The effect of side chain association on thermal and viscoelastic properties. Cellulose acetate based polycaprolactones

Cellulose acetate-based polycaprolactones (CAPCL's) were synthesized by the polymerization of epsilon-caprolactone which was initiated by non-substituted OH group in cellulose acetate. The CL/OH (mol mol(-1)) ratios of the CAPCL's were changed from 2 to 20. Thermal and viscoelastic properties of the CAPCL sheets were studied by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Glass transition, cold crystallization and melting were determined by DSC. Dynamic modules (E'), dynamic loss modules (E ") and tan delta were measured in a temperature range from -150 to 50 degrees C by DMA. Apparent activation energy of a dispersion was calculated from the frequency dependency of E " peak temperature. It was found that the main chain motion of both CA and PCL is observed in a CL/OH ratio from 0 to 10 mol mol(-1). However, when CL/OH ratio exceeds 10 mol mol(-1), the crystalline region which is rearranged by the PCL chain association is observed and only the main chain motion of PCL can be detected.