Development of Novel Polymer Matrix Composites and their Processing for Enhanced Damping

This thesis advances the field of polymer matrix composites by developing materials with enhanced damping properties. The focus is on the integration of soft elastomers along with the proper use of compatibilizers and basalt fibers into methyl methacrylate-acrylonitrile butadiene styrene (MABS) matrix. By employing a novel multiphase binary polymer blend approach, this research investigates the viscoelastic property enhancement through the strategic incorporation of dynamically vulcanized alloys, specifically ethylene propylene diene monomar rubber (EPDM) particles within a polypropylene (PP) matrix (Santoprene) and a styrene-based thermoplastic elastomer (VDT).

The research employs a methodology that combines experimental and computational modeling to develop polymer blends with superior damping properties. This includes detailed morphological, mechanical, and viscoelastic characterizations using stateof- the-art techniques such as differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), Fourier-transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR), laser microscopy, and scanning transmission electron microscopy (STEM). The comprehensive analysis reveals that the integration of VDT into MABS matrices significantly enhances damping performance due to its superior compatibility and dispersion, as compared to those of Santoprene. The improvement in damping properties with the addition of soft elastomeric phases, although affecting tensile strength, opens new avenues for the application of these materials beyond hearing aids, including in automotive, aerospace, and consumer electronics industries where vibration damping is crucial.

Moreover, the successful integration of basalt fibers not only enhances the composite’s mechanical performance and damping efficacy but also highlights the fibers sustainable and environmentally friendly nature. This integration is in alignment with the broader research objective of developing advanced materials that balance performance with ecological sustainability. Parallelly, this thesis develops predictive computational models based on viscoelastic theory, validated against experimental data, to elucidate the complex interactions within these novel polymer composites. These models provide a foundational tool for predicting material behavior and guiding the design of next-generation polymer blends with tailored viscoelastic properties for specific industrial applications.

In summary, this work contributes to significant advancements in materials science by elucidating the mechanisms underlying enhanced damping in polymer composites through the synergistic use of compatibilizers and basalt fibers. It presents a pioneering approach to material design that not only has implications for the hearing aid industry but also for a broad spectrum of applications requiring advanced vibration damping solutions. The integration of computational modeling with experimental investigations further exemplifies a comprehensive methodology for accelerating the development and optimization of high-performance material systems.