Photodegradation in Aqueous Solution of a Polyamidehydroxyurethane Type Polymer. Temperature Effect on the Process of Degradation
Titel:
Photodegradation in Aqueous Solution of a Polyamidehydroxyurethane Type Polymer. Temperature Effect on the Process of Degradation
Auteur:
Onu, Ana Palamaru, Mircea Tutovan, Elena Ciobanu, Constantin
Verschenen in:
International journal of polymeric materials
Paginering:
Jaargang 37 (1997) nr. 3-4 pagina's 263-273
Jaar:
1997-06-01
Inhoud:
The present research shows some aspects of temperature effect on the process of photodegradation in aqueous solution of a polyamidehydroxyurethane type polymer. The process of photodegradation in aqueous solution of the studied polymer proceeds with chain scissions, what is promoted at elevated temperatures. At the temperatures 45°C and 65°C the values of the number average of chain scissions, S, and of the quantum yield of chain scission, φcs, are greater at the initial moments of the process than the correspondent values at 25°C and 35°C. At elevated temperatures there is an increase in the probability of the process of recombination of macroradicals, formed during chains scission. The values of S at 45°C and 65°C by the end of the process are smaller than those at 35°C and 25°C. It can also be noticed, that the values of φcs at 45 °C and 65°C continuously decrease after the initial moments of irradiation till the end of the process of degradation, while at 25°C the values of φcs increase practically during the whole process. At 35°C the behaviour of the system is more unusual.