Fitriani Fitriani, Aprilia Sri, Bilad Muhammad Roil, Arahman Nasrul, Usman Anwar, Huda Nurul, Kobun Rovina
Doctoral Program, School of Engineering, Post Graduate Program, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia.
Department of Chemical Engineering, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia.
Polymers (Basel). 2022 Jul 25;14(15):3006. doi: 10.3390/polym14153006.
This study employed response surface methodology to optimize the preparation of biocomposites based on whey protein isolate, glycerol, and nanocrystalline cellulose from pineapple crown leaf. The effects of different concentrations of nanocrystalline cellulose as a filler and glycerol as a plasticizer on the thickness, the tensile strength, and the elongation at break on the resulting biocomposite films were investigated. The central composite design was used to determine the optimum preparation conditions for biocomposite films with optimum properties. The regression of a second-order polynomial model resulted in an optimum composition consisting of 4% glycerol and 3.5% nanocrystalline cellulose concentrations, which showed a desirability of 92.7%. The prediction of the regression model was validated by characterizing the biocomposite film prepared based on the optimum composition, at which the thickness, tensile strength, and elongation at break of the biocomposite film were 0.13 mm, 7.16 MPa, and 39.10%, respectively. This optimum composition can be obtained in range concentrations of glycerol (4-8%) and nanocrystalline cellulose (3-7%). Scanning electron microscope images showed that nanocrystalline cellulose dispersed well in the pure whey protein isolate, and the films had a relatively smooth surface. In comparison, a rough and uneven surface results in more porous biocomposite films. Fourier transform infrared spectroscopy revealed that nanocrystalline cellulose and glycerol showed good compatibility with WPI film by forming hydrogen bonds. The addition of nanocrystalline cellulose as a filler also decreased the transparency, solubility, and water vapor permeability and increased the crystallinity index of the resulting biocomposite film.
本研究采用响应面法优化基于乳清分离蛋白、甘油和菠萝冠叶纳米晶纤维素的生物复合材料的制备。研究了不同浓度的纳米晶纤维素作为填料和甘油作为增塑剂对所得生物复合膜的厚度、拉伸强度和断裂伸长率的影响。采用中心复合设计确定具有最佳性能的生物复合膜的最佳制备条件。二阶多项式模型的回归得出最佳组成，即甘油浓度为4%，纳米晶纤维素浓度为3.5%，可取性为92.7%。通过对基于最佳组成制备的生物复合膜进行表征，验证了回归模型的预测，此时生物复合膜的厚度、拉伸强度和断裂伸长率分别为0.13毫米、7.16兆帕和39.10%。在甘油（4 - 8%）和纳米晶纤维素（3 - 7%）的浓度范围内可获得这种最佳组成。扫描电子显微镜图像显示纳米晶纤维素在纯乳清分离蛋白中分散良好，且膜表面相对光滑。相比之下，粗糙不平的表面会导致生物复合膜有更多孔隙。傅里叶变换红外光谱表明，纳米晶纤维素和甘油通过形成氢键与乳清分离蛋白膜具有良好的相容性。添加纳米晶纤维素作为填料还降低了所得生物复合膜的透明度、溶解性和水蒸气透过率，并提高了结晶度指数。
