Specific features of uranyl ions extraction by interpolymer system based on polyacrylic acid and polyethyleneimine hydrogels

Uranyl ions sorption of by interpolymer system consisting of polyacrylic acid hydrogel (hPAA) and polyethyleneimine hydrogel (hPEI) has been studied. Rate of uranyl ions extraction by the initial polymers and interpolymer system hPAA-hPEI, polymeric chain binding rate and dynamic exchange capacity of initial polymers and interpolymer system hPAA-hPEI were calculated. Based on obtained outcomes it was found that area of maximum rate of uranyl ions extraction is within the ratios of 67%hPAA:33%hPEI and 33%hPAA:67%hPEI. Maximum uranyl ions extraction rate after 48 hours of hydrogels remote interaction was 90.0 %, when polymeric chain binding rate was 9.1 % and dynamic exchange capacity was 1.14 mmol/g. Rate of uranyl ions extraction by the initial polymer hydrogels 100 % hPAA and 100 % hPEI was 68.0 % and 52.0%. Obtained outcomes showed changes of initial polymeric hydrogels sorption properties in intergel system leading to functional groups obtaining higher reactive ability, which makes it possible to use them for further development of highly efficient uranyl ions extraction sorption technology.

Influence of basalt fiber on tribological properties of secondary polyethylene terephthalate

The article considers the influence of discrete (3 mm) basalt fiber on the tribological properties of secondary agglomerated polyethylene terephthalate. It was found that the introduction of the filler reduces the coefficient of friction and the intensity of linear wear of the initial polymer 1,5 and 4,5 times, respectively, reaching the minimum values at a basalt fiber content of 5 mass.%. The obtained results are due to the fact that the appearance of basalt fiber strengthens the polymer matrix that confirms the increase in hardness by 15%, and inhibits the development of cracks on the surface of the composite. The study of the temperature in the contact zone showed its increase that is due to the low thermal conductivity of the filler (0,064 - 0,096); as a result, there is an accumulation of heat in the friction zone. Further increase in fiber content (up to 10 mass.%) leads to a sharp deterioration of the tribological and physico-mechanical properties of basaltoplastics because of the increase in the defect of the material. It is determined that the effective content of filler in the polymer matrix is 5 mass.%. As a result, this composite was recommended for the manufacture of parts for movable joints of agricultural, automotive and metallurgical equipment.

EFFICIENCY OF NANOPOLYMER APPLICATION ON THE GROWTH, DEVELOPMENT AND YIELD OF SOYBEAN

The current study was carried out to analyze the effects of agro-nanopolymer preparations application on the seed germination, seedling and root sprout lengths, growth, development, yield, and resistance to Fusarium wilt in Baraka and Selecta-302 soybean variety under laboratory condition. For encapsulation of soybean seeds and nanopreparation UZHITAN, nanochitosan, chitosan (initial), polymer metallocomplexes (PMCs) of copper and silver ions were used at various ratios for nanoascorbate chitosan, ascorbate chitosan, polymer metallocomplex (PMC) Cu2+:Ag 7:3 and PMC Cu2+:Ag 8:2 preparations,. Results of the study revealed a significant effect of these agronanoplymers on the studied soybean varieties; application of this nanoascorbate chitosan, ascorbate chitosan, polymer metallocomplex (PMC) Cu2+:Ag 7:3 and PMC Cu2+:Ag 8:2 showed 17 g, 14.6 g, 13.5 g, and 11.9 g weight of the 1000-grains respectively which was significantly higher than the Gaucho treatment. Further, these agronanoplymers also have a significant effect on the various yield attributes such as number of beans per plant, number of seeds per bean, and seed mass per bean. Application of chitosan and PMC agronanopolemers increased productivity by 4.5-6.1 kg/ha and 3.3-5.1 kg/ha, respectively, compared to the control. Also, the effect of these agro nanopolymer preparations on enzyme activity and protein content was studied in the current study. Among the various tested nanopreparation, the greatest effect on total soybean yield was observed when seeds were treated with nano ascorbate chitosan. All nanopreparation treated seeds has a significant effect on the accumulation of macro and micronutrient accumulation in Soybean seed and except few one rest are the superior to the control and UZHITAN.

Optimization of Film Composite Functional Properties for Sewing Products

The process technological parameters of forming a film composite for making heat-protective clothing have been developed. The peculiarities of its application in sewing production are taken into account. The effect of the initial polymer compositions formulation on the formed composites physical-mechanical and technological properties was studied. It has been found that the use of the composite film material developed reduces the compounds permeability of protective clothing.

Polymeric Tribotechnical Composites on the Basis of Polytetrafluoroethylene and Complex Fillers

Perspective polymeric materials for use in frictional units as bearings and sliding supports, the mobile sealants of piston rings, cuffs are composites on the basis of polytetrafluoroethylene (PTFE). They significantly improve the performance of equipment at low temperatures, reduce repair expenses and losses from idle times. When modifying polymers, physical methods of exposure are increasingly used, ensuring the activation of materials and high performance characteristics. Objective: the effect of complex fillers, obtained by their joint activation in a planetary mill, on the deformation and strength and tribological characteristics of composites based on PTFE. This work shows the promise of using the joint mechanical activation of components of different nature to obtain complex fillers. The use of the modified ultradispersed polytetrafluoroethylene (UPTFE) of zeolite as a filler of PTFE leads to complex improvement of properties of composites: the tensile strength and elongation at rupture increase by 20% in comparison with initial polymer. The wear resistance increases by 3-6 times in comparison with the composites containing only the activated zeolite and by 900 times in comparison with initial polymer. The addition of the modified UPTFE of a magnesium aluminate spinel (MAS) leads to increase in deformation and strength properties by 10-30% and an increase in wear resistance by 140 times in comparison with initial polymer.

