Thermoplastics Reinforced with Self-Welded Short Carbon Fibers: Nanoparticle-Promoted Structural Evolution

Abstract

The large volume of currently available fiber-reinforced polymer composites critically limits the intrinsic versatility of fibers such as high mechanical strength, heat resistance, and excellent thermal/electrical conductivity. We proposed a facile and widely applicable strategy to promote self-organization of randomly dispersed short carbon fibers (CFs) into a three-dimensionally continuous scaffold. The morphological evolution and structural reinforcement of the self-welded CF-polyamide 6 (PA6) scaffold in polystyrene (PS) matrix were investigated, with carbon black (CB) or titanium dioxide (TiO2) nanoparticles (NPs) selectively localized in the PA6 domains. Surprisingly, all of the PA6 droplets once dispersed in the PS matrix can migrate and evenly encapsulate onto the CF surface when 5.8 wt % CB is incorporated, whereas in the TiO2-filled system, the PA6 droplets preferentially segregate at the junction point of CFs to fasten the self-welded CF structure. In addition, a remarkable increase in the interfacial adhesive work between PA6 and CF was observed only when TiO2 is added, and a loading of even less than 0.8 wt % can effectively abruptly strengthen the self-welded CF scaffold. We clarified that the structural evolution is promoted by the nature of self-agglomeration of NPs. CB is highly capable of self-networking in the PA6 domain, resulting in high encapsulation of PA6, although the capillary force for preferential segregation of PA6 at the junction point of CFs is reduced. By contrast, the TiO2 particles tend to form compact aggregates. Such an agglomeration pattern, together with enhanced interfacial affinity, must contribute to a strong capillary force for the preferential segregation of PA6.

Recent Progress on the Confinement, Assembly, and Relaxation of Inorganic Functional Fillers in Polymer Matrix during Processing

“…As expected, the degree of wrapping has important influence on the assembly behavior of MWNTs, with higher wrapping density leading to weaker assembly behavior and lower conductivity. The assembly behavior between different polymers could be used as a tool to construct self‐welded filler network . The network formed with filler possessing micrometer size could be used to enhance a range of functionalities as well as mechanical properties of the composites.…”

Chemical Cross‐linked Electrode–Electrolyte Interface Boosting the Structural Integrity of High Nickel Cathode Materials

“…[12][13][14][15][16][17][18][19][20][21][22] Surface coating is a traditional modification strategy to enhance the interface stability of NCM, whose key mechanism is that the coating layer serves as a shield barrier between NCM and electrolyte, enhancing the interfacial chemical properties, and mitigating the occurrence of side reactions. [23][24][25][26] However, no matter how the high-nickel cathode materials are modified, the adverse side reactions always ultimately occur at the electrode side. Therefore, it is crucial to construct a stable and robust electrode-electrolyte interface (CEI).…”