Journal of Applied Research of Chemical -Polymer Engineering

Abstract Research subject: This study investigates the effect of poly(butyl acrylate) (PBA)-based polymeric plasticizers on the performance of poly(vinyl chloride) (PVC) films. The main objectives were the synthesis and evaluation of graft copolymer plasticizers, PVC-g-PBA, with varying PBA chain lengths, and the examination of their impact on the microstructure, mechanical properties, and stability of PVC films.
Research approach: PBA chains with different molar percentages (40–80%) were grafted onto PVC chains via atom transfer radical polymerization (ATRP). The microstructures of the synthesized copolymers were confirmed using Fourier-transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (¹H-NMR). These copolymers were then used as plasticizers (at 22 wt%) in the preparation of PVC films. The mechanical properties (tensile strength and elongation at break), morphology (via wide-angle X-ray diffraction (WAXD)), plasticizer stability in the PVC matrix (extraction test), and thermomechanical behavior (via dynamic mechanical thermal analysis (DMTA)) were evaluated.
Main results: Increasing the molar percentage of PBA in the copolymers reduced the yield stress from 53 to 10 MPa, while significantly increasing the elongation at break from 9% to 162%, indicating enhanced flexibility of the PVC films. WAXD results revealed that at lower PBA contents (up to 63%), chain ordering improved, whereas higher PBA incorporation (73%) led to a notable reduction in crystallinity due to the amorphous nature of PBA. The extraction test confirmed the high stability of the synthesized plasticizers in the PVC matrix after 24 hours. DMTA analysis indicated shifts in the glass transition temperature between phases as the PBA content increased. Compared to the conventional plasticizer dioctyl phthalate (DOP), the synthesized plasticizers exhibited superior mechanical performance and are proposed as a highly stable alternative for PVC applications.

 

Abstract Research subject: Oil-based wastewater treatment is essential to prevent environmental harm and comply with regulations. Membrane processes are ideal for this due to their efficiency, low energy use, and ability to handle complex emulsions effectively.
Research approach: The primary goal of this study is to employ an ultrafiltration membrane separation process for the treatment of wastewater containing oil compounds (e.g., diesel fuel). To achieve this, polyethersulfone/sulfonated-polyethersulfone (PES/SPES) blend membranes with various SPES loadings were fabricated using the nonsolvent-induced phase separation (NIPS) method. The effects of SPES loading on the membrane morphology, surface roughness, surface hydrophilicity, mechanical strength, porosity, and water and wastewater flux were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle measurement, mechanical strength testing, and filtration performance tests, respectively.
Main results: The results showed that adding SPES to PES and increasing the loading of SPES led to the formation of macrovoids in the membrane cross-section, enhanced surface roughness and hydrophilicity, increased porosity, improved water and wastewater flux, and increased the pure water flux recovery ratio. However, these benefits came with reduced mechanical strength and increased membrane compaction. Among the prepared membranes, the PES/SPES (60/40 wt./wt.) blend membrane exhibited the best filtration performance, achieving a final wastewater flux of 34.78 L/m²·h, compared to 11.35 L/m²·h for the neat PES membrane. Meanwhile, the PES/SPES (40/60 wt./wt.) composite demonstrated the highest surface roughness, hydrophilicity, and flux recovery ratio. Notably, all membranes synthesized in this study achieved over 99% rejection efficiency for the diesel fuel-water emulsions, which is significant for practical and industrial applications.

