Yabing Tian,Xuezhen Feng,Jing Wang,Shibin Shang,Fang Liu,Jianxin Jiang,Haibo Zhang,Yuxiang Chen,Zhanqian Song
Designing degradable foams with excellent Joule heating and electromagnetic interference (EMI) shielding properties are crucial for protecting both the environment and low-temperature sensitive electronic devices. In this work, we used 1,3-diaminopropane carbamate (DPC) as a latent foaming-curing agent to prepare soft-hard tunable, degradable bio-based epoxy foams through one-step chemical foaming method. Subsequently, using F3 foam with outstanding reversible compressibility as the substrate, we developed a silver-plated foam, F3A3, with predominantly reflective and high EMI shielding performance via silver mirror reaction. The silver-plated foam F3A3 exhibited an electromagnetic interference shielding effectiveness (EMI SE) of 76.37 dB in the X-band (8.2–12.4 GHz), achieving a shielding efficiency as high as 99.99999%. Additionally, under an input voltage of 1.0 V, the surface saturation temperature of F3A3 rapidly increased from room temperature to 104.0 °C and demonstrated excellent stability and durability in low-voltage Joule heating. Due to the presence of dynamic ester bonds and tertiary amine structures in the F3A3 foam, it exhibited catalyst-free self-healing capability. These superior properties make the silver-plated foam highly promising for applications in military equipment, aerospace, and wearable electronic devices.
Shaolong Wei,Jie Yuan,Xiulu Gao,Yichong Chen,Ling Zhao,Dongdong Hu
Branched poly (butylene succinate- co -butylene terephthalate) (BPBST) was synthesized by in-situ poly co ndensation to enhance the foamability of poly (butylene succinate-co-butylene terephthalate) (PBST) and was blended with cellulose nanocrystals (CNC) to address foam shrinkage. The introduction of 2 wt% CNC increased the crystallization temperature of BPBST from 66.6 °C to 87.7 °C, accelerating its crystallization rate and improving both the mechanical properties and complex viscosity of the polymer matrix. Microcellular foams were produced using supercritical CO 2 as a blowing agent, with CNC serving as heterogeneous nucleation sites. The addition of CNC reduced the average cell diameter of the foam and increased the cell density, enhancing the dimensional stability of the foam. BPBST/CNC foam with 1 wt% CNC exhibited a high expansion ratio of 24.7 without shrinkage, along with a low thermal conductivity of 0.0354 W/(m·K), indicating excellent thermal insulation performance. Furthermore, CNC improved the hydrophilicity of the foams and accelerated their degradation. The BPBST/CNC2 foam with an expansion ratio of 17 exhibited a 72.2 % weight loss after 10 d of hydrolysis, showing excellent degradation. This study combines the tunable molecular structure of in-situ copolymerization with the efficiency of melt blending to provide an effective strategy for the production of biodegradable, functionalized foams.
Wentao Guo,Zhirui Wang,Xiulu Gao,Meixia Zhang,Yichong Chen,Ling Zhao,Dongdong Hu
Degradable poly(butylene succinate- co -butylene adipate- co -butylene 5-sodiosulfoisophthalate) (PBSAS) incorporating sodium dimethyl isophthalate-5-sulfonate (SIPM) units were synthesized via an optimized two-step melt transesterification polycondensation. The introduced ionic groups enhanced polarity for microwave heating, while simultaneously reducing crystallinity and broadening the melting range from 23 to 35°C. They also acted as cross-links, improving melt strength and mechanical properties. Consequently, PBSAS5 foam achieved exceptional stability (25.3 times), a tunable bimodal cell structure, superior compression performance, and an ultralow thermal conductivity of 35.2 mW/m·K. Furthermore, SIPM imparted pronounced hydrophilicity and pH-responsive degradation, resulting in an accelerated degradation rate of PBSAS foams under acidic conditions. This integrated strategy of efficient polymerization and microwave-assisted foaming enables the fabrication of ultralight PBSAS foams, providing a universal method for the sustainable production of degradable materials.
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