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

ABSTRACT 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.