Computer-aided design of thermosetting benzoxazoles containing bis-endoalkynyl groups: Low melting points and high thermal stability

• Published in: European polymer journal 2024-11, Vol.220, p.113503, Article 113503
• Main Authors: Zhang, Jiahang, Jiang, Zhengtao, Zhuang, Qixin, Zuo, Peiyuan, Liu, Xiaoyun
• Format: Article
• Language: English
• Subjects: Dielectric property; Processability; Screen method; Thermal stability; Thermosetting benzoxazole
• ISSN: 0014-3057
• DOI: 10.1016/j.eurpolymj.2024.113503

[Display omitted] •Design and synthesize thermosetting benzoxazoles containing bis-endoalkynyl groups firstly.•Two thermosetting benzoxazoles have low melting points and excellent thermal stability.•A substantial improvement in balancing thermal stability, dielectric properties, and processability. High-temperature-resistant polybenzoxazoles (PBOs) have recently become a prominent research area due to their potential applications in aviation and aerospace. However, achieving a balance between thermal stability and processability remains a significant challenge. In this study, a computer-aided method to develop PBOs with high thermal stability and processability is explored. First, thermoset benzoxazoles (CPBOs) are designed using a material genomic approach. Subsequently, their zero shear viscosity, temperature at 50 % thermal weight loss, dielectric constant and dielectric loss are predicted using a computer-aided method. Finally, two screened thermosetting benzoxazoles, CPBO-1 and CPBO-6, are synthesized and experimentally validated. The experiments indicate that their melting points are below 100 °C, with the lowest melt viscosities being 0.5 Pa•s and 1.5 Pa•s, respectively. The corresponding polymers, pCPBO-1 and pCPBO-6, feature high thermal stability. The 5 % weight loss temperature of pCPBO-1 in N2 is 618.9 °C, while the dielectric constant and dielectric loss are 3.1 and 0.0063, respectively. These are excellent values for thermosetting resins. This computer-aided screening method is more efficient and cost-effective compared to conventional trial-and-error methods.