Search

Natural fiber composites (NFCs) have seen an increased innovation and research activities due to their strength, environmental impact, and low cost. NFCs are used in aerospace, construction, leisure, packing, sport, and automotive industries. One such NFC, ramie fiber-reinforced composite has gained more importance due to its high mechanical strength, stiffness, and easy availability to all other natural fibers. In this review, an insight of the research works focusing on ramie fiber, and its reinforced polymer composite has been summarized. Factors such as fiber content, surface treatment, manufacturing techniques, and coupling agents influencing the mechanical properties (tensile, flexural, and impact) have been summarized. It is evident that the surface modification of ramie fiber through chemical treatment and the addition of coupling agents directly impact the mechanical properties of the composite. Furthermore, the usage of ramie fiber composite is still inadequate due to its poor fire and moisture-resistant properties. [ABSTRACT FROM AUTHOR]

Hybrid composite's flame retardancy properties play a dynamic role in structural applications. When inorganic nanomaterials form organic/inorganic nanocomposites, they exhibit superior flame‐retardant effects. Therefore, the current work investigates the combined effects of halogen‐free fire‐retardant ammonium polyphosphate (APP) and graphene (GR) nanofillers on the mechanical, and fire‐resistant behavior of hybrid composite fabricated using a vacuum bag process. Mechanical study affirmed that the concurrent incorporation of APP and GR hybrid composite improved the hardness, flexural, and tensile properties by 7%, 26%, and 16%, respectively. Scanning electron microscopy (SEM) confirms that the dispersion of 0.75 wt% GRs improved the mechanical properties by preventing crack propagation and strong binding between fiber‐matrix in the hybrid composite. The vibrational analysis reveals an improved natural frequency (NF) value was obtained with 0.75 wt% GR; further addition of GR increased the damping due to an increase in nanoparticle agglomeration. The combined effect of APP and GR decreased the hybrid composite's water uptake and porosity by 52% and 80%, respectively. The flammability study (Vertical burning) affirmed that the composite's grade score was improved from V‐1 to V‐0. Therefore, the current study emphasizes that this optimized hybrid composite can be utilized in fire‐sensitive structural applications. Highlights: UL‐94 VB test reveals the flammability of the hybrid composite.Examine the combined effect of APP and GR in strength and flame‐retardant properties.GR and APP added sample shows better mechanical and flame resistance properties.The optimized wt% of GR and APP for better results is 0.75% and 9.25%.The prepared composite may suitable fire‐sensitive structural applications. [ABSTRACT FROM AUTHOR]

Hybrid polymer composites (synthetic and/or natural fiber) are highly prominent in the fields of automotive, aerospace, construction, and marine. This work aims at developing a novel epoxy/glass/ramie (EGR) hybrid composite incorporated with ammonium polyphosphate (APP) using a vacuum bag technique, thus by changing the weight percentage of APP. The hybrid composites were characterized for the fire‐retardant (vertical and horizontal burning test), mechanical (hardness, tensile, and flexural testing), wettability, porosity (ethanol infiltration), and vibrational properties. The flammability data show that the hybrid composites made of 10, 15, and 20 weight percentages of APP obtained V‐1, V‐0, and V‐0 grades in the UL‐94 vertical burning test. Furthermore, there is an enhancement in hardness properties, but it reduces the tensile and flexural strength. However, the integration of APP reduces the water absorption rate of the composite from 11% to 5%. This study found that APP‐reinforced EGR hybrid composite improves fire resistance, thereby reducing the water absorption rate, which hikes the usage of the material for structural application. [ABSTRACT FROM AUTHOR]

Natural fiber reinforced hybrid polymer composites have gained extensive applications in recent decades owing to their damping, low density, biodegradability, and low‐cost benefits. This research explores the impact of the surface treatment, and the number of ramie fiber layers on the vibrational and mechanical characteristics of a glass/ramie fiber reinforced hybrid polymer composite. The composite is made of outer layer (glass fiber) and inner layer (ramie fiber) at different concentrations (varying between 2, 3, and 4). The ramie was pre‐treated with sodium hydroxide (NaOH) at different weight percentages (1%, 2%, and 5%). The composites have been fabricated using the vacuum bag technique. The composites have been characterized for chemical, mechanical, morphological, and free vibrational analysis. Fourier transform infrared spectroscopy and scanning electron microscope have been used to study the chemical characteristics and morphological study of the composites respectively. The mechanical properties of the composite were evaluated through tensile and flexural testing. The hybrid composite reinforced with two layers of ramie fiber as the core with 2% pre‐treated shows the maximum tensile strength of 120 MPa and flexural modulus of 12,147 MPa. Overall, the hybridization and NaOH pre‐treatment to certain ratio helps in increase in the hybrid composite's mechanical strength compared to the natural fiber composite. [ABSTRACT FROM AUTHOR]