Carbon/Kevlar/PEEK Thermoplastic Composites

Thermoplastic composites were developed from carbon/hybrid (1: 1)/Kevlar fabrics using a high-performance polyether ether ketone (PEEK) matrix. The mechanical properties and microstructure of the composites show that the type of fiber has a strong influence on the fiber-matrix bonding and fracture behavior of the composites. The fracture energy of the composites was of the order of -30 kJ m-2 for carbon/PEEK and hybrid/PEEK composites.

Structural, transport and optical properties of (La0.6Pr0.4)0.65Ca0.35MnO3 nanocrystals: a wide band-gap magnetic semiconductor

(La0.6Pr0.4)0.65Ca0.35MnO3 system has been synthesized via a sol-gel route at different sintering temperatures. Structural, transport and optical measurements have been carried out to investigate (La0.6Pr0.4)0.65Ca0.35MnO3 nanoparticles. Raman spectra show that Jahn-Teller distortion has been decreased due to the presence of Ca and Pr in A-site. Magnetic measurements provide a Curie temperature around 200 K and saturation magnetization (MS) of about 3.43μB/Mn at 5 K. X-ray photoemission spectroscopy study suggests that Mn exists in a dual oxidation state (Mn(3+) and Mn(4+)). Resistivity measurements suggest that charge-ordered states of Mn(3+) and Mn(4+), which might be influenced by the presence of Pr, have enhanced insulating behavior in (La0.6Pr0.4)0.65Ca0.35MnO3. Band gap estimated from UV-Vis spectroscopy measurements comes in the range of wide band gap semiconductors (∼3.5 eV); this makes (La0.6Pr0.4)0.65Ca0.35MnO3 a potential candidate for device application.

Enhanced performance of PEM fuel cell using MWCNT reinforced carbon paper

Porous conducting carbon paper has been identified as one of the most suitable materials to be used as a fuel cell electrode backing.

Multifunctional, robust, light-weight, free-standing MWCNT/phenolic composite paper as anodes for lithium ion batteries and EMI shielding material

Multifunctional, MWCNT/polymer composite of 140 μm thickness is demonstrated as an anode material for Li-ion battery and efficient EMI shielding material.

Improved microwave absorption in lightweight resin-based carbon foam by decorating with magnetic and dielectric nanoparticles

Carbon foam (CFoam) decorated with Fe₃O₄–ZnO nanoparticles significantly improved electromagnetic radiation shielding effectiveness which is mainly dominated by absorption component.

Electrospun composite nanofiber-based transmucosal patch for anti-diabetic drug delivery

The intention of the present investigation was to develop an oral formulation for an anti-diabetic drug that not only could deliver it in the active form but also provide a sustained and controlled release profile. A biodegradable poly(vinyl alcohol) (PVA) and sodium alginate (NaAlg) electrospun composite nanofiber based transmucosal patch was developed and the anti-diabetic drug insulin was loaded in it by active loading. The drug entrapment in the composite nanofibers during the processing was confirmed by scanning electron microscopy, atomic force microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The in vivo studies were carried on male Wistar rats by the sublingual route. The mucoadhesive strength results confirmed that the drug loaded PVA-NaAlg nanofiber patch had the highest strength among the PVA, PVA-NaAlg and drug loaded PVA-NaAlg samples, due to its higher water holding capacity. The in vitro activity provided a sustained and controlled release pattern of the drug from the nanofiber patch. In vivo activity validated the fact that insulin was delivered in its active state and showed appreciable results when compared to the commercial formulation. The insulin release follows first order kinetics followed by an initial burst release necessary to produce the desired therapeutic activity. Furthermore an encapsulation efficacy of 99% of the experimental formulation provides sufficient indication that the composite nanofibers serve as an ideal carrier for the delivery of insulin via the sublingual route. Thus the present investigation gives impetus to work in the direction of delivering anti-diabetic drugs (proteins and peptides) via the oral route using electrospun composite nanofiber transmucosal patches.

Electrospun polyacrylonitrile nanofibrous membranes for chitosanase immobilization and its application in selective production of chitooligosaccharides

Polyacrylonitrile nanofibrous membranes (PANNFM) were prepared by electrospinning from 10 wt.% of PAN solution and its surface was modified by amidination reaction. A new chitosan degrading enzyme from Aspergillus sp. was covalently immobilized on PANNFM. Immobilization efficiency of 80% was achieved by activating PANNFM surface for 30 min followed by 2 h treatment with enzyme solution. The optimum temperature and pH for immobilized enzyme were 50°C and 5.8, respectively. The immobilized chitosanase retained >70% activity after ten repeated batch reaction and could be stored up to 60 days at 4°C with minor loss in activity. Chitosan hydrolysis using different substrates were studied using immobilized chitosanase in batch conditions. Continuous selective production of chitooligosaccharides (dimer to hexamer) by changing the temperature was achieved by PANNFM-chitosanase.

Influence of Surface Modified MWCNTs on the Mechanical, Electrical and Thermal Properties of Polyimide Nanocomposites

Polyamic acid, the precursor of polyimide, was used for the preparation of polyimide/multiwalled carbon nanotubes (MWCNTs) nanocomposite films by solvent casting technique. In order to enhance the chemical compatibility between polyimide matrix and MWCNTs, the latter was surface modified by incorporating acidic and amide groups by chemical treatment with nitric acid and octadecylamine (C₁₈H₃₉N), respectively. While the amide-MWCNT/polyimide composite shows higher mechanical properties at low loadings (<3 wt%), the acid-MWCNT/polyimide composites perform better at higher loadings (5 wt%). The tensile strength (TS) and the Young’s modulus (YM) values of the acid-MWCNT/polyimide composites at 5 wt% MWCNT loadings was 151 and 3360 MPa, respectively, an improvement of 54% in TS and 35% in YM over the neat polyimide film (TS = 98 MPa; YM = 2492 MPa). These MWCNT-reinforced composites show remarkable improvement in terms of thermal stability as compared to that for pure polyimide film. The electrical conductivity of 5 wt% acid modified MWCNTs/polyimide nanocomposites improved to 0.94 S cm⁻¹(6.67 × 10⁻¹⁸ S cm⁻¹for pure polyimide) the maximum achieved so far for MWCNT-polyimide composites.

Ultrasonic evaluation of pleural opacities

Fifty patients of pleural effusion were subjected to radiological and ultrasonic examinations. The results of both examinations were compared and presented here. The study was undertaken to assess the comparative efficacy of ultrasonography in diagnosing pleural effusion.