However, PVC exhibits a fast zipper dehydrochlorination
, while the dehydrochlorination
of CPE is a slow elimination of random chlorine and occurs at a relatively higher temperature (33), (34).
As stated earlier, it is well recognized that PVC undergoes decomposition by dehydrochlorination
at elevated temperatures, resulting in conjugated double bonds in the polymer chains and noticeable color change (from yellow to pink, orange, red, brown, and finally black) when the conjugated polyene sequences contain more than four to five double bonds (38), (39), (51), (52).
The results suggest that UVA plays a more important role than HALS in protecting the blends from dehydrochlorination
3] enhances the dehydrochlorination
process of PVC.
Due to the relatively strong irradiation of mercury lamp, YI increases rapidly during the first 3 days, which indicates the dehydrochlorination
reaction and the formation of long conjugated polyene sequences on the irradiated PVC surface.
This enhances the catalytic action on PVC dehydrochlorination
, and consequently the cross-linking.
They explained this result by the dehydrochlorination
of PVC initiated by untreated Si[O.
However, WPVC composites may be thermally and photochemically unstable due to dehydrochlorination
and photo-oxidation reactions.
Many studies investigated the dehydrochlorination
of PVC, using both dry and wet processes [2-11].
And mercaptide organotin stabilizers were revealed to initiate a remarkable color development of PVC films in the presence of ultraviolet light because the decomposition of UV sensitive Sn--S bond accelerated dehydrochlorination
of PVC [13, 17].
It has been suggested that mercaptan organotin is UV-sensitive because of the covalent bond of Sn--S whose decomposition will accelerate dehydrochlorination
05 g were introduced into a 100 ml flask to conduct the polycondensation at 65[degrees]C under a nitrogen atmosphere for 16 h accompanied by dehydrochlorination