Polymers

Zhu, Chenjing;Ning, Yi;Jiang, Yizhi;Li, Guangji;Pan, Qiwei

doi: 10.3390/polym14173435pmid: 36080510

Solid-state polymer electrolytes have become promising candidates for high-energy-density lithium metal batteries (LMBs). However, they suffer from low ionic conductivities at room temperature. In this work, two types of composite polymer electrolytes based on a double-network polymer, an ionic liquid (IL) of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (Pyr14TFSI) or 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl) imide (EmimTFSI), and bis(trifluoromethane)sulfonamide lithium salt (LiTFSI) were prepared by a facile one-pot method. The two types of CPEs possess good mechanical properties, excellent thermal stability, and high ionic conductivities greater than 10−4 S cm−1 at 20 °C with 26 wt% IL. The performance diversity of the CPEs was also carefully investigated through a series of electrochemical measurements. Although the CPEs containing EmimTFSI show higher ionic conductivities than those of CPEs with Pyr14TFSI, the latter ones have wider electrochemical stability windows and better resistance to the growth of lithium dendrites. Moreover, CPE with 34 wt% Pyr14TFSI leads to Li/LiFePO4 batteries with favorable rate capability and cycling stability and a columbic efficiency of 98.8% at 20 °C, which suggests that CPEs are promising for practical application in solid-state LMBs.

Wang, Huiqi;Ullah, Aman

doi: 10.3390/polym14173436pmid: 36080511

Polymeric micelle forming from self-assembly of amphiphilic macromolecules is one of the most potent drug delivery systems. Fatty acids, naturally occurring hydrophobic lipid components, can be considered as potential candidates for the fabrication of block copolymer micelles. However, examples of synthesis of responsive block copolymers using renewable fatty acids are scarce. Herein, we report the synthesis, characterization and testing of block copolymer micelles composed of a renewable fatty-acid-based hydrophobic block and thermoresponsive hydrophilic block for controlled drug delivery. The block copolymers of functionalized fatty acid and poly(N-isopropylacrylamide) (PNIPAM) were prepared via consecutive microwave-assisted reversible addition fragmentation chain transfer (RAFT) polymerization. The block copolymers with variable hydrophobic block length self-assembled in aqueous media and formed spherical nanoparticles of ~30 nm with low critical micelle concentration (CMC). To demonstrate the proof-of-concept, carbamazepine (CBZ) was used as a hydrophobic model drug to evaluate the performance of these micelles as nanocarriers. The in vitro drug release tests were carried out below (25 °C) and above (37 °C) the lower critical solution temperature (LCST) of the block copolymer. The drug release showed obvious temperature-triggered response and an accelerated drug release at 37 °C.

de Araújo Moura, Ruan Carlos;Lima, Paulo Roberto Lopes;Ribeiro, Daniel Véras

doi: 10.3390/polym14173437pmid: 36080516

Glass fiber reinforced polymer (GFRP) bars have been increasingly used as reinforcement in concrete structures. However, when the bars are exposed to high temperatures, there is a change in the internal structure of the polymer which affects the tensile strength of the matrix and its adhesion with the fibers, reducing the mechanical strength of the bar. In addition, with increasing temperature, the bar-concrete interface is also damaged by the decomposition of hydration products from the cement paste and the loss of surface adhesion. The intensity of these changes is associated with the type of resin used as a matrix since each polymer has its own molecular structure that provides a greater or lesser ability to resist the changes imposed by temperature. The present study evaluates the mechanical behavior of reinforced concrete containing different types of GFRP bars and subjected to temperatures of 150 °C, 300 °C, and 350 °C. The GFRP bars with three types of matrices (polyester, vinyl ester, or epoxy) were mechanically evaluated under tension in two conditions: isolated and inserted into reinforced concrete specimens with a thickness of 20 mm, using two types of concrete (with and without silica fume). Degradation mechanisms at the bar/concrete interface were evaluated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), differential thermal analysis (DTA), and bond techniques. The results showed that the type of matrix has a significant influence on the tensile behavior of GFRP bars, with the epoxy matrix showing the best performance, followed by bars with vinyl ester and polyester matrix resins. The use of silica fume improved the performance of the concrete coating and, consequently, improved the protection of GFRP bars, hindering the diffusion of oxygen and heat; bar/concrete adhesion was compromised by thermal degradation of GFRP bar ribs.

