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Oxidation of polythene stabilized with monophenol antioxidant
August 1992
Additives for Polymers
Oxidation of polythene stabilized with monophenol antioxidant
Oxidation of HDPE at 200”, containing the antioxidant 2,6-di -tert-butyl-phenylphenol (monophenol) has been investigated. Monophepol is a weak antioxidant, and in its presence the induction period is low and is linearly dependent on the concentration of antioxidant, the latter being consumed at a constant rate. The initial rate of absorption of O2 reduces rapidly and increases slowly with low and high concentrations of monophenol, respectively, whereas during the course of a separate test, it slowly increased with the time of oxidation. Conclusions concerning the low effectiveness of monophenols in comparison with biphenols drawn from previous studies of the oxidation of PP have been confirmed. (9 refs). Int. Poly. Sci. & Tech., 1992, 19, (2) TIOI-105 (Translated
from: Vysokomolekulyarnye Soedineniya, Kratkie Soobshcheniya,1991 (12) 899) Photodegradation of polythene Thin polyethylene films containing various additives as photoinitiators were photooxidized in natural weathering conditions and under accelerated conditions using xenon radiation at the University of Brussels. The photoinitiators included iron carboxylate, ally1 ether and ester and various aryland aralkylketones. Main chain scission is the main degradation reaction which occurs when polyethylene containing Ir. St. is degraded in natural weathering conditions. This process would result mainly from the decomposition of isolated hydroperoxides. In the presence of other photoinitiators, main chain scission follows disproportionation of peroxy radicals but a few cross-links are also formed. When the xenon arc is used, the spectral distribution of the radiation is very similar to that of the sun, but the temperature is higher. Chain propagation is then favoured, which leads to a higher concentration of P and PO. radicals in clusters and hence to a higher probability of crosslinking. (28 refs). Poly. Degmd. & Stabil., 1992, 37, 233-245
Photoprotecting behaviour of a phenylformamidine light stabilizer
The photoprotecting behaviour and effectiveness of three UV-stabilizers, N-(-p-ethoxy-carbonylphenyl-)-N’-ethyi_N’ phenyl-formamidine(UV1),2-hydroxy-4-octoxy benzophenone (UV2) and 2-(2’hydroxy-3’,5’-ditert-buty;-phenyl)-5chlorobenzotriazole (UV3) have been studied by IR, UV and fluorescence spectroscopies at the Institute of Chemistry, Beijing, China.
o1992 Elsevier Science Publishers Ltd.
Additives for Polymers
Oxidation of polythene stabilized with monophenol antioxidant
Oxidation of HDPE at 200”, containing the antioxidant 2,6-di -tert-butyl-phenylphenol (monophenol) has been investigated. Monophepol is a weak antioxidant, and in its presence the induction period is low and is linearly dependent on the concentration of antioxidant, the latter being consumed at a constant rate. The initial rate of absorption of O2 reduces rapidly and increases slowly with low and high concentrations of monophenol, respectively, whereas during the course of a separate test, it slowly increased with the time of oxidation. Conclusions concerning the low effectiveness of monophenols in comparison with biphenols drawn from previous studies of the oxidation of PP have been confirmed. (9 refs). Int. Poly. Sci. & Tech., 1992, 19, (2) TIOI-105 (Translated
from: Vysokomolekulyarnye Soedineniya, Kratkie Soobshcheniya,1991 (12) 899) Photodegradation of polythene Thin polyethylene films containing various additives as photoinitiators were photooxidized in natural weathering conditions and under accelerated conditions using xenon radiation at the University of Brussels. The photoinitiators included iron carboxylate, ally1 ether and ester and various aryland aralkylketones. Main chain scission is the main degradation reaction which occurs when polyethylene containing Ir. St. is degraded in natural weathering conditions. This process would result mainly from the decomposition of isolated hydroperoxides. In the presence of other photoinitiators, main chain scission follows disproportionation of peroxy radicals but a few cross-links are also formed. When the xenon arc is used, the spectral distribution of the radiation is very similar to that of the sun, but the temperature is higher. Chain propagation is then favoured, which leads to a higher concentration of P and PO. radicals in clusters and hence to a higher probability of crosslinking. (28 refs). Poly. Degmd. & Stabil., 1992, 37, 233-245
Photoprotecting behaviour of a phenylformamidine light stabilizer
The photoprotecting behaviour and effectiveness of three UV-stabilizers, N-(-p-ethoxy-carbonylphenyl-)-N’-ethyi_N’ phenyl-formamidine(UV1),2-hydroxy-4-octoxy benzophenone (UV2) and 2-(2’hydroxy-3’,5’-ditert-buty;-phenyl)-5chlorobenzotriazole (UV3) have been studied by IR, UV and fluorescence spectroscopies at the Institute of Chemistry, Beijing, China.
o1992 Elsevier Science Publishers Ltd.