Mechanical behavior of glass fiber‐reinforced Nylon‐6 syntactic foams and its Young's modulus numerical study

Abstract

Glass fiber‐reinforced Nylon‐6 syntactic foams (GRSF) were fabricated by melt mixing, adding silane‐modified hollow glass microspheres (HGMf) at 5, 10, 15, and 20 wt% and an impact modifier at 15 wt. Tensile test results showed that the foam's strength increased with the addition of HGMs but started to decrease when the volume fraction of the spheres was higher than 18 vol% (10 wt%). To elucidate the reinforcement mechanism, a numerical simulation of GRSF was carried out. It revealed that HGMs progressively become the reinforcement phase of GRSFs, as their volume fraction increased due to the load transfer occurring more readily in the HGMs than the fiber, which is expected to be the reinforcement. Hence, for a desired weight‐strength ratio, thicker walls are necessary to delay the elastic relaxation of the microspheres and the impairing of the composite as a whole in the context of strength. HGMs with relative wall thickness τ = 0.04 produce an impairing on Young's modulus, if the volume fraction of microspheres is exceeded than 18 vol% because the microspheres are not able to endure increased loads. In addition, a significant reduction of the density was observed by up to 12% in the GRSFs with 30 wt% of both fibers and HGMs. The insight gained of GRSFs role and the numerical simulation achieved through this work, is a significant step toward developing applications of these lightweight materials, since they show good combination of strength, toughness, density, and thermal insulation performance, which can be useful in the automotive, aeronautical and sports industries.

Modified hollow glass microsphere isocyanate-based polyimide foam composite with improved mechanical and thermal insulation properties

“…Finally, the excessive M-HGM agglomerates in the foams matrix and further destroys the structure of some cells, resulting in the decrease of mechanical properties. 29,30 Therefore, the compression strength and modulus of the prepared foams increase first then decrease.

Figure 6.Stress-strain curves of PIF with different M-HGM contents (a). Compressive strength (σ10%) and compressive modulus (E) for PIF (b).

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“…Finally, the excessive M-HGM agglomerates in the foams matrix and further destroys the structure of some cells, resulting in the decrease of mechanical properties. 29,30 Therefore, the compression strength and modulus of the prepared foams increase first then decrease.…”

Preparation Methods, Performance Improvement Strategies, and Typical Applications of Polyamide Foams

“…In another study, Yańẽz-Maci ́as et al fabricated glass fiber-reinforced Nylon-6 syntactic foams (GRSF) and subsequently added silane-modified hollow glass microspheres (HGMF) to regulate the foams' properties. 50 Young's modulus of GRSF increased as the function of HGMF content up to 10 wt % due to the high compatibility between the matrix and particles. Tensile tests showed that the foam's strength increased with the addition of HGMFs but started to decrease when the volume fraction of the spheres was higher than 18 vol % (10 wt %).…”

Numerical Study Using Microstructure Based Finite Element Modeling of the Onset of Convective Heat Transfer in Closed-Cell Polymeric Foam

“…The effective thermal conductivity is considered as additive contributions of the conductive ( ) and convective ( ) paths . More details on the numerical methodology for averaging quantities over the surface of the REV (2 D domain), used to predict material parameters (thermal conductivity) from constitutive equations (Fourier’s law) can be found in [ 10 ], which was also used to predict material parameters over volume microstructural analysis [ 26 , 27 ] using COMSOL Multiphysics.…”