Diarylethenes for Memories and Switches

PEEK Biomaterials in Trauma, Orthopedic, and Spinal Implants

Lignocellulosic biomass: a sustainable platform for the production of bio-based chemicals and polymers

In this article, several applications of nanomaterials in food packaging and food safety are reviewed, including: polymer/clay nanocomposites as high barrier packaging materials, silver nanoparticles as potent antimicrobial agents, and nanosensors and nanomaterial-based assays for the detection of food-relevant analytes (gasses, small organic molecules and food-borne pathogens). In addition to covering the technical aspects of these topics, the current commercial status and understanding of health implications of these technologies are also discussed. These applications were chosen because they do not involve direct addition of nanoparticles to consumed foods, and thus are more likely to be marketed to the public in the short term.

Applications of nanotechnology in food packaging and food safety: Barrier materials, antimicrobials and sensors

Bio-nanocomposites for food packaging applications

Synthesis of novel siloxane block copolymers for use in photophysical studies

Ultrasonic and dielectric studies of segmented ester polyurethanes

A study on the effect of alkalisaton using 3% NaOH solution was carried out on Flax, Kenaf, Abaca and Sisal to observe the impact that the common pre-treatment process has on fibre mechanical properties. The result of the investigation indicated that over-treatment of natural fibres using NaOH could have a negative effect on the base fibre properties. It is concluded that a treatment time of less than 10 minutes is sufficient to remove hemicelluloses and to give the optimum effect.

The effect of alkalisation on the mechanical properties of natural fibres

The effects of moisture absorption on the dielectric properties of a rubber-modified, mineral-filled, epoxy resin based on the diglycidyl ether of bisphenol A cured with dicyandiamide are reported. Samples of the resin were aged by immersing in deionized water, or 5% w/w NaCl solution, at elevated temperatures. Dielectric measurements were carried out over the frequency range 10 (1) to 6 X 10(5) Hz. A featureless dielectric spectrum was observed with both real and imaginary dielectric permittivity increasing with the amount of absorbed water. The change in the dielectric properties with absorption of water was independent of presence of salt, temperature of exposure, and aging history, although a hysteresis of the hydration- dehydration process was observed at low frequencies. Two types of absorbed water were observed-water molecularly dispersed within the epoxy matrix and clustered water in spherical microcavities. The time dependence of the real dielectric permittivity measured at 10 kHz was found to closely resemble that of the water absorption, which allowed the activation energy of diffusion to be calculated from both dielectric and gravimetric data.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/app.10368

Hygrothermal aging of rubber-modified and mineral-filled dicyandiamide-cured DGEBA epoxy resin. III. Dielectric spectroscopy investigation

N-formylmorpholine (NFM)+ water mixtures are used to extract aromatics from petroleum feed-stocks. In this paper possible conformational and structural causes of this specific solvation are investigated using ultrasonic attenuation and velocity measurement complemented by 13C n.m.r., density and viscosity observations. The conformational studies suggest that gross rearrangements of the morpholine ring are relatively slow (below 60 MHz) but that inversion at the nitrogen atom is faster, with lower activation energy, than in other morpholine analogues. The effect is magnified by the presence of water, and it is suggested that this greater ‘planarity’ of aqueous NFM permits the stronger interaction with aromatic rings.Structural information is inferred mainly from excess volumes and adiabatic compressibilities of mixing. The observations suggest that when NFM is added to water it first introduces hydrogen bonding and ordering of water molecules not bound into an extended ice I tetrahedral structure; then at higher concentrations it disrupts this structure to a less open, but no less compressible, hydrogen-bonded array of ‘quasi-planar’ NFM capable of absorbing aromatic rings.

Richard A. Pethrick

Papers

Synthesis of novel siloxane block copolymers for use in photophysical studies

Ultrasonic and dielectric studies of segmented ester polyurethanes

The effect of alkalisation on the mechanical properties of natural fibres

Hygrothermal aging of rubber-modified and mineral-filled dicyandiamide-cured DGEBA epoxy resin. III. Dielectric spectroscopy investigation

Ultrasonic studies of N-formylmorpholine + water mixtures