of vehicle emissions (because of the less
combustible consumption of lighter vehicles)
-Conservation of other natural resources (natural gas,
mineral oil and coal).
-Recycling (natural fibers decompose completely without the
appearance of any toxic intermediates also being their removing possible through
biodegradation processes).
-Alternatives for agriculture (for increasing the production
of with them related-plants)
-Cost-competitive to mineral filler/glass fiber based
plastics/composites (wood for inexpensive fillers and natural fibers for glass fibers).
Presently, for most polymer-based applications in vehicle
components with some structurally, glass fibers are being used. These fibers are
potentially dangerous for human health and can damage the processing equipment. So that,
they will be possibly removed in the next-coming years if standardised products with
similar properties are developed.
In fact in recent years an increase of interest in the use of
natural fibers as reinforcement of polymer based composites has been reported. Some
advantages related to natural fibers with respect to glass fibers in composites are:
-Annual growing and biodegradability
-Low density values <1.4 g/cm3.
-Good specific mechanical properties.
-Good flexural behaviour and toughness properties (they
fail with a characteristic tear).
-Easy cutting.
-Less abrasive than glass fibers (longer life for
processing tools).
-Interesting acoustic and thermal insulation properties
due to their cellular structure.
-Very good flexibility to complex shapes.
-No residues at the end of the life cycle
Nevertheless, some problems as the constancy on properties remain to be improved. In particular the following drawbacks influence the properties of natural fibers and consequently have to be controlled for their use in NFC materials:
-Quality fluctuations: standardisation becomes
necessary.
-High processing temperatures can damage the fibers.
-Low fiber/matrix compatibility
-Wetting and good dispersion during processing is
difficult. Need for fiber treatments.
-Water absorption and dimensional changes due to water
uptake. They can be reduced by using of coupling agents.
From a mechanical point of view the following parameters have to be considered for using NFC materials:
-Fibre volume, dispersion and orientation in the
composite
-Fiber/matrix interfacial adhesion
-Fiber length and diameter
-Size of the crystalline fibrils and non-crystalline
regions
-Spiral angle of fibrils
-Supramolecular structure (degree of crystallisation)
-Polymerisation degree
-Crystal-structure (type of cellulose and defects)
-Void structure (content of pores, specific interface,
size of pores)
-Type (hair, bast or hard) and origin.
Most of the available information published over the last 5 years on natural fibre/wood composites concerns the following topics:
-Identification and classification of fibres.
-Treatment and adaptation of natural fibres.
-Study of compatible fibre/matrix composites.
-Determination of fiber and composite mechanical
properties.
-Humidity effects.
-Potential applications as substitutes for other
materials.
However, as above mentioned, more extensive work is necessary to asses the standard quality of the fibers (function of raw material optimisation, growth-maturity-retting-decortication processes, intelligent preparation and processing of fibers) and also to improve the compatibility between the (hydrophobic-thermoplastic or hydrophilic -thermoset) matrix and the cellulose-based hydrophilic natural fibers. Finally, very few efforts have been devoted to the processability of this materials. The development of specific manufacturing technologies must be addressed in order to obtain reliable products based on these materials.
The fiber quality together with the knowledge of the
relationships concerning to the tetranomium MECHANIC-MORPHOLOGY-SURFACE-CHEMISTRY,
function of the components used for composite building-up and also of the manufacturing
technologies and conditions used, have to allow for the development of competitive natural
fiber composites against glass fiber-based ones.
Depending on the matrix and the fiber size and orientation, a
variety of low cost processing technologies are suitable. So, technologies such as
extrusion or using of intensive mixers allow for the manufacturing of discontinuously
short fiber reinforced NFC, which can be subsequently processed by conventional
technologies as injection or compression moulding. Presently, these technologies are
useful for thermoplastics (TP) as polypropylene for which processing temperatures do not
exceed 200ēC and so natural fibres do not suffer degradative processes.
Fibre/matrix interface optimisation by
coupling/compatibilizing agents can be performed during mixing of the components. These TP
matrix-based composites can be used for applications where no high structurality is
demanded because the fiber size to be used is not high and besides, it can be lowered
during manufacturing of the component.
