Preparation and Properties Investigation of Polyphenylene Oxide Modified Epoxy Resin Composites for High-Frequency Copper Clad Laminates

As electronic technology swiftly progresses, conventional epoxy resins can no longer fully meet the demands of copper-clad laminates (CCLs). To develop an epoxy resin exhibiting superior thermal performance, low dielectric properties, and reduced moisture absorption, low-molecular-weight TMBPA-MPPO-2OH was successfully synthesized using TMBPA and DMP as comonomers. The molecular structure of TMBPA-MPPO-2OH was comprehensively characterized by FT-IR and 1 H NMR spectroscopy. Subsequently, the synthesized monomer was employed to modify epoxy resin E51 in combination with 4,4′-diaminodiphenylmethane (DDM). Modified epoxy resin composites (E51/DDM/TMBPA-MPPO-2OH) were prepared through a casting method, with TMBPA-MPPO-2OH and E51 mixed in varying mass ratios. The effects of TMBPA-MPPO-2OH incorporation on both the curing kinetics and final characteristics of the modified epoxy resin systems were systematically investigated. Results showed that E51/DDM/TMBPA-MPPO-2OH composites possessed a high glass transition temperature (T g = 178.77 ~ 194.16°C), along with excellent thermal stability (T d5% = 355 ~ 360°C) and flexural strength (67.31 ~ 75.28 MPa). Additionally, the inclusion of TMBPA-MPPO-2OH reduced the dielectric constant, dielectric loss tangent, and moisture absorption rate of E51/DDM/TMBPA-MPPO-2OH. When the TMBPA-MPPO-2OH content was 20 wt%, the dielectric constant (10 MHz, 3.2), dielectric loss (10 MHz, 0.015), and moisture absorption rate (1.7%) of E51/DDM/TMBPA-MPPO-2OH showed reductions of 16%, 58%, and 32%, respectively, compared to the pure epoxy resin.