Novel shear thickening gel/high‐performance fiber reinforced flexible composites: Multi‐velocity impact and functional properties

This study proposes a process for the preparation of composite laminates using the shear thickening fluid (STF) impregnated aramid fabric and presents some fabric panel configuration strategies. Firstly, this study prepared two kinds of STF using 20 nm and 500 nm silica particles. Then, the STF‐impregnated Kevlar fabrics were laminated and hot‐pressed to form the fabric panels. After that, the ballistic performance of the fabric panels was evaluated by firing the 9 mm steel core projectile using a gas gun. The ballistic tests showed that the ballistic performance of the hybridized configuration panels using STF‐20 treated fabrics as the front panels and STF‐500 treated fabrics as the backing panels was superior, with a reduction of 36.1%–37.6% in the number of perforated layers (4.7–5 layers) compared to a single STF‐treated panel. This study provides a new idea and method for applying STF in protective equipment.Highlights Shear thickening fluid (STF) and aramid fabric are better combined by hot pressing lamination process; The ballistic properties of fabric panels are significantly improved by hybrid configuration; The ballistic performance enhancement mechanism of composite bulletproof plate was revealed.

Section: Introductionmentioning

confidence: 99%

Study on the enhancement mechanism of ballistic properties of shear thickening fluid impregnated aramid fabric composite plates

Zhang,

Chang,

et al. 2024

“…33,34 HF is not as tough or strong as high-performance synthetic fibers such as aramid fibers, and the length of HF is considerable shorter in rubber composites with poorer rubber reinforcement under the traditional high-shear rubber process. 35,36 Short fiber can be easily pulled out in the process of composite materials failure, but long fiber must be broken; thus, the reinforcing effect of long fiber is far better than that of short fiber. 37 Long-fiber-reinforced thermoplastic composites have been extensively studied for many year.…”

Section: Introductionmentioning

confidence: 99%

“…Fiber length has a significant impact on the performance of the reinforced rubber composites, the shorter the fiber length, the lower the reinforcement effect of the fiber 33,34 . HF is not as tough or strong as high‐performance synthetic fibers such as aramid fibers, and the length of HF is considerable shorter in rubber composites with poorer rubber reinforcement under the traditional high‐shear rubber process 35,36 . Short fiber can be easily pulled out in the process of composite materials failure, but long fiber must be broken; thus, the reinforcing effect of long fiber is far better than that of short fiber 37 .…”

Section: Introductionmentioning

confidence: 99%

Fatigue‐crack‐propagation behavior and mechanism of long hemp‐fiber‐enhanced styrene–butadiene rubber/carbon black compounds

Liang,

Zhang,

Luo

et al. 2023

Biomass renewable fiber has the advantages of low cost and environmental friendliness; however, its application as a reinforcement material is limited owing to its poor reinforcement effect. Thus, expanding its application is still a major challenge. This study investigates the effect of hemp fiber (HF) of different lengths on the mechanical properties and fatigue behavior of styrene‐butadiene rubber/carbon black (SBR/CB) compounds using high‐pressure low‐shear extrusion. The results showed that the length of the HF retained by the extrusion process was approximately 10 times that of the traditional internal mixing process (internal mixing and open mixing). Interface bonding between the long HF coated with butadiene‐vinyl pyridine latex (VPL) and the SBR/CB matrix was improved significantly. This inhibited the fatigue‐crack propagation and considerably improved the dynamic fatigue life of the notched specimens. The dynamic fatigue life of the notched specimens of the composite prepared by the extrusion process was approximately nine times longer than that of the traditional internal mixing process. The results showed that the long HF length retained after the extrusion process effectively enhanced the strength of the rubber composites and significantly improved the dynamic fatigue life of rubber products under alternating stress.Highlights The raw material, hemp fiber, is a renewable resource, low cost and environmentally friendly. Pioneering a new process for preparing rubber composite materials, replacing the traditional process for preparing composite materials. High‐pressure, low‐shear extrusion process retains the length of the hemp fibers and improves rubber composites properties. Compared to traditional processes，long fiber length is 10 times longer by the extrusion process and fatigue life is increased to 9 times. High‐pressure, low‐shear extrusion process enables mass production, opening up new ideas for rubber industrial production.

“…During the past decades, a variety of soft, hard, and soft composite bulletproof vests and bulletproof helmets based on high performance fibers and fabrics (including carbon fibers, Kevlar, aromatic heterocyclic fiber, ultrahigh molecular weight polyethylene fiber (UHMWPE), and so on) have been developed. [1][2][3] Kevlar fibers and fabrics are one of the most widely used materials because of their excellent comprehensive performance. Its specific strength, modulus, and toughness are 5-6 times, 2-3 times, and 2 times than those of steel, respectively, but its density is only 1/5 of steel.…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of shear thickening fluid/carbon nanotubes/Kevlar composite materials

Lu,

Li,

et al. 2023

Shear thickening fluid (STF), carbon nanotubes (CNTs) are both promising in body protection and anti‐impact for the drastic viscosity change of STF and the extremely high tensile strength and elongation of CNTs. The excellent performance of the above two combined with traditional Kevlar fabrics can significantly improve the mechanical properties and reduce the number of layers used for body protection. This work reports a new method to prepare STF/CNTs/Kevlar with excellent tensile properties and anti‐impact performance by spraying method with 1 wt% polyvinyl alcohol (PVA) solution as a binder for better integration between CNTs and Kevlar. Surface morphology changes in the preparation process indicate the combined structure of PVA binder, CNTs, and STF, presenting a uniform macroscopic and nonuniform microscopic surface of STF/CNTs/Kevlar composite. The tensile strength and anti‐impact properties including punch residual velocity and energy absorbed were studied and results for STF/CNTs/Kevlar composite are 669.8 ± 18.1 MPa, 1.602 ± 0.045 m/s, and 21.683 ± 1.182 J in 12 ms, increased by 46.4%, 23.0%, and 240.2%, respectively, compared with neat Kevlar, owing to the improved tight bonding and friction between fabrics yarns caused by PVA adhesive and tangled CNTs, accompanied with the enhanced viscosity of STF under forces.Highlights Composites were made by spraying PVA, CNTs, and STF onto Kevlar fabrics; The tensile strength of the composite was 46.4% higher than Kevlar; The energy absorbed in 12 ms in anti‐impact tests was improved by 240.2%; Tight bonding and friction between yarns are reasons to improve properties; The raised viscosity of STF under forces is useful for mechanical properties.