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The effect of molecular weight in the crystallization kinetics of glassy nylon 6
Author(s) -
Engler Philip,
Carr Stephen H.
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.760180606
Subject(s) - crystallization , differential scanning calorimetry , materials science , glass transition , dispersity , kinetics , thermodynamics , polymer , analytical chemistry (journal) , polymer chemistry , chemical engineering , chromatography , composite material , chemistry , physics , quantum mechanics , engineering
Crystallization of glassy nylon 6 has been investigated with differential scanning calorimetry and wide angle X‐ray diffraction in order to determine the effect of average molecular weight. Samples were prepared by quenching molten films between platens: chilled with liquid nitrogen. These films had number average molecular weights ranging from 10,000 to 42,000 and had polydispersity indices ranging from 2.0 to 3.1. Crystallization kinetics at large undercoolings were measured in terms of the systematic dependence of conversion half time, Avrami exponent and heat of crystallization. Number average molecular weight was observed to influence crystallization rate at large undercoolings through its effect on glass transition temperature. At intermediate undercoolings, molecular weight affected crystallization rate through terms other than the glass transition temperature. In addition, a dependence on the degree of order of the macromolecules, both prior to and after crystallization, was observed.