Enthalpy relaxation in poly(ethylene terephthalate) and related polyesters

Enthalpic relaxation data are presented on poly(ethylene terephthalate), poly(ethylene naphthalate) and their copolymers. Analysis of these data allows the determination of the amount of energy absorbed at the glass transition, Qt, and the location of the enthalpic recovery peak, Tmax, as a function of the time of ageing of the samples. Ageing measurements were carried out for periods of up to 2016 h and at temperatures between 40 °C and 110 °C, depending upon the chemical composition of the system being investigated. The enthalpic relaxation rates are influenced by the chemical structure and reflect the effects of local order pinning the chains and influencing the rate of enthalpic recovery.

[1]  S. D. Jenkins,et al.  Physical ageing in poly(ethylene terephthalate)—its influence on cold crystallisation , 1999 .

[2]  J. C. Cañadas,et al.  Comparative TSPC, TSDC and DSC physical ageing studies on PET-a , 1998 .

[3]  V. Vittoria,et al.  Influence of ageing on the cold crystallization of glassy poly(ethyleneterephthalate) , 1997 .

[4]  Liheng Wu,et al.  The effects of physical ageing on conformational changes of poly(ethylene terephthalate) in the glass transition region , 1996 .

[5]  A. Mahendrasingam,et al.  Time-resolved two-dimensional small angle X-ray scattering studies of oriented poly-(ethylene terephthalate) (PET) using paracrystalline modeling techniques , 1995 .

[6]  D. Rueda,et al.  Physical aging in poly(ethylene naphthalene-2,6-dicarboxylate) in relation to sorbed water, enthalpic relaxation, and mechanical properties , 1995 .

[7]  P. Cortés,et al.  Physical ageing studies in semicrystalline poly(ethylene terephthalate) , 1995, Journal of Materials Science.

[8]  J. N. Hay.  The physical ageing of amorphous and crystalline polymers , 1995 .

[9]  J. Hutchinson,et al.  Physical aging of polymers , 1995 .

[10]  K. Itoyama.  Effects of thermo-mechanical glass-forming histories on enthalpy relaxation of amorphous poly(ethylene terephthalate) , 1994 .

[11]  G. Vigier,et al.  Physical ageing of amorphous and semicrystalline poly(ethylene terephthalate) , 1993 .

[12]  F. Calleja,et al.  Physical transitions and crystallization phenomena in poly(ethylene terephthalate) studied by microhardness , 1993 .

[13]  John M. G. Cowie,et al.  Physical aging studies in poly(vinylmethyl ether). I. Enthalpy relaxation as a function of aging temperature , 1989 .

[14]  P. Cortés,et al.  Effect of previous thermal history on physical aging of amorphous poly (ethylene terephthalate) , 1989 .

[15]  Y. Q. Zhou,et al.  Sub‐Tg storage of amorphous polymers , 1988 .

[16]  S. Montserrat,et al.  Analysis of enthalpy relaxation in amorphous poly(ethylene terephthalate) , 1988 .

[17]  J. N. Hay,et al.  Physical ageing in glassy polymers. An i.r. spectroscopic investigation of poly(ethylene terephthalate) , 1982 .

[18]  G. Wilkes,et al.  Physical aging studies of semicrystalline poly(ethylene terephthalate) , 1981 .

[19]  J. Hutchinson,et al.  Isobaric volume and enthalpy recovery of glasses. II. A transparent multiparameter theory , 1979 .

[20]  S. Petrie.  The effect of excess thermodynamic properties versus structure formation on the physical properties of glassy polymers , 1976 .

[21]  S. E. B. Petrie,et al.  Thermal behavior of annealed organic glasses , 1972 .

[22]  O. S. Narayanaswamy.  A Model of Structural Relaxation in Glass , 1971 .

[23]  G. Yeh,et al.  Crystallization of polyethylene terephthalate from the glassy amorphous state , 1967 .

[24]  F. Bueche.  Rate and Pressure Effects in Polymers and Other Glass-Forming Substances , 1962 .