AbstractSamples of nylon 6 have been prepared by the hexamethylene diamine‐initiated polymerization of ϵ‐caprolactam at 220°C. Fractionation of these withm‐cresol–diethyl ether at 26°C yielded 15 amino‐terminated fractions of M̄nof 337–10,940 determined conductometrically. Below M̄n= 4,306 the Mark‐Houwink parameters inm‐cresol at 30°C areK= 3.0 × 10−3dl/g andv= 0.53 ± 0.02. Thereaftervexhibits a pronounced increase. The value ofKis similar to the values ofKθ derived from Stockmayer‐Fixman plots of published data in good solvents. The findings thus corroborate a current hypothesis that fractionated, low molecular weight polymers in good solvents tend to behave viscometrically, as if they were under θ con
展开▼
