This study introduces a novel sandwich-structured composite incorporating varying contents of zirconium diboride (ZrB 2 ), with polybenzimidazole (PBI) as the resin matrix and quartz fiber felt (QF) as the reinforcement. The ablative performance of the composites was assessed under high-energy continuous wave laser conditions, featuring a laser power density of 30 MW m -2 , and the laser ablation morphology and ablation mechanism of the ZrB 2 /PBI/QF composites were investigated. Further analysis examined the effects of ZrB 2 ceramic content on the density, thermal stability, mechanical properties, ablation characteristics, and rear surface temperature of the composites. Upon laser ablation, ZrB 2 oxidizes, forming a protective white ZrO 2 layer. At a 60% ZrB 2 content, the rear surface temperature of the composites reached 1031 °C after 42 s, resulting in a low linear ablation rate (0.12 mm s -1 ). The gases and residual carbon produced by the pyrolysis of PBI resin, the melting of QF, and the release of SiO 2 gas contribute to the formation of a SiO 2 protective layer. Building on this foundation, the incorporation of ZrB 2 further enhances energy dissipation and facilitates the development of a ZrO 2 -SiO 2 protective layer with increased reflectivity. This layer, along with another oxidation product, B 2 O 3 gas, serves to isolate oxygen and mitigate erosion. The findings suggest significant potential for developing advanced materials for high-energy continuous wave laser protection.
Xiaoge Ye,Dongna Li,Yamin Zhang,Zhen Li,Xukang Feng,Shiyao Huang,Xiaojun Ma,Jianing Li
The development of sustainable adhesives that reconcile mechanical robustness, environmental resilience, and multifunctionality remains a formidable challenge. Inspired by the passive unfolding-retraction mechanism and hierarchical micro-nano textures of beetle wings, where rigid elytra provide structural support and flexible hindwings enable energy dissipation, we report a fully bio-based adhesive system that integrates rigid-flexible synergy with multifunctional nanoarmor for sustainable adhesion. Lignin was covalently grafted onto natural rubber latex (NRL) via ammonium persulfate-initiated radical polymerization (NRL- g -Lignin), constructing a three-dimensional “rigid skeleton-flexible matrix” network. The resulting NRL- g -Lignin adhesive exhibits a 40.7 % increase in shear strength (0.878 MPa vs. 0.624 MPa) and a significant thermal stability enhancement (T max = 392.2 °C). Furthermore, the incorporation of cinnamaldehyde-tannic acid nanoemulsions (CA/TA NEs) introduces a homogeneous nanoarmor that improves interfacial adhesion, crack deflection, and offers up to 98.8 % antioxidant (ABTS) and > 99 % antimicrobial efficacy. The adhesive maintains outstanding performance across −18 °C to 100 °C, exhibits excellent substrate compatibility, can be reprocessed via hot-pressing, and demonstrates a 31.4–50.6 % mass loss after 60 days of soil burial, evidencing its biodegradability and reduced persistence. This multiscale, sustainable design paradigm opens new avenues for high-performance adhesives in recyclable composites, biomedical interfaces, and eco-friendly packaging.
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