Xiao Zhong#, Xutong Yang#, Kunpeng Ruan, Junliang Zhang*, Haitian Zhang and Junwei Gu*. Discotic Liquid Crystal Epoxy Resins Integrating Intrinsic High Thermal Conductivity and Intrinsic Flame Retardancy. Macromolecular Rapid Communications, 2022, 43(1): 2100580. 2020IF=5.734
https://doi.org/10.1002/marc.202100580
Abstract
The integration of intrinsic thermal conductivity and intrinsic flame retardancy of epoxy resins shows wider application prospects in electricals and electronics. Discotic liquid crystal epoxy (D-LCE) is synthesized from pyrocatechol, 2-allyloxyethanol and 3-chloroperoxybenzoic acid. P/Si synergistic flame-retardant co-curing agent (DOPO-POSS, DP) is synthesized from p-hydroxybenzaldehyde, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and amino terminated polysilsesquioxane (POSS). Finally, D-LCE is cured within liquid crystal range with 4, 4’-diaminodiphenyl methane (DDM) and DP, to obtain intrinsic highly thermal conductive/flame-retardant epoxy resins (D-LCERDP). D-LCERDP-10.0 (10.0 wt% DP) synchronously possesses excellent intrinsic thermal conductivity and intrinsic flame retardancy, with thermal conductivity coefficient in vertical and parallel direction (λ⊥ and λ∥) of 0.34 W m-1 K-1 and 1.30 W m-1 K-1, much higher than that of general bisphenol A epoxy resin (E-51, λ⊥ of 0.19 W m-1 K-1, λ∥ of 0.65 W m-1 K-1). The limiting oxygen index (LOI) value of D-LCERDP-10.0 reaches 31.1, also better than those of E-51 (19.8) and D-LCER (21.3).
集本征導熱及本征阻燃功能為一體的環氧樹脂在電子電氣領域具有廣闊的應用前景。本文以鄰苯二酚、乙二醇單烯丙基醚和間氯過氧苯甲酸為主要原料合成的苯并菲類盤狀液晶環氧（D-LCE）為基體，4, 4’-二氨基二苯甲烷（DDM）為固化劑，以對羥基苯甲醛、端胺基聚倍半硅氧烷（NH2-POSS）和9, 10-二氫-9-氧雜-10-磷雜菲-10-氧化物（DOPO）為主要原料合成的DOPO-POSS（DP）為共固化劑，澆注成型制備本征型高導熱/阻燃液晶環氧樹脂（D-LCERDP）。結果表明：當DP的用量為10.0 wt%時，D-LCERDP具有優異的本征導熱性能和最優的本征阻燃性能。D-LCERDP-10.0垂直方向和水平方向的導熱系數（λ⊥和λ∥）分別為0.34 W/（m·K）和1.30 W/（m·K），遠優于E-51的λ⊥（0.19 W/（m·K））和λ∥（0.65 W/（m·K））；其極限氧指數（LOI）提高至31.1，也遠優于E-51（19.8）和D-LCER（21.3）。
論文創新點
1. 通過引入盤狀液晶結構和P/Si協同阻燃基團，分別合成了苯并菲類盤狀液晶環氧（D-LCE）和DOPO-POSS（DP）共固化劑，進而制備得到本征型高導熱/阻燃液晶環氧樹脂（D-LCERDP）。
2. 當DP的用量為10.0 wt%時，D-LCERDP-10.0垂直方向和水平方向的導熱系數（λ⊥和λ∥）分別為0.34 W/（m·K）和1.30 W/（m·K），遠優于E-51的λ⊥（0.19 W/（m·K））和λ∥（0.65 W/（m·K））。
3. D-LCERDP-10.0具有優異的本征阻燃性能，其極限氧指數（LOI）為31.1（阻燃等級達到UL-94 V-0級），遠優于E-51（19.8）和D-LCER（21.3）。