New type of UV cured low dielectric naphthalene resin: Structure-activity relationship of different substitution sites

Abstract

UV-curing low dielectric materials exhibit wide applications in the field of additive manufacturing of electronic packaging, owing to their environmental protection, good thermal stability, low dielectric constant (Dk), and dielectric loss (Df). Wherein, one-step UV curing realizes process simplification of low dielectric materials gradually sparked widespread research. In this work, a series of novel naphthalene-based low dielectric materials were prepared for one-step UV curing. The double bond conversion rate of resins exceeds 90 % in a short time and the resins perform exceptional dielectric properties (Dk < 2.8, Df < 0.009, 110 MHz), high thermal stability (T5% > 270 °C), and hydrophobicity (water contact angle > 95°). Notably, 1,6-naphthalene dimethacrylate/Trihydroxymethylbutyl trimethylacrylate (1,6-NEA/TMPTA) suggests lowest dielectric performance (Dk = 2.19, Df = 0.005) with significant thermal stability (Tg = 190 °C, T5% = 367.4 °C) because the π-π conjugation of the asymmetric structure of 1,6-NEA, which allows for a greater variety of stacking patterns and increases the effective collisions between the reactive sites of the photosensitive monomer and the reactive diluent. This work has revealed the structure-activity relationship between the substituents on naphthalene derivatives and their photochemical properties, providing a novel methodology for the development of low dielectric electronic packaging materials through additive manufacturing techniques.