caa a22 4500 465755291 CHVBK 20180323111845.0 cr unu---uuuuu 170327e19900101xx s 000 0 eng 10.1007/BF00503873 doi (NATIONALLICENCE)springer-10.1007/BF00503873 Crystallization and fibril formation in polymers [Elektronische Daten] [E. Clark, J. Hoffman] Solutions of crystallizable polymers subjected to orientation crystallize in a fibrillar morphology if the polymer is solidified rapidly. The central core of the polymer fibers consists of thin, extended chain crystallites interspersed with disordered regions. The extended chain crystals are small fibrils having diameters generally less than a few hundred angstroms, while the lengths are usually not more than 5000 Å. These dimensions are limited by an unknown mechanism, because even in a saturated solution, the fibril crystal size is limited. Hoffman's theory of flow-induced crystallization predicts that cumulative strain limits the growth of the central core fibril such that the diameter and length of the fibril are an inverse function of undercooling. This study was undertaken to obtain data to test the theory. The dependence of the fibril dimensions on undercooling at the time of orientation has been studied. Polyethylene fibrils were made by shearing a dilute solution between two slides under isothermal conditions at an elevated temperature, and the dimensions of the resulting fibrils were measured with transmission electron microscopy. The fibril diameter appeared to be a function of undercooling, while the fibril length was constant and not a function of undercooling. Plenum Publishing Corporation, 1990 crystallization nationallicence fibrils nationallicence flow-induced nationallicence orientation-induced nationallicence polymers nationallicence polyethylene nationallicence undercooling nationallicence Clark E. Thermophysics Division, National Institute of Standards and Technology, 20899, Gaithersburg, Maryland, USA aut Hoffman J. Michigan Molecular Institute, 48640, Midland, Michigan, USA aut International Journal of Thermophysics Kluwer Academic Publishers-Plenum Publishers 11/1(1990-01-01), 225-237 0195-928X 11:1<225 1990 11 10765 https://doi.org/10.1007/BF00503873 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00503873 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Clark E. Thermophysics Division, National Institute of Standards and Technology, 20899, Gaithersburg, Maryland, USA aut NATIONALLICENCE 700 1- Hoffman J. Michigan Molecular Institute, 48640, Midland, Michigan, USA aut NATIONALLICENCE 773 0- International Journal of Thermophysics Kluwer Academic Publishers-Plenum Publishers 11/1(1990-01-01), 225-237 0195-928X 11:1<225 1990 11 10765 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer