Abstract：
Piperic acid, a natural product-based derivative, has been used with polyvinyl alcohol for the first time to form polymer composite films for its suitable modification in physicochemical and antimicrobial properties. Initially, piperic acid was synthesized from piperine, a natural alkaloid extracted from black pepper (Piper nigrum). The solvent casting method was used for the synthesis of PVA-piperic acid composite films. The films were characterized by various spectral and microscopic techniques like UV-visible spectroscopy, FT-IR, SEM, XRD, and TGA. The antibacterial activity was shown by these polymer composites of piperic acid against Gram-positive Staphylococcus aureus (S. aureus-ATCC8738P) and Gram-negative Escherichia coli (E. coli-ATCC8739) was worthwhile. The antifungal activity of the composite films was evaluated by the food poisoning technique. Percentage mycelial growth inhibition was found maximum against Fusarium solani than Aspergillus and Penicillium. The water vapour and oxygen barrier properties are enhanced with the incorporation of increased content of piperic acid. Also, enhancement in the tensile strength of PVA/PA composite film was observed, while elongation at break shows decreased trend with the addition of piperic acid. The surface properties of polymer composite films were determined by contact angle measurements. Contact angle shows a considerable increase in these films when compared to virgin PVA film. It was increased by 56.1° in 15 mL composite film containing a higher concentration of piperic acid than virgin PVA.
摘要：
胡椒酸,一种基于天然产品的衍生物，由于其在物理化学和抗菌性能方面的合适改性，首次与聚乙烯醇一起用于形成聚合物复合膜。最初，以胡椒碱为原料合成胡椒酸,从黑胡椒（Pipernigrum）中提取的一种天然生物碱。采用溶剂流延法合成PVA-胡椒酸复合薄膜。通过各种光谱和显微技术如紫外可见光谱对薄膜进行了表征，FT-IR,SEM,XRD,和TGA。胡椒酸的这些聚合物复合材料对革兰氏阳性金黄色葡萄球菌（S.金黄色葡萄球菌-ATCC8738P）和革兰氏阴性大肠杆菌（E.大肠杆菌-ATCC8739）是值得的。通过食物中毒技术评估了复合膜的抗真菌活性。与曲霉和青霉菌相比，对枯萎镰刀菌的菌丝体生长抑制作用最大。水蒸气和氧气阻隔性能随着胡椒酸含量的增加而增强。此外，观察到PVA/PA复合膜的拉伸强度增强，随着胡椒酸的加入，断裂伸长率呈下降趋势。通过接触角测量确定聚合物复合膜的表面性质。当与原始PVA膜相比时,这些膜的接触角显示出相当大的增加。与原始PVA相比，在15mL含有更高浓度的胡椒酸的复合膜中，它增加了56.1°。
