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Insights into in Situ Compatibilization of Polydimethylsiloxane-Modified Thermoplastic Polyurethanes by Dynamic Crosslinking: Relating Experiments to Predictive Models

Sharma, S and Basu, B (2022) Insights into in Situ Compatibilization of Polydimethylsiloxane-Modified Thermoplastic Polyurethanes by Dynamic Crosslinking: Relating Experiments to Predictive Models. In: ACS Applied Polymer Materials, 4 (5). pp. 3752-3769.

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Official URL: https://doi.org/10.1021/acsapm.2c00250


Thermoplastic polyurethane (TPU)-based biomaterials are widely investigated in fabricating biomedical implants and devices. The present study describes a dynamic vulcanization-inspired reactive melt-blending methodology to modify TPU with polydimethylsiloxane (PDMS) and ensure the selective in situ crosslinking of the PDMS phase. The influence of the peroxide crosslinker during melt-processing was assessed, and, thereupon, a complete set of dynamically vulcanized blends was prepared with varying PDMS contents (10-40 wt ). The obtained thermoplastic vulcanizates (TPVs) were characterized for their crosslink density, mechanical properties, morphology, and thermal stability; and benchmarked against the uncrosslinked, pristine blends. The fractographic examination of the blend surfaces demonstrated a remarkable improvement in interfacial adhesion and a more refined microstructure for the TPVs, while a gross phase-separation was evident in the uncrosslinked blends. The experimentally determined tensile/compression response for the dynamically vulcanized system was in good agreement with the theoretical predictions, based on the Halpin-Tsai, Coran, and Takayanagi models. The pristine blends, devoid of crosslinking, largely conformed to the lower-bound series model, implying an immiscible and uncompatibilized behavior. The analysis of stress-concentration parameters was also performed to gain further insights into the discontinuities in the stress transfer in the dual-phase blend system. Taken together, the obtained results affirmed the superior properties of TPVs and established the efficacy of dynamic vulcanization for the in situ compatibilization of the TPU/PDMS system, in good corroboration with the predictive models. © 2022 American Chemical Society.

Item Type: Journal Article
Publication: ACS Applied Polymer Materials
Publisher: American Chemical Society
Additional Information: The copyright for this article belongs to the American Chemical Society.
Keywords: Blending; Dynamics; Microchannels; Morphology; Phase separation; Polydimethylsiloxane; Polymer blends; Polyurethanes; Reinforced plastics; Rubber; Silicones; Stress concentration, Cross-link densities; Dynamic vulcanization; Phase morphology; Phenomenological models; Predictive models; Situ compatibilization; Stress-concentration parameter; Thermoplastic polyurethane/polydimethylsiloxane blend; Thermoplastic polyurethanes; Thermoplastic vulcanizates, Crosslinking
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Division of Interdisciplinary Sciences > Centre for Biosystems Science and Engineering
Date Deposited: 27 May 2022 05:50
Last Modified: 27 May 2022 05:50
URI: https://eprints.iisc.ac.in/id/eprint/72742

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