Sheet‐extruded films from the blends of hydroxypropylated normal corn starch (HP) and native normal corn starch (NS) at weight ratios of 100:0, 90:10, 70:30, 50:50, 30:70, and 0:100 were prepared and characterized. Glycerol and water were added as plasticizers at 11 and 27% starch weight, respectively. The highest tensile strength (TS) and longest elongation to break (EB) for dry films were observed at 70:30 HP: NS ratio, which was 25.76 MPa, and 3.97%, respectively. However, TS and EB of this 70:30 blend extruded starch film exhibited low resistance upon wetting for 10s. The film TS and EB were reduced to 13.26 MPa and 3.35%, respectively. Addition of 0.5% (wt/wt starch) succinic acid (SA) as a cross‐linker to 70:30 HP: NS starch blend before film extrusion positively affected both TS and EB of films upon wetting; rather higher TS (16.64 MPa) and EB (4.85%) values were observed, which indicated improvement in water resistance of the films. Sheet‐extruded films from 70:30 HP: NS blends resulted in improved dry strength, and upon cross‐linking with SA, improved wet strength as well. The films had smooth and compact structure, which was explained by esterification/transesterification reactions promoted by SA, and confirmed by Fourier‐transform infrared spectroscopy analysis. PRACTICAL APPLICATIONS: Manufacturing packaging films from biological sources, as well as coating materials, would be beneficial to the environment along with wider applications. Biobased packaging materials include both edible coatings and edible films along with primary and secondary packaging materials, and could also have non‐food applications. They are derived from renewable sources and are potentially biodegradable through composting (which is a technique for waste management). Hydroxypropylation of starch results in wider functionality, and sheet‐extrusion can result in more flexible and transparent films. Blends of 70:30 HP: NS resulted in stronger sheet‐extruded films; testing of both dry and wet strengths of films indicated its suitability for both as edible coating (wet application), and other dry coatings/ films. These blend film can be an alternative to synthetic packaging films within their limitations.

中文翻译：

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羟丙基化和天然玉米淀粉混合物的片材挤出薄膜及其表征

由羟丙基化普通玉米淀粉 (HP) 和天然普通玉米淀粉 (NS) 以 100:0、90:10、70:30、50:50、30:70 和 0 的重量比混合而成的片材挤出薄膜：制备并表征了 100 个。分别以 11% 和 27% 的淀粉重量添加甘油和水作为增塑剂。干膜的最高拉伸强度 (TS) 和最长断裂伸长率 (EB) 在 70:30 HP: NS 比率下观察到，分别为 25.76 MPa 和 3.97%。然而，这种 70:30 共混挤出淀粉薄膜的 TS 和 EB 在润湿 10 秒后表现出低阻力。薄膜 TS 和 EB 分别降低到 13.26 MPa 和 3.35%。将 0.5% (wt/wt 淀粉) 琥珀酸 (SA) 作为交联剂添加到 70:30 HP: NS 淀粉混合物中，在薄膜挤出前对润湿薄膜的 TS 和 EB 产生积极影响；相当高的 TS (16. 观察到 64 MPa) 和 EB (4.85%) 值，这表明薄膜的耐水性有所改善。由 70:30 HP: NS 共混物制成的片材挤出薄膜提高了干强度，并且在与 SA 交联后，也提高了湿强度。薄膜具有光滑致密的结构，这可以通过 SA 促进的酯化/酯交换反应来解释，并通过傅里叶变换红外光谱分析证实。实际应用：从生物来源制造包装薄膜，以及涂层材料，将有利于环境以及更广泛的应用。生物基包装材料包括可食用涂层和可食用薄膜以及初级和次级包装材料，也可用于非食品应用。它们来自可再生资源，并且可能通过堆肥（这是一种废物管理技术）进行生物降解。淀粉的羟丙基化产生更广泛的功能，而片材挤出可以产生更柔韧和透明的薄膜。70:30 HP: NS 的共混物产生更强的片材挤出薄膜；薄膜的干强度和湿强度测试表明其适用于可食用涂层（湿应用）和其他干涂层/薄膜。在其局限性范围内，这些混合薄膜可以替代合成包装薄膜。薄膜的干强度和湿强度测试表明其适用于可食用涂层（湿应用）和其他干涂层/薄膜。在其局限性范围内，这些混合薄膜可以替代合成包装薄膜。薄膜的干强度和湿强度测试表明其适用于可食用涂层（湿应用）和其他干涂层/薄膜。在其局限性范围内，这些混合薄膜可以替代合成包装薄膜。