Junfeng Cheng,Jun Zhou,Cheng Zhang,Zheng Cao,Dun Wu,Chunlin Liu,Hui Zou
To achieve an enhanced laser marking for polypropylene , the “core-shell” ATO@PI (antimony-doped tin oxide@polyimide) laser-sensitive composite was successfully designed and prepared. This laser-sensitive composite consisted of an ATO “core” with high photothermal conversion efficiency and a PI “shell” with high laser induced carbonization rate. Compared with pure ATO, the results showed that 0.3 wt% of the ATO@PI composite endowed polypropylene with an enhanced laser marking performance. The results of SEM and TEM revealed that PI was tightly coated around the ATO surface and the laser-sensitive composite particles were approximately spherical. Both Raman and near infrared (NIR) absorption spectrum observed that, after irradiation of 1064 nm laser, the carbonization degree of polypropylene using ATO@PI was much higher than that of only using pure ATO. The photothermal conversion of ATO and the local carbonization of PI in the composite synergistically increase the degree of laser induced carbonization of polypropylene. Importantly, the “core-shell” laser-sensitive composite designed here further broadens the application prospects of inorganic particles in the field of polymer laser marking.
Porous materials are widely used for sound attenuation, but achieving broadband absorption remains challenging. Under the guidance of finite element simulations, this study designed and fabricated a gradient porous sound-absorbing material via the air bubble method and freeze-casting technique. The gradient pore structure, constructed via a dual-templating approach using ice crystals and air bubbles, dissipates sound waves in a stepwise manner, thereby enhancing the sound absorption performance of traditional PI aerogels. Subsequently, iron-trimesic metal organic framework (FeBTC), as an acoustic metamaterial, was introduced into foam aerogel through the liquid diffusion method to form a hierarchical sound-absorbing composite structure. The synergistic effect of the hierarchical composite structure significantly improves the sound absorption and insulation performance of foam aerogels. The FF 2 P composite aerogel exhibits an average sound absorption coefficient (ASAC) of 0.82 and an average sound transmission loss (ASTL) of 26.6 dB across the broad frequency range of 500–6300 Hz. Meanwhile, the small-pore layer with ice crystal pores enables composite aerogels to retain excellent thermal insulation performance (0.04 W/m·K). Besides, the introduction of a foam gradient structure enables foamed aerogels to achieve excellent mechanical durability. The successful development of the gradient hierarchical composite aerogel provides a novel approach for designing high-performance, low-cost noise absorbers.
Polyimide (PI) materials are highly valued in tribological applications due to their excellent friction-reduction and wear-resistance properties under extreme conditions. However, their relatively low tensile properties limit their effectiveness as standalone materials, necessitating reinforcement. Poly(p-phenylene benzobisoxazole) (PBO) fibers, known for their superior mechanical and tribological properties, struggle with effective interfacial bonding with PI due to low surface activity. This gap in effective reinforcement strategies is critical for advancing PI applications. Here, we address this challenge by anchoring graphene oxide (GO) nanosheets onto PBO fibers using rare-earth (lanthanum) ions, producing RE-GO-RE-PBO fibers with a multi-scale reinforcement structure. The study involved optimizing the rare-earth solution (RES) concentration and characterizing the fiber surfaces. Our results indicate that an optimal RES concentration of 0.3 wt% achieves uniform and stable GO deposition, significantly enhancing interfacial bonding with the PI matrix. The resulting RE-GO-RE-PBO/PI composite exhibited a 91.74% increase in tensile strength and a 58.44% increase in modulus compared to pure PI, alongside improved wear resistance and a low friction coefficient. These findings present a novel strategy for designing high-performance tribological composites by integrating rare-earth-modified nanomaterials into fiber-reinforced matrices. This approach not only addresses the critical challenge of enhancing interfacial bonding but also provides a theoretical and experimental foundation for advanced applications in aerospace and other high-tech sectors, pushing the boundaries of tribological material performance.
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