The preparation of many bio-composite materials require the use of interfacial materials to ensure they deliver the required level of performance in their target application. These interfacial additives are included to achieve a number of different end-goals. They can be used to; (a) reduce the level of filler aggregation, so maximising the benefits of a specific functional insert, (b) improve the quality of the interface between the filler and the polymer matrix, so as to maximise the mechanical properties that are exhibited by the composite material and (c) improve the processing characteristics of either/both the filler (improving flow) and/or composite formulation (reducing the shear forces required to disperse the filler during processing). They typically contain two differing functionality within the same molecule, e.g. a functional chain which exhibits a high affinity for the bio-composite’s polymer matrix and (b) a head group which will seek to partition to the filler surface. In many cases these dispersant structures are designed and processed to encourage bonding interaction to the filler surface to strengthen their link and to make them more capable of undergoing the shear forces encountered during processing of the final composite. This work reports on the facile synthesis of both dispersant coated glass and nanoparticle filler species via either batch dip coating using mild conditions for premade glass fillers or continuous coating in which the nanoparticles are both synthesised and coated with dispersant via a single stage flow process. The dispersants were optimised to contain multiple head groups, as these candidates were shown to be superior to those which possessed only single head groups. The quality of the coating was explored using XPS, TGA and SEM/TEM analysis, and the subsequent efficacy of the coatings in increasing the interfacial activity of the filler was exemplified via introducing them to specifically designed extraction/dispersion efficiency tests. These elevations demonstrated that all the dispersant coatings had changed the interfacial behaviour of the final filler structure. Finally, these materials were subjected to extrusion processing to produce medical devices by being co-processed with a polyurethane matrix polymer. This process work was conducted with collaborators at Virginia Tech/ Children’s National Hospital (Washington), who will present a paper discussing the processing and Ultrasound results in greater detail.

Synthesis of dispersant coated fillers designed to improve the ultrasound response of biocomposites

254th National Meeting (2017)

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