Basalt fibers (BFs) possess exceptional mechanical properties, yet their widespread application is hindered by the persistent challenge of weak interfacial bonding with non-polar polymer matrices. To bridge this gap, we developed a biomimetic interfacial engineering strategy by constructing a zinc oxide (ZnO) nano-coating on the BF surface (ZBF). This functionalization induces thermodynamically-driven enrichment of the supramolecular nucleating agent (WBG) at the polypropylene (PP)/ZBF interface. During melt-processing, the enriched WBG molecules self-assemble into branched structures, creating a root-like interlocking architecture at the interface. Systematic analysis reveals that the reinforcement efficiency strongly depends on the scale of the interfacial assemblies. By constraining the assembly size at approximately 300 μm, the interfacial morphology is maximized, thereby achieving enhanced strength. Mechanical testing confirms the substantial improvement of this interlocked interface, with the PP/ZBF composites achieving a 170% increase in interfacial shear strength, a 310% increase in impact toughness, and a 50% improvement in flexural strength compared to untreated systems. Beyond mitigating the interfacial deficiency in basalt fiber composites, this work demonstrates a thermodynamically driven approach for constructing interlocked interfaces through interfacial migration and self-assembly, offering a potential route toward high-performance thermoplastic composites.
Silane coupling agents (SCAs) can improve the interfacial adhesion of basalt fiber (BF)/epoxy composites, but conventional experimental screening is costly and time-consuming. Herein, a multistage strategy integrating molecular simulation and experimental validation was developed to screen SCAs for BF/diglycidyl ether of bisphenol A epoxy resin (E51) composites. The results show that SCA reinforcement is governed by the combined effects of local reactivity, surface polarity, resin affinity, and interfacial accessibility rather than by a single reactivity descriptor. N-[3-(trimethoxysilyl)propyl]ethylenediamine (SCA14) exhibited strong interfacial interactions and high debonding resistance owing to enhanced electrostatic interactions and the synergistic effect of chemical grafting and physical adhesion. Experiments confirmed that SCA14 was successfully introduced onto the BF surface, increased the polar surface component, and improved E51 wettability. BFRP-SCA14 achieved a flexural strength and modulus of 560.06 MPa and 22.61 GPa, increasing by 22.9% and 42.5%, respectively, while maintaining low dielectric loss and high breakdown strength. Single-fiber IFSS and short-beam ILSS reached 7.3 and 41.12 MPa, respectively, corresponding to improvements of 78.0% and 25.5% over the laboratory reference. This strategy provides an efficient route for interfacial molecular design of BF/epoxy composites for electrical-insulation applications.
Filler dispersion, distribution and connectivity are central to multifunctional polymer nanocomposites. High-aspect-ratio nanofillers such as carbon nanotubes can form continuous networks at low content, enabling reinforcement and transport enhancement without significant impact on density, processability and cost. Here, multi-walled carbon nanotube (MWCNT)-reinforced hydrogenated nitrile butadiene rubber (HNBR) was investigated to clarify how nanotube percolation affects rheology, thermal conductivity, electromechanical response and fatigue resistance. MWCNTs were effectively dispersed during compounding and formed a distinct electrical percolation network in the cured HNBR at approximately 3.2 phr. Increasing MWCNT loading shortened curing time and increased the torque differential and apparent crosslink density, with the latter reflecting contributions from chemical crosslinks and filler-induced physical constraints. Thermal conductivity increased progressively with MWCNT loading, indicating the development of heat-transfer pathways. Dynamic mechanical analysis showed increased storage moduli and reduced loss factors with MWCNT content, while the nearly unchanged glass transition temperature suggests that reinforcement arises mainly from physical nanotube-network constraints rather than altered segmental dynamics. Thermomechanical analysis identified a mechanically relevant percolation regime near 8 phr, where thermal expansion was strongly suppressed. The percolated MWCNT network also improved fatigue resistance by suppressing crack propagation and extending the stabilization regime to larger strain amplitudes, potentially through crack pinning, deflection and network deformation. These results reveal distinct yet coupled electrical, thermal and mechanical percolation behaviours, establishing nanotube-network connectivity as a key design parameter for multifunctional HNBR nanocomposites.
Aramid fiber (AF) reinforced epoxy resin (EP) composite laminates are prone to fiber debonding and delamination due to weak interfacial bonding. In this study, the carbon nanotubes (CNTs) were evenly dispersed by microfluidization technology, and unidirectional (UD) AF/EP composite laminates with CNTs-modified epoxy matrices were fabricated via a wet filament winding process.The fiber volume fraction was approximately 60%. The effects of CNTs structure (functional groups, aspect ratios) and content (0.5-3.0 wt%) on interfacial and mechanical properties of UD laminates were systematically investigated. At identical CNTs content, high-aspect-ratio carboxyl-functionalized CNTs (H-CNT-C) exhibited superior reinforcing effects than low-aspect-ratio carboxyl-functionalized CNTs (L-CNT-C). Moreover, low-aspect-ratio amino-functionalized CNTs (L-CNT-N) outperformed H-CNT-C in terms of reinforcing efficiency. The UD AF/EP laminates with 1.5 wt% L-CNT-N achieved optimal mechanical performance: tensile strength, bending strength, impact resistance, and interlaminar shear strength (ILSS) increased by 44.76%, 9.24%, 8.54% and 23.07%, respectively, compared with the composite without CNTs. When L-CNT-N content reached 3.0 wt%, interfacial shear strength (IFSS) was increased by 26.71% and fiber-resin contact angle was decreased from 46.68° to 38.02°, while mechanical properties reduced. Micro-CT showed that excessive CNTs loading increased resin viscosity and laminate porosity. The XPS and DMA results indicated that amino-functionalized CNTs enhanced interfacial interaction and molecular constraint, likely through epoxy ring-opening reactions together with hydrogen bonding and mechanical interlocking. As a result, CNTs with high aspect ratio, amino functional group and appropriate amount were significantly beneficial to regulate interface between fiber and resin. This work provides a novel strategy for interfacial design in high-performance AF/EP composites.
To address the severe space electron radiation environment, PP-MA/MWCNTs composite films were fabricated for electron shielding. Interfacial adhesion was further promoted via APTES surface amino-functionalization, facilitating favorable interfacial interactions within the PP-MA/MWCNTs-NH2 system. Geant4 Monte Carlo simulations reveal that at an equivalent areal density, the secondary bremsstrahlung generated by the composite film is reduced by nearly a factor of three compared to traditional aluminum plates, significantly decreasing the absorbed dose for downstream electronics and human bodies. During the 110 keV electron beam tests, the films achieved nearly 100% total interception of primary electrons, and the measured shielding advantage margin (16.5%) showed excellent agreement with the simulated prediction (15.5%). Electrothermal characterizations identified 3.5 wt% as the optimal conductive percolation threshold. The unmodified MWCNTs group exhibited superior electrical conductivity and higher thermal resistance owing to its intact structural network, whereas the amino-functionalized group (MWCNTs-NH2) significantly decreased the maximum thermal degradation rate through robust interfacial chain-segment restriction. Following 110 keV full-penetration irradiation, analytical results confirmed that the material retained excellent chemical backbone and lattice stability. The enhanced interfacial interaction in the amino-functionalized system effectively restricted chain-segment mobility and improved structural stability under extreme irradiation conditions. Consequently, this study demonstrates that the tailored nanocomposite possesses promising electron shielding capability, secondary photon suppression capabilities, and remarkable structural-functional reliability under high-energy electron irradiation conditions.
