In this work, we designed a eugenol-based intrinsically flame-retardant epoxy monomer bis(2-methoxy-4-(oxirane-2-ylmethyl) phenyl) phenyl phosphonate (BEEP). At first, an intermediate product BEP was compounded by eugenol and phenyl phosphonic dichloride, and the bio-based epoxy monomer BEEP was acquired by the epoxidation of BEP with 3-chloroperoxybenzoic acid. Then different ratios of BEEP and commercial bisphenol A-type epoxy resin (DER) were blended and cured with 4,4-diaminodiphenyl methane (DDM). The addition of BEEP enhanced the reactivity of DER/BEEP-DDM systems, whose activation energy fitted by Kissinger's and Ozawa's theories decreased from 50.66 and 55.12 kJ/mol to 47.49 and 51.63 kJ/mol, respectively. Compared with neat DER-DDM epoxy, the flexural strength and flexural modulus promoted from 69.4 MPa and 1.57 GPa to 74.5 MPa and 3.60 GPa, when adding 20 wt% of BEEP (D8B2), due to the stiffness of benzene rings in BEEP. Importantly, with a low phosphorus content of 1.0% in the D8B2 sample, the cured epoxy achieved 27.5% of the limit oxygen index and UL-94 V0 rating. Overall, this work provides a facile route for preparing a bio-based epoxy monomer to enhance the flame-retardancy and mechanical performance of DGEBA epoxy resin.

在这项工作中，我们设计了一种基于丁香酚的本征阻燃环氧单体双（2-甲氧基-4-（环氧乙烷-2-基甲基）苯基）苯基膦酸酯（BEEP）。首先将丁香酚与苯基二氯化膦复合得到中间产物BEP，将BEP与3-氯过氧苯甲酸环氧化得到生物基环氧单体BEEP。然后将不同比例的 BEEP 和商业双酚 A 型环氧树脂 (DER) 混合并用 4,4-二氨基二苯甲烷 (DDM) 固化。添加 BEEP 增强了 DER/BEEP-DDM 系统的反应性，Kissinger 和 Ozawa 理论拟合的活化能分别从 50.66 和 55.12 kJ/mol 降低到 47.49 和 51.63 kJ/mol。与纯 DER-DDM 环氧树脂相比，弯曲强度和弯曲模量从 69.4 MPa 和 1.57 GPa 提升到 74。5 MPa 和 3.60 GPa，当添加 20 wt% 的 BEEP (D8B2) 时，由于 BEEP 中苯环的刚度。重要的是，由于 D8B2 样品中磷含量低至 1.0%，固化的环氧树脂达到了 27.5% 的极限氧指数和 UL-94 V0 等级。总体而言，这项工作为制备生物基环氧树脂单体以提高 DGEBA 环氧树脂的阻燃性和机械性能提供了一条简便的途径。