Development of Multifunctional Composites Based on Ultrahigh Molecular Weight Polyethylene

The present study investigates the influence of carbon fibers of «Belum» brand on the performance properties of polymer composites based on ultrahigh-molecular weight polyethylene. It was established that the composite complex with the content of carbon fibers in the amount of 5 wt.% has the optimum complex of properties. The rate of mass wear is reduced by 3.3 times while maintaining the physical and mechanical characteristics at the level of the original polymer. It was established that the creep of PCM with the composition of UHMWPE + 5 wt.% Belum is 2 times less than the initial polymer. Also, the properties of the developed material based on UHMWPE were compared with unfilled and modified polytetrafluoroethylene (PTFE). It is shown that the creep of UHMWPE is less than the creep of PTFE by 12.5 times. The creep of the composite based on UHMWPE is less than the creep of the composite based on PTFE 13 times.

Investigation on the Polymer Drawing Model of the Centrifugal Spinning

Background and Objective: Some patents have reported the centrifugal spinning method which utilizes the centrifugal force produced by a high speed rotating device to fabricate fibers from polymer melts or solutions. Recently, with the development of technologies, centrifugal spinning was employed to produce ultrafine fibers and nanofibers. In order to improve the equipment and technology of centrifugal spinning and obtain finer fibers, it is important to model the polymer drawing of the centrifugal spinning. Methods: The polymer drawing in the centrifugal spinning is modeled and simulated. The force balance equation and heat transfer balance equation are established after analyzing the motion and heat transfer of the polymer melts. These nonlinear equations are solved based on the least square method to obtain the radius of excircle and the shape of streamline. A fourth order Runge-Kutta method is utilized to obtain the diameter and temperature of the threadline because there are initial value problems of first order ordinary differential equations. Streamlines and diameter of polymer melts at different viscoelasticities and different spinning temperatures are obtained. The simulation results are compared with the measured results to verify the polymer drawing model. Results: The viscoelastic force in the centrifugal spinning changes constantly at a fixed rotation speed of the rotating spinneret. As the spinneret is rotating, the radius of excircle R1 increases slowly when the time passes, which means the viscoelastic force decreases slowly. The change of the viscoelastic force accelerates the increase of the radius vector. The simulation results show that the threadline diameter under the condition of changing viscoelastic forces is smaller than that under the condition of fixed visoelastic forces. The temperature of the polymer melts decreases faster under the condition of changing viscoelastic forces than that under the condition of fixed visoelastic forces. The threadline diameter decreases with the increase of the rotation speed. Higher initial polymer temperatures yield smaller fiber diameters. Conclusion: The polymer drawing in the centrifugal spinning is modeled and simulated. The simulation results tally with the measured results confirming the effectiveness of the polymer drawing model. The simulation results show that the change of the viscoelastic force is favorable to the polymer drawing and both larger rotation speeds and higher initial polymer temperatures can produce finer fibers, which lays a good foundation for the computer-assisted design of the centrifugal spinning.

Vapor phase infiltration of zinc oxide into thin films of cis-polyisoprene rubber

Vapor phase infiltration (VPI) of ZnO into the elastomeric polymer polyisoprene creates an organic-inorganic hybrid material. Inorganic loading and hybrid structure depend upon the initial polymer free volume and the extent of polymer oxidation.

Study of the Lamellar and Micellar Phases of Pluronic F127: A Molecular Dynamics Approach

In this work, we analyzed the behavior of Pluronic F127 through molecular dynamics simulations at the coarse-grain level, focusing on the micellar and lamellar phases. To this aim, two initial polymer conformations were considered, S-shape and U-shape, for both simulated phases. Through the simulations, we were able to examine the structural and mechanical properties that are difficult to access through experiments. Since no transition between S and U shapes was observed in our simulations, we inferred that all single co-polymers had memory of their initial configuration. Nevertheless, most copolymers had a more complex amorphous structure, where hydrophilic beads were part of the lamellar-like core. Finally, an overall comparison of the micellar a lamellar phases showed that the lamellar thickness was in the same order of magnitude as the micelle diameter (approx. 30 nm). Therefore, high micelle concentration could lead to lamellar formation. With this new information, we could understand lamellae as orderly packed micelles.

Electrospun Sesbania Gum-Based Polymeric N-Halamines for Antibacterial Applications

Microorganism pollution induced by pathogens has become a serious concern in recent years. In response, research on antibacterial N-halamines has made impressive progress in developing ways to combat this pollution. While synthetic polymer-based N-halamines have been widely developed and in some cases even commercialized, N-halamines based on naturally occurring polymers remain underexplored. In this contribution, we report for the first time on a strategy for developing sesbania gum (SG)-based polymeric N-halamines by a four-step approach Using SG as the initial polymer, we obtained SG-based polymeric N-halamines (abbreviated as cSG-PAN nanofibers) via a step-by-step controllable synthesis process. With the assistance of advanced techniques, the as-synthesized cSG-PAN nanofibers were systematically characterized in terms of their chemical composition and morphology. In a series of antibacterial and cytotoxicity evaluations, the as-obtained cSG-PAN nanofibers displayed good antibacterial activity against Escherichia coli and Staphylococcus aureus, as well as low cytotoxicity towards A549 cells. We believe this study offers a guide for developing naturally occurring polymer-based antibacterial N-halamines that have great potential for antibacterial applications.