Wang, Wanru;Wang, Zhen;Guo, Rui;Xian, Guijun

doi: 10.3390/polym14173438pmid: 36080512

Traditional steel surface treatment (e.g., sand blasting, or silane treatment) was regarded as an effective method to improve the bonding strength of steel–epoxy single-lap joints. In the present study, a new steel surface treatment method was developed. With this method, the steel surfaces were treated with suspensions of nano-sized and micro-sized Al2O3 particles in ethanol/water mixture using the dip-coating method. Both Al2O3 particle sizes were previously treated or not treated with silane. Single-lap shear tests of the steel–epoxy bonds were conducted to compare the effects of the treating methods. According to the testing results, the highest increase in the bonding strength (by 51.8%) was found for the steel coated with the suspension of silane treated nano-Al2O3 particles. Scanning electron microscopy (SEM) analysis and energy dispersive spectrometer (EDS) analysis indicates that the nano-Al2O3 particles were clearly attached to the treated steel surfaces. Moreover, the steel surface with the silane-treated nano-Al2O3 particles was found to clearly enhance the contact angle between the steel and epoxy resin. The fracture morphology analysis of the single-lap shear testing specimen shows that the bonding between the steel and adhesive changed from steel–epoxy interfacial failure to cohesive failure when the steel surfaces were treated with the nano-Al2O3 particles suspension. The developed steel surface treatment method with the suspension of nano-particles proves to be effective and reliable in enhancing the bonding strength of the steel-to-epoxy adhesives.

Guo, Xiaohui;Yuan, Xiaojing;Hou, Genliang;Zhang, Ze;Liu, Guangyong

doi: 10.3390/polym14173439pmid: 36080513

We aim to predict the natural aging life of 8016 ethylene propylene rubber accurately and quickly. Based on the time-temperature equivalent superposition principle, the artificial bee colony algorithm was introduced to calculate the acceleration factor of the accelerated aging test, and the calculation of the acceleration factor was considered an optimization problem, which avoided the error superposition problem caused by data fitting at each temperature. Based on the traditional Arrhenius equation, a power exponential factor was introduced to consider the non-Arrhenius phenomenon during the rubber aging process. Finally, the aging prediction curve of 8106 ethylene propylene rubber at 25 °C was obtained. The prediction results show that the artificial bee colony algorithm can quickly and accurately identify the acceleration factor of the accelerated aging test. The dispersion coefficients between the predicted and measured results of the improved and traditional Arrhenius equations are 1.0351 and 1.6653, respectively, which indicates that the improved Arrhenius equation is more advantageous in predicting the long-term aging process of rubber products.

Rodríguez-Soto, María A.;Polanía-Sandoval, Camilo A.;Aragón-Rivera, Andrés M.;Buitrago, Daniel;Ayala-Velásquez, María;Velandia-Sánchez, Alejandro;Peralta Peluffo, Gabriela;Cruz, Juan C.;Muñoz Camargo, Carolina;Camacho-Mackenzie, Jaime;Barrera-Carvajal, Juan Guillermo;Briceño, Juan Carlos

doi: 10.3390/polym14173440pmid:

Bliznyuk, Valery N.;Kutsevol, Nataliya V.;Kuziv, Yuliia I.;Husson, Scott M.;DeVol, Timothy A.

