Papers by Keyword: Polystyrene

Abstract: In this paper we present comparative study of frequency dependencies of an effective nonlinear elastic modulus of the three widely used glassy polymers, polystyrene, PMMA and polycarbonate. For measurements we use the methodology based on the acousto-elastic effect and analysis of variations in ultrasonic wave velocities under static stress applied to samples. The absolute values of the effective modulus γ = l − 2m, representing a combination of the Murnaghan moduli l and m, demonstrated pronounced nonlinear dependencies on the ultrasonic wave frequency for polystyrene and PMMA. At higher frequencies above ∼1 MHz no significant variations of the modulus occurred, while at lower frequencies down to 400 kHz its absolute value demonstrated a rapid rise of more than an order of magnitude. In polycarbonate the dependence was much less evident, the modulus γ also demonstrated some slight rise in the absolute value at lower frequencies, but the rise was not profound, less than two-fold and almost within the experimental error bars. The origin of the differences in nonlinear elastic properties of polystyrene/PMMA and polycarbonate requires further and more detailed investigation.

Abstract: The housing sector accounts for a high percentage of total energy consumption in Iraq, with most energy usage on air-conditioning systems in summer to provide comfort to residents. This study simulates energy consumption for a typical 200 m², two-story, single-family building in Al Amarah city, Iraq, to compare heating, cooling, and total energy use across three different building configurations. Locally manufactured hollow concrete blocks made with 40 × 20 × 20 cm3 dimensions were adopted to improve their thermal performance by filling the cavities with Polystyrene insulation. The research examined three residential building configurations: (i) a base case built with traditional fired-clay brick, (ii) hollow concrete block walls free of insulation, and (iii) hollow concrete block walls incorporating thermal insulation. Energy simulations using eQUEST software were conducted, utilising the thermal response factor method as the primary tool to analyse the impact of external environmental conditions on cooling and heating loads. The results demonstrated significant annual energy savings for the building with hollow concrete blocks with and without insulation. However, insulated hollow concrete blocks showed reduced annual energy consumption compared to the common brick building system. Specifically, the insulated and uninsulated blocks attained energy savings by 29.4% and 16.08%, respectively, for north-facing orientation.

Abstract: Polystyrene (PS) is widely used in industries like packaging and insulation, but its performance can be enhanced by incorporating calcium carbonate as a filler. To improve polymer-filler compatibility, calcium carbonate was surface-modified with oleic acid, and PS-calcium carbonate composites were synthesized using the melt blending method, followed by citric acid treatment. X-ray diffraction (XRD) and FTIR analyses revealed no chemical interaction between the phases, with a reduction in calcium carbonate content due to citric acid treatment, suggesting partial dissolution of the filler. Scanning electron microscopy (SEM) images showed the formation of cavities in the matrix, especially in TPS3. Hardness testing indicated a decrease in hardness with increasing oleic acid concentration, with TPS3 exhibiting the lowest hardness (63.4 Shore D). Photoluminescence measurements showed a blue shift at lower oleic acid concentrations, while higher concentrations caused a red shift and broader emission, which was stabilized by citric acid treatment. Solvent absorption tests indicated that citric acid-treated composites had an enhanced absorption capacity, with TPS3 showing 38.3 % absorption in vegetable oil, suggesting potential for adsorption applications. Overall, the oleic acid and citric acid treatments significantly modified the mechanical, morphological, and optical properties of PS-calcium carbonate composites, creating tunable materials with potential for sensing applications.

Abstract: Herein, a one-pot solvothermal method was employed to synthesize Fe-doped carbon nanodots using waste expanded polystyrene as the carbon source and ferric chloride hexahydrate for iron doping. Three synthesis parameters-reaction time, temperature, and dopant weight-were optimized using Response Surface Methodology (RSM) based on Box-Behnken design, with relative fluorescence (FL) intensity as the response. Model validation showed a percentage error of 0.66% between replication experiments and predicted maximum intensity, confirming the model's reliability to maximize FL intensity in synthesis. FTIR spectroscopy identified the presence of a medium peak at 538 cm^-¹, associated with Fe-O stretching, indicating successful Fe doping, supported by EDX analysis. TEM analysis confirmed the nanosized properties of Fe-CDs, with an average particle size of 1.84 nm, and HR-TEM revealed an onion-like structure with a lattice spacing of 0.369 nm, and the presence of amorphous shells, suggesting structural heterogeneity. The synthesized doped and undoped CDs were employed in a drop-casting method to produce films that were used for carbon monoxide detection. Results displayed significant effects of operating temperature and gas concentration on the gas response of Fe-CDs and CDs films on resistance. The significant statistical difference in gas response between Fe-CDs and undoped CDs suggests that Fe doping enhances electron mobility, due to more pronounced changes in resistivity, yielding higher responses to carbon monoxide gas.

