In this work, the effects of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) grafted epoxidized soybean oil (ESO-G-DOPO) on mechanical properties and flame retardant of rice husk silica filled epoxy based composite were investigated detail. The silica was extracted from rice husk before using as reinforcement for epoxy resin. While the epoxidized soybean oil (ESO) was synthesized from soybean oil via epoxidation processing prior to react with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to form ESO-G-DOPO. The Fourier transform infrared spectroscopy and nuclear magnetic resonance were used to confirm the chemical structure of silica, ESO and ESO-G-DOPO. The content of rice husk silica was also kept at constant of 20 wt.% while the content of ESO-G-DOPO was varying in range from 0 to 15 wt.% according to epoxy weight. The experimental results indicated that the presence of ESO-G-DOPO help to enhance the fracture energy, tensile strength, flexural strength up to 111.36, 67.26, and 87.79 %, respectively in comparison with virgin sample. Especially, the results of cone calorimeter testing, limiting oxygen index indicated that the flammability of epoxy resin was extremely reduced with presence of ESO-G-DOPO. A mechanism of flame retardant was also proposed to answer for the question how ESO-G-DOPO acted in a flame.

中文翻译：

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DOPO接枝环氧大豆油对环氧树脂/稻壳二氧化硅杂化材料断裂韧性和阻燃性的影响

在这项工作中，9,10-二氢-9-氧杂-10-菲菲-10氧化物（DOPO）接枝的环氧化大豆油（ESO-G-DOPO）对稻壳二氧化硅填充环氧树脂的机械性能和阻燃性的影响基复合材料进行了详细研究。从稻壳中提取二氧化硅，然后将其用作环氧树脂的增强剂。而环氧大豆油（ESO）是由大豆油通过在与9,10-二氢-9-氧杂-10-磷酸菲吩-10氧化物（DOPO）反应形成ESO-G-DOPO之前进行环氧化处理。用傅里叶变换红外光谱和核磁共振技术确定了二氧化硅，ESO和ESO-G-DOPO的化学结构。稻壳二氧化硅的含量也保持恒定为20重量％，而ESO-G-DOPO的含量根据环氧重量在0至15重量％的范围内变化。实验结果表明，与原始样品相比，ESO-G-DOPO的存在有助于将断裂能，拉伸强度，弯曲强度分别提高至111.36％，67.26％和87.79％。特别地，锥形量热仪测试的结果，极限氧指数表明，在存在ESO-G-DOPO的情况下，环氧树脂的可燃性大大降低。