Using a sulfur-bearing silane to improve rubber formulations for potential use in industrial rubber articles

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Adhesion Science and Technology on 13/08/2012, available online: http://dx.doi.org/10.1080/01694243.The availability of the coupling agent bis (3-triethoxysilylpropyl)-tetrasulfide (TESPT) has provided an opportunity for enhancing the reinforcing capabilities of precipitated amorphous white silica in rubber. Styrene-butadiene rubber, synthetic polyisoprene rubber (IR), acrylonitrile-butadiene rubber, and natural rubber (NR) containing the same loading of a precipitated silica filler were prepared. The silica surface was pretreated with TESPT, which is a sulfur-bearing bifunctional organosilane to chemically bond silica to the rubber. The rubber compounds were subsequently cured by reacting the tetrasulfane groups of TESPT with double bonds in the rubber chains and the cure was optimized by adding sulfenamide accelerator and zinc oxide. The IR and NR needed more accelerators for curing. Surprisingly, there was no obvious correlation between the internal double bond content and the accelerator requirement for the optimum cure of the rubbers. Using the TESPT pretreated silanized silica was a very efficient method for cross-linking and reinforcing the rubbers. It reduced the use of the chemical curatives significantly while maintaining excellent mechanical properties of the cured rubbers. Moreover, it improved health and safety at work-place, reduced cost, and minimized damage to the environment because less chemical curatives were used. Therefore, TESPT was classified as "green silane" for use in rubber formulations

Automating Pre-Stack Migration Enhancement and Image Quality Analysis

The quality of a seismic migration image strongly depends on an accurate velocity model. However, the migration velocity model often contains errors causing artifacts that degrade seismic resolution and fidelity. Here, I propose a method to enhance the seismic migration image using processes in angle domain common image gathers (ADCIGs), without requiring modification to the velocity model. The ADCIGs impacted by velocity errors show non-flat reflections and scattered noise. To enhance the imaging quality in ADCIGs, these problems need to be treated before applying a stack. The ideal case of layers in ADCIGs should be flat without smear amplitude throughout all angles. Using this principle, I process one reflection at a time in each iteration by isolating it into a local window and then flattening it. Also, I apply internal processing steps in order to enhance the signal. The algorithm of segregating a reflection is called the connected-component labeling (CCL) method and is the leading technique to extract any feature that has a continuous form within the ADCIGs. Moreover, this method is insensitive to scattered noise so that it is a suitable approach to classify what is reflection or noise. To test the efficiency of this algorithm, I create ADCIGs which contain a relatively poor-quality image using an inaccurate migration velocity model. The primary objective is to show how well the CCL method can select various forms of reflections with associated noise levels. The results show that the CCL method is capable of decomposing a reflection individually, which can facilitate processing in the internal workflow. Finally, I evaluate the quality of processed migration images by comparing the processed Poynting-vector reverse time migration (PVRTM) images with reverse time migration (RTM) used Laplacian filter and partial stacked PVRTM. These comparable migration images are benchmarked against the synthetic reflector model being used as a baseline. As a result, the essential improvements of our method are addressed in the migration sections, namely the removal of diffraction artifacts at both small and large scales and the improvement of phase coherency. The final stacked migration image of the proposed method shows clearer geological features that are capable of delivering a more reliable seismic interpretation.Earth and Atmospheric Sciences, Department o

COMPARISON OF FILLER TYPES IN POLYLACTIC ACID COMPOSITES FOR 3D PRINTING APPLICATIONS

This research is a comparison of the addition of different fillers in polylactic acid (PLA) affecting the three-dimensional printing technique and their properties. The fillers consist of Wood flour (WF), Talc (TC), Calcium Carbonate (CaCO3), Microballoon (MB) and Silicon Dioxide (SiO2). The 5%wt fillers were added into PLA to fabricate the filaments by single screw extruder. The specimens were fabricated by Fuse Deposition Modeling (FDM) technique. The effects of fillers on the physical, mechanical, flow, thermal and morphological properties of polymers were of interest. It was found that the 3D printed parts were completely in shape during fabrication. The 3D printed parts of PLA composites were a difference in color and texture, and exhibited a lower tensile strength than those with the neat PLA, except for the PLA/WF. The glass microballoons mixed-PLA composites gave the higher Young's modulus compared to those with composites. The 3D printed parts of PLA/TC composites had greater flexural strength than that of neat PLA and PLA composites. The impact strength and melt flow rate of PLA/MB composites were higher than that of neat PLA and PLA composites. The Vicat softening point of PLA/MB was similar to neat PLA, while PLA/CaCO3, PLA/WF, PLA/TC and PLA/SiO2 was lower compared with neat PLA

Effects of recycled PVC content and processing temperature on the properties of PVC foam products

This work used different types of recycled PVC products including PVC pipes and bottles, as rigid recyclates, and PVC plastic coverings, as soft recyclate. The PVC recyclates were added into virgin PVC foam, ranging from 0-100wt%. The PVC blends were then moulded with different processing temperatures, and their properties were monitored. It was found that the concentration of the pipe recyclates up to 60 wt% could be used to add into the PVC virgin for production of rigid PVC foam products. The higher the recyclate content led to the higher the blend density and the mechanical properties (flexural and impact strength, and hardness). For bottle recyclates, up to 60 wt% of bottle recyclates could be used for rigid PVC foam production, but the overall properties, except for the impact strength, of the PVC foam did not improve withincreasing the recycled bottles. For recycled coverings, increasing plastic coverings led to an increase in average cell size, but resulted in decreases of impact and hardness resistances. The flexible or soft PVC foam products could be manufactured with use of 0-100wt% recycled coverings. In summary, it could be concludedthat recyclates of pipes, bottles and plastic coverings can be mixed with virgin PVC foam for making foam products