Department of Thermal Technology and Food Process Engineering, University of Life Sciences in Lublin, Lublin, Poland.
Department of Physics, University of Life Sciences in Lublin, Lublin, Poland.
PLoS One. 2019 Feb 13;14(2):e0212070. doi: 10.1371/journal.pone.0212070. eCollection 2019.
The paper presents the results of studies related to the impact of functional additives in the form of polylactide (PLA), polyvinyl alcohol (PVA), and keratin hydrolysate (K) on the physical characteristics of biopolymer foils. TPS granulate was obtained using a TS-45 single-screw extruder with L/D = 16. Foil was produced with the use of an L/D = 36 extruder with film-blowing section. The impact of the quantity and type of the functional additives on the processing efficiency and energy consumption of granulate extrusion, as well as the physical characteristics of the foil produced: thickness, basis weight, and colour were determined. By measuring the FTIR spectra it was determined the type and origin of the respective functional groups. It was observed that foils produced from granulates with the addition of 3% PVA were characterised by the lowest thickness and basis weight. Addition of 2 and 3% of PLA increased thickness and basis weight of starch-based foils significantly. Increasing the content of keratin in SG/K samples resulted in a decrease of brightness and intensify the yellow tint of foils, especially when 2 and 3% of keratin was used. In terms of the other samples, it was observed that the colour remained almost unchanged irrespective of the percentage content of the additive used. Infrared analyses conducted on foil containing PVA, PLA, and K revealed a change in spectra intensity in the frequency range associated with-OH groups originating from the forming free, intra- and intermolecular hydrogen bonds. Based on an analysis of the respective bands within the IR range it was also concluded that considerable structural changes took place with respect to the glycosidic bonds of starch itself. The application of the mentioned additives had a significant structural impact on the produced starch-based foils. Furthermore, the conducted UV-Vis analyses revealed a substantial increase in absorbance and a related reduction of the permeability (colour change) of the obtained materials in the range of ultraviolet and visible light.
本文介绍了在研究中添加聚乳酸（PLA）、聚乙烯醇（PVA）和角蛋白水解物（K）等功能添加剂对生物聚合物薄膜物理特性的影响。使用 TS-45 单螺杆挤出机（长径比为 16）获得 TPS 粒料。使用 L/D=36 的挤出机和吹膜段生产薄膜。确定了不同数量和类型的功能添加剂对粒料挤出加工效率和能耗的影响，以及所生产薄膜的物理特性：厚度、基重和颜色。通过测量 FTIR 光谱确定了各自功能基团的类型和来源。观察到添加 3% PVA 的粒料生产的薄膜具有最低的厚度和基重。添加 2%和 3%的 PLA 显著增加了淀粉基薄膜的厚度和基重。增加 SG/K 样品中角蛋白的含量会降低薄膜的亮度并使黄色调加深，特别是当使用 2%和 3%的角蛋白时。对于其他样品，观察到无论使用的添加剂百分比如何，颜色几乎保持不变。对含有 PVA、PLA 和 K 的薄膜进行的红外分析显示，在与形成自由、内和分子间氢键相关的频率范围内，光谱强度发生变化。基于对红外范围内相应带的分析，还得出结论，淀粉本身的糖苷键发生了相当大的结构变化。所提到的添加剂的应用对生产的淀粉基薄膜具有显著的结构影响。此外，进行的 UV-Vis 分析表明，所得材料在紫外线和可见光范围内的吸收率显著增加，相关的透过率（颜色变化）降低。
