| Abstract: | CONCLUSION. ˙ VIS radiation has a crucial influence on the first stage of oxidation/light induced oxidation of groundwood paper (creation of carbonyls) ˙ UV radiation influences next stage of oxidation/ light induced oxidation (splitting of lignin molecule, creation of degradation products, etc.) ˙ UV filter does not stop the initiation of light induced oxidation, where VIS has a crucial influence. Filter significantly prevents degradation related to gradual disintegration of lignin molecule from its continuation ˙ UV filter significantly blocks the creation of degradation products, acidity of paper is increased much more slowly and yellowing is partly limited ˙ For long-term storage of groundwood papers it is necessary to eliminate particularly VIS radiation, which starts the light induced oxidation, but also UV radiation, which causes further disintegration ˙ Mg bond on some lignin structure during dea-cidification (with methyl methoxymagnesium carbonate) significantly inhibits the light induced oxidation of groundwood paper ˙ Both UV radiation and VIS radiation have an influence on the yellowing of groundwood paper ˙ The first stage of oxidation (creation of carbonyls) is considerably more influenced by UV radiation than in non-deacidified papers ˙ Light induced oxidation in neutral or alkaline medium is significantly activated by UV radiation and it is related to the splitting of the lignin molecule and creation of the degradation products UV filter only partly inhibits the first stage of oxidation in an alkaline environment (creation of carbonyls) probably by reducing the creation of radicals UV filter considerably reduces the creation of colour degradation products and this way it significantly slows down the yellowing of paper and increasing its acidity For long-term storage of deacidified groundwood papers (MMMC application) it is very important to eliminate both radiation components from illumination |
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