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Boat Hulls with Enhanced Performance

This ambitious project aims to develop new environmentally friendly manufacturing processes using lightweight fibre reinforced thermoplastic for the production of composite structural vehicles. As an example, the technology will be be used to produce an innovative semi-trailers and boat hull at lower cost, with enhanced performance and inherent recyclability.

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Composite materials offer the designer the ability to manufacture lightweight structures coupled with high strength/stiffness and excellent corrosion resistance. Composite materials are widely employed in the manufacture of work and leisure boats; however, these composite materials are predominantly based on room temperature curing resins such as polyester, vinyl ester, etc which emit a solvent during processing and are difficult to recycle. In recent years, the same materials have been increasingly used within road vehicles such as cars, trucks and semi-trailers. The key problem addressed by this project is the manufacture of large surface area structures (e.g. boat and semi-trailers) utilising liquid thermoplastic composite resins, which contain no solvents and which polymerise within the mould to form a high performance environmentaly stable structures that have better results over conventional thermoset resins. These thermoplastic structures are easier to recycle into short fibre reinforced components for re use across a wide range of industries.


This project aims to use an innovative form of thermoplastic composite resin based on polybutylene teraphthalate (PBT) oligomer technology to address the shortcomings of the above products and processes.

This technology involves using PBT oligomers that melt at low temperatures (160ºC) into low viscosity liquids (i.e. 20 centipoise), which can then be used to impregnate or wet-out the fibres and thereby achieve a high fibre content (50% by volume) and thus a product that has enhanced structural performance. The PBT oligomers are polymerised in the mould using a catalyst in the melt. Once the PBT oligomer polymerises in the mould, fibre-reinforced PBT polymer composites are formed that have exceptionally good mechanical properties and a melting temperature of 260ºC.

PBT oligomer technology enables composite structures to be processed utilising conventional liquid thermosetting resins processes (i.e. vacuum infusion, preimpregnation, etc.) but with all the benefits of thermoplastics.

Large heavy goods vehicles offer great scope for weight reduction
Large heavy goods vehicles offer great scope for weight reduction
Euro-Projects LTTC Ltd

Description of work

Basmiler and Halmatic will provide detailed product specifications for the 13.6 m flat bed semi-trailer and 8 m boat hull respectively. These specifications will form the focus of the project against which the developed thermoplastic composite case study applications will be measured. Cyclics will develop the low melting point and low viscosity thermoplastic PBT oligomers. These compounds will include the catalyst, pigmentation and fire resistance compounds. Cyclics will work closely with Ahlstrom and supply the PBT oligomers in a form suitable for incorporating with continuous fibre reinforcement fabrics. Ahlstrom will develop all the necessary fibre-coupling agents and sizes necessary to achieve good fibre-resin interfacial strength. Ahlstrom will also develop techniques to incorporate the PBT oligomers into the fibre fabrics for ease of handling and use by Halmatic and EPL during processing trials. EPL and IKV will determine the optimum processing windows (time, temperature, pressure) and process conditions for achieving good wet-out of the fibres and low voidage. IKV will determine the mechanical properties of test laminates moulded under optimum conditions. This data will be used by EPL to design the 13.6 m semi-trailer and 8 m boat hull. In order to validate the design, critical sections of the semi-trailer and boat hull will be moulded by Halmatic and tested by IKV. Critical sections include measuring the pullout strength of inserts and joints, etc. Having determined a design, Halmatic will produce prototype moulds for the semi-trailer and boat hull. Halmatic will then manufacture the semi-trailer and boat hull case study structures that will be tested by Basmiler and Halmatic respectively. Throughout the course of the project, IKV will develop techniques to recycle and reprocess all the thermoplastic composite materials produced during all the various processing steps, including the final moulded parts.


Key deliverables will be:

  1. Confirmation of the technical, economic and environmental benefits
  2. Development of PBT oligomers with low melting point (150ºC) and low viscosity (20 cP)
  3. Development of PBT composites with up to 50% Vf with excellent mechanical properties
  4. Demonstration that critical sections of two case study components can be manufactured
  5. Two moulded case study components (boat hull and semi-trailer) that have been evaluated under in-service conditions.
Socio-market benefits include:


Lower weight means more payload, fewer journeys, fuel savings, emission and CO2 reductions, less road damage when empty, improved air quality. The integrated design means reduced cost, more efficient design and better crash structures. Socio-economic factors include increased competitiveness, recyclable product, longer life (40 vs. 20 years) raw material savings, aerodynamics provide 7.5% fuel savings equal to £3 000 per year and 8.5 tonnes CO2, and no volatile organic compounds (VOCs).


Physical benefits include increased toughness, impact resistance and longer life. Manufacture benefits include reduced labour, and the automated process provides knowledge and technical advantage over cheaper imports. Socio-economic factors include it being recyclable, has no VOCs and a clean technology.

Composite boats benefit greatly from composite materials
Composite boats benefit greatly from composite materials
VT Halmatic