Biodegradable films are used in a variety of applications, including packaging. However, their use is limited due to their high moisture and water sensitivity. In this work, cassava starch (CS) was blended with poly(vinyl alcohol) (PVA). Silica particles (SiO₂) were incorporated to increase the hydrophobicity of the blend by intermolecular interaction through hydrogen bonding between the three components. Instead of a plasticizer or crosslinker, a small amount of triethylamine was added to eliminate residual acetate groups in PVA. The miscibility of CS and PVA phases was confirmed by smooth fracture surfaces and a single glass transition temperature. When SiO₂ content was below 5% (wt), the particles were well dispersed in a continuous phase of polymer matrix. At this loading of SiO₂, the increase in tensile strength was as high as 170% and in elongation-at-break, 250%. All loadings of SiO₂ increased thermal stability of the blend films because silanol groups on the surface of SiO₂ particles formed effective interfacial interactions with hydroxyl groups of the polymers. These interactions also prevented the ingress of water molecules, significantly increasing the hydrophobicity of the films. The water contact angle increased as high as 113° and moisture absorbency and water solubility were low. These highly hydrophobic, photodegradable, biodegradable CS/PVA/SiO₂ films show great potential as a low-cost, eco-friendly material.

中文翻译：

---

使用二氧化硅颗粒增强木薯淀粉基生物降解膜的阻水性能

可生物降解的薄膜用于包括包装在内的多种应用。然而，由于其高的湿气和水敏感性，它们的使用受到限制。在这项工作中，将木薯淀粉（CS）与聚乙烯醇（PVA）混合。掺入二氧化硅颗粒（SiO ₂）以通过三种组分之间的氢键分子间相互作用增加共混物的疏水性。代替增塑剂或交联剂，加入少量的三乙胺以消除PVA中残留的乙酸酯基团。CS和PVA相的混溶性通过光滑的断裂表面和单一的玻璃化转变温度来确认。当SiO ₂含量低于5％（重量）时，颗粒充分分散在聚合物基质的连续相中。在这种SiO含量下_由图2可知，抗拉强度的增加高达170％，断裂伸长率为250％。SiO _2的所有负载都增加了共混膜的热稳定性，因为SiO ₂颗粒表面的硅烷醇基团与聚合物的羟基形成了有效的界面相互作用。这些相互作用还防止了水分子的进入，从而大大增加了膜的疏水性。水接触角增加至高达113°，并且吸湿性和水溶性低。这些高度疏水，可光降解，可生物降解的CS / PVA / SiO ₂薄膜具有低成本，环保材料的巨大潜力。