Abstract Biocomposites with high performance and biobased contents were prepared from renewable feedstocks, i.e., hemp fibers (HFs) and acrylated epoxidized soybean oil (AESO). Two bifunctional isocyanates, i.e., isocyanatoethyl methacrylate (IEM) and 3-isopropenyldimethylbenzyl isocyanate (TMI), were used as reactive diluents for AESO, respectively. The incorporated IEM or TMI carrying both C C bonds and isocyanate groups not only crosslinked with the C C bonds of AESO by a free-radical polymerization, but also reacted with the –OH groups of both AESO and HFs to concurrently improve the unsaturation level of AESO monomers and the interfacial adhesion between HFs and AESO matrix, which was verified by FTIR and DSC analyses. Both IEM-AESO and TMI-AESO resins exhibited favorable viscosities and curing temperatures for the production of HFs-reinforced composites while without the emission of hazardous air pollutants. The composite with 15 wt% IEM modified AESO (based on the total weight of IEM-AESO blend) had comparable tensile and flexural strengths with the composite from 30 wt% styrene; while the 15 wt% TMI resulting composite obtained higher tensile strength and modulus as well as flexural strength and modulus than the composites from 15 wt% IEM or 30 wt% styrene. This indicated that TMI has a higher reinforcing efficiency on the composites than IEM. Significant improvements in storage modulus, glass transition temperature, and water resistance were obtained for the composites from IEM or TMI relative to the composite from pure AESO resin, which is attributed to the simultaneously improved crosslinking density and interfacial adhesion of the composites as confirmed by SEM analysis.

中文翻译：

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同时提高大麻纤维增强丙烯酸酯化环氧化大豆油复合材料的交联度和界面粘合度

摘要 以大麻纤维 (HFs) 和丙烯酸化环氧化大豆油 (AESO) 为原料，制备了具有高性能和生物基含量的生物复合材料。两种双官能异氰酸酯，即甲基丙烯酸异氰酸根合乙酯 (IEM) 和 3-异丙烯基二甲基苄基异氰酸酯 (TMI)，分别用作 AESO 的反应性稀释剂。引入的同时带有 CC 键和异氰酸酯基团的 IEM 或 TMI 不仅通过自由基聚合与 AESO 的 CC 键交联，而且还与 AESO 和 HF 的 -OH 基团反应，同时提高了 AESO 单体的不饱和度以及 HF 和 AESO 基质之间的界面粘附，这通过 FTIR 和 DSC 分析得到验证。IEM-AESO 和 TMI-AESO 树脂均表现出良好的粘度和固化温度，可用于生产 HFs 增强复合材料，同时不会排放有害空气污染物。含有 15 wt% IEM 改性 AESO（基于 IEM-AESO 共混物的总重量）的复合材料与含有 30 wt% 苯乙烯的复合材料具有相当的拉伸和弯曲强度；而 15 wt% TMI 所得复合材料比 15 wt% IEM 或 30 wt% 苯乙烯的复合材料获得更高的拉伸强度和模量以及弯曲强度和模量。这表明 TMI 对复合材料的增强效率高于 IEM。相对于纯 AESO 树脂的复合材料，IEM 或 TMI 的复合材料在储能模量、玻璃化转变温度和耐水性方面获得了显着改善，