Premium
Studies on sublimation of disperse dye out of dyed polymers. I. Rate of sublimation and amorphous transition points of poly(ethylene terephthalate)
Author(s) -
Ito Ichiro,
Okajima Saburo,
Shibata Fumio
Publication year - 1970
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.1970.070140304
Subject(s) - amorphous solid , sublimation (psychology) , crystallinity , glass transition , activation energy , materials science , disperse dye , polymer chemistry , crystallization , atmospheric temperature range , analytical chemistry (journal) , polymer , crystallography , thermodynamics , polyester , chemistry , composite material , organic chemistry , psychology , physics , psychotherapist
Four samples of poly(ethylene terephthalate) film of various crystallinities and orientation were dyed with p ‐nitroaniline and disperse dyes. When these films were heated under a 2–3 × 10 −3 mm Hg vacuum at a specified temperature T , the dye sublimed out of the dyed specimen. The amount ( M t / M ∞ ) of sublimed dye is in linear proportion to the square root of the sublimation time, t ½ , where M t and M ∞ are the amounts of dye sublimed for times t and t = ∞. The diffusion coefficient D , calculated from the slope of the above plot, is independent of the dye concentration of the film. When log D is plotted against 1/ T °K over the temperature range 320–520°K, the relation is composed of two to four intersecting lines with the slope decreasing with elevation of temperature and with the breaks at about 89°–98°, 122°–135°, 155° and 175°–176°C. These breaks are the amorphous transitions: the first is the glass transition temperature T g , the second and the fourth are the amorphous transitions corresponding to the crystalline transition points, i.e., the cold crystallization temperature and the smectic–triclinic transition temperature. With some exceptions, these amorphous transitions are found also by dilatometry and electrical conductivity measurements. The apparent activation energy for diffusion decreases from about 100 kcal/mole for the glass state to 22–24 kcal/mole for the region above 180°C. The activation energy for each region changes slightly with the size of dye molecule and the crystallinity and orientation of the film.