Fiber-Reinforced Nanocomposites: Fundamentals and Applications
Abstract Microwave absorbing polymer composites are important for strategic applications in sever... more Abstract Microwave absorbing polymer composites are important for strategic applications in several defense systems for detection and/or deception purposes as well as for other industrial applications, where the enclosed electronic gadgets or human beings need shielding from electromagnetic radiations from the environment. The extent of absorption or reflection of the microwave by these composites, however, can be controlled by proper selection of type of constituting base polymers and reinforcement types, nature of different additives, crosslinking agents used in the polymer formulation, and also on the nature of fabrication of suitable structures, that is, by combination or layering of different constitutive components of the functionally gradient composites. Carbon, besides being an excellent dielectric and lightweight material, exists in various forms like carbon nanotubes, nanospheres, graphene, carbon black, nanofibers, hollow carbon nanostructures, etc. and many of these, especially the carbon nanofibers (CNFs), which are conventionally used as reinforcing fillers for development of polymer composites, are also found to be excellent microwave absorbers. In this chapter, the various formulations, fabrication, characterization of CNF-reinforced polymer nanocomposites for microwave absorption are given and the same are discussed in detail. Besides, the factors affecting the microwave absorption properties, effect of bandwidth on the extent of reflection loss and plausible mechanism of microwave absorption have also been described. Essentially, this recent investigations reported on the microwave absorption properties of nonmetallic advanced fiber-reinforced polymer composites establish the achievement of very effective microwave absorption in a broad frequency range, resulting in lightweight materials for thinnest possible structures.
We show for the first time the greatly enhanced magnetic and magnetorheological (MR) properties o... more We show for the first time the greatly enhanced magnetic and magnetorheological (MR) properties of CoFe2O4–Silicone elastomer (cross-linked polydimethylsiloxane) composites containing electrospun CoFe2O4 nanofibers. The effects of CoFe2O4 particle shape (spherical to fibrous), concentration and degree of alignment in the elastomeric matrix are explored. Low nanofiber loadings (5-10 wt. %) give the MR properties comparable to those obtained by much higher microparticle additions (60-80 wt. %) for the same polymer matrix. Compared to spherical nanoparticles, the nanofiber composites have 100%-400% improvement in the MR properties that are vital in tunable rheology applications such as vibration damping, variable stiffness devices, actuators, etc. Nanofibers effectively formed interconnected network within the polymer matrix but nanoparticles exhibited large gaps between two disconnected short particles chains at lower filler loading. Spherical particles with 69.46 emu/g saturation mag...
Smart elastomeric hydrogels based on polyacrylamide containing ferrimagnetic nanoparticles of BaF... more Smart elastomeric hydrogels based on polyacrylamide containing ferrimagnetic nanoparticles of BaFe12O19 alone or a combination of BaFe12O19 and graphene oxide were synthesized. An improvised sample preparation technique was evolved to design actuators, where the hydrogel samples in rolls form were inserted into cut pieces of hard plastic sleeve in order to fabricate a lab-level actuator. The magneto-responsive actuation behaviour was measured by applying an external magnetic field with the help of a hand-held square type of NdFeB magnet. While the sample containing only 20 wt% BaFe12O19 exhibited only 15 mm deflection at threshold magnetic field of 28 mT, the deflection was significantly enhanced up to 23 mm for the sample containing 1 wt% GO and 20 wt% BaFe12O19 at a threshold magnetic field of 36.7 mT. Up to 20 wt% BaFe12O19, the hydrogels showed a heterogeneous dispersion of large-sized BaFe12O19 clusters and addition of a small percentage, e.g. 1% of GO resulted in significant i...
Objectives: Developing appropriate extraction conditions and the analytical method for quantitati... more Objectives: Developing appropriate extraction conditions and the analytical method for quantitative estimation of additives. Optimization of extraction conditions specially solvent system and extraction time. Comparison of extraction efficiency between Microwave and Soxhlet method.
Cobalt ferrite nanofiber filled polydimethylsiloxane nanocomposites show 100–400% improvement in ... more Cobalt ferrite nanofiber filled polydimethylsiloxane nanocomposites show 100–400% improvement in magnetorheological properties compared to that with nanoparticles.
The poly(ether ether ketone) micro/nanocomposite reinforced with N-(2-aminoethyl)-3-aminopropyl t... more The poly(ether ether ketone) micro/nanocomposite reinforced with N-(2-aminoethyl)-3-aminopropyl triethoxy silane treated micro- and nano-sized nickel and zirconia (0.5, 1, and 3 wt%) were prepared by melt mixing in a co-rotating twin screw extruder followed by test specimen fabrication in microinjection molding. The resulting nanocomposites with 3 wt% Ni and ZrO2 nanoparticles exhibit the maximum improvement in tensile and flexural strength as well as the modulus with respect to neat poly(ether ether ketone). The lowest specific wear rate of 17.6 × 10−4 mm3/N/m has been achieved with 3 wt% nano-Ni-filled composite in comparison to neat poly(ether ether ketone)’s value 191.5 × 10−4 mm3/N/m. The thermal stability of micro- and nano-particle reinforced poly(ether ether ketone) composites measured by thermogravimetric analysis found to be higher than the unfilled poly(ether ether ketone).
