APPLIED RESEARCH IN CHEMICAL POLYMER ENGINEERING
Year:2020 | Volume:3 | Issue:4 |Papers Count:6

Research subject: Due to the public attention to the environmental issues as well as strict environmental regulations, eco-friendly methods for synthesis of nanoparticles have received considerable attention in recent years. Research approach: In the present study, a mixed oxide nanoparticle containing cerium and zirconium (Cex-Zr1-xO2) was fabricated the in supercritical water (SCW) medium. The synthesized nanoparticles were characterized by various techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Main results: Results demonstrated that fine nanoparticles with mean size of 13± 3 nm, with high crystallinity, and with appropriate size distribution and surface area were synthesized by SCW. Moreover, an oxygen storage capacity (OSC) as high as 1. 25 mmol O2/g was estimated for Cex-Zr1-xO2 nanoparticles through temperature programmed reduction in hydrogen (H2-TPR). According to the obtained results, the Cex-Zr1-xO2 nanoparticles could be a suitable candidate for catalysts of oxidation processes as well as three-way catalyst for control of automotive exhaust gases.

Research subject: The use of scrap tires to recover energy and their compounds is an effective way to protect the environment and recover energy and materials. Research approach: The aim of this research is to investigate the process of tire pyrolysis as well as the simultaneous pyrolysis (copyrolysis) process of tire and mazut. Here, the effect of different operating conditions such as temperature, volumetric nitrogen gas, heating rate and size of tire parts on the physical quantities and physical properties of the products manufactured by these processes have been investigated. Main results: The optimal operating conditions for these experiments are 420 ° C, the volumetric gas flow rate is 100 ml / min and the heating rate is 3 ° C / min. The volume of the reactor is 500 ml and the amount of mazut in the copyrolysis process is 30 wt %. The highest amount of liquid produced in the process of pyrolysis was achieved using tire parts with the particle size of 0. 5×2×4 cm3, which is %43. 3 by weight. In contrast, the largest liquid product produced in the simultaneous pyrolysis process of the tire and mazut was obtained using tire parts with a size of 0. 5×4×4 cm3, which is %52. 3 by weight. In this study, the physical properties of liquid products produced by two processes of pyrolysis of tire and copyrolysis of tire and mazut, such as kinematic viscosity, density and refractive index, have been investigated.

Research Subject: Regarding new researches on chemorheology of highly-filled composites, it is determined that HTPB slurry should have convenient viscosity for ease of casting. In the other words, available time for appropriate casting of highly-filled composite after curing agent addition called pot-life. Long pot-life of HTPB binder system is necessary for good processability and non-defect production of highly-filled composite grains. In addition to long pot-life, the physicalmechanical properties of HTPB-based highly-filled composite are also important. Research Approach: In this research, effect of curing agent type (molecular structure), casting temperature and the amount of DBTDL as a curing catalyst on chemorheological behavior of HTPB binder system and physical-mechanical properties of highly-filled composite were investigated. Toluene diisocyanate (TDI), isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI) were selected in order to investigate the role of molecular structure of curing agent on chemorheology of binder system and its slurry and also on physical-mechanical properties of highly-filled composite. Moreover, temperatures of 50, 40, and 60 ˚ C, were selected to study the effect of casting temperature on chemorheology. Main Results: By every 10 ˚ C decreasing of casting temperature, potlife of binder system (based on IPDI and TDI) was increased about 10 min. Pot-life of binder system and highly-filled composite slurry based on IPDI in the presence of %0. 005 DBTDL (the optimum content) showed the longest pot-life at similar temperatures. The elastomer and highly-filled composite based on IPDI showed the highest crosslinking density (CLD) and modulus in comparison to other curing agents, retaining tensile strength and adequate elongation.

