氟化硅氧烷改性环氧树脂的制备与性能

Preparation and properties of fluorinated siloxane modified epoxy resins

首先,以全氟(2-甲基-3-氧杂己基)氟化物(六氟环氧丙烷二聚体)和N-(β-氨乙基)-γ-氨丙基三甲氧基硅烷(KH792)为原料制备一种氟化硅氧烷,用FTIR和1HNMR表征其结构。然后,将氟化硅氧烷与聚醚胺共同固化环氧树脂DGEBA(双酚A型二缩水甘油醚),测试了改性环氧树脂复合材料的性能。结果表明,与未改性环氧树脂相比,加入氟化硅氧烷使含氟量1%(以DGEBA质量计)改性环氧树脂复合材料的表面静态水接触角由72.0°增至103.2°,表面能由(42.08±2.17)mN/m降至(20.55±1.45)mN/m,40 d吸水率由1.75%降至1.38%,有效提高了材料的疏水性;介电常数由3.83降低至3.63;材料热分解5%温度由339℃升高至347℃;拉伸及弯曲力学性能分别提高了8.5%及7.7%。含氟量为1%时,改性环氧树脂复合材料的综合性能最佳,差式量热扫描和动态力学性能测试结果表明,少量改性剂可以促进环氧树脂的固化反应,提高固化度和交联密度;当氟化硅氧烷添加量增加时,材料内部发生显著的微相分离并导致性能逐渐下降。

A fluorinated siloxane was prepared from 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoylfluorid(hexafluoropropylene oxide dimer) and N-(β-aminoethyl)-γ-aminopropyltrimethyl oxysilane(KH792), and characterized by FTIR and 1HNMR. Fluorinated siloxane and polyetheramine were used to cure epoxy resin. The properties of the modified epoxy resin composites were tested. The results showed that the addition of fluorinated siloxane improved the hydrophobicity of the material. The static water contact angle of the material surface from 72.0° to 103.2°, the surface energy decreased from(42.08±2.17) mN/m to(20.55±1.45) mN/m, and the water absorption rate(40 d) was reduced from 1.75% to 1.38% compared with those of the unmodified epoxy resin. Furthermore, the dielectric constant was reduced from 3.83 to 3.63, the thermal decomposition temperature(T5%) of the material was increased from 339 ℃ to 347 ℃. The tensile and bending mechanical properties were increased by 8.5% and 7.7%, respectively. When the fluorine element was 1% of epoxy resin mass, the comprehensive performance of the modified epoxy resin composite was the best. DSC and DMA results showed that a small amount of modifier could promote the curing reaction of epoxy resin and improve curing degree and cross-linking density. While the addition of fluorinated siloxane increased, significant microphase separation occurred inside the material and the performance gradually decreased.