Biopolymer Composites With High Dielectric Performance: Interface Engineering
01 Jan 2017-pp 27-128
TL;DR: In this article, the preparation and dielectric behavior of various biopolymer composites is presented, including metal nanoparticles and carbon-based nanofillers such as carbon nanotubes, graphene, etc.
Abstract: In recent years, there is a growing interest in studying the dielectric behavior of biopolymer composites due to their potential application as a dielectric material in various electronic devices such as microchips, transformers, and circuit boards. Conducting electroactive polymer composites have also been investigated for various potential applications which include biological, biomedical, flexible electrodes, display devices, biosensors, and cells for tissue engineering. In this chapter, the preparation and dielectric behavior of various biopolymer composites is presented. These biopolymer composites generally consist of nanoscale metal nanoparticles and carbon-based nanofillers such as carbon nanotubes, graphene, graphene oxide (GO), etc., dispersed into the polymer matrix. The physical and chemical properties of these fillers and their interactions with polymers have a significant effect on the microstructure and the final properties of nanocomposites. The biopolymer composites with excellent dielectric properties show great promise as an energy storage dielectric layer in high-performance capacitor applications such as embedded capacitors. This chapter highlights some of the examples of such biopolymer composites; their processing and dielectric behavior will be discussed in detail.
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References
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TL;DR: A new aqueous-based preparation method for silk spheres with controllable sphere size and shape is reported, based on phase separation between silk fibroin and polyvinyl alcohol (PVA) at a weight ratio of 1/1 and 1/4.
378 citations
Journal Article•
TL;DR: In this paper, the authors compared the performance of FGS-PVDF composites and EG-pVDF nanocomposites and found that FGS remains well dispersed in the composites as evidenced by the lack of the characteristic graphite reflection in composites.
Abstract: PVDF nanocomposites based on functionalized graphene sheets, FGS prepared from graphite oxide, and exfoliated graphite, EG, were prepared by solution processing and compression molding. FGS remains well dispersed in the PVDF composites as evidenced by the lack of the characteristic graphite reflection in the composites. Although the α-phase of PVDF is seen in the EG-based composites, a mixture of α- and β-phases is present in the FGS analogs. SEM and TEM imaging show smooth fractured surfaces with oriented platelets of graphite stacks and obvious debonding from the matrix in the EG-PVDF composites. In contrast, the FGS-PVDF composites show a wrinkled topography of relatively thin graphene sheets bonded well to the matrix. Storage modulus of the composites was increased with FGS and EG concentration. A lower percolation threshold (2 wt %) was obtained for FGS-PVDF composites compared to EG-PVDF composites (above 5 wt %). Lastly, the FGS-PVDF composites show an unusual resistance/temperature behavior. The resistance decreases with temperature, indicating an NTC behavior, whereas EG-PVDF composites show a PTC behavior (e.g., the resistance increases with temperature). We attribute the NTC behavior of the FGS based composites to the higher aspect ratio of FGS which leads to contact resistance predominating over tunneling resistance.
376 citations
TL;DR: In this article, thermoplastic starch (TPS)/clay hybrids were prepared by melt intercalation and three organically modified montmorillonite (MMT) with different ammonium cations and one unmodified Na+ MMT (Cloisite Na+) were used.
Abstract: Biodegradable thermoplastic starch (TPS)/clay hybrids were prepared by melt intercalation. Three organically modified montmorillonite (MMT) with different ammonium cations and one unmodified Na+ MMT (Cloisite Na+) were used. Cloisite Na+ showed the best dispersion in the TPS matrix. It was observed that the TPS/Cloisite Na+ hybrid showed an intercalation of TPS in the silicate layer due to the matching of the surface polarity and interactions of the Cloisite Na+ and the TPS, which gives higher tensile strength and better barrier properties to water vapor as compared to the other TPS/organoclay hybrids as well as the pristine TPS. It was found that the dynamic mechanical properties of the TPS/clay hybrids were also affected by the polar interactions.
369 citations
TL;DR: In this paper, the authors proposed a method to increase the dielectric constant of polymer-based capacitors by using conductive fillers (e.g., metal particles).
Abstract: The mechanical flexibility and tunable properties of polymer-based materials make them attractive ones for a lot of applications. Exploring polymer-based dielectrics, such as ones used for capacitors and charge-storage applications, with high dielectric constant (high-j) has recently aroused considerable interest. Especially, motivated by higher function and further miniaturization of electronics, embedding (or integrating) polymer-based capacitors into the inner layers of organic printed circuit boards (PCBs) allows packaging substrate miniaturization and better electrical performance, which is a key for organic-based system-on-package technologies. But as capacitors, the relative dielectric constant j of general polymers (being good insulators) is too low (e.g., j< 5).Thus, a key issue is to substantially raise the dielectric constant of the polymers while retaining low dielectric loss. A few strategies have been developed to raise the j of polymer-based materials. A common approach is to add high-j ceramic fillers (e.g., BaTiO3) into a polymer. High loading of the ceramic fillers in the polymer composite, usually over 50 vol %, can increase j by about ten times relative to the polymer matrix, but dramatically decreases the adhesion of the composite (and increases its porosity) thus deteriorating the adaptability between the composite and the organic circuit boards. Another strategy is to fabricate percolative composite capacitors by using conductive fillers (e.g., metal particles). As the volume fraction f of the fillers increases to the vicinity of the percolation threshold fc, j of the composites can be dramatically enhanced as described by the well-known power law
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TL;DR: In this article, thermal, mechanical and barrier properties of corn, cassava and yam starch films were determined and the behavior of these three starches films under a controlled storage (64% RH and 20°C) was compared.
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