Toughness, Ductility, and Thermal Stability HBonded Amorphous Polymer Glass Nanofibers with Simultaneously Large Enhancement in Strength

AbstractUnderstanding the direct effects of hydrogen bonding (Hbonding) on the mechanical response of glassy state polymers remains a challenge, largely owing to the use of semicrystalline polymers in such studies, wherein, separating the contributions due to the changes in degree of crystallinity and direct Hbonding effects on the observed mechanical properties is extremely difficult. This limitation is overcome by studying the mechanical behavior of amorphous, glassy polyvinylpyrrolidone (PVP), Hbonded with tannic acid (TA). Uniaxial tension experiments on individual submicron scale PVP fibers (0.61.0m diameters) with different TA concentrations are conducted to capture their elastoplastic deformation characteristics. Amorphous PVPTA complexes exhibited some distinctive trends in elastoplastic properties with increasing Hbond density, which are not observed earlier. These distinctive trends are discussed in terms of the competing effects of Hbond driven crosslinking and TAinduced reduction in entanglement density, and their differing roles during elastic and plastic deformation. The improvements in elastoplastic properties (particularly ductility and toughness) are simultaneously accompanied by uniquely significant thermal stability (i.e., glass transition temperature, Tg) improvements, that can help improve the practical applicability, operational life, and performance of these materials.

HBonded Amorphous Polymer Glass Nanofibers with Simultaneously Large Enhancement in Strength, Toughness, Ductility, and Thermal Stability Academic Article