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

Abstract

The crystallization kinetics behavior of PVA (poly (vinyl alcohol)) /TP (tea polyphenol) composites was studied in this paper. Results showed that the addition of TP component in such composites would reduce the crystallinity, leading to the formation of a lower Avrami exponent, n, based on crystal structures and nucleation. 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 were 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) = a₆₋b₆F^PVA/TP_H−bonding+c₆F^2PVA/TP_H−bonding, where a, b and c are positive constants.