Qin Zhiyong, Mo Liuting, Liao Murong, He Hua, Sun Jianping
School of Resources, Environment and Materials, Guangxi university, Nanning 530000, China.
Polymers (Basel). 2019 Nov 7;11(11):1835. doi: 10.3390/polym11111835.
Soy protein isolate (SPI) has attracted considerable attention in the field of packaging technology due to its easy processability, biodegradability, and good film-forming characteristics. However, SPI-based films often suffer from inferior mechanical properties and high moisture sensitivity, thus restricting their practical application. In the present study, herein, a biobased nanocomposite film was developed by cross-linking SPI matrix from the synergistic reinforcement of cellulose nanofibers (CNF) and nano-silica (NS) particles. First, we functionalized the CNF with NS using a silane agent (KH560) as an efficient platform to enhance the interfacial interaction between SPI and CNF/NS, resulting from the epoxy-dominated cross-linking reaction. The chemical structure, thermal stability, and morphology of the resultant nanocomposite films were comprehensively investigated via Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). These results supported successful surface modification and indicated that the surface-tailored CNF/NS nanohybrid possesses excellent adhesion with SPI matrix through covalent and hydrogen-bonding interactions. The integration of CNF/NS into SPI resulted in nanocomposite films with an improved tensile strength (6.65 MPa), representing a 90.54% increase compared with the pristine SPI film. Moreover, the resulting composites had a significantly decreased water vapor permeation and a higher water contact angle (91.75°) than that of the unmodified film. The proposed strategy of synergistic reinforcements in the biobased composites may be a promising and green approach to address the critical limitations of plant protein-based materials in practical applications.
大豆分离蛋白（SPI）因其易于加工、可生物降解和良好的成膜特性，在包装技术领域引起了广泛关注。然而，基于SPI的薄膜通常机械性能较差且对水分敏感，从而限制了它们的实际应用。在本研究中，通过纤维素纳米纤维（CNF）和纳米二氧化硅（NS）颗粒的协同增强作用交联SPI基体，制备了一种生物基纳米复合薄膜。首先，我们使用硅烷试剂（KH560）对CNF进行功能化，以NS作为有效平台，通过环氧主导的交联反应增强SPI与CNF/NS之间的界面相互作用。通过傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、扫描电子显微镜（SEM）和热重分析（TGA）对所得纳米复合薄膜的化学结构、热稳定性和形态进行了全面研究。这些结果支持了成功的表面改性，并表明表面定制的CNF/NS纳米杂化物通过共价和氢键相互作用与SPI基体具有优异的粘附性。将CNF/NS整合到SPI中得到的纳米复合薄膜具有更高的拉伸强度（6.65MPa），与原始SPI薄膜相比提高了90.54%。此外，所得复合材料的水蒸气渗透率显著降低，水接触角（91.75°）比未改性薄膜更高。在生物基复合材料中提出的协同增强策略可能是一种有前途的绿色方法，可解决植物蛋白基材料在实际应用中的关键局限性。
