Photodegradation of Polymers: Physical Characteristics and ApplicationsIn this book on physical characteristics and practical aspects of polymer photodegradation Rabek emphasizes the experimental work on the subject. The most important feature of the book is the physical interpretation of polymer degradation, e.g. mechanism of UV/light absorption, formation of excited states, energy transfer mechanism, kinetics, dependence on physical properties of macromolecules and polymer matrices, formation of mechanical defects, practics during environmental ageing. He includes also some aspects of polymer photodegradation in environmental and space condition. |
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Page 80
... polymer alkyl radical ( –CH2 – CH – CH2- ) under UV irradiation . Further warming reconverts the polymer alkyl radicals to stable allylic radicals [ 688 , 689 ] : - hv 2 —CH2 – CH = CH – CH – CH2 — CH2- ( septet - line ESR spectrum ) ...
... polymer alkyl radical ( –CH2 – CH – CH2- ) under UV irradiation . Further warming reconverts the polymer alkyl radicals to stable allylic radicals [ 688 , 689 ] : - hv 2 —CH2 – CH = CH – CH – CH2 — CH2- ( septet - line ESR spectrum ) ...
Page 88
... polymer alkyl radical ( P · ) formation is given by ri = ki [ R • ] ( 4.129 ) ( 4.130 ) where ki is the polymer alkyl radical formation constant ( 1 mol - ' s - 1 ) . If both radicals R1 and R2 are able to abstract hydrogen with the ...
... polymer alkyl radical ( P · ) formation is given by ri = ki [ R • ] ( 4.129 ) ( 4.130 ) where ki is the polymer alkyl radical formation constant ( 1 mol - ' s - 1 ) . If both radicals R1 and R2 are able to abstract hydrogen with the ...
Page 127
... polymer alkyl radical ( P. ) is very fast and reaction of hydrogen abstraction by polymer peroxy radical ( POO · ) comparatively slow ; typically k2 / k3 ≫ 106 . Under the steady - state conditions : ri = Ip = It r1 = k1la Ip = k2 [ P ...
... polymer alkyl radical ( P. ) is very fast and reaction of hydrogen abstraction by polymer peroxy radical ( POO · ) comparatively slow ; typically k2 / k3 ≫ 106 . Under the steady - state conditions : ri = Ip = It r1 = k1la Ip = k2 [ P ...
Contents
Preface | 1 |
Electronically Excited States in Polymers | 9 |
Electronic Energy Transfer Processes in Polymers | 20 |
Copyright | |
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Other editions - View all
Photodegradation of Polymers: Physical Characteristics and Applications Jan F. Rabek Limited preview - 2012 |
Photodegradation of Polymers: Physical Characteristics and Applications Jan F. Rabek No preview available - 2011 |
Common terms and phrases
ablation absorption absorption spectrum acceptor molecules Allen NS amorphous and/or Appl Polym Sci bonds carbonyl CH₂ chemical chromophores chromophoric groups coefficient concentration crosslinking decrease density depolymerization diffusion dissociation donor and acceptor efficiency emission energy migration energy transfer process equation etching Europ Polym excimer excited donor excited singlet fluence fluorescence formation free radicals free volume hydrogen hydroperoxide increases initial interaction intersystem crossing irradiation ketone kinetics laser radiation lifetime Macromolecules main chain scission McKellar JF mechanism molecular weight molecule monomer occur oxidation photochemical photodegradation Photodegradation of Polymers photoinitiator photolysis Phys plastics po/qo poly poly(methyl methacrylate polyethylene polyimide Polym Degrad Stabil Polym Sci Chem polymer alkyl radical polymer chain polymer matrix polymeric material polypropylene polystyrene POOH quantum yield quenching radiation absorbed radiative energy transfer rate constant reaction reactive S₁ sample singlet oxygen solvent spin trap stress surface T₁ temperature tensile thermal triplet viscosity wavelength