doi: 10.3390/polym14173441pmid: 36080514

We explored two approaches to recover uranium and plutonium from aqueous solutions at pH 4 and pH 7 using water-soluble star-like polyacrylamide polymers with a dextran core. In the first approach, a solution comprising a neutral or ionomer polymer was mixed with a radionuclide solution to form polymer–metal complexes that were then retained by ultrafiltration (UF) membranes under applied pressure. The same polymers were first deposited on the membrane in the second approach using pressure-driven flow. The applied polymers had an overall diameter of gyration of 120 nm, which exceeded the nominal diameter of the UF membrane pores. The polymers showed a high affinity to uranyl but could also be used to extract Pu from neutral or near-neutral pH solutions. Direct-flow single-step filtration and alpha spectrometry demonstrated that the UF membranes containing star-like copolymers could recover 99% of U and up to 60% of Pu from deionized water after filtering 15 mL solutions containing 25 ppm and 33 ppb of the actinides, correspondingly. The sorption capacity of the polymers for uranium could be measured as 1mg U per mg of the polymer after six subsequent filtration steps. Alpha spectroscopy of the deposited actinides revealed peculiarities of the structural organization of polymers and their complexes with U or Pu, depending on the approach. Though both approaches were efficient, the second approach (deposition of the polymer on the membrane followed by filtration) has an additional advantage of protecting the membrane pores from capillary collapse by filling them with the polymer chains. Therefore, these polymer-modified membranes could be used either in continuous or multi-step filtration process with drying after each step without deterioration of their sorption characteristics.

Buckley, Ciara;Murphy, Emma J.;Montgomery, Therese R.;Major, Ian

doi: 10.3390/polym14173442pmid: 36080515

The inclusion of physiologically active molecules into a naturally occurring polymer matrix can improve the degradation, absorption, and release profile of the drug, thus boosting the therapeutic impact and potentially even reducing the frequency of administration. The human body produces significant amounts of polysaccharide hyaluronic acid, which boasts exceptional biocompatibility, biodegradability, and one-of-a-kind physicochemical features. In this review, we will examine the clinical trials currently utilizing hyaluronic acid and address the bright future of this versatile polymer, as well as summarize the numerous applications of hyaluronic acid in drug delivery and immunomodulation.

Jin, Lei;Jang, Giseok;Lim, Hyunmin;Zhang, Wei;Park, Sungjun;Jeon, Minhyuk;Jang, Hohyoun;Kim, Whangi

doi: 10.3390/polym14173443pmid: 36080518

Polymer electrolytes (PEs) based on poly(ethylene oxide) (PEO) have gained increasing interest in lithium-ion batteries (LIBs) and are expected to solve the safety issue of commercial liquid electrolytes due to their excellent thermal and mechanical stability, suppression of lithium dendrites and shortened battery assembly process. However, challenges, such as high interfacial resistance between electrolyte and electrodes and poor ionic conductivity (σ) at room temperature (RT), still limit the use of PEO-based PEs. In this work, an in situ PEO-based polymer electrolyte consisting of polyethylene glycol dimethacrylate (PEGDMA) 1000, lithium bis(fluorosulfonyl)imide (LiFSI) and DMF is cured on a LiFePO4 (LFP) cathode to address the above-mentioned issues. As a result, optimized PE shows a promising σ and lithium-ion transference number (tLi+) of 6.13 × 10−4 S cm−1 and 0.63 at RT and excellent thermal stability up to 136 °C. Moreover, the LiFePO4//Li cell assembled by in situ PE exhibits superior discharge capacity (141 mAh g−1) at 0.1 C, favorable Coulombic efficiency (97.6%) after 100 cycles and promising rate performance. This work contributes to modifying PEO-based PE to force the interfacial contact between the electrolyte and the electrode and to improve LIBs’ performance.

Resner, Leszek;Lesiak, Pawel;Taraghi, Iman;Kochmanska, Agnieszka;Figiel, Pawel;Piesowicz, Elzbieta;Zenker, Marek;Paszkiewicz, Sandra

doi: 10.3390/polym14173444pmid: 36080519

Cross-linked polyethylene (XLPE) is one of the most popular insulation materials used in the production of medium and high voltage cables (MV, HV). This article presents the results of research carried out on two types of commercially used insulation materials, modified with the addition of organophilic phyllosilicate (CLOISITE C20A)and halloysite nanotubes (HNTs). The influence of fillers on the mechanical properties of insulating materials is discussed as a potential mechanism for increasing their resistance to the phenomenon of water-tree. SEM and XRD analyses were performed to investigate the morphology and DSC for comparing phase transitions. Mechanical and functional properties for different concentrations of nanofillers, such as their hybrids, were also investigated.