Search

Bio-based thermoset polymers were produced from epoxidised waste vegetable oils (WVOs) cured with anhydrides at different molar ratios. Properties were compared to analogues produced with neat oil and diglycidyl ether of bisphenol A as a feedstock. The thermal stability proved to be affected by the molar ratio, and the use of feedstock from waste oil resulted in no effect on this property. A dynamic mechanical analysis has shown that higher concentrations of anhydride enhance the storage modulus, glass transition temperature (up to 42·5°C) and cross-link density. The frying process proved to play a minor role in tuning the dynamic mechanical properties. However, the contribution of the anhydride was demonstrated to be significant enough to mitigate the losses caused by the waste oil, as shown statistically in a design of experiment study. All formulations were chemically resistant to aqueous, organic and acidic media. The identification of the effects of critical parameters on the properties of WVO-based thermosets enables the further production of polymers from waste streams.

This review surveys the problem of surface contamination of cars, which poses a growing engineering challenge to vehicle manufacturers, operators and users. Both the vision of drivers and the visibility of vehicles need to be maintained under a wide range of environmental conditions. This requires managing the flow of surface water on windscreens and side glazing. The rate of deposition of solid contaminants on glazing, lights, licence plates and external mirrors also needs to be minimised. Maintaining vehicle aesthetics and limiting the transfer of contaminants to the hands and clothes of users from soiled surfaces are also significant issues. Recently, keeping camera lenses clean has emerged as a key concern, as these systems transition from occasional manoeuvring aids to sensors for safety systems. The deposition of water and solid contaminants on to car surfaces is strongly influenced by unsteady vehicle aerodynamic effects. Airborne water droplets falling as rain or lifted as spray by tyres interact with wakes, vortices and shear flows and accumulate on vehicle surfaces as a consequence. The same aerodynamic effects also control the movement of surface water droplets, rivulets and films; hence, particular attention is paid to the management of surface water over the front side glass and the deposition of contaminants on the rear surfaces. The test methods used in the automotive industry are reviewed, as are the numerical simulation techniques.

Bacterial and fungal degradation of wheat straw has become intensively scrutinised in recent years because of the growing interest in procuring useful feedstocks and chemicals from lignocellulosic sources. Typically, after the extraction of valuable sugars and phenolics, significant quantities of solid biomass remain as waste. In this work, it has been shown that the leftover fermented wheat straw can be successfully used to reinforce epoxy resins, providing better strength properties compared to non-degraded straw. A 12% and a 22% increase in Young’s modulus and ultimate tensile strength respectively were observed for degraded wheat straw/epoxy composites compared to composites containing non-degraded straw. The improvement in mechanical strength is explained in terms of the structural and morphological transformations that occurred in the fibres during the fermentation process. The opportunity to use degraded natural fibres in the manufacturing of composites, in addition to the production of chemicals from lignocellulosic feedstocks, looks promising for improving biorefinery economics further.

A detailed understanding of charge density and its origins during the electrospinning process is desirable for developing new electrospinnable polymer-solvent systems and ensuring mathematical models of the process are accurate. In this work, two different approaches were taken to alter the charge density in order to measure its effect on the Taylor cone, mass deposition rate and initial jet diameter. It was found that an increase in charge density results in a decrease in the mass deposition rate and initial jet diameter. A theory is proposed for this behaviour in that an increase in charge density leads to the tip of the Taylor cone forming a smaller radius of curvature resulting in the concentration of electric stresses at the tip. This leads to the electrostatic forces drawing the initial jet from a smaller effective area or “virtual orifice”.