Department of Coatings and Polymeric Materials, North Dakota State University, Fargo, ND, USA.
Biomacromolecules. 2011 Jun 13;12(6):2416-28. doi: 10.1021/bm200549c. Epub 2011 May 24.
Novel highly functional biobased epoxy compounds, epoxidized sucrose esters of fatty acids (ESEFAs), were cross-linked with a liquid cycloaliphatic anhydride to prepare polyester thermosets. The degree of cure or conversion was studied using differential scanning calorimetry (DSC), and the sol content of the thermosets was determined using solvent extraction. The mechanical properties were studied using tensile testing to determine Young's modulus, tensile stress, and elongation at break. Dynamic mechanical analysis (DMA) was used to determine glass-transition temperature, storage modulus, and cross-link density. The nanomechanical properties of the surfaces were studied using nanoindentation to determine reduced modulus and indentation hardness. The properties of coatings on steel substrates were studied to determine coating hardness, adhesion, solvent resistance, and mechanical durability. Compared with the control, epoxidized soybean oil, the anhydride-cured ESEFAs have high modulus and are hard and ductile, high-performance thermoset materials while maintaining a high biobased content (71-77% in theory). The exceptional performance of the ESEFAs is attributed to the unique structure of these macromolecules: well-defined compact structures with high epoxide functionality. These biobased thermosets have potential uses in applications such as composites, adhesives, and coatings.
新型高官能度生物基环氧化合物，脂肪酸氧化蔗糖酯（ESEFAs），与液态脂环族酸酐交联，制备聚酯热固性塑料。采用差示扫描量热法（DSC）研究固化程度或转化率，采用溶剂萃取法测定热固性塑料的固含量。采用拉伸试验研究力学性能，以确定杨氏模量、拉伸应力和断裂伸长率。采用动态力学分析（DMA）测定玻璃化转变温度、储能模量和交联密度。采用纳米压痕法研究表面的纳米力学性能，以确定弹性模量和压痕硬度。研究了钢基体上涂层的性能，以确定涂层硬度、附着力、耐溶剂性和机械耐久性。与对照物，即氧化大豆油相比，酸酐固化的 ESEFAs 具有高模量，硬度和韧性高，是具有高生物基含量（理论上为 71-77%）的高性能热固性材料。ESEFAs 的优异性能归因于这些大分子的独特结构：具有高环氧官能度的定义明确的紧密结构。这些生物基热固性塑料在复合材料、胶粘剂和涂料等应用中有潜在用途。
