Coltelli Maria-Beatrice, Bertolini Alice, Aliotta Laura, Gigante Vito, Vannozzi Alessandro, Lazzeri Andrea
Department of Civil and Industrial Engineering, University of Pisa, 56122 Pisa, Italy.
National Interuniversity Consortium of Materials Science and Technology (INSTM), 50121 Florence, Italy.
Polymers (Basel). 2021 Sep 9;13(18):3050. doi: 10.3390/polym13183050.
The present work focused on the research, design, and study of innovative chain extender systems of renewable origin for PLA-based biocomposites, reinforced with wheat bran as filler. The majority of employed chain extender compounds belongs to fossil world, affecting the biodegradability property which characterizes biopolymers. The aim of this work was thus to find promising biobased and sustainable alternatives to provide the same enhancements. According to this objective, epoxidized soybean oil (ESO) was chosen as principal component of the chain extender systems, together with a dicarboxylic acid, malic acid (MA), or succinic acid (SA). The reactivity of the modifier systems was previously studied through thermogravimetric analysis (TGA) and IR spectroscopy, to hypothesize the reaction mechanism in bran-filled blends. Hence, small-scale extrusion was carried out to investigate the effects of ESO/MA and ESO/SA on formulations of different composition (both pure PLA blends and composites). The variation of melt fluidity parameters was analyzed to define the optimized concentration of modifier systems. A comparison between the effects on blends of designed biobased systems and the action of fossil-based Joncryl was performed, to understand if the developed green solutions could represent competitive and efficient substitutes. The modified composites were characterized in terms of mechanical tests, degradation and thermal studies (TGA and DSC), and morphological analysis (SEM), to figure out their main features and to understand their potential in possible industrial applications.
本研究聚焦于以麦麸为填料增强的聚乳酸基生物复合材料的可再生来源创新扩链剂体系的研究、设计与探索。大多数使用的扩链剂化合物源自化石资源，这影响了生物聚合物所具有的生物降解性。因此，本研究的目的是寻找有前景的生物基和可持续替代品，以实现相同的增强效果。根据这一目标，选择环氧大豆油（ESO）作为扩链剂体系的主要成分，同时搭配二元羧酸苹果酸（MA）或琥珀酸（SA）。此前通过热重分析（TGA）和红外光谱研究了改性剂体系的反应活性，以推测在含麸皮共混物中的反应机理。因此，进行了小规模挤出实验，以研究ESO/MA和ESO/SA对不同组成配方（纯聚乳酸共混物和复合材料）的影响。分析熔体流动性参数的变化，以确定改性剂体系的最佳浓度。对设计的生物基体系对共混物的影响与基于化石资源的容克瑞尔（Joncryl）的作用进行了比较，以了解所开发的绿色解决方案是否可以成为具有竞争力和高效的替代品。对改性复合材料进行了力学性能测试、降解和热性能研究（TGA和DSC）以及形态分析（SEM），以确定其主要特性，并了解它们在可能的工业应用中的潜力。
