Highly reinforced blends based on in-situ synthesized polyurethane-urea and nitrile butadiene rubber
Event:187th Technical Meeting Location: Greenville, SC Date: April 27, 2015 Author: M. Tahir*, K. W. Stöckelhuber, N. Mahmood, S. Wießner, G. Heinrich Paper Number:
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The present study investigates the effectiveness of a novel reactive blending method by showing structural, mechanical, dynamic-mechanical and morphological characteristics of a new kind of blends composed of polyurethane-urea (PUU) and nitrile butadiene rubber (NBR). The distinctive spectrum of superior mechanical properties of polyurethane-ureas inspires their blending with rubbers for new material possibilities; this however is constrained by high temperatures required for the melt-blending process. In the present investigation, this challenge has been countered by the in-situ synthesis of PUU via the pre-polymer route during blending with NBR in internal mixer. The proposed reactive blending process was carried out in an internal mixer followed by the structural characterization of prepared PUU/NBR blends by 1H NMR spectroscopic analysis to confirm the in-situ addition polymerization of isocyanate terminated pre-polymer with chain extender. The vulcanizates of PUU/NBR blends show significant improvements in stress-strain behavior, tear strength, abrasion loss and high temperature dynamic-mechanical behavior. Scanning electron microscopy (SEM) of cryogenically fractured surfaces reflects strong interfacial adhesion between dispersed PUU domains and continuous NBR matrix. Further microscopic investigation of blend vulcanizates reflects clearly the formation of an interphase between two obvious phases, which supports the substantial improvements in mechanical and dynamic-mechanical characteristic of self-compatibilized PUU/NBR blend vulcanizates. The new PUU/NBR blend vulcanizates possess a new profile of attractive properties and may be considered for applications like belting, pump impellers, rubber rollers, industrial wheels etc.