International Journal of Polymer Analysis and Characterization最新文献

The properties of films prepared from polystyrene (PS), poly(methyl methacrylate) (PMMA), and polystyrene (PS)/poly(methyl methacrylate) (PMMA) blends and composite films prepared with metal ion-centered complexes were compared. New complexes of Cr(III), Co(II), Ni(II), and Cu(II) prepared according to the template were synthesized from ligand L (4-hydroxy-N-[2-[(4-hydroxybenzoyl)amino]ethyl]benzamide) prepared by condensation of 4-hydroxybenzoic acid and ethylenediamine. Structural analysis of ligands and complexes were determined by LC-MS, ¹H-NMR, FTIR, UV-Vis, and XRD. The conductivities and magnetic susceptibility of novel complexes were measured. Morphological properties of the transparent films by SEM and AFM, their thermal stabilities by TGA, and their optical properties by refractometry were characterized. Original composite films of PS, PMMA, and PS/PMMA blend modified with novel complexes were obtained as thermally stable, transparent, and foldable composite films with permanent colors.

Poly(ethylene oxide) has been intercalated inside the interlayer galleries of montmorillonite clay and the electrochemical properties of the nanocomposite have been investigated. Interlayer spacing and clay gallery width increase with increasing MMT concentration confirming intercalation of PEO into MMT as observed from XRD results. The fraction of free anions as calculated from FTIR, increases with increasing clay content and remains constant beyond 7.5 wt. % of clay content. Ionic conductivity of the order of 10⁻⁴ Scm⁻¹ has been obtained in the case of MMT based electrolytes. The initial increase of conductivity with increasing MMT content can be attributed to the increase fraction of free ions which eventually increases ionic conductivity. After 7.5 wt. % of MMT loading ionic conductivity decreases due to the high viscosity of MMT. Interfacial stability results show that passivation takes place very slowly in MMT based electrolytes. Dielectric properties show that at high frequency relaxation takes place due to the segmental motion of polymer chains and it proves the hopping of ions.

Astronauts suffer from natural space radiation as high-energetic protons, heavy ions, and secondary particles produced in collisions. Galactic cosmic rays and solar particle events are the basic parts of space radiation spectra. Wears and accessories designs for use by astronauts aim to minimize these deleterious effects of this environment. Polymeric materials are preferred in astronaut suits because they are lightweight, inexpensive, and durable. Teflon, KEVLAR, ethylene tetrafluoroethylene, DYNEEMA, and NOMEX polymeric astronaut wear materials were exposed to high energetic proton irradiations by the use of Monte Carlo simulation tools SRIM-2013 and FLUKA 2011.1. Proton energies are applied as 1, 2, and 3 GeV known as in order of space radiation magnitude. Besides, displacement per atom calculations were done and results were discussed in the plane of structural changes in the given polymeric materials. After interacting with protons with 1, 2, and 3 GeV energies, the material with the lowest Displacement per atom value among the five studied materials is DYNEEMA with values of 1.01E − 25, 9.96E − 26, and 1.00E − 25, respectively. Again, among the materials studied for these three proton energies, DYNEEMA has the highest electronic stopping power values are, respectively, 2.11E − 03, 2.10E − 03, and 2.31E − 03. DYNEEMA has the highest nuclear stopping power values as 2.23E − 07, 1.53E − 07, and 4.27E − 07, respectively.

In the present work we are aimed to use powerful and state of the art methodology to optimize catalyst synthesis procedure. In this way, the preparation process of supported Ziegler–Natta catalysts was simulated and optimized through artificial intelligence (AI) methodology coupled with genetic algorithm (GA). The yield of preparation process was investigated through assessing the catalyst activity. The effects of several variables including TiCl₄ injection temperature, TiCl₄/toluene ratio, and TiCl₄ injection time on the activity of prepared catalyst were investigated. In model development, leave-one-out technique was used for training the network. The developed neural network model can be utilized to enhance the efficiency of the catalyst preparation process.

A novel nanocomposite consisting of polyurethane (PU), poly(o-phenylenediamine) (PoPD), and silicon carbide (SiC) nanoparticles was investigated for its application in marine environment through electrochemical techniques. The PoPD/SiC nanofillers were characterized by TGA, XRD, SEM/EDX, and TEM analyses. The anticorrosion and mechanical properties of different coating formulation in marine environment were evaluated by electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM). It was also found that the coating resistance of PU-PoPD/SiC nanocomposite was over 41 times higher than that of the PU coating. The PU-PoPD/SiC coatings on the brass showed low current of 1.9 I/nA due to copper dissolution and 6.8 I/nA due to zinc dissolution because of the well distribution of PoPD/SiC nanofiller in PU coating. The analyses of the resultant degradation products by SEM/EDX and XRD techniques confirmed the presence of Si which has a major role in protecting the brass surface against corrosion. Results showed that the PU composite with 2 wt.% PoPD/SiC hybrid nanofillers had outstanding coating performance. This nanocomposite demonstrated improved corrosion protection. As a result, the developed PU-PoPD/SiC nanocomposite has exceptional adhesion strength and anticorrosion properties and might be exploited to develop next-generation anticorrosive coatings.