Abstract Research subject: The flare, as an integral part of petrochemical plants, not only ensures the safety of operations and personnel but is also a major source of pollutant emissions and volatile organic compounds. The gases directed to the flare often contain valuable components whose recovery can significantly enhance production, increase revenues, and reduce greenhouse gas emissions. Therefore, investigating the recovery of flare gases and their reuse in petrochemical processes is of considerable importance.
Research approach: In this study, aimed at recovering flare gases in the Zagros Petrochemical Complex, process simulation and energy–exergy analyses were performed. The proposed process consisted of a methane steam reformer operating at 1000 K and 101.3 kPa, a system of heat exchangers, a water–condensate separator, and a gas compression unit increasing the recovered gas pressure to 7600 kPa in accordance with the methanol synthesis reactor conditions. Furthermore, a sensitivity analysis was conducted to examine the effect of steam-to-carbon ratio and reformer feed temperature on the overall energy and exergy performance of the system.
Main results: The results indicated that the optimum steam-to-carbon ratio in the reformer was 13, at which all methane was converted into syngas. Increasing the feed temperature reduced reformer energy consumption, enhanced energy efficiency, and decreased exergy destruction. Exergy analysis showed that the reformer accounted for the highest share of exergy destruction (49.43%), while the water separator contributed none. The overall energy efficiency of the process was calculated as 56.43%, with 17 GJ of input energy utilized. The specific energy loss and exergy destruction per ton of recovered gas were 13.13 GJ and 2.62 GJ, respectively. Methanol synthesis unit simulation revealed that syngas recovery increased methanol production by 9.16%, equivalent to 462.39 tons per day. Finally, the evaluation confirmed that implementing flare gas recovery completely eliminated CO2 emissions from flaring, thereby reducing the CO2 footprint from this source to zero.

Abstract Research subject: This study employs a novel approach to the synthesis of liquid polysulfide. One of the drawbacks of synthesizing liquid polysulfide is the use of 1,2,3-trichloropropane (TCP) as a crosslinking agent, which poses significant toxicity and carcinogenic hazards. Glutaraldehyde (GLH) was utilized as a crosslinking agent in this study, as it is safer than TCP.
Research approach: Bis(2-chloroethyl) formal and sodium tetrasulfide (Na2S4) monomers were used in a surface suspension reaction to create liquid polysulfide, with glutaraldehyde (GLH) serving as a crosslinking agent. The organic monomer, bis(2-chloroethyl) formal, was also produced by reacting ethylene chlorohydrin with paraformaldehyde. The organic monomer's synthesis and purity were assessed using gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR). The produced liquid polysulfide was then subjected to FTIR, viscometry, T-peel, tensile, and hardness tests for analysis. This study examined the effect of GLH concentration on the flowability, mechanical, and adhesion properties of liquid polysulfide by varying its proportion in the polymer.
Main results: The viscosity of liquid polysulfide with 1.5 to 2 wt. % GLH (LP-3 and LP-4) was 6800 and 11000 mPa.s, respectively, surpassing that of samples with 0.5 to 1 wt. % GLH (LP-1 and LP-2), with viscosities of 3900 and 4100 mPa.s, respectively. Samples LP-3 and LP-4 exhibited superior tensile strength compared to samples LP-1 and LP-2. The adhesion to metal in samples LP-1 and LP-2 exceeded that of samples LP-3 and LP-4. The optimal GLH composition, based on tensile properties and hardness, lies between 1.5 and 2 wt.%. However, due to the elevated viscosity of liquid polysulfide containing 2 wt.% GLH (LP-4) and its inadequate fluidity at ambient temperature as a sealant, along with the lower adhesion of sample LP-4, samples LP-2 and LP-3 were identified as the most suitable compositions in terms of viscosity, hardness, tensile strength, and peel strength for formulating a reliable liquid polysulfide sealant.

Abstract Research subject: In this study, a conductive sensitive layer composed of polybenzimidazole (PBI) and carbon nanotubes (CNTs) was designed and fabricated via electrospinning for the detection of volatile organic compounds (VOCs)—(methanol, ethanol, isopropyl alcohol (IPA), acetone—and water vapor.
Research approach: This study employed an experimental approach. In the first stage, various processing parameters—such as flow rate, voltage, and needle-to-collector distance—were optimized to enable the fabrication of uniform fibers with nanometric diameters. Subsequently, the fibers were deposited onto an interdigitated gold-on-glass electrode (IDE) as the sensor base to form the sensitive layer of the sensor. Finally, the dynamic response of the fabricated sensor was evaluated using a custom-built measurement system developed by the research group.
Main results: Optimal electrospinning conditions were established at a flow rate of 0.5 cc h⁻¹, an applied voltage of 24 kV, and a nozzle-to-collector distance of 15 cm, enabling the production of uniform nanofibers, as confirmed by scanning electron microscopy (SEM). Brunauer–Emmett–Teller (BET) analysis revealed a fiber specific surface area corresponding to 18.23 m² g⁻¹. Dynamic sensing experiments demonstrated strong sensor responses toward alcohols and acetone, with response intensity correlating inversely with alcohol polarity from methanol to IPA. The sensors exhibited an exceptionally short response time (< 10 s), attributed to the nanofibrous architecture of the sensing layer, which promotes rapid vapor diffusion and access to active sites. Furthermore, the response trends and selectivity toward target vapors were analyzed in the context of thermodynamic parameters, including the Flory–Huggins interaction parameter.

