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Stabilization of gamma‐irradiated poly(vinyl chloride) by epoxy compounds. III. Conjugated double bonds and degree of unsaturation in gamma‐irradiated PVC–stabilizer mixtures
Author(s) -
Lerke G.,
Lerke I.,
Szymański W.
Publication year - 1983
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.1983.070280208
Subject(s) - degree of unsaturation , polyene , double bond , epoxy , polymer chemistry , chemistry , conjugated system , diglycidyl ether , vinyl chloride , epoxide , organic chemistry , bisphenol a , polymer , copolymer , catalysis
The concentration of conjugated polyene sequences was studied in γ‐irradiated PVC with 4% admixture of four epoxy stabilizers: diglycidyl ether of 2,2‐bis(4‐hydroxy‐3‐methylphenyl)propane (I), styrene oxide (1,2‐epoxy ethyl benzene) (IV), epoxidized ricinus oil (VI), and epoxidized soybean oil (Drapex 6.8) (VII). As in the former investigations (Papers I and II), the process of the formation of the polyenes occurs in two stages. The concentration of polyene sequences with n double bonds, H n the total amount of polyene sequences, ∑ H n , the average length of the polyene sequence, n , and the two extents of reaction x and p , were computed. The stabilizing effect of all compounds used agrees with the increasing content of epoxy groups. The addition of stabilizers diminishes the value of n . The decrease of the fraction of long sequences and the increase of short ones occurs. Apart from the binding of evolved HCl, the protective effect towards the macromolecules of PVC consists mainly in the inhibition of growth of chain dehydrochlorination by the epoxy groups.