As a result, conjugated polyene sequences are formed from the beginning of the reaction, and they give rise to discoloration of the polymer.
The main characteristic feature of irradiated PVC is the dehydrochlorination reaction, which develops extensively and leads to the formation of conjugated polyene sequences (1), (29).
This equation describes correlation of DRE and Randic index ([chi]) for the linear simple conjugated polyene compounds (I).
In this study, the structural relationship between Randic indices, the determinants of the adjacency matrixes and distance matrixes and Dewar resonance energy of linear simple conjugated polyene compounds (I) were presented and disscused.
Kise reported that the reaction of PVC powder with aqueous sodium hydroxide in the presence of quaternary ammonium or phosphonium halides yielded several dehydrochlorinated products with a conjugated polyene
It is well known that the main characteristics of photodegradation of PVC is the dehydrochlorination reaction, which leads to the formation of conjugated polyene sequences with concomitant evolution of HCl [3, 14].
As the conjugated polyene structures are formed, the polyene sequences lengthen by "zip" propagation phenomena with concomitant evolution of HCl.
The thermal degradation of PVC involves the production of conjugated polyene
sequences (C=C), identified in IR spectrum by a peak at 1602 [cm.sup.-1], which form an autocatalytic reaction and a release of ClH .
It has been found that with predominantly thermal degradation, where little oxygen is present, the degradation proceeds by a process of dehydrochlorination, which leads to the formation of conjugated polyene
The chain growth of conjugated polyene
sequences in PVC is a well-studied photoreaction whose depth dependence is controlled by the subsurface availability of oxygen.
Because of the residual catalysis or polymer oxidation, labile Cl radials eliminated from unstable structure of macrochains abstract H from adjacent carbon atom with the formation of conjugated polyenes (32).
5), which restrains the formation of long conjugated polyenes. In addition, oxygen can also cause bleaching of polyene structure in the dark through a charge-transfer complex as shown in Eq.