Abstract Research subject: The formulation of sublimation inkjet inks based on disperse dyes requires precise control of dispersion stability and rheological behavior to achieve consistent print quality and printer compatibility. One of the main challenges in this field is establishing an appropriate balance between polymeric dispersants and low-molecular-weight surfactants to prevent sedimentation, viscosity fluctuations, and surface tension instability. This study investigates the influence of nonionic surfactant concentration on the physical characteristics, dispersion stability, and rheological behavior of Disperse Blue 359 in aqueous sublimation inkjet ink formulations.
Research approach: Dye concentrates were prepared using a jar mill in the presence of a polymeric dispersant, glycerol, and deionized water. The concentration of the nonionic surfactant was varied from 0 to 7.1 wt%. The samples were characterized in terms of color strength by UV-vis spectrophotometry, particle size by dynamic light scattering, surface tension by the Wilhelmy method, and rheological behavior by a rotational rheometer. Dispersion stability was also monitored by turbidity measurements over different time intervals.
Main results: The results revealed that the simultaneous presence of the polymeric dispersant and the nonionic surfactant significantly improved the stability and flowability of the system. Specifically, the sample with the optimally concentrated surfactant exhibits turbidity oscillation of less than 30 NTU and a viscosity below 8.5 cp, while the surfactant-free sample experiences a turbidity reduction exceeding 500 NTU over the test duration and a viscosity above 17 cp. At an optimal surfactant concentration of approximately 3.6 wt%, the particle size reached its minimum, color strength reached its maximum, and dispersion stability was maximized. Conversely, both higher and lower surfactant concentrations led to particle aggregation, increased turbidity, and diminished print quality. These findings highlight the critical importance of accurately tuning the ratio of surfactant to dispersant in designing reliable sublimation inkjet inks with desirable optical and rheological properties.

Abstract Research subject: In recent decades, water and gas injection have gained significant attention for enhancing oil recovery. However, some engineers believe that alternative methods can play a more pivotal role in this field. The use of surfactants is considered an innovative technique that has had a notable impact on the oil industry. Nevertheless, the large-scale production of such materials is financially costly. Additionally, their synthesis results in the generation of toxic and hazardous waste, posing various threats to human health and the environment, ultimately leading to widespread and irreparable pollution. The use of natural surfactants has emerged as a viable solution with relatively high efficiency. These natural surfactants are extracted from the leaves of native plants, offering a cost-effective approach. Moreover, they are biodegradable and pose no risks to human health or the environment.
Research approach: The combination of these natural surfactants in oil-related experiments has yielded satisfactory results, demonstrating their effectiveness in reducing interfacial tension between water and oil, as well as modifying the viscosity of crude oil. This study specifically examined the interaction between surfactants and divalent ions at their lowest concentrations. One of the testing processes involved injecting these solutions into a micromodel, which was subsequently analyzed.
Main results: The combination of these surfactants with divalent ions and crude oil significantly reduced interfacial tension. Notably, the combination of Morus leaf extract with calcium ions reduced the interfacial tension of crude oil to 15.6 mN/m, while Citrus extract with sulfate ions reduced it to 13.6 mN/m. Additionally, in many viscosity tests, a reduction in crude oil viscosity was observed. The combination of calcium ions with Morus extract resulted in approximately 41% oil recovery, whereas sulfate ions with Citrus extract led to a 50% final recovery rate.