Application of the modified avrami equations to polymer crystallisation kinetics

Explanations of the deviations of polymer crystallisation isotherms from Avrami equations are considered in the light of the assumptions inherent in the derivation of the equations and analysis of the crystallisation isotherms; these explanations are rejected. Modified equations which allow for the presence of several crystallisation mechanisms and recrystallisation are considered to be a more satisfactory physical model of spherulitic crystallisation from the melt. While they describe the crystallisation isotherms more accurately than a single Avrami process, non-random deviations which cannot be satisfactorily explained still exist. Further modifications to include changing nucleation characteristics, induction periods, etc., do not improve the fit of these modified equations.

[1]  U. R. Evans.  The laws of expanding circles and spheres in relation to the lateral growth of surface films and the grain-size of metals , 1945 .

[2]  I. H. Hillier,et al.  The bulk crystallization kinetics of polypropylene and polybutene , 1965 .

[3]  I. H. Hillier,et al.  Mechanism of secondary crystallization of polymethylene , 1965 .

[4]  P. Parrini,et al.  The influence of molecular weight distribution on the primary crystallization kinetics of isotactic polypropylene , 1963 .

[5]  J. N. Hay.  A thermostat control unit for a polarizing microscope , 1964 .

[6]  R. Roe,et al.  The crystallization of polyethylene I , 1963 .

[7]  L. Mandelkern.  The Crystallization Of Flexible Polymer Molecules , 1956 .

[8]  G. F. Schmidt,et al.  Über Langperioden bei verstrecktem Polyäthylen , 1962 .

[9]  L. B. Morgan,et al.  Crystallization phenomena in polymers - Effect of melt conditions and the temperature of crystallization on the course of the crystallization in polyethylene terephthalate , 1954, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[10]  M. Avrami.  Kinetics of Phase Change. II Transformation‐Time Relations for Random Distribution of Nuclei , 1940 .

[11]  J. N. Hay,et al.  Crystallization kinetics of high polymers. Polyethylene oxide—Part II , 1969 .

[12]  H. D. Keith,et al.  Spherulitic Crystallization from the Melt. I. Fractionation and Impurity Segregation and Their Influence on Crystalline Morphology , 1964 .

[13]  F. L. Swinton,et al.  The crystallization of polydecamethylene terephthalate , 1963 .

[14]  W. Banks,et al.  The AVRAMI equation in polymer crystallization , 1963 .

[15]  M. Avrami.  Granulation, Phase Change, and Microstructure Kinetics of Phase Change. III , 1941 .

[16]  H. D. Keith,et al.  A Phenomenological Theory of Spherulitic Crystallization , 1963 .

[17]  J. Hoffman,et al.  X‐Ray Study of Isothermal Thickening of Lamellae in Bulk Polyethylene at the Crystallization Temperature , 1965 .

[18]  L. B. Morgan.  Crystallization phenomena in polymers - The course of the crystallization , 1954, Philosophical transactions of the Royal Society of London. Series A: Mathematical and physical sciences.

[19]  M. Avrami.  Kinetics of Phase Change. I General Theory , 1939 .

[20]  M. Hatano,et al.  Crystallization of poly-[3,3-bis(chloromethyl)oxacyclobutane] , 1961 .

[21]  M. Gordon,et al.  The crystallization of polyethylene after partial melting , 1963 .