Abstract
Highly cross-linked polyurethanes have a high elastic modulus and creep resistance, but they undergo a brittle fracture below the glass transition temperature. The lack of substantial toughness in these polymers limits their use in practical engineering applications. One method that has shown promise in recent years is the creation of local regions of reduced modulus that absorb strain energy and act to toughen the polymer. For instance, rubbers are typically added to epoxy which phase separate upon polymerization and create local elastic regions that significantly toughen the polymer. Here a variety of two-phase polyurethanes in the form of single inclusions is designed to study the toughening mechanism of the local regions of reduced modulus with an embedded crack. Synthesized heterogeneous polyurethanes show a transition from brittle to ductile behavior in addition to a drastic increase in the maximum load that the polymer can withstand. Fracture mechanics experiments demonstrate that a small reduction in the inclusion's Young's modulus (∼10%) leads to an increase in the toughness by factor of 7 (∼700%). The finite element method and digital image correlation are utilized to study this toughening mechanism. Optical strain measurements confirm the numerical simulation results and possible toughening and strengthening mechanisms.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
