Xiaode Guo

Ammonium perchlorate (AP) is widely employed as the primary oxidizer in composite solid propellants (CSPs) due to its high oxygen content and enthalpy of formation. Constituting over 50% of typical...

Amorphous Co–B–O–C catalyst is used to activate PMS for the degradation of PNP, which is ultimately broken down into CO ₂ , H ₂ O, and NO ₃ ⁻ .

Nitroguanidine (NQ) is a high-nitrogen energetic compound whose high decomposition temperature and incomplete combustion hinder its efficiency and environmental performance. Herein, we report a nanoscale interfacial-catalysis strategy in which lead carbonate (PbCO₃) is transformed via high-energy ball milling into nanostructured particles, then ultrasonically dispersed to form intimate contact interfaces with NQ crystals. Detailed structural characterization (XRD, SEM) confirmed the formation of PbCO₃ with sub-100 nm dimensions and a high surface area, promoting extensive NQ-catalyst interfacial interactions. TGA-DSC revealed that these engineered interfaces lower the onset decomposition temperature of NQ by up to 23.7 °C and reduce its apparent activation energy from 130.9 to 105.2 kJ·mol^-1, indicative of accelerated surface-mediated bond rupture. TGA-FTIR analyses demonstrated that PbCO₃ surfaces facilitate early stage heat release and redirect reaction pathways to suppress HCN formation, converting it into cleaner exhaust species. Solid-phase residue examination (XPS, XRD) further demonstrated that the reduction of solid-phase residues in the reaction system improves overall combustion integrity. By elucidating how the interface chemistry of nanostructured PbCO₃ regulates the kinetics and product distribution of NQ combustion, a new avenue has been opened for the design of advanced energy materials with customized properties.

Material self‐healing involves the dissociation and reorganization of the dynamic bonds of materials. Thus, the material self‐healing process is primarily driven by the dynamic nature of bonds and the high mobility of molecular chains. However, the low bond energy of these dynamic bonds limits the enhancement of the strength of materials, and their inability to withstand harsh real‐world conditions compromises their service life. Therefore, the current research focus in this field remains on high‐strength self‐healing materials. In this study, a hierarchical hydrogen‐bonded crosslinking network was constructed and a high‐strength self‐healing polyurethane material was successfully synthesized. Infrared and hydrogen spectroscopy analyses reveal that the hierarchical hydrogen‐bonded crosslinked network features both strong and weak hydrogen bonds. The strong hydrogen bonds preserve the mechanical strength of the polyurethane material, whereas the breaking and rapid reformation of the weak hydrogen bonds support its self‐healing ability. The experimental data show that PUGI‐A ₁ O ₁ exhibits a high tensile strength of 49 MPa and a self‐healing rate of 98% at 80°C for 12 h.

Ammonium perchlorate (AP), a widely used oxidizer in solid propellants, requires the incorporation of combustion catalysts to enhance its thermal decomposition efficiency. However, such modifications often compromise safety performance. Inspired by the rapid metal-ion-induced gelation of sodium alginate (Na-A), this study introduces a novel “droplet-solution contact assembly” strategy to encapsulate AP within a three-dimensional porous network framework derived from cobalt alginate (Co-A), thereby fabricating spherical AP/Co-A composites with simultaneously improved catalytic activity and safety. During thermal decomposition, Co-A breaks down into catalytically active nano-Co₃O₄ particles uniformly dispersed on a carbonized porous framework. The unique architecture facilitates efficient charge transfer and synergistically accelerates AP decomposition. In the event of collision and friction, the spherical morphology of AP/Co-A minimizes localized hot spot formation under mechanical stress, while the organic framework formed by Co-A functions as a spring-like buffer network to alleviate collision and friction energy, significantly enhancing the safety performance. The study provides a simple and safe preparation method for spherical composite materials and offers novel insights into its design.

Composite solid propellant often needs to add solid catalysts to improve its combustion performance, but result in the reduced mechanical properties. According to the situation, a novel research strategy was proposed, which ammonium perchlorate (AP) was packed into the layered porous structure of copper alginate (Cu-A). Cu-A effectively enhances the interfacial interaction between AP and binder matrix by reacting with toluene diisocynate. In addition, Cu, Cu ₂ O and CuO produced by the decomposition of Cu-A are well dispersed in carbonated porous framework decomposed by Cu-A with electrical conductivity, which realizes the efficient catalysis for AP. After being applied to AP-based propellant, AP/Cu-A strengthens its ignition capacity and combustion rate, which organic porous structure of Cu-A plays a role in combustion-supporting effect. The tensile results show the maximum tensile strength of the propellant is increased with the reduced adhesion index. It confirms the enhanced interface force between AP and binder matrix by Cu-A, which alleviates the dewetting phenomenon. It is clearly that AP/Cu-A improves the negative effect of solid combustion catalysts on the mechanical performance of prepared propellant, which has both excellent combustion and mechanical properties. The study offers a new perspective for the selection of combustion catalysts for the propellant.

Cu–Co–O/N-doped carbon catalysts display excellent catalytic performances toward the hydrogenation reduction reaction of 4-nitrophenol (PNP), where a high activity parameter of 300 s ⁻¹ g ⁻¹ can be obtained when the NaBH ₄ : PNP molar ratio was 100 : 1.

Self‐healing materials have not been able to solve the problem of the coexistence of mechanical strength and self‐healing function. Despite years of research, high‐strength self‐healing materials still require external factors to accelerate their self‐healing process. For this reason, in this study, two kinds of chain extenders were inserted into the hard segment to design the molecular structure of polyurethane. The introduction of two chain extenders not only provided multiple binding modes for hydrogen bond recombination, but also formed more types of hydrogen bonds. Based on the design, a polyurethane elastomer PUGI‐D₃B₂ with high strength and excellent self‐healing properties was synthesized. Data such as FTIR and ¹H NMR spectra clearly demonstrate the successful synthesis of PUGI‐D₃B₂. The mechanical strength of PUGI‐D₃B₂ is 15.34 MPa, and its surface scratches can completely disappear after self‐healing at 60°C for 10 h，and 98.02% of the mechanical strength is restored after 12 h of heal. Therefore, combining the excellent self‐healing properties of PUGI‐D₃B₂, we prepared a multifunctional superhydrophobic material (SHN‐SiO₂/PUGI‐D₃B₂). It can be used in a wide range of applications such as waterproof coatings, biomedicine and flexible electronics, which provides a new idea for the future direction of multifunctional materials.