Intrinsic viscosity–molecular weight relationship for low molecular weight nylon 6

Abstract

SynopsisSamples of nylon 6 have been prepared by the hexamethylene diamine-initiated polymerization of ecaprolactam a t 220°C. Fractionation of these with m-cresol-diethyl ether at 26OCyielded 15 amino-terminated fractions of M,, of 337-10,940 determined conductometrically. Below an = 4,306 the Mark-Houwink parameters in m-cresol at 30°C are K = 3.0 X 10-3 dl/g and Y = 0.53 f 0.02. Thereafter Y exhibits a pronounced increase. The value of K is similar to the values of Kederivedfrom 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 8 conditions (i.e., K = K e and Y = 0.50).

Simulation of hydrolytic polymerization of .epsilon.-caprolactam in various reactors. A review on recent advances in reaction engineering of polymerization

“…Tai et al ( 108) carried out the simulation calculations for the sealed CSTR under various conditions using eq 32 as the E function. The resulting mean kinetic data at the outlet of the reactor were demonstrated as the functions of the inlet composition w0, T, and r, an example of which is shown in Figure 6.…”

“…Now, a fully automatic apparatus may also be available. The solvents used for the viscometry are concentrated sulfuric acid (11,51,71,94,99), mcresol (32,46,59,89,114), formic acid (25,51,63,98), tetrafluoropropanol-H20-LiCl (114), tricresol (97), trifluoroethanol (63), phenol-tetrachloroethane (84), ethanol-LiCl3 or LiN03 (13), and antimony trichloride (2) (concentrated sulfuric acid and formic acid are recommended in JIS relation can be expressed by the Kuhn-Mark-Houwink-Sakurada equation. In table XIV are listed the constants of the equation together with the solvents and temperatures used for the observations.…”

Measurement and modeling of poly(vinyl acetate)–solvent viscosity mixtures

“…There are experimental methods for determining the molecular weights of polymers. Osmotic pressure6, 7 and intrinsic viscosity ([η])8–12 methods are used for the determination of M n 13, 14. Sedimentation,15, 16 diffusion,17–19 and light scattering20–24 methods are suitable for the determination of M w .…”