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Title: Solvent-free, liquid processable bismaleimide-triazine resins
Author: Iredale, Rob
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2019
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This thesis is concerned with the development of novel bismaleimide-triazine (BT) resin blends, with particular emphasis being placed on enhancing the understanding of systems that exhibit low temperature processability. These resins combine the chemistries of cyanate ester (CE) and bismaleimide (BMI) monomers to produce materials with desirable mechanical properties, thermal stability and electrical performance, making them attractive to industries as diverse as microelectronics and aerospace. A eutectic blend containing a new BMI monomer was used as a route to creating BMI materials with lower melting points and a decreased dependence on toxic precursors. This was then melt-blended with a low viscosity CE monomer to create homogeneous blends with low viscosities (< 1000 mPa s) at room temperature, without the need for any solvents. The storage stability of these materials was improved by adding higher viscosity components. It was found that the eutectic BMI blend was able to catalyse the CE curing reaction, reducing the peak exotherm temperature by up to 67 °C, providing a route to improved reactivity without the need for complicated catalyst addition and dispersion. The reaction kinetics were studied in detail, alongside a comparison of dynamic and isothermal experiments. The physicomechanical properties of the cured blends in terms of stiffness, glass transition temperature, electrical properties, outgassing performance and thermal stability are improved compared to the benchmark industrial standard. With increasing BMI addition, the solvent resistance of the materials increases, however there is also a negative effect on water uptake. The viscosity modifiers exhibit opposing effects on the properties of the cured materials obtained. Glass fibre composites were prepared from the cured materials via a vacuum assisted resin transfer moulding method, however it was determined that these low viscosity materials are better suited to high pressure methods thanks to their propensity to absorb moisture. Three different glass fibre surface treatments were investigated, with Volan functionalised fibres proving to be the most appropriate for BT resins. This was followed by a more thorough investigation into the processability of the blends, including their suitability to alternative manufacturing procedures.
Supervisor: Hamerton, Ian ; Ward, Carwyn Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Composite materials