Abstract: One of the most significant environmental challenges nowadays is the rising manufacturing of non-biodegradable polymer wastes like polystyrene. In order purpose of manufacture environmentally friendly polystyrene that easily decomposes, a solvent approach was used to create polystyrene based zinc oxide- graphite composites. The surface morphology and materials contained in the modified polystyrene were evaluated by scanning electron microscopy-energy dispersive X-ray analysis to verify the dispersion and distribution of the nanoparticles by scanning electron microscopy and the material contents by energy dispersive X-ray analysis. While the crystal structure, chemical bonds, and functions were determined by X-ray Diffraction and Fourier transform infrared, no change in the chemical structure occurred in polystyrene. Thermogravimetric analysis was used to assess the thermal decomposition. And its results found that the temperature of the decomposition was 46.78° lower in zinc oxide and graphite-based polystyrene composites than in pure polystyrene. It came to light that the presence of zinc oxide nanoparticles causes phase separation and consequently impacts the thermal behaviour of graphite-based polystyrene composites. The phase separation was demonstrated by the Thermogravimetric curves showing two degrading steps. This satisfies the urgent demand to synthesize polystyrene that is eco-friendly and easy to thermally decomposition, as well as easy to recycle, which benefits both the environment and the commercial side.

Abstract: The current study ensures the possibility of improving the mechanical and dielectric properties of polystyrene/kaolin reinforced with glass fibers. Polystyrene was dissolved using coloring in a ratio of 1 to 2. The prepared composites were studied and the results of the tensile, impact, hardness, thermal conductivity, and dielectric, has been obtained. Through the tensile results, it was found that with an increase in the addition of kaolin, both the yield points and the Young modulus decreased with a small and noticeable increase for the sample with the percentage of addition beyond 8 percent in Elongation, and shown high flexibility. The highest tensile strength appeared in the pure sample (x= 0%), where the value reached 22.85 MPa, while the lowest was for the sample with ratio 2%. While the impact result showed a noticeable increase with the increase in the percentage of addition of kaolin in the few percentages only. The sample with an addition rate of 8% kaolin, showed a high rebound energy, through the results of the energy absorption test, and it had the highest thermal conductivity and dielectric coefficient.

Abstract: Anti-reflective polystyrene nanopillar arrays were fabricated by the process of hot embossing where it utilizes the nickel coated anodised aluminium oxide template. Electroless plating being a catalytic method of plating uniformly coats the membrane which increases its strength. The supporting layer of nickel makes AAO template suitable to be used as a mould multiple times. Highly conformal nanopillars of average diameter 400nm and length 30 μm to 50μm were fabricated on the area of ⁓5cm². Hot embossing process ensures repeatability with precision and high throughput. The enhanced light entrapping is attributed to the multiple internal reflection in the nanopillars of high aspect ratio.

Abstract: Membrane distillation (MD) being an emerging technology, it suffers from many limitations. One of which is the need for membranes with specific characteristics to ensure successful operation and sustainable performance. Membrane wetting phenomenon is one of the significant disadvantages of MD which take place primarily due to membrane pore wetting with the operating liquids. The present work studies the effect of addition of graphene nanoplatelets (GNPs) on enhancing the antiwetting properties of enhanced polystyrene (PS₁₂-SDS) nanofibrous membranes. Results showed that adding 0.5wt% of GNPs to the PS₁₂-SDS polymer matrix enhanced the hydrophobicity of the produced membranes and decreased the mean fiber diameter of the produced membranes by about 5.5% and 36.6%, respectively. The composite (PS₁₂-SDS-GNPs) membrane also showed better salt rejection compared with PS₁₂-SDS at all studied feed flow rates.

Abstract: In the present study the surface morphology of electrospun fibers at different polystyrene (PS) solution concentration was studied by SEM imaging to determine the best PS solution concentration yielding continuous uniform beadles fibers. Contact angle measurements of the optimum fabricatedPS-18 membrane confirmed the super hydrophobic property of the membrane that exhibited a static water contact angle of 145o. Numerical investigation of the performance of PS-18 membrane at different membrane thicknesses and porosities on direct contact membrane distillation showed that increasing the membrane porosity increases the permeate flux considerably.

Abstract: The aim of this paper is to review the literature on Materials science to identify the current research and to provide direction for future research in thermal properties of the concrete block composite, either with Polyethylene Terephthalate (PET) or Polystyrene (PS), presenting the opportunity to make an important methodological contribution by applying systematic review in three areas of Materials science: Composites, Building Materials, as well as Testing and Evaluation of Materials. This is a growing interdisciplinary field since there are no current comparative papers addressing both PET and PS in the same research for concrete composites. Papers investigating to what extent, what type and how academic publications are integrated on the analysis of the characteristics of the two recycled polymers (PET and PS), to improve the thermal properties of the concrete block and contribute to the research of sustainable thermal comfort in homes. They were reviewed, keywords were identified within a framework of composites, building materials, as well as testing and evaluation of materials, and a lexical analysis of the papers was conducted. The results of current research show that both forms of recycling (PS and PET), combined with concrete, have sustainability in thermal comfort. The analysis reveals that previous research has focused on PET-Concrete (i.e., concrete-PET polymer composite) since it is more viable, due to its large amount of recycling. While this has benefited home builders in their ability to respond with some thermal comfort with higher construction efficiency, it also clarifies that there has been research done on PS-Concrete (i.e., concrete-PS polymer composite), presenting greater thermal comfort, because it has lower thermal conductivity. This finding suggests the need for further research within this narrow field, with absence of data, since most prescriptive recommendations have not been tested and lack practical applications, which is why the need for more empirical and experimental studies are identified. Based on the novelty of the PET or PS recycling concepts, we highlight the need of better collaboration between academic disciplines, such as engineering and architecture to provide better experimental evidence for recycling of polymers, including empirical approaches for the different types of composites and aggregate distributions, which can be made with concrete to improve thermal insulation performance and energy savings for manufacturers.