The demand for stretchable, skin-mountable, and wearable strain sensors is burgeoning because they are required for several budding applications in various emerging fields, such as health monitoring, human-machine interfaces, wearable electronics, soft robotics, human motion detection, virtual reality (VR), and so forth. Recently, strain sensors based on composite materials comprising stretchable elastomer and conductive nano-filler have gathered attention on account of their ample flexibility, record stretchability, excellent durability, customizable characteristics for strain-sensing, and simpler fabrication techniques. This quality write-up discusses current developments in the field of flexible strain sensors (FSSs). We effectively summarized how advanced mechanisms, such as crack propagation, disconnection, and tunneling effect, which are quite different from traditional strain sensing techniques, are used to develop FSS. Various factors and their effects that need to be kept in mind while developing high-performance, high-quality FSSs are also debated. The performance of recently reported FSSs is comprehensively discussed, and the huge potential that FSSs hold has been comprehensively reviewed in this survey.

Influence of concentration of introduction the different industrial organic additives into the epoxy resin on wetting contact angle is studied experimentally. Epoxy resin ED-20 is modified with small concentrations of polydimethyl siloxane, OH-polymer silicone rubber, monoglycidyl ether of butyl cellosolve (Laproxide 301B), tris(2-chloroethyl) phosphate. The importance of these studies is related to the need to improve the adhesive properties of repair compounds based on epoxy resin, which are associated with the value of the contact angle. The contact angle of the resin drop is measured for glass, metal, asbestos cement, and concrete surfaces. The effect of the mass fraction of additives on the contact angle is more pronounced on smooth surfaces of dense materials, and less pronounced on rough surfaces of porous materials. It is observed that all dependences of contact angle on the mass fraction of additives in the range of 0.5–2% wt are linear. The linear equation $\theta =s\cdot c+{\theta }_0$ describing the contact angle θ dependence on the mass fraction c of additives, which sufficiently fitting the experimental data with calculated coefficients s and θ₀, is found.

We have developed conductive, lightweight, and porous composite of polyvinylidene difluoride by blending with synthesized conjugated terpolymer and graphene for conductive polymer composite applications. The new conjugated terpolymer designated as PEPy-TP is synthesized from 3,4-ethylenedioxythiophene, 1-pyrenecarboxzaldehyde, and heptaldehyde through friedel craft reaction. The synthesized terpolymer PEPy-TP have been blended with polyvinylidene difluoride and graphene nanosheets to form porous composite and has been characterized using XRD, TGA, TG-DSC, DTA, DTG, SEM, EDX, and Dielectric spectroscopy. The porous composite is comprised of varying weight percentages of (1, 3, and 5%) of GNS and 10 wt% PEPy-TP in PVDF. The thermal studies on the porous composites indicated that the decomposition occurred at a temperature around 270 and 470 °C corresponds to the PEPy-TP and PVDF/PEPy-TP/GNS (1, 3, and 5%), respectively. The EDX spectrum of neat PEPy-TP polymer and their porous composites of PVDF/PEPy-TP/GNS (1, 3, and 5%) result clearly shows the presence of all elements, such as C, O, S, and F with an atomic weight percentage also. The PVDF/PEPy-TP/5% GNS porous composites having a tremendous electrical conductivity and the dielectric constant value is 56 at 1 MHz and their conductivity of this polymer porous composites value is determined to be 4.9 × 10⁻⁶ S/cm at 100 kHz, respectively.

This paper aimed at the problem of uneven heating of ultra-high molecular weight polyethylene (UHMWPE) bearing in the process of UHMWPE was made into water-lubricated bearing, and have used ICEPAK software to study the temperature distribution of the UHMWPE during hot pressing. Research indicated that hot pressing UHMWPE was an unsteady heat transfer in the process of heating and holding. Air convection had little effect on the overall process. During processing, the slow heating method to process smaller UHMWPE water-lubricated bearing could effectively reduce the temperature difference. It made the inner heating of UHMWPE uniform and equated to the temperature of the shaft sleeve. This research can provide data support for temperature control and process optimization for the UHMWPE-based water-lubricated bearing hot pressing process.

The improvement of adsorbent materials with specific characteristics is very important in different environmental applications such as the removal of undesirable elements (wastewater treatment) or separation of elements or radionuclides and remediation of organic pollutants from their solutions. Herein, a cross-linked poly(acrylic acid-dimethyl aminoethyl methacrylate) was prepared by a copolymerization technique in the existence of N, Ǹ-methylene bis-acrylamide as a cross-linked agent using gamma irradiation (γ-rays) to induce the polymeric reaction at a minimum radiation dose of 30kGy. The optimization of polymer preparation was done using different parameters such as radiation dose, cross-linker amount, and monomer ratios. The batch mode was applied for the investigation of copper removal from their aqueous solutions using the synthesized polymer. Besides, the theoretical models were checked for experimental data to describe the nature of the adsorption process. Also, the confirmation of adsorption was evaluated using SEM, EDX, XRD, and FTIR to explain the adsorption processes. Furthermore, desorption prepared polymer was tested and the results exhibited that the HNO₃ is the best desorption agent. The reusability of the synthesized polymer also was examined for six cycles and the results confirmed that there is no remarkable change in the uptake of polymer.