Bio-based Low-k Polymers at High Frequency Derived from Anethole: Synthesis and the Relationship between the Structures and the Properties

Abstract

Bio-based polymers have been widely investigated as sustainable low dielectric (low-k) materials in past decades. Nevertheless, a few of the polymers with excellent comprehensive properties have been achieved to satisfy the requirements of highfrequency communication application. In this paper, two fluorinated monomers (BCB-F and 2BCB-F) have been designed and successfully prepared from biomass anethole. The thermal-cross-linkable benzocyclobutene and polyfluorobenzene groups were introduced in order to obtain low-k polymers with good comprehensive properties. A control monomer C1 was prepared from the estragole, the isomer of anethole, to study intensively the effect of structures on properties. Among the thermally cured polymers, cured BCB-F with higher fluoride content shows a comparable dielectric constant (D k ) of 2.62 and lower dielectric loss (D f ) of 1.31 × 10 −3 at a frequency of 10 GHz, as well as better hydrophobic properties with a water uptake of 0.18%. Such good hydrophobic properties enable it to maintain the good dielectric properties even after being soaked in boiling water for 96 h. Cured 2BCB-F with bifunctional benzocyclobutene groups displays excellent heat resistance with a high glass transition temperature (T g ) of 408 °C and a low coefficient of thermal expansion (CTE) of 52 ppm/°C in the temperature range 30−300 °C. Cured 2BCB-F also shows good dielectric properties with a D k of 2.61 and a D f of 2.60 × 10 −3 at a frequency of 10 GHz. The good comprehensive properties reveal that the anethole-based polymers are suitable candidates as matrix or encapsulation resins for application in electronics and microelectric fields.

Curing Behavior and Properties of Active Ester Cured Cycloaliphatic Epoxy Resins

“…The catalyst 4-dimethylaminopyridine (DMAP) facilitates the reaction between epoxy and the active ester, resulting in the opening of the ring to produce ether and ester without generating hydroxyl groups. , This reaction pathway is highly advantageous for developing materials exhibiting excellent dielectric properties and low hygroscopicity, despite research on the interaction between active ester and epoxy dating back to 1988–1994 by Nishikubo et al, − with limited subsequent studies on the matter. With the rapid advancement of communication technology and related fields, the pursuit of electronic devices capable of faster signal transmission and higher frequencies necessitates materials with improved dielectric properties, including low dielectric constant, low dielectric loss, and adequate stability. ,, Active esters are gaining attention as potential hardeners, leading to several studies exploring their advantages. ,− …”

Low-Temperature-Curable and Photo-Patternable Benzocyclobutene-Derived Aggregation-Induced Emission (AIE)-Active Polymer Dielectrics

“…250 degC). [22][23][24][25][26][27] It is well-established that the introduction of substituents onto the four-membered ring of BCB can substantially reduce the activation energy barrier for ring-opening reactions, consequently lowering the ring-opening temperature (as indicated by the peak temperature of DSC curves). Previously, Chino et al have reported several BCB monomers with the ring-opening temperatures [?]…”