Final Report Summary - CLEANMOULD (Boat Hulls with Enhanced Performance) The CLEANMOULD project aimed to assist sustainability in the European transports and manufacturing sectors through the development of adequate composite materials, which would be used to produce complex components through the application of innovative, sustainable production techniques. The project developed a polybutylene terephthalate glass fibre (PTB-GF) thermoplastic composite material, along with modified versions of a vacuum bag (VB) consolidation process, a vacuum assisted resin transfer moulding (VARTM) process and a vacuum infusion (VI) process to mould components from the material. In addition, a prepreg version of the PTB-GF material and the vacuum bag process were implemented on a large scale to manufacture a flat-bottom boat and a flatbed semi-trailer. Finally, a methodology for recycling PTB-GF components after completion of their commercial life was developed and verified. The material structure was based on cyclic polybutylene terephthalate (CBT) oligomer resins, which were refined to acquire desirable properties. Non-crimp woven glass fibre reinforcement fabrics were manufactured and utilised with liquid forms of the resin. The methodologies employed for the prototypes preparation were lamination, which did not obtain promising results in terms of drape and handling characteristics but could be scaled to industrial applications and extrusion, whose outcomes appeared commercially exploitable but were not yet applicable at a large scale. Excellent mechanical properties were achieved by all production attempts. The examined case studies and the produced prototypes proved the benefits of the utilisation of thermoplastic components to the end-user, while the material was advantageous compared to conventional thermoset composite systems. The end products were light and aerodynamic; thus, fuel consumption during their life cycle was reduced, and they lasted longer than conventional boats and trailers. Furthermore, the manufacturing process was environmentally friendly with reduced emissions, and the final products were recyclable. Thus, CLEANMOULD contributed directly to the sustainable development of the composite materials sector. Additional indirect benefits of CLEANMOULD were the reduction of the transportation grid maintenance requirements, the expected increase in the sector employment rates and the reduction in volatile emissions and solid waste. A research and development (RD) strategy was developed as part of the project. Knowledge was disseminated across the sector professionals and the project outcomes received increased publicity, which would allow for refinement and commercial application of the technology in the near future. As a first step, two commercial products, a boat and a semi-trailer, were selected and deconstructed to define specifications for the prototypes' production. The PBT oligomer was designed and alternative processes for the final material production were examined and modified, so as to result in a PBT-GF with desirable properties. Furthermore, the three alternatives for final products' manufacturing were developed. The mechanical properties of the constructed laminates were analysed, in order to optimise processing parameters, evaluate the different methods and select the most promising between them, compare the produced material with the conventional products and assess the PBT-GF long-term properties. The VB method was selected as being the simplest to upscale. The finalised product had comparable properties to commercial thermoset materials and outperformed polyester flexibility. Moreover, its durability was high, resulting in prolonged life cycle. Nevertheless, further investigation was necessary to assess both the repeatability of the initial properties and the long-term product characteristics. Given that the quality of laminates depended on manufacturing, it was expected that future refinement of the industrial cycle would result in further improvement of the mechanical properties. The selected VB procedure resulted in poor drape and lack of tack; hence, the trailer design had to be based on a constant cross-section which satisfied structural requirements while maintaining shape simplicity. The aerodynamic performance of the trailer was assessed, while an optimal design with no shape limitations was additionally proposed. Both concepts reduced drag compared to the conventional steel trailer. Special attention was given on the manufacturing of critical cross-sections of both prototypes, since they were large, complex and highly stressed. Moreover, a series of tools used in the production chain were designed and tested so as to meet the applications' requirements. Fabricated steel sheet was utilised for the trailer tools and a carbon-epoxy prepreg was selected for the boat case study. However, the initially selected boat prototype was not constructed and existing steel tools were employed for manufacturing the smaller alternative. Both prototypes were innovative; the trailer was the largest thermoplastic component that was ever made and the boat was the first application of structural thermoplastic composite in a balsa-cored sandwich panel. However, the boat was not tested due to issues of bridging around the core in the floor construction. The trailer on the other hand went through a series of shake-down tests and non-destructive static and dynamic tests. Finally, the recyclability of structures made by the developed material was evaluated. Laminates were produced, shredded and mixed with high quality PTB-GF to construct recycled components. The mechanical properties of the outcome were deviating; nevertheless, they were excellent for an added value recycled product which could be used for the design of complex shapes, while the created recycling techniques were successfully implemented. The proposed innovations were promising and allowed for future commercial exploitation plans; however, further research was required prior to their application at an industrial scale. Additional development should focus on overcoming manufacturing difficulties, improving the prepreg properties and reducing the raw material cost and energy consumption in the production phase, so as to render the technology economically attractive. The trailer in particular formed an attractive sustainable solution to the problems of the European road haulage sector. The weight reduction and its aerodynamic performance resulted in direct and significant cost savings to the operator. Moreover, the fuel savings corresponded to CO2 emissions reduction, which could assist the European Community in reaching the Kyoto agreement targets. Related documents Final Report - CLEANMOULD (Boat Hulls with Enhanced Performance)
