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A composite material with improved characteristics can be produced by combining metal‐organic frameworks (MOFs) with polymer fibers. In contrast to commonly used powdered MOFs, polymer fibers can offer flexible support for MOFs, and some of the fibers can even work in concert with MOFs. The molecular transport channels are significantly enlarged when polymer fibers are employed as the base material for composites rather than conventional polymer films and mixed matrix films. This makes it simpler for the molecules to bind to the active site, speeding up the reaction. First, a brief analysis of the binding of MOFs to fibers is provided, followed by a systematic summary of the MOF forming process, including the synthesis and modification of MOFs, which lays the foundation for the subsequent summary of the synthesis methods of MOFs–fiber composites. In this article, three strategies are presented for attaching MOFs to polymer fibers: cospinning MOFs with fibers, depositing MOFs on fiber surfaces, and in situ growing MOFs on fiber surfaces. Different binding techniques make MOFs–fiber composites promising for many applications. Finally, the improvement of MOFs–fiber composites and their possible application scope are discussed. [ABSTRACT FROM AUTHOR]

We proposed a thermo-mechanical coupled model to better understand the coupling effects of thermo-oxidative aging and braiding structure on the high-speed impact responses of 3D braided carbon fiber reinforced epoxy composite. The impact responses of the aged and unaged braided composites with different braiding structures were experimentally and numerically investigated. We found that both thermo-oxidative aging and braiding structure have a significant influence on the impact responses of braided composites, and they also affect each other. Stress, adiabatic temperature rise, thermal strain and thermal stress of composites will decrease after aging, while increase with the increase of braiding angle. Increasing the braiding angle of the braided composite can effectively reduce the effect of thermo-oxidative aging on the impact responses. When the braiding angle is 42, the mechanical properties and damage of the composites are almost unaffected by thermo-oxidative aging, but the thermal stress in the impact process decreases significantly after aging. • The coupling effects of braiding structure and thermo-oxidative aging on the high-speed impact responses were experimentally and numerically investigated. • Stress, adiabatic temperature rise, thermal strain and thermal stress of composites will decrease after aging, while increase with the increase of braiding angle. • Increasing the braiding angle of the braided composite can effectively reduce the effect of thermo-oxidative aging on the impact responses. [ABSTRACT FROM AUTHOR]

Textile technology offers a plethora of design and production alternatives for composite reinforcements. In this study, highly aligned continuous hemp tape was produced based on hemp sliver and used to prepare unidirectional composites with optimized mechanical properties. The fiber content, preform areal density, and fiber orientation were considered to investigate the mechanical properties of the composite. The areal density of the hemp tape felt was contingent on the hemp sliver drafting multiple. Both composite tensile and flexural strength reached the maximum of 166.85 MPa and 207.68 MPa at drafting multiple i=2 and 30% fiber content, which were comparable with those reported for hemp fiber composites. The hemp tape was favorable for more complex shapes for applications. The superior mechanical properties and discrimination between the composites enhanced with two typical orthogonal reinforcement diversified the application potential in the field of automotive, furniture and architectural panels. • Hemp tape with highly aligned fibers was produced by self-designed equipment. • Low tape areal density aids fiber alignment accompanied with delamination risk. • Hemp tape-based composite properties are not proportional to fiber orientation. [ABSTRACT FROM AUTHOR]

Building reinforcement projects are designed to meet the requirements of modern sustainable development. However, the weak bonding performance of continuous glass fiber textiles to mortar presents a challenge in the manufacturing of GTRM composites, hindering their development and application. In this study, the gradient composite design technique was used to modify the interface transition zone between continuous glass fiber textile and mortar by introducing epoxy resin. This successfully resolved the issue of poor bonding between the continuous glass fiber textile and mortar interface, and promoted effective stress transfer between the two materials. The GTRM composites with an interfacial gradient structure exhibit excellent mechanical properties, including a tensile strength of 8 MPa and an interfacial shear force exceeding 27 KN. In addition, digital image correlation (DIC) was utilized to investigate the growth and development of cracks in GTRM composites, and the failure mechanism of tensile and interfacial shear tests was analyzed. Finally, the externally bonded GTRM composites were subjected to a three-point bending test, which demonstrated a significant improvement in the flexural strength and crack resistance of concrete beams. [ABSTRACT FROM AUTHOR]

For decades, single fiber reinforced composites exhibited defects of low damage tolerance resulting from brittle failure mode, which limits their further application. Therefore, hybrid composites are emerging as a new research hotspot. In this work, three-dimensional five-direction hybrid braided composites composed of different configurations of carbon and aramid yarn was manufactured. The short beam shear experiments and full-size mesoscale numerical simulation based on real braided structure computed by computed tomography (CT) image were established to investigate the hybrid effect and progressive damage process of composite. Studies have shown that neat carbon composites display the characteristics of brittle fracture, and hybrid composites demonstrate a remarkably toughening effect. The KaCb (CaKb) sample displays a 102.0% (58.7%) greater failure displacement than neat carbon composite under transverse (longitudinal) loading. Through the increasing bending deformation, the damage mode transforms to a ductile failure. The stress localization in the loaded area is retarded, and the synergistic load-bearing capacity of axial and braiding yarn is improved. This work reveals the synergistic bearing mechanism and progressive damage process of multicomponent composites with complex textile structures, which provides a theoretical basis for designing more types of hybrid composite. [ABSTRACT FROM AUTHOR]

The limitation of plant fiber length can be overcome by using staple spinning to achieve continuity on short fibers. Ramie fiber staple yarn reinforced unsaturated polyester composites (RSYCs) were fabricated with ramie fiber and unsaturated polyester matrix. The unique fiber packing density of staple yarn must be tackled first to reflect the structure of RSYCs. The relationship between fiber packing density of staple yarn and fiber volume fraction of composite was evaluated to investigate the effect of fiber packing density on properties and predict the tensile strength of RSYCs using the rule of mixture. A scanning electron microscope illustrated fiber packing density of staple yarn. When the twist factor was 380 with the optimal yarn count of 80 tex, the fiber packing density was 19.9% higher than that at 260. Compared with the minimum tensile strength of RSYCs at 120 tex, the maximum of RSYCs at 380 was 399.2 MPa, improved by 238.6%. Measured by dynamic mechanical analysis, the viscoelastic rigidity and damping property of RSYCs was the best at 380, with the storage modulus of 31.9 GPa at 40 °C and the tan delta of 0.1226 at 80.59 °C. Compared with the neat resin and ramie fiber, the onset temperature of weight loss of RSYCs tested by thermogravimetric was reduced. The increasing fiber packing density significantly reduced the resin permeability of RSYCs, according to the contact angle and ultrasonic nondestructive testing results. There is no doubt that the obtained fiber packing density possessed great potential for promoting the development of RSYCs. [Display omitted] • Fiber packing density adjusted by yarn count and twist factor. • Fiber packing density influenced the tensile properties of ramie fiber staple yarn reinforced composites. • Fiber packing density overruled fiber volume fraction to improve the rule of mixture. [ABSTRACT FROM AUTHOR]