Development of functionally graded vapor-grown carbon-fiber/polymer materials

Abstract

We successfully produced vapor-grown carbon-fiber (VGCF)-incorporated polymer-based functionally graded materials (FGMs) using a centrifugal method. Gradual VGCF incorporation within an epoxy resin effectively produced depth gradients in the fiber distribution, microstructure, mechanical, and electrical conductivities and microwave absorbing properties. This VGCF-grading capability indicated that it is possible to tailor desired gradient filler content distributions by careful selection of the processing parameters to control variations in the property and microstructure precisely. The results confirmed that the volume content of VGCF in the epoxy substrate increased as a function of the normalized thickness along the centrifugal force direction, which caused a gradient. A uniform VGCF gradient in the composite can also be observed using field-emission scanning electron microscopy. In the case of the electrical properties, for example, the volume resistance exhibited a depth-graded distribution in the matrix as the electrical conductivity of the FGM nicely followed the grading direction; this is considered to be ideal for applications demanding an electrically conductive surface and an insulating core for FGMs. The results of microwave absorption behavior of FGMs indicate that the grading structure can lead to a graded absorption ability, which could be a better design for microwave absorption materials. The concept of FGMs bridges conventional materials and nanocomposites and will be effective for wider material applications. POLYM. COMPOS., 34:1774COMPOS., 34: -1781COMPOS., 34: , 2013

Soft Functionally Gradient Materials and Structures – Natural and Manmade: A Review

“…While soft FGMs present enormous opportunities, considerable challenges associated with materials, design, and fabrication methodologies remain, as illustrated in Figure 9. Soft FGMs that have been discussed so far are mostly made of polymer blends, [149][150][151][152][153] or polymer composites with metallic, [194,200,201] carbonaceous, [116,123,188,199] or ceramic fillers [15,210,301] to attain specific functionalities. A significant challenge in such multimaterial systems is the incompatibility of constituent materials, especially polymers, in processing and use.…”

Effect of Kaolin powder on the static and dynamic behavior of heterogeneous laminate constituted of functionally graded material layers

“…2,3 They have many applications in automotive and aerospace engineering. 4 The manufacturing process of FGMs can be divided into building a successive inhomogeneous structure called “gradation” and converting this structure into bulk material called “consolidation”. 5…”

“…2,3 They have many applications in automotive and aerospace engineering. 4 The manufacturing process of FGMs can be divided into building a successive inhomogeneous structure called "gradation" and converting this structure into bulk material called "consolidation". 5 Researchers have processed polymeric FGMs using many methods, such as hot isostatic pressing, 6,7 gravity molding, 8 compression molding, 9,10 centrifugation, 8,[11][12][13][14] and selective laser sintering.…”

Feasibility study: Resin-based functionally graded material incorporated with carbonized waste rice husk

“…Carbon materials such as carbon nanotubes, vapor grown carbon fibre, and their derivatives/hybrids, are widely utilized as the filler materials in composite materials for reinforcement/functionality, including FGM [3][4][5][6]. Alternatively, carbon materials derived from agricultural waste materials such as rice husk (RH) or sawdust, offer a unique opportunity, due to the low cost and abundancy [7][8][9][10].…”