Fiber-Reinforced Nanocomposites: Fundamentals and Applications
Abstract Microwave absorbing polymer composites are important for strategic applications in sever... more Abstract Microwave absorbing polymer composites are important for strategic applications in several defense systems for detection and/or deception purposes as well as for other industrial applications, where the enclosed electronic gadgets or human beings need shielding from electromagnetic radiations from the environment. The extent of absorption or reflection of the microwave by these composites, however, can be controlled by proper selection of type of constituting base polymers and reinforcement types, nature of different additives, crosslinking agents used in the polymer formulation, and also on the nature of fabrication of suitable structures, that is, by combination or layering of different constitutive components of the functionally gradient composites. Carbon, besides being an excellent dielectric and lightweight material, exists in various forms like carbon nanotubes, nanospheres, graphene, carbon black, nanofibers, hollow carbon nanostructures, etc. and many of these, especially the carbon nanofibers (CNFs), which are conventionally used as reinforcing fillers for development of polymer composites, are also found to be excellent microwave absorbers. In this chapter, the various formulations, fabrication, characterization of CNF-reinforced polymer nanocomposites for microwave absorption are given and the same are discussed in detail. Besides, the factors affecting the microwave absorption properties, effect of bandwidth on the extent of reflection loss and plausible mechanism of microwave absorption have also been described. Essentially, this recent investigations reported on the microwave absorption properties of nonmetallic advanced fiber-reinforced polymer composites establish the achievement of very effective microwave absorption in a broad frequency range, resulting in lightweight materials for thinnest possible structures.
We show for the first time the greatly enhanced magnetic and magnetorheological (MR) properties o... more We show for the first time the greatly enhanced magnetic and magnetorheological (MR) properties of CoFe2O4–Silicone elastomer (cross-linked polydimethylsiloxane) composites containing electrospun CoFe2O4 nanofibers. The effects of CoFe2O4 particle shape (spherical to fibrous), concentration and degree of alignment in the elastomeric matrix are explored. Low nanofiber loadings (5-10 wt. %) give the MR properties comparable to those obtained by much higher microparticle additions (60-80 wt. %) for the same polymer matrix. Compared to spherical nanoparticles, the nanofiber composites have 100%-400% improvement in the MR properties that are vital in tunable rheology applications such as vibration damping, variable stiffness devices, actuators, etc. Nanofibers effectively formed interconnected network within the polymer matrix but nanoparticles exhibited large gaps between two disconnected short particles chains at lower filler loading. Spherical particles with 69.46 emu/g saturation mag...
Smart elastomeric hydrogels based on polyacrylamide containing ferrimagnetic nanoparticles of BaF... more Smart elastomeric hydrogels based on polyacrylamide containing ferrimagnetic nanoparticles of BaFe12O19 alone or a combination of BaFe12O19 and graphene oxide were synthesized. An improvised sample preparation technique was evolved to design actuators, where the hydrogel samples in rolls form were inserted into cut pieces of hard plastic sleeve in order to fabricate a lab-level actuator. The magneto-responsive actuation behaviour was measured by applying an external magnetic field with the help of a hand-held square type of NdFeB magnet. While the sample containing only 20 wt% BaFe12O19 exhibited only 15 mm deflection at threshold magnetic field of 28 mT, the deflection was significantly enhanced up to 23 mm for the sample containing 1 wt% GO and 20 wt% BaFe12O19 at a threshold magnetic field of 36.7 mT. Up to 20 wt% BaFe12O19, the hydrogels showed a heterogeneous dispersion of large-sized BaFe12O19 clusters and addition of a small percentage, e.g. 1% of GO resulted in significant i...
Objectives: Developing appropriate extraction conditions and the analytical method for quantitati... more Objectives: Developing appropriate extraction conditions and the analytical method for quantitative estimation of additives. Optimization of extraction conditions specially solvent system and extraction time. Comparison of extraction efficiency between Microwave and Soxhlet method.
Cobalt ferrite nanofiber filled polydimethylsiloxane nanocomposites show 100–400% improvement in ... more Cobalt ferrite nanofiber filled polydimethylsiloxane nanocomposites show 100–400% improvement in magnetorheological properties compared to that with nanoparticles.
The poly(ether ether ketone) micro/nanocomposite reinforced with N-(2-aminoethyl)-3-aminopropyl t... more The poly(ether ether ketone) micro/nanocomposite reinforced with N-(2-aminoethyl)-3-aminopropyl triethoxy silane treated micro- and nano-sized nickel and zirconia (0.5, 1, and 3 wt%) were prepared by melt mixing in a co-rotating twin screw extruder followed by test specimen fabrication in microinjection molding. The resulting nanocomposites with 3 wt% Ni and ZrO2 nanoparticles exhibit the maximum improvement in tensile and flexural strength as well as the modulus with respect to neat poly(ether ether ketone). The lowest specific wear rate of 17.6 × 10−4 mm3/N/m has been achieved with 3 wt% nano-Ni-filled composite in comparison to neat poly(ether ether ketone)’s value 191.5 × 10−4 mm3/N/m. The thermal stability of micro- and nano-particle reinforced poly(ether ether ketone) composites measured by thermogravimetric analysis found to be higher than the unfilled poly(ether ether ketone).
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