Intrinsic viscosity–molecular weight relationship for polychlorotrifluoroethylene

Abstract

A high temperature osmotic pressure technique has been used to obtain molecular weight data on fractions of polychlorotrifluoroethylene. Samples representing a range of molecular weight of 74,000 to 510,000 were studied. Intrinsic viscosity data were obtained on the samples at 130°C. using a dilution viscometer. The principal solvent used in these studies was 2,5‐dichlorobenzotrifluoride. The plot of π/C vs. C yields satisfactory linear relationships with a slope closely equal to zero. The log log plot of molecular weight and intrinsic viscosity gives the following relationship: The value of the exponent 0.74 suggests a relatively rigid molecule. This is consistent with the results of x‐ray studies.

Gamma irradiation of fluorocarbon polymers

“…The ZST data for PCTFE show a good linear relationship between the reciprocal of the number-average molecular weight, 1/M n and the radiation dose, indicating a rather constant G (scissions) of 0.67, i.e., nearly 0.67 scissions per 100 electron-volts of energy absorbed from the radiation, independent of the presence of air. The scatter of individual determinations was of the order of 5 percent, in agreement with earlier experience [ 11 , 13 ]. The G (scissions) is low compared to values for typical degrading polymers such as polymethyl methacrylate (PMMA) and polyisobutylene (PIB), for which G (scissions) are 1.6 and 5, respectively [ 15 , 16 ].…”

“…For PCTFE the molecular weight data derived from ZST-molecular weight correlations [ 11 , 13 , 14 ] are shown in table 8 and in figure 1 . Correlations are not available for the other polymers, and the plots are of log ZST, which in general should have a linear relationship with molecular weight [ 11 , 13 ]. The ZST data for TFE-HFP copolymer are given in table 9 and figure 2 ; for HFP-YF copolymer in table 9 and figure 3 ; and for two grades of CTFE-VF copolymer in table 9 and figure 4 .…”

“… a ZST measured at 250 °C on standard notched strip [ 12 , 13 ] unless otherwise indicated. b From correlation chart [ 11 , 13 , 14 ]. c Irradiated in vacuum.…”

(Co)polymers of Chlorotrifluoroethylene: Synthesis, Properties, and Applications

“…As mentioned earlier, PCTFE is insoluble in most common organic solvents, and high temperatures (above 120 °C) are often required to achieve solubility. ,,, Suitable solvents include 1,2-dichloro and 2,5-dinitrotrifluorobenzene (130 °C), 2,5-dichlorotrifluoromethylbenzene (130 °C), benzene (200 °C), cyclohexane (>235 °C), toluene (142 °C), carbon tetrachloride (114 °C), 1,1,1-trichloroethane (120 °C), and 1,2,3-trifluoropentachloropropane. ,,, …”