Instead, for higher performance applications equilibrated or
preferentially oriented wovens based on longer fibers have to be used. At present, the
building-up of these wovens becomes completely necessary for obtaining structurally
interesting NFC materials able to be used in automotive applications.
In the latter years a widespread technology used for
manufacturing of vehicle components is liquid moulding as resin transfer moulding (RTM),
which allows to achieve high performance components with thermosetting matrices (TS).
Unsaturated polyesters are the most used resins for impregnating glass fibers previously
disposed into the moulds with the desirable orientations. For a higher quality of the
product the higher cost epoxy resins can also be used. These thermosetting resins can be
burned without emission of toxic compounds. Therefore, for NFCs using of epoxy matrices
will solely have interest for long or woven fibers to achieve the required high
performances in some parts of the vehicles.
For both TP and TS matrices the equipment needed to produce
the composites is presently available and not large investments seem to be needed for
their adequation for working with natural fibers. However, a study and optimisation of
these moulding technologies are required for using of these new type of composites.
2.2 Scientific and Technological
Approach
In spite of the development of several works for achieving
NFC-based competitive products in automotive applications, or optimisation of quality
constancy neither that for surface aspect, above all for high amounts of NF, have been
still obtained. Other important objective to be fulfilled is related to the development of
structural parts based on these new NFC materials.
All that asks for the development of RDT projects, on the one
hand related to materials in that concerning to constancy on fiber properties,
compatibilization amongst fiber and matrix, durability of the composites, and good
finishing of components, and on the other hand, referred to the optimisation of the
industrial technologies for long series in a sector as the automotive, where quality
constancy of parts is a main criterium of selection. So, at short term the technological
objectives connected to manufacturing of parts will lead to using of processing
technologies able for assuring high quality and low cost of the product, whose will be:
-coinjection and compression molding for TP-based natural
fiber composites,
-for components for which higher structurality is required
both TS matrices and reinforcing agents as the long natural fibers, presently in
development, will be required therefore leading to technologies as RTM. For TP matrices
NMT (natural mat technology), and thus compression, can also be used through the project.
The above considerations will allow to extend using of NFC
materials in automotive parts so contributing to the building-up of a more nature-friendly
society because of their recycling advantages which, in the long term, can even conduct to
fully biodegradable materials for automotive applications. Moreover, using of natural
fibers will help for reduction of emissions as well as for conservation of resources and
for complete recycling of the parts previously made with mineral fibers for which
decomposition and/or recycling is very difficult.
The use of natural fiber composites for automotive components made with the proposed manufacturing technologies will present several advantages with respect to the previously employed reinforcing agents. The main ones can be resumed as:
- Obtaining fibers with controlled quality and
properties
- Weight reduction in final components
- Possibility for lowers production and recycling costs
- Performing of decorative finishing
- Development of structural components based on natural
fibers
- Total recyclability of components
2.4 Scientific and Technological Research Objectives
Two main technical and scientific orientations are defined in this proposal. Firstly, the proposal intends to develop innovative production technologies for vehicle parts based on renewable natural fiber composites. The objectives related to this orientation are:
. Standardisation of fibers properties to guarantee
quality constancy and product reliability
. Assurance of a good fiber/matrix compatibility
. Optimisation of the composite durability
. Obtaining of a good finishing in vehicle parts made
with these materials.
Secondly, the proposal intends to approach the adequation and optimisation of the manufacturing technologies used with these materials in order to obtain large series parts in a sector, which demands constant quality products. Therefore, at short term the objective is the using of technologies, which allow attaining high quality/low cost parts made with NFC materials. The following technological solutions have been envisaged as those with higher potential for the objectives proposed:
- The development of the coinjection technology for
thermoplastic matrices
- For structural parts the development of thermosetting
matrices reinforced with long natural fibers which are presently being developed in the
market. The processing of these materials will require the adequation of technologies as
RTM for manufacturing of NFC-based components. (and also NMT for TPs)
- Also compresion technologies for the processing of
structural parts with thermoplastic matrices and natural fibers (NMT) will be analyzed in
analogy with GMT processes for glass fiber composites.
