A New Class Of Polymer Nanocomposites

2013 ◽  
pp. 381-398
2019 ◽  
Vol 9 (4) ◽  
pp. 4315-4321 ◽  
Author(s):  
M. Danikas ◽  
D. Verginadis ◽  
R. Sarathi

A new class of insulating materials is the class of polymer nanocomposites. In the past twenty-five years, a lot of attention was paid to the various electrical, thermal and mechanical properties of polymer nanocomposite materials. In the present work, epoxy resin samples without and with nanoparticles (0 wt%, 1 wt%, 3 wt%, 5 wt%, and 10 wt%) are investigated regarding the surface discharges and the flashover voltages. Four different water droplet arrangements were used, with eight different water conductivities in order to see the effect of the nanoparticle.


2018 ◽  
Vol 280 ◽  
pp. 284-293 ◽  
Author(s):  
M.N. Ervina Efzan ◽  
N. Siti Syazwani

Polymer nanocomposites represent a new class of materials that offer an alternative to the conventional filled polymers. In this new class of materials, nanosized reinforcement are dispersed in polymer matrix offering tremendous improvement in performance properties of the polymer. The combination of nanoscale reinforcement and polymer matrix possess outstanding properties and functional performance which play an important role in many field of applications. This review addresses the types of nanoscale materials reinforced in polymer matrix such as nanocellulose, carbon nanotubes (CNTs), graphene, nanofibers and nanoclay followed by the discussion on the effect of these nanoscale reinforcement on mechanical properties of polymer nanocomposites. Besides, the potential use of polymer nanocomposite reinforced with those nanoscale reinforcements in various field of applications also discussed.


2015 ◽  
Vol 22 (5) ◽  
Author(s):  
Yamen Maalej ◽  
Luc Dormieux ◽  
Eric Lemarchand

AbstractAchieving remarkable mechanical properties for very low levels of reinforcement, nanocomposites are nowadays a new class of materials with high potential. Thanks to the stiffening aspect of the interface region between the matrix and the inclusions, nanocomposites often exhibit improved mechanical and physical properties compared to the conventional composites reinforced with micron-sized particles. This paper presents a strategy based on the introduction of an equivalent inclusion phase that allows managing the ellipsoidal morphology of inhomogeneous inclusion nanophase in the determination of estimates for the homogenized elastic moduli. Application to clay-polymer nanocomposites is presented in the framework of the dilute scheme. The latter gives theoretical estimates in good agreement with experimental results reported in the literature.


Author(s):  
Frances M. Ross ◽  
Peter C. Searson

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.


Author(s):  
G. C. Ruben ◽  
K. Iqbal ◽  
I. Grundke-Iqbal ◽  
H. Wisniewski ◽  
T. L. Ciardelli ◽  
...  

In neurons, the microtubule associated protein, tau, is found in the axons. Tau stabilizes the microtubules required for neurotransmitter transport to the axonal terminal. Since tau has been found in both Alzheimer neurofibrillary tangles (NFT) and in paired helical filaments (PHF), the study of tau's normal structure had to preceed TEM studies of NFT and PHF. The structure of tau was first studied by ultracentrifugation. This work suggested that it was a rod shaped molecule with an axial ratio of 20:1. More recently, paraciystals of phosphorylated and nonphosphoiylated tau have been reported. Phosphorylated tau was 90-95 nm in length and 3-6 nm in diameter where as nonphosphorylated tau was 69-75 nm in length. A shorter length of 30 nm was reported for undamaged tau indicating that it is an extremely flexible molecule. Tau was also studied in relation to microtubules, and its length was found to be 56.1±14.1 nm.


Author(s):  
T. F. Kelly ◽  
P. J. Lee ◽  
E. E. Hellstrom ◽  
D. C. Larbalestier

Recently there has been much excitement over a new class of high Tc (>30 K) ceramic superconductors of the form A1-xBxCuO4-x, where A is a rare earth and B is from Group II. Unfortunately these materials have only been able to support small transport current densities 1-10 A/cm2. It is very desirable to increase these values by 2 to 3 orders of magnitude for useful high field applications. The reason for these small transport currents is as yet unknown. Evidence has, however, been presented for superconducting clusters on a 50-100 nm scale and on a 1-3 μm scale. We therefore planned a detailed TEM and STEM microanalysis study in order to see whether any evidence for the clusters could be seen.A La1.8Sr0.2Cu04 pellet was cut into 1 mm thick slices from which 3 mm discs were cut. The discs were subsequently mechanically ground to 100 μm total thickness and dimpled to 20 μm thickness at the center.


Author(s):  
J. Fink

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.


2020 ◽  
Vol 7 (3) ◽  
pp. 786-794 ◽  
Author(s):  
Jingqi Han ◽  
Kin-Man Tang ◽  
Shun-Cheung Cheng ◽  
Chi-On Ng ◽  
Yuen-Kiu Chun ◽  
...  

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.


2020 ◽  
Vol 11 (24) ◽  
pp. 3940-3950 ◽  
Author(s):  
Patrick Verkoyen ◽  
Holger Frey

Amino-functional polyethers have emerged as a new class of “smart”, i.e. pH- and thermoresponsive materials. This review article summarizes the synthesis and applications of these materials, obtained from ring-opening of suitable epoxide monomers.


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