Quantitatively evaluation of the hydrogen bonding effects on the thermal properties of poly(vinyl alcohol)/tea polyphenols composites

The effects of the hydrogen, H, bonding on the thermal properties of poly(vinyl alcohol), PVA,/tea polyphenols, TP, composites have been quantitatively evaluate. Initially, the thermal properties of PVA/TP composites with various blending ratios were characterized by differential scanning calorimetry, DSC, and thermogravimetry. Results showed that the glass transition temperature, T g , of such green composites was enhanced with the TP component increase and capably obtained by both the DSC measurement and empirical equations estimation. The increase of TP component can enhance the thermal stability for these composites before 400℃ because the TP molecules would be greatly thermally degraded after this temperature. Then, the effects of H-bonding on composites were quantitatively evaluated by taking the H-bonding factor, F , as the function of those thermal parameters, respectively. Results further showed that the T g was affected by H-bonding following a relationship as T g = A 1 -B 1 F PVA/TP H-bonding + C 1 F 2PVA/TP H-bonding , and the relationship on the crystallization temperature, T C , and thermal degradation temperature, T d , with the F followed as T C = A 4 -B 4 e (FPVA/TP H-bonding -C 4 )/D 1 and T d = A 7 + B 7 F PVA/TP H-bonding , respectively, where A, B and C all were constants.