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Structural and conformational changes in solid‐phase chlorinated polyethylene
Author(s) -
Stoeva S.
Publication year - 2004
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.20854
Subject(s) - chlorine , polyethylene , amorphous solid , phase (matter) , methylene , macromolecule , tacticity , chemistry , absorption (acoustics) , vinyl chloride , infrared spectroscopy , polymer chemistry , polymer , absorption spectroscopy , materials science , crystallography , organic chemistry , polymerization , quantum mechanics , copolymer , composite material , biochemistry , physics
The structural and conformational changes in solid‐phase chlorinated polyethylene samples of different average molecular masses were studied with infrared spectroscopy. Characteristic absorption bands for both chlorinated polyethylene and chlorinated high‐molecular‐mass polyethylene, containing 1–56% Cl, were identified. The chlorine content in the macromolecular chains, ranging from 1 to 15%, was associated with the presence of single chloromethylene groups and short syndiotactic structural sequences of poly(vinyl chloride) derived from them. Higher degrees of chlorination, ranging from 20 to 56%, resulted in an increase in the relative part of the heterotactic structures with 1,2‐, 1,3‐, and 1,2,3‐modes of mutual location of the chlorine atoms within a fragment. Moreover, solid‐phase chlorinated polyethylenes with chlorine concentrations as high as 56% were polymers with a mixed amorphous–crystalline structure. On the basis of the intensity ratio of the absorption at 610 cm −1 to the absorption at 660 cm −1 for the corresponding characteristic absorption bands, the substitution of the hydrogen atoms for chlorine ones occurred predominantly in the trans ‐methylene groups, which were located within the amorphous and intermediate phases of polyethylene with chlorine concentrations as high as 20%. Consequently, the relative part of the gauche chlorinated methylene groups increased. A trans‐to‐gauche conformational change was thought to have taken place during the solid‐phase chlorination of polyethylene under the influence of the bulky chlorine atoms. These changes were facilitated by the corresponding segmental mobility of the macromolecular chains. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 189–196, 2004