This article reports on the ultrasound-assisted acid hydrolysis for the synthesis and evaluation of starch nanoparticles (SNP) as nanofillers to improve the physical, mechanical, thermal, and barrier properties of polyurethane (PU) films. During the ultrasonic irradiation, dropwise addition of 0.25 mol L^-1 H₂SO₄ was carried out to the starch dispersion for the preparation of SNPs. The synthesized SNPs were blended uniformly within the PU matrix using ultrasonic irradiation (20 kHz, 220 W pulse mode). The temperature was kept constant during the synthesis (4 °C). The nanocomposite coating films were made with a regulated thickness using the casting method. The effect of SNP content (wt%) in nanocomposite coating films on various properties such as morphology, water vapour permeability (WVP), glass transition temperature (Tg), microbial barrier, and mechanical properties was studied. The addition of SNP to the PU matrix increased the roughness of the surface, and Tg by 7 °C, lowering WVP by 60% compared to the PU film without the addition of SNP. As the SNP concentration was increased, the opacity of the film increased. The reinforcement of the SNP in the PU matrix enhanced the microbial barrier of the film by 99.9%, with the optimal content of SNP being 5%. Improvement in the toughness and barrier properties was observed with an increase in the SNP content of the film.

本文报道了超声辅助酸水解用于合成和评估作为纳米填料的淀粉纳米粒子 (SNP) 以改善聚氨酯 (PU) 薄膜的物理、机械、热和阻隔性能。超声波照射时，滴加0.25 mol L ^-1 H ₂ SO ₄对淀粉分散体进行SNP的制备。使用超声波照射（20 kHz，220 W 脉冲模式）将合成的 SNP 均匀混合在 PU 基质中。在合成过程中温度保持恒定（4°C）。使用流延法制备具有调节厚度的纳米复合涂层膜。研究了纳米复合涂层膜中SNP含量（wt%）对形貌、水蒸气渗透性（WVP）、玻璃化转变温度（Tg）、微生物屏障和力学性能等各种性能的影响。与未添加 SNP 的 PU 膜相比，向 PU 基体中添加 SNP 使表面粗糙度和 Tg 提高了 7 °C，WVP 降低了 60%。随着 SNP 浓度的增加，薄膜的不透明度增加。PU基质中SNP的增强使薄膜的微生物屏障增强了99.9%，SNP的最佳含量为5%。随着薄膜 SNP 含量的增加，观察到韧性和阻隔性能的改善。