Related Experiment Video
Updated: Sep 9, 2026
Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites
Published on: September 19, 2020
Economical bisphenol-based dibenzocyclobutene resins with excellent thermal and dielectric properties for
Honghui Cheng1, Lei Wu1, Jiafeng Di1
1College of Chemistry and Materials Science, Hengyang Normal University Hengyang China laixhua163@163.com.
Abstract:
Benzocyclobutene (BCB) resins have recently gained significant attention as dielectric materials, yet most suffer from high costs. Herein, five economical bisphenol-based dibenzocyclobutene resins (BCB-A, BCB-AF, BCB-F, BCB-B and BCB-O) were readily synthesized from 4-bromobenzocyclobutene and commercial bisphenols via an Ullmann reaction. Upon thermal curing, the corresponding crosslinked polymers were obtained. All cured BCB resins exhibited high glass transition temperature (T g) values of 287-329 °C, excellent thermal stability with 5% weight loss temperatures (T 5%) of 408-445 °C, and CTE values as low as 23.8 ppm °C-1. The cured resins also exhibited good flexural properties, with flexural strengths of 63.7-98.4 MPa and flexural moduli of 2.2-2.7 GPa. Notably, they also demonstrated favorable high-frequency dielectric properties at 10 GHz, with dielectric constant (D k) values of 2.54-2.83 and dissipation factor (D f) values of 2.32 × 10-3 to 3.63 × 10-3. Considering the low cost of bisphenols, the facile Ullmann reaction and the good overall performance, these bisphenol-based dibenzocyclobutene resins are promising candidates for high-frequency communication applications.
Related Concept Videos
01:28Stability of Conjugated Dienes
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
01:17Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
01:24π Molecular Orbitals of 1,3-Butadiene
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
01:16Structure of Conjugated Dienes
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...