2026-09-21T01:31:28Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/71812 2023-07-11 col_2142_5131 col_2142_47053 com_2142_5130 com_2142_47052 com_2142_234

O'Connor, Kevin Michael 2014-12-16T20:51:58Z 2014-12-16T20:51:58Z 10000-01-01 1984 1984 The mechanical property development associated with the healing of polymer-polymer interfaces was studied using theoretical and experimental approaches. The healing of crazes in atactic polystyrene (PS) and microvoids in styrene-isoprene-styrene block copolymers was described phenomenologically, from dark-field optical microscopy and light transmission measurements. For the healing of bulk polymer surfaces, molecular-level models were coupled with experiments to investigate the effects of healing time t, temperature T, and molecular weight M. The reptation theory of self-diffusion in entangled polymers was used to describe chain motions and interpenetration at a polymer-polymer interface. Various dynamic quantities, including the average segment interpenetration depth (gamma), were related to the fracture strength (sigma) and fracture energy E through microscopic fracture criteria. For a polybutadiene elastomer, (sigma)(,o) is the surface wetting contribution, K is a constant, and t(,(INFIN)) is the time to achieve full healing. A reanalysis of literature data for natural rubber showed (sigma) (TURN) M('- 1/4) for a constant t 2.5 x 10('5). The M(' 1/2) behavior is consistent with chain pullout, and M('o) is consistent with chain fracture. Made available in DSpace on 2014-12-16T20:51:58Z (GMT). No. of bitstreams: 1 8422787.pdf: 4093512 bytes, checksum: 477bf9c969c3a08471a56be33d9c0e0f (MD5) Previous issue date: 1984 Embargo set by: Seth Robbins for item 71978 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 190 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984. http://hdl.handle.net/2142/71812 (UMI)AAI8422787 Engineering, Materials Science Crack Healing in Polymers (Fracture, Reptation, Tack) text Metallurgy and Mining Engineering Metallurgical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.