Ionomers are interesting due to their applications in coatings, adhesives, films and packaging materials. A study of the underlying mechanisms for fracture in ionomers is consequently of both practical as well as theoretical interest. In this study, we employ high speed imaging coupled with uniaxial extensional rheometry to delineate the mechanics leading to the brittle fracture of ionomer melt...

A generalized method for characterizing mechanical stresses in brittle materials during crack tip propagation is presented. This approach was derived from classical fracture mechanics and is therefore mechanism independent and applies to any isotropic brittle material, including glasses, fine grained ceramics or metals, and high stiffness polymers. A practical implementation demonstrates the me...

sudden fracture is one of the major failure modes in brittle materials. plexiglass (polymethyl methacrylate) is a well known brittle polymer, widely used in various industries. many types of notches, particularly v-shaped notches, are sometimes used in the components made of plexiglass. these notches can dramatically decrease the load bearing capacity of components due to the concentration of s...

_______________________________________________________________________________________ A fracture mechanics approach has been used to investigate how the addition of high-temperature resistant thermoplastic modifiers can increase the fracture energy, Gc, of brittle cyanate-ester polymers. Tests were performed using adhesive joint specimens at -55, 21 and 150°C. The fracture energies of poly(et...

Crazing is a failure mode of bulk polymers and occurs under predominant uniaxial tensile load when the bulk eventually forms denser ligaments (or fibrils) while preserving its continuity. The bridging of cracks by such fibrils is an importantmechanism for energy dissipation and toughening in thermoplastic polymers. However, craze phenomena are not observed in thermosetting polymers such as epox...

IMPACT RESISTANT GLASSY POLYMERS: PRE-STRESS AND MODE II FRACTURE FEBRUARY 2013 JARED STEVEN ARCHER B.S., WESTERN WASHINGTON UNIVERSITY M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Alan J. Lesser Model glassy polymers, polymethyl methacrylate (PMMA) and polycarbonate (PC) are used to experimentally probe several aspects of polymer f...

Whether used as structural components in design or matrix materials for composites, the mechanical properties of polymers are increasingly important. The compressive response of extruded polymethyl methacrylate (PMMA) rod with aligned polymer chains and Al-Ni-PMMA particulate composites are investigated across a range of strain rates and temperatures. The particulate composites were prepared us...