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Microscopic flow and failure processes in polymer glasses
Author(s) -
Morgan Roger J.,
O'Neal James
Publication year - 1978
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760181408
Subject(s) - crazing , materials science , polycarbonate , composite material , polymer , cavitation , shear (geology) , flow (mathematics) , deformation (meteorology) , mathematics , mechanics , physics , geometry
The microscopic flow and failure processes, the structural parameters controlling these processes, and how such processes are modified by the service environment are presented for three classes of polymer glasses: polycarbonate, polyimides, and epoxies. The microscopic flow characteristics of polycarbonate are controlled by (a) the ease of shear band deformation which depends on free‐volume and previous thermal history and (b) surface crazes whose characteristics depend on exposure to organic compounds, thermal history, and to surface crystallization and fabrication stresses. Polyimides deform and fail in the bulk by crazing with extensive fibrillation. The growth and development of shear bands from microvoids in polyimides are discussed. Epoxies predominantly deform and fail by crazing with regions of high crosslink density remaining intact during the flow processes. Craze cavitation and growth are enhanced in epoxies by the presence of absorbed moisture.