Chemiluminescence – a tool for determination of degree of oxidation of polymers + Residual service life Jozef Rychlý Polymer Institute Dúbravská cesta 9, Bratislava, Slovak Republic Polyfriend workshop, september

What chemiluminescence is? Polyfriend workshop, september

Chemiluminiscencia z disproporcionácie polymérnych peroxylových radikálov Polyfriend workshop, september

Scheme of the light emission accompanying the oxidation of synthetic and natural polymers Polyfriend workshop, september

Chemiluminescence (isothermal, non-isothermal) Chemiluminescence method is one of the supporting methods of investigation of development of oxidation degradation for a large spectrum of polymers (kinetic studies). The predictions of the remaining service life becomes more and more elaborated. The most of polymers studied so far giving a bright light emission when oxidized have in the vicinity of potentially formed hydroperoxidic group carbonyl, carbamido, carboxylic, alcoholic group; isolated hydroperoxides provide only weak light emission The chemiluminescence from polymers is pronounced when lower molar mass compounds are either present of being formed during oxidation process. It becomes also very important method in determination degradation progress of polymers where carbonyl groups are inherent part of the chain structure. Polyfriend workshop, september

FTIR spectra of the polymers investigated Polyfriend workshop, september

Instrumentation, , new instrument designed at the PISAS in 1968 Polyfriend workshop, september

Polyolefins and polydienes Polyfriend workshop, september

Tertiary carbons + double bonds C=C > Double bonds > Tertiary carbons > Single C-C bonds Polyfriend workshop, september

The effect of initial molar mass PP, oxygen, 120 o C Polyfriend workshop, september

Bábika, ako model prirodzeného starnutia polymérov Polyfriend workshop, september

Inert atmosphere By means of chemiluminescence we can detect the levels of hydroperoxides in polymers Polyfriend workshop, september

Nonisothermal experiments Polymer is heated according to pre-set programme as in DSC measurements Polyfriend workshop, september

Polypropylene with fillers Polyfriend workshop, september

Conclusions 1.Chemiluminescence method is one of the most elegant method of investigation of development of oxidation degradation for a large spectrum of polymers (kinetic studies) and still brings to experimentators new surprises. 2.The main emphasis has been put on CL from oxidation of polyolefins and other polymers were somehow neglected. 3. The most of polymers studied so far were not characterized properly from the viewpoint of residual catalysts, defect structures, stabilizers, etc, which may be the source of conflicting data. 4. As we measure the light emission and any filter and/or absorber may modulate the observed light intensity we should be aware of some limitations; the combination with other methods is always necessary. Polyfriend workshop, september