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The specific volume of poly (chlorotrifiuoroethylene) has been measured from -400 to + 260 0 C. Both q uenched and well-crystallized. ~pecimens prepared by reproducible procedures were studied. Well-defined glass tranSitIOns were found close to 52 0 C in both specimens. Hence t he glass temperature of t his polymer is essentially independent of t h e ~egree of ?rystallinit:y. The. quasi~eq~ilibrium melting point of the particular type of crystal~Ized speCimen used III the l~lVestlgatlOn was 216 0 C. The equilibrium melting temperature IS undoubtedly somewhat higher, and probably lies between 2200 and 225 0 C. The d egree ?f crystallinity of the crystallized and quenched specimens was calculated at T I from speCific-volume J?easurements alone, using a straightforward thermodynamic procedure. The method aVOids a long "unguided" extrapolation of the liquid data to low te~per:;ttures, and does not involve the inexact approximation that the volu me-temperature denvattv.e.of the glas y and cryst~lline states are the same. It has the further advantage of not regumn g a pure crystal denSity from another source, such as a unit-cell determination from X-ray ? ata. It was fo und that th.e quenched sample was 39 p ercent crystalline and the well-cry:st.alhzed one 82 percent. A sl~ple extension of the theory permit the degree of crystalh1l1ty to be comp uted as a functlOn of temperature. The results are compared with those obtained in earlier investigations. The sp ecific vo.lumes and volum~-temperature derivatives of the pure supercooled liquid, g~3:s y, and crystallme phases are estimated over a wid e range of temperature. Certain quant ities re lated to the free volume of the glassy state are discussed . The methods outli ned may be of utility in analyzing specific-volume-temp erature data on other semi crystalline polymers where the rapid onset of crystallization interferes with a direct s~udy of the sLIpercoole~ liquid and glassy states, and where independent data on the properties of the pure crystallme phase are not availa ble.

journal of research of the national bureau of standards

Specific volume and degree of crystallinity of semicrystalline poly(chlorotrifluoroethylene), and estimated specific volumes of the pure amorphous and crystalline phases