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Effect of prior high‐pressure treatment on nylon 6 films: Swelling and other studies
Author(s) -
Chaudhuri N. K.,
Singh L. P.
Publication year - 1979
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1979.070241104
Subject(s) - swelling , crystallinity , crystallite , materials science , diffusion , analytical chemistry (journal) , composite material , chemistry , thermodynamics , organic chemistry , physics , metallurgy
The effect of prior high‐pressure treatment on nylon 6 films has been investigated, using weight swelling, density, infrared crystallinity index, x‐ray diffraction, and relative viscosity measurements. Pressures in the range of 0–25 tons/sq. in. were used. Swelling measurements, using benzyl alcohol as the swelling agent, show that the initial slope of the weight swelling‐versus‐(time) 1/2 plots, divided by equilibrium weight swelling, increases with increasing pressure, indicating enhancement of the diffusion coefficient with pressure. The sigmoidal nature of the plots is reduced with pressure, but the relaxation‐controlled non‐Fickian behavior persists within the pressure range used. With increase of pressure up to 10 tons/sq. in., the equilibrium weight swelling records a substantial increase, and slight increases in density and infrared crystallinity are concomitantly observed but an opposite effect occurs with x‐ray order factor. Beyond 10 tons/sq. in. pressure, these quantities become more or less stationary. Relative viscosity of formic acid solution of pressure‐treated samples remains unaltered with pressure. An integrated interpretation of all these changes is found in the degeneration of larger crystallites into smaller ones with the molecules sandwiched between new surfaces. The newly created crystallites are too small to produce x‐ray diffraction peaks. Pressure‐induced γ ⇄ α conversion processes are also found to occur.