Decoupling of reactions in reactive polymer blending for nanoscale morphology control

Authors

  • Prashant A. Bhadane,

    1. CREPEC, Department of Chemical Engineering, École Polytechnique de Montréal, 2900 Édouard Montpetit, P.O. Box 6079, Station Centre-Ville, Montréal, Québec, Canada H3C 3A7
    Current affiliation:
    1. Cerestech Inc., Pavilion J.-A Bombardier, 5155 Av. Decelles, Montréal, Québec, Canada H3T 2B1
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  • John Cheng,

    1. ExxonMobil Chemical Company, Global Polyolefin Technology, 5200 Bayway Dr, Baytown, Texas 77520
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  • Maria D. Ellul,

    1. ExxonMobil Chemical Company, Global Specialty Polymers Technology, 388 South Main Street, Akron, Ohio 44311-1065
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  • Basil D. Favis

    Corresponding author
    1. CREPEC, Department of Chemical Engineering, École Polytechnique de Montréal, 2900 Édouard Montpetit, P.O. Box 6079, Station Centre-Ville, Montréal, Québec, Canada H3C 3A7
    • CREPEC, Department of Chemical Engineering, École Polytechnique de Montréal, 2900 Édouard Montpetit, P.O. Box 6079, Station Centre-Ville, Montréal, Québec, Canada H3C 3A7
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Abstract

In this study, a dynamic vulcanized alloy of brominated poly(isobutylene-co-p-methylstyrene) (BIMSM) and polyamide (PA) has been investigated. An interfacial reaction between BIMSM and PA and a crosslinking reaction between BIMSM molecules is carried out simultaneously during melt blending. To form a vulcanized, nanoscale elastomer dispersion, the timing of these reactions is key and the interfacial reaction should be well advanced before the vulcanization reaction initiates. At a blending temperature of 205 °C, independent of the processing conditions, it is found that the interfacial reaction dominates the phase morphology development. Increasing the melt processing temperature, however, begins to favor the vulcanization reaction over the interfacial reaction. In nonplasticized blends, it is found that increasing the temperature above 235 °C increases the speed of the vulcanization reaction to a level that it dominates the phase morphology development. As a result, the phase size increases by 2.5-fold because the system is vulcanized before the interfacial modification step is complete. Adding plasticizer to the PA matrix increases the overall phase size, but shows a similar behavior with increase in temperature from 205 to 255 °C. The critical temperature where the vulcanization reaction starts dominating phase morphology in the plasticized systems is at 225 °C. Once the processing temperature is above the critical temperature, it is found that the mixing sequence can be used to time and decouple the reactions. The work demonstrates that a close control over the temperature and processing conditions can be used to decouple the interfacial and vulcanization reactions resulting in vulcanized, nanoscale dispersions for the BIMSM and PA system. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

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