Quantitative evaluation of the hydrogen bonding effects on the crystallization kinetics of poly(vinyl alcohol)/tea polyphenol composites

Abstract

The crystallization kinetics behaviors of PVA (poly (vinyl alcohol))/TP (tea polyphenol) composites were studied. Results showed that the addition of TP component in PVA formed composites would reduce the crystallinity (%), leading to the formation of a lower Avrami exponent, n. Under the fixed cooling rate condition, the n values of Avrami and α values of Mo are both higher for the above composites with TP ingredient at 10–20%. Subsequently, the influence of the hydrogen bonding (H-bonding) in PVA/TP composites, pure PVA and non-hydrogen bonding (non-H-bonding) in such composites were further quantitatively assessed by analyzing the H-bonding factor, F%, in relation to different crystallization kinetic parameters including Avrami exponent n, Z_t, α and F(T). Results showed that the relationship of Avrami exponent n and α were presented as n = -a₁ + b₁F^PVA/TP_H-bonding-c₁F^2PVA/TP_H-bonding and α = -a₅ + b₅F^PVA/TP_H-bonding-c₅F^2PVA/TP_H-bonding. The Z_t was described as the functions like Z_t = a₂-b₂e^(FPVA/TP_H-bonding^−c₂^)/d, Z_t = -a₃ + b₃F^PVA_H-bonding-C₃F^2PVA_H-bonding, and Zt = a₄(F_{non-H-bonding}-b₄)^c₄, respectively. The F(T) was presented as F(T) = a_6-b₆F^PVA/TP_H-bonding+c₆F^2PVA/TP_H-bonding, where a, b and c are positive constants.