PHOTOCHAIN FREE-RADICAL OXIDATION OF CELLULOSE IN PULP AND PAPER MATERIALS

Highly effective processes of photo-oxidation of lignocelluose materials affected by light with λ=253.7nm are found. The quantum yield of oxygen absorption ($\phi$02) and evolution of photodegradation gaseous products ($\phi$gas) exceed the unity considerably ($\phi$02=2.5-25). By comparison of $\phi$02 with the quantum yield of initiation, (∼10-3), it is concluded that chain oxidation reactions with a kinetic chain length of 104 - 105 units develop here. An effective evolution of gaseous products ( $\phi$gas 3-50), among them CO2, testifies that there takes place a deep photo-degradation of macromolecules with breaking of C-C bonds in the main polymer chain. The cellulose photo-oxidation under the natural sunlight occurs by the mechanism close to the hydroperoxide one: the length of the photo-oxidation kinetic chain reaches about 40 units.