POLYMER COMPOSITE MATERIALS BASED ON BAMBOO FIBRES

Author

Researcher: Ir. Eduardo Trujillo Supervisors: Prof. Jan Ivens, Dr. Aart Van Vuure

PROJECT DESCRIPTION

Composites allow light-weight design and are as such environmentally friendly materials. However, there is an increasing interest in so-called renewable materials, to which category natural fibres clearly belong. Natural fibres can, if mechanical recycling into secondary applications is not feasible, be thermally recycled or if a biodegradable matrix is used, be landfilled for biodegradation. Both last options are largely CO2 neutral. Natural fibres like bamboo also require much less energy for cultivation and extraction than is used for the synthesis of glass and particularly carbon fibre, which gives them a very favorable carbon footprint. For these reasons natural fibres are emerging as good alternative reinforcing materials for the future. Nowadays exploitation and use of sustainable natural resources are a necessity and they will play a crucial role in the near future. Bamboo Guadua angustifolia, from Colombia, appears like one of these valuable resources with a high potential thanks to its excellent mechanical properties and availability. The use of its fibres has not been considered so often yet, particularly because of difficulties in extracting high quality, undamaged fibres (See figure 1).

 

Fig. 1: Technical bamboo fibres used in composite materials

OBJECTIVES

The main purpose of this project with Colombian bamboo fibres, is to develop a natural fibre composite with high mechanical properties and to present it as a new natural and renewable option to reinforce both thermoplastic and thermoset matrices, which fits into the requirements (properties, availability and cost) established in the field of reinforcements for composites. The aim is to offer an alternative for other natural and particularly synthetic fibres such as glass fibre, used nowadays for this purpose. For these reasons, the main objectives for this PhD research are:

• To explore processing feasibility of bamboo fibre composites by different techniques and to study the resulting fibre and composite properties

• To carry out a systematic study of the influence of processing parameters on the mechanical properties of bamboo fibres and bamboo fibre composites

BAMBOO FIBRE COMPOSITES

1. Thermoset bamboo fibre composites

Thermoset bamboo fibre composites will be characterized. Several production techniques are available to produce them (e.g. resin transfer moulding (RTM)). In order to evaluate the behaviour of bamboo fibre composites with a thermoset matrix (epoxy resin), tensile and flexural tests will be conducted with two types of fibres disposition (longitudinal and transverse) with the purpose of determining mechanical properties of the composite and the interface. (See figure 2)

2. Thermoplastic bamboo fibre composites

For bamboo/thermoplastic composites, a number of variables such as temperature, time of exposure to the consolidation temperature, pressure and polymer type, will be studied in order to optimize the composite properties. These composites will be prepared by compression moulding with different fibre distributions and different fibre volume fractions. The main production variables will be analyzed statistically by factorial design, to establish the optimum process parameters for bamboo fibre composites fabrication. Fibre treatments (as shortly described in paragraph 2.1.3) as well as matrix modifications (e.g. Maleic Anhydride grafted Polypropylene) will be applied. 

3. Continuous and discontinuous unidirectional composites

The fibre lay-out plays a significant role in the final mechanical properties of a composite. For this reason, a continuous and discontinuous unidirectional disposition of bamboo fibres in thermoset and thermoplastic composites will be evaluated. The main interest in this case, is to understand after systematic study, the impact of the fibre length and distribution on the final mechanical properties of the composite. This work will also provide useful information about the most suitable fibre overlap patterns. 

4. Composite consolidation under inert atmosphere

The overall advantages of natural fibres such as bamboo fibres are not yet exploited for high performance materials and engineering composites. Practical applications of these composites are still limited to fairly low melting temperature thermoplastics (e.g. Polypropylene). Natural fibres’ thermal stability is one of the major drawbacks since the first degradation occurs typically at low temperatures in detriment to the mechanical properties of the fibre and hence of the entire composite.

The aim of using inert atmosphere during composite processing, supported by the earlier study on single fibres, is to adapt process parameters preventing fibre damage and to expand the range of possibilities for thermoplastic matrices, without significant reduction in mechanical properties of the composite.

Fig. 2: Bamboo fibre/epoxy composite

CHARACTERISATION AND TESTING OF COMPOSITES

For all prepared composites the tensile mechanical properties (stiffness, strength and strain to failure) will be measured. Properties will also be predicted by existing composite analysis tools, based on fibre and matrix properties. Predicted results will be compared to the measured ones for further analysis.

 Fig. 3: Tensile test for UD bamboo fibre composites

Composite mechanical properties will be characterised and benchmarked against natural and synthetic fibre composites to evaluate the relative performance. 

For further details log on website :
https://www.mtm.kuleuven.be/Onderzoek/Composites/people/EfrainEduardoTrujilloDeLosRios/Polymercompositematerialsbasedonbamboofibres