Research subject: In recent years, there are so many attractions in the field of effective detection and discrimination of volatile organic compounds (VOCs). Detection of VOCs is of great importance in many applications and industries, such as air pollution control, air quality control, food packaging, food quality control, disease diagnostic, agriculture, etc. Sensitivity and selectivity of the prepared sensors to detect VOCs need to be improved. Research approach: A conductive polymer composite sensitive layer based on poly(lactic acid) as polymer matrix and multiwall carbon nanotubes as conductive filler was prepared to detect VOCs. For this purpose, the porous sensitive layer was prepared by non-solvent induced phase separation (NIPS) method. In this structure, chloroform (low-boiling point temperature) was used as the solvent and ethanol (high-boiling point temperature) was used as a non-solvent. The sensitive layer was used to detect toluene, methanol, and chloroform. The structure and morphology of synthesized layer was investigated by means of scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) techniques. Main results: The investigation indicated that the phase separation method induced the open cell morphology into the conductive composite. The BET results showed that the specific surface area of composite increased to 22. 3 m2/g. The experimental results showed that the response properties of porous layers was improved dramatically in comparison with the dense layers. It was related to the increase in the specific surface area of polymer composite and therefore increase in the diffusion coefficient of analyte molecules in the polymer matrix. Finally, the sensitivity and selectivity of porous sensitive layers were investigated based on Flory-Huggins interaction parameter.

Research subject: Selectivity and permeability are major properties of polymeric membranes in gas separation process. Hence, nowadays modification of membranes has been highly noticed in order to improve the aforementioned properties. Research approach: In this study, in order to improve the performance of polymeric membranes, blend membranes containing Pebax® 1657 and poly(vinyl alcohol) (PVA) were synthesized for CO2 separation. The effect of concentration of PVA in Pebax matrix was investigated on structure, morphology, and gas separation properties of the resultant membranes. Formation of chemical bonds, crystallinity, and crosssectional morphology were studied using Fourier-transform infrared spectroscopy (FTIR), differential scanning caxlorimetry (DSC), and field emission scanning electron microscopy (FESEM), respectively. Main results: DSC results indicated an increase in the crystallinity and also glass transition temperature in presence of 5 to 15 wt. % of PVA, while the membrane crystallinity decreased by increasing the PVA content up to 20 wt. %. FESEM images demonstrated a uniform crosssection without any cracks and defects for the neat Pebax membrane but by adding PVA to Pebax matrix, cracks and cave structures appeared on the cross-section of the blend membranes. The CO2/N2 separation performance of membranes was measured using a constant-volume set-up at 30° C and feed pressure of 2, 6 and 10 bar. The obtained results revealed that the CO2 permeability in blend membranes improved with increase in the PVA content. The best CO2 permeability with the value of 204. 64 Barrer was obtained at 20 wt. % of PVA in the blend at feed pressure of 10 bar. Moreover, the highest selectivity of CO2/N2 for the blend membrane containing 15 wt. % of PVA was about 100. 21 at 10 bar and 30° C.

Parkinson’ s disease (PD) is a neurodegenerative disorder with no treatment due to the blood-brain barrier (BBB) existence. However, if dopamine (DA) molecule is able to pass through the BBB, it can be considered as a cure for PD. The aim of this study was to prepare biodegradable nanoparticles (NPs) carrying DA for crossing the BBB, using ion polymerization and solvent. Particle size and size distribution, zeta potential, entrapment efficiency, and in vitro drug release behavior were determined at pH=7. The drug-loaded nanoparticles were found to be spherical with fluffy exterior, average size of 110 nm and zeta potential of-7. 61 mV. Fourier-transform infrared (FTIR) spectroscopy (FTIR) verified polymerization of butyl cyanoacrylate monomers and physical encapsulation of DA in the polymer, poly(butyl cyanoacrylate) (PBCA). Loading and drug encapsulation efficiencies were 35 and 52 w/v %, respectively, characterized by high performance liquid chromatography (HPLC). The in-vitro drug release profile of DA-loaded PBCA nanoparticles exhibited a gradual release of more than 20 ٪ w/w of the drug after 51 h. Investigation of in-vivo release of fluorescein isothiocyanate from nanocarrier as a model drug for dopamine in brain proved its gradual release using fluorescent microscopy. In this study, PBCA nanoparticles were successfully introduced as a delivery system for the hydrophilic DA, providing a promising approach for improvement of PD.