Thermal Crystallization of Poly(ethylene Terephthalate) and Its Copolyesters: Effect of Degree of Polymerization and Copolymerized Components

Abstract

The effect of the degree of polymerization and the copolymerized components on the thermal crystallization of poly(ethylene terephthalate) (PET) and its copolyesters was investigated at a temperature just above glass transition. The crystallinity of PET increased with the decrease of [η], but the apparent activation energy of crystallization was scarcely influenced by [η]. Crystallization of PET appears to occur from a definite state of thermal motion of the polymer segment, the isoviscous state. Comparing undrawn PET with quenched bulk PET, the crystallinity and activation energy indicate that fiber formation near the spinning nozzle develops the aggregation polymer seg ments for crystallization. Crystallinity and the apparent activation energy of crystal lization for poly(ethylene terephthalate/isophthalate) and poly(ethylene terephthalate/ p-oxybenzoate) indicate behavior that is different from PET. The thermal motion of segments for copolyesters varies with the copolymerized components.

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References

Dole, M. , and Wunderlich, B. , Melting Points and Heat of Fusion of Polymers and Copolymers, Makromol. Chem. 34, 29 (1959).

Edgar, B.O. , and Hill, R. , The p-Phenylene Linkage in Linear High Polymers: Some Structure-Property Relationships , J. Polym. Sci. 8, 1 (1952).

Kawaguchi, T. , Studies on Straining of Amorphous Polyethylene Terephthalate above the Glass Temperature, J. Appl. Polym. Sci. 5, 482 (1961).

Ke, B. , Differential Thermal Analysis of High Polymers, IV: Saturated Linear Polyesters , J. Appl. Polym. Sci. 6, 624 (1962).

Kissinger, H.E. , Reaction Kinetics in Differential Thermal Analysis , Anal. Chem. 29, 1702 (1957).

Marshall, I. , and Todd, A. , The Thermal Degradation of Polyethylene Terephthalate , Trans. Faraday Soc. 49, 67 (1953).

Parks, G.S. , et al., Thermal Data on Organic Compounds, XXV: Some Heat Capacity, Entropy and Free Energy Data for Nine Hydrocarbons of High Molecular Weight , J. Am. Chem. Soc. 71, 3386 (1949).

Rybinkar, F. , Tani Poly-∈-Kaproamidu a Polyethylentereftalatu , Chem. Listy 52, 1042 (1958).

Smith, C.W. , and Dole, M. , Specific Heat of Synthetic High Polymers, VII: Polyethylene Terephthalate , J. Polym. Sci. 20, 37 (1956).

10.

Takahashi, M. , and Nishio, M. , Transition Temperature of Polyethylene Isophthalate Terephthalate Copolymer, Chem. High Polym. Jpn. 14, 649 (1957).