相转化法制备温敏性聚氨酯缓释保鲜膜及其应用

Preparation of Polyurethane-based Sustained Release Thermal Sensitive Plastic Wrap by Phase Inversion and Its Application

本文筛选了香芹酚作为抗菌保鲜剂,以合成聚氨酯为原料,采用相转化法制备了温敏性聚氨酯缓释保鲜膜。通过差示热扫描量热仪、傅里叶红外光谱仪、X射线衍射仪等手段对温敏性聚氨酯缓释保鲜膜的相转变温度、透气性、缓释性能以及抑菌效果进行了测定,并研究了其在广式焙烤食品包装保藏中的应用。结果表明：香芹酚与聚氨酯以物理共混形式成膜,制得的膜的相转化温度为47.90℃,当温度从30℃升高到50℃时,膜的透气性以及抗菌剂的缓释性有大幅提升,其透气率由最初的85.01 g/m2·24 h跃升到469.50 g/m2·24 h,香芹酚的缓释速率由最初的0.90%跃升到3.28%,添加了香芹酚的防腐复合膜对大肠杆菌、枯草杆菌、霉菌都具有明显的抑制作用。将此温敏性聚氨酯缓释保鲜膜材料应用于保藏面包、牛角包、月饼等食品的实验表明,该材料具有良好的抑菌保鲜效果,产品保质期延长2~4倍。

Polyurethane-based sustained release thermosensitive plastic wrap was prepared using phase inversion, with carvacrol and synthetic polyurethane as the antimicrobial preservative and the raw material, respectively. The phase transition temperature, vapor permeability, release properties, and antibacterial effects of the polyurethane-based sustained release thermosensitive plastic wrap were measured by using a differential scanning calorimeter, Fourier transform infrared spectrometer, and X-ray diffractometer, and its application in Cantonese-style bakery packaging was studied. The results showed that carvacrol and polyurethane formed a film by physical blending, and the phase inversion temperature of this film was 47.9 ℃. Following an increase in the temperature from 40 ℃ to 50 ℃, the vapor permeability and sustained release of the wrap were dramatically increased. The vapor permeability rate increased from 158.01 g×m-2×24 h to 469.50 g×m-2×24 h, and the sustained release rate increased from 1.06% to 3.28%. Furthermore, the composite film showed a significant inhibitory effect against Escherichia coli, Bacillus subtilis, and mold. When used for the preservation of bread, croissants, moon cake, and other food items, polyurethane-based sustained release thermosensitive plastic wrap showed excellent antimicrobial effects and it was able to extended the product shelf life two to four times.