Micromechanisms of kinking in rigid-rod polymer fibres
dc.contributor.author | Martin, David C. | en_US |
dc.contributor.author | Thomas, E. L. | en_US |
dc.date.accessioned | 2006-09-11T15:09:58Z | |
dc.date.available | 2006-09-11T15:09:58Z | |
dc.date.issued | 1991-10 | en_US |
dc.identifier.citation | Martin, D. C.; Thomas, E. L.; (1991). "Micromechanisms of kinking in rigid-rod polymer fibres." Journal of Materials Science 26(19): 5171-5183. <http://hdl.handle.net/2027.42/44702> | en_US |
dc.identifier.issn | 0022-2461 | en_US |
dc.identifier.issn | 1573-4803 | en_US |
dc.identifier.uri | https://hdl.handle.net/2027.42/44702 | |
dc.description.abstract | The tensile strengths of fibres of the rigid-rod polymers poly(paraphenylene benzobisthiazole) (PBZT) and poly(paraphenylene benzobisoxazole) (PBZO) are excellent, and therefore are of particular interest for high-performance structural applications. However, these fibres are a factor of ten weaker in compression, with failure occurring by strain localization in welldefined kink bands. Here, we study the morphology of PBZT and PBZO kink bands in detail, in order to help elucidate the molecular mechanisms involved in this deformation process. We found that the typical dimensions of a kink in the direction of the fibre axis (∼ 30 nm) were smaller than the length of an average PBZT or PBZO molecule (100 nm). Also, the boundary between the kinked and unkinked regions was well-defined. Low-dose, high-resolution electron microscopy (HREM) of the kink interior revealed local, high-angle changes in chain orientation, indicative of covalent bond bending or breaking. The kink boundaries exhibit “sharp” or “smooth” features which seem to be related to the local tensile or compressive nature of the stress field. A model for kink nucleation and propagation in terms of partial dislocations is presented and discussed. A stress analysis using this model has been developed, and comparison with experimental data suggests that kinks tend to propagate towards regions of higher compressive stress. This observation is interpreted in terms of dislocation pinning (in areas of hydrostatic tension) and the nucleation of dislocation pairs (in areas of hydrostatic compression) due to the asymmetric nature of the intermolecular energy potential. Finally, practical methods for improving compressive strength based on these mechanistic insights are proposed. | en_US |
dc.format.extent | 3166301 bytes | |
dc.format.extent | 3115 bytes | |
dc.format.mimetype | application/pdf | |
dc.format.mimetype | text/plain | |
dc.language.iso | en_US | |
dc.publisher | Kluwer Academic Publishers; Chapman & Hall ; Springer Science+Business Media | en_US |
dc.subject.other | Industrial Chemistry/Chemical Engineering | en_US |
dc.subject.other | Chemistry | en_US |
dc.subject.other | Polymer Sciences | en_US |
dc.subject.other | Characterization and Evaluation Materials | en_US |
dc.subject.other | Mechanics | en_US |
dc.title | Micromechanisms of kinking in rigid-rod polymer fibres | en_US |
dc.type | Article | en_US |
dc.subject.hlbsecondlevel | Materials Science and Engineering | en_US |
dc.subject.hlbsecondlevel | Engineering (General) | en_US |
dc.subject.hlbtoplevel | Engineering | en_US |
dc.description.peerreviewed | Peer Reviewed | en_US |
dc.contributor.affiliationum | Polymer Science and Engineering, The University of Massachusetts at Amherst, 01003, Amherst, MA, USA; Materials Science and Engineering, The University of Michigan, H. H. Dow Building, 48109-2136, Ann Arbor, MI, USA | en_US |
dc.contributor.affiliationother | Polymer Science and Engineering, The University of Massachusetts at Amherst, 01003, Amherst, MA, USA; Materials Science and Engineering, Massachusetts Institute of Technology, Room 13-5066, 02139, Cambridge, MA, USA | en_US |
dc.contributor.affiliationumcampus | Ann Arbor | en_US |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/44702/1/10853_2005_Article_BF01143210.pdf | en_US |
dc.identifier.doi | http://dx.doi.org/10.1007/BF01143210 | en_US |
dc.identifier.source | Journal of Materials Science | en_US |
dc.owningcollname | Interdisciplinary and Peer-Reviewed |
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