STABILIZATION AND MODIFICATION OF CELLULOSE DIACETATE - Photochemical Reactions in Heterochain Polymers - page 97

processes of oxidation and decomposition of PVA take place. DTG curves indicate that
maximum rate of mass loss pf initial PVA is observed at 267°C. This index of dyed samples
shifts in the direction of higher temperatures, and maximum of loss of mass of covalently
linked dye LIX is at 375°C which is 100° higher than that of initial PVA. Data on the thermal
stability of dyed PVA in comparison with undyed ones, obtained on the basis of TG curves
are presented in Figure 2.35. These curves show that thermal stability of PVA after addition
of dye increases as intensive destruction of dyed samples begins at higher temperatures and
depth of destruction at one and the same temperature decreases. Dyes covalently linked with
PVA, especially LIX dye, display the highest thermostabilizing activity.
Figure 2.34. View of curves DTA (a) and DTG (b) of dyed PVA-films: 1 - undyed, 2 - dyed by LIX, 3
- dyed by LX, 4 - dyed by LXI, 5 - dyed by LXII.