Synthesis and properties of fluorinated bis-benzocyclobutene-terminated arylene ether monomers

Four novel bis-benzocyclobutene-endcapped arylene ether monomers, 1,1′-bis[4-(4′-benzocyclobutenyloxy)phenyl]-1-phenyl-2,2,2-trifluoroethane (BOPP3FE), 1,1′-bis[4-(4′-benzocyclobutenyloxy)phenyl]-1-(3′,5′-ditrifluoromethyl)phenyl-2,2,2-trifluoroethane(BOPP9FE), 2,2′-bis[4-(4′-benzocyclobutenyloxy)phenyl]-1,1,1,3,3,3-hexfluoropropane (BOP6FP), and 2,2′-bis[4-(4′-benzocyclobutenyloxy)phenyl]-propane (BOPP) were prepared and characterized. All the four monomers showed similar curing behaviors under N₂ (Differential scanning calorimetry: extrapolated onset and peak temperatures at 225–229°C and 261–263°C) and demonstrated low and steady melt viscosities between 110 and 200°C, indicating their good processability. After cure, the resulting BCB resins exhibited high T_g (232–282°C) and excellent thermal stability (T_5% > 433°C). The resins also showed good mechanical properties with the flexural strengths of 68–88 MPa and the flexural modulus of 2.52–3.15 GPa. Moreover, the resins also exhibited low dielectric constants (2.58–2.88), low dissipation factors (2.7 to 8.4 × 10−4) and low water absorptions in boiling water for 24 h (0.29–0.59%). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009