A list of verifiable objectives of this project includes:
- Development of at least one processing technology to
produce thermoplastic matrix-natural fiber composite parts for automotive applications
- Development of at least one processing technology to
produce thermosetting matrix-natural fiber composite parts for automotive applications
- Development and standarisation of at least one processing
technology to produce constant quality natural fibers for NFC
- Development of procedures to increase the compatibility of
resins and fibers
- Production of at least one prototype of an automotive part
in thermoplastic matrix NFC
- Production of at least one prototype of an automotive part
in thermoset matrix NFC
- Development of a set of standard procedures for quality
control of fibers and of NFC parts
- Development of a set of standards to characterize the
durability of NFC parts
- Development of at least one recycling route for NFC
- A database which includes properties of natural fibres,
thermosetting and thermoplastic resins and natural fibre based composites, studied and
manufactured in the project.
- Technical, economical and life cycle assessment of the
production and recycling of components of natural fibre based composites
The main objective to reach in the proposed project consists on the development of a competitive natural fibre reinforced composite for automotive applications. Despite the long expertise present among the partners, the technical risks associated to the project are considered medium:
ˇ Availability of sufficient quantity and quality of
fibres at stable prices. The presence of natural fibre suppliers in the consortium will
assure the homogeneity of the raw material in order to obtain comparative data of the
results. Although the project is strongly focused on the utilization and standarization of
European fibers, the risk envisaged here can be overcome with the utilization of
extracomunitary natural fibers widely available in the international market.
ˇ A further problem may be associated with the uncontrolled
decomposition of the constituents of natural components, which can produce
“fogging” process. Additive systems have already developed and have to be
studied to improve fibre stabilisation. The subsistance of this risk will be managed
as an element of decition on the target of the project. For example low pressure and
temperature processes could be privileged as they are less subjected to this rik. Moreover
internal components, less exposed to environmental agressive conditions could also be
privileged if this risk cannot be overcome with the use of proper additives.
ˇ To obtain a suitable matrix/reinforcement interface for a
good stress transfer from the matrix to the reinforcement. This risk is anticipated and it
will be controlled by the activities considered in WP 5 with the expertise of the partners
involved. In fact, this is the main risk with respect to the materials behavior. However,
this risk is strongly dependent on the quality of the raw materials utilized. For example,
compatibilization methods for pure cellulose fibers have been already reported but there
are expensive. Then, the main question will be the availability of low compatibilization
methods that do not cancel the original cost advantages of the fibers. The main effects of
this risk wll be reflected in the cost-benefit final balance.
ˇ Achieving the required specifications will require the use
of reinforcing fibres in the matrix. The main risk is the inhomogeneity of fibre
distribution within the matrix. The optimised manufacturing technologies should address
this risk. This is again the main risk regarding the availability of proper process
technologies able to produce a good dispersion of the fibers in the polymeric matrix. From
our experience this risk is again connected to the manufacturing cost as the development
of a good dispersion process is not impossible but could be costly. In any case this risk
could also affect the choice of the polymeric matrix as low viscosity thermosets will
easily disperse the fibers with respect to viscous thermoplastic matrix.
ˇ Development of suitable manufacturing route/process for
the production volumes required. This is an extension of the previous risk which is
connected to the final application of the proposed manufacturing route. Our purpose is to
also evaluate the possibility to produce constant and high quality products for the
automotive industry with the proposed materials. However, some of the required operations
(raw materials conditioning and handling, part finishing operations could not be fully
compatible with current production practice. In any case this risk is out of the
objectives of this project and could be analyzed in an eventual demonstration project as a
continuation of this one.
ˇ Low cost of natural fibres can be increased by the use of
stabilisation additives and treatments, however no disposal taxes have to be paid at the
end-life step of the use cycle, then competitive prices can be reached in comparison with
nowadays used materials. This risk is associated with the economic considerations
expressed before. In any case we consider that also in the case that the economic benefits
are strongly reduced by the material treatment requirements, the vantages associated to
ecological and social factors will always determine a positive balance for the use of
vegetal fibers in composite materials for automotive applications.