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AbstractIn this paper, we used Monte Carlo simulations in two dimension (2D) to investigate field driven polymer translocation through a nanochannel with Bond Fluctuation Method. Accordingly, we studied the static properties of a polymer chain by calculating the mean-squared end-to-end distance 〈R2〉 and the average squared radius of gyration 〈Rg2〉 of the polymer. In addition, the scaling behavior of radius of gyration and end-to-end distance with respect to chain length N has been investigated. And we got non-universal and non-monotonic scaling behavior. Moreover, we investigated the probability distribution of the escape time of the chain in the presence of an external field, and the most probable escape times were calculated.The influences of the external force F and the chain length N on the escape time has been also studied in terms of the scaling exponent α and δ (τ∼F−δ and τ∼Nα). We found that the scaling exponents α = 2.1 for weak force and 1.80 for strong force; while δ = 0.97 for N = 31 and 0.74 for N = 71. Finally, the effect of the channel size on the translocation time of the polymer has been investigated. Our result indicates that escape times decreases rapidly with increasing channel width and the escape time τ increases with increasing channel length. [ABSTRACT FROM AUTHOR]

A novel poly(phenazine‐alt‐pyromellitic anhydride) (PPPA) has been successfully designed and synthesized via a condensation polymerization strategy as promising cathode material in organic zinc‐ion batteries. Electrochemical quartz crystal microbalance (EQCM), FTIR and XPS characterizations verify a reversible Zn2+‐coordination mechanism in our PPPA cathode. Intriguingly, an ultrahigh Zn2+ diffusion coefficient of 1.2×10−7 cm2 s−1 was found in this large π‐conjugated system, which is the highest one among all organic cathode materials for zinc‐ion batteries. Theoretical calculations reveal the extended π‐conjugated plane in our PPPA sample results in a significant reduction on energy gap, effectively accelerating intramolecular electron transfer during charge/discharge process. Our finding provides insights to achieve high zinc‐ion transport kinetics by a design strategy on planar polymer system. [ABSTRACT FROM AUTHOR]

The growing use of branched polymers in various industrial and technological applications has prompted significant interest in understanding their properties, for which accurate structure determination is vital. This work is the first instance where the macromolecular structures of dendrimers, linear polymers, and hyperbranched polymers with analogous 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) backbone groups were synthesized and analyzed via tandem mass spectrometry (MS/MS). When comparing the fragmentation pathways of these polymers, some unique and interesting patterns emerge that provide insight into the primary structures and architectures of each of these materials. As expected, the linear polymer undergoes multiple random backbone cleavages resulting in several fragment ion distributions that vary in size and end group composition. The hyperbranched polymer dissociates preferentially at branching sites; however, differently branched isomers exist for each oligomer size, thus giving rise again to several fragment distributions. In contrast, the dendrimer presents a unique fragmentation pattern comprising key fragment ions of high molecular weight; this unique characteristic stands out as a signature for identifying dendrimer structures. Overall, dendrimers, hyperbranched polymers, and linear polymers display individualized fragmentation behaviors, which are caused by differences in primary structure. As a result, tandem mass spectrometry fragmentation is a particularly useful analytical tool for distinguishing such macromolecular architectures.

• Bentonite-polymer composite geosynthetic clay liners (BPC GCLs) may contain water-soluble (linear) or water-insoluble (crosslinked) polymers. • Generally, BPC GCLs with high initial polymer loading had relatively lower hydraulic conductivity than those with low initial polymer loading. • For BPC GCLs containing linear polymer, polymer elution occurred when permeated with water or leachate. • There was no correlation between the percentage of polymer retained and final hydraulic conductivity of the BPC GCLs containing linear polymer. A study was conducted to evaluate the hydraulic conductivity (k) of six bentonite-polymer composite (BPC) geosynthetic clay liners (GCLs) using five synthetic municipal solid waste incineration ash (IA) leachates with ionic strength (I) ranging from 174 to1978 mM. The BPC GCLs contained a dry blend of bentonite and proprietary polymers and had polymer loading ranging from 0.5 to 5.5%. The polymers used in the BPC GCLs were classified as linear polymer (LP) or crosslinked polymer (CP) based on the swelling characteristics of specimens extracted from the GCLs. Comparable hydraulic conductivity tests were also performed on two conventional bentonite (CB) GCLs as controls. The BPC GCLs had k of 2.6 – 6.7 × 10-11 m/s when permeated with IA leachate with I = 174 mM, whereas the CB GCLs had k > 5.0 × 10-8 m/s when permeated with the same leachate. However, k of the BPC GCLs ranged from the order of 10-10 to 10-7 m/s when permeated with IA leachates with I > 600 mM. BPC GCLs with high polymer loading generally had lower k compared to those with lower polymer loading when permeated with the same IA leachate, regardless of the polymer type. Polymer eluted from the BPC GCLs containing LP during permeation with DI water or IA leachate. Unlike CPs, LPs are water-soluble, therefore, they seem to easily migrate during permeation. There was no correlation between the percentage of polymer retained and the final hydraulic conductivity of the LPB GCLs used in this study. [ABSTRACT FROM AUTHOR]

Organic carbonyl electrode materials are widely employed for alkali metal‐ion secondary batteries in terms of their sustainability, structure designability and abundant resources. As a typical redox‐active organic electrode materials, pyrene‐4, 5, 9, 10‐tetraone (PT) shows high theoretical capacity due to the rich carbonyl active sites. But its electrochemical behavior in secondary batteries still needs further exploration. Herein, PT‐based linear polymers (PPTS) is synthesized with thioether bond as bridging group and then employed as an anode material for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). As expected, PPTS shows improved conductivity and insolubility in the non‐aqueous electrolyte. When used as an anode material for LIBs, PPTS delivers a high reversible specific capacity of 697.1 mAh g−1 at 0.1 A g−1 and good rate performance (335.4 mAh g−1 at 1 A g−1). Moreover, a reversible specific capacity of 205.2 mAh g−1 at 0.05 A g−1 could be obtained as an anode material for SIBs. [ABSTRACT FROM AUTHOR]

3D printing is becoming a disruptive technology and shows great potential for various practical applications. Specially, digital light processing (DLP) 3D printing demonstrates advantages in high resolution and high efficiency. However, extensive production of infusible and insoluble thermosets in DLP printing causes serious resource waste and environmental problems after its disposal. Herein, a reprintable linear polymer is reported for repeatable DLP printing. Taking advantage of the dissolution of linear polymer in its monomer, printed objects can be recycled into liquid resin and reprinted via the same DLP. Polymerization kinetics and printing resolution of recycled resins and mechanical properties of reprinted polymers retain identical as the original. The thermoplastic nature of linear polymer endows 3D objects with welding and reshaping property. Recyclable composites are also successfully fabricated, and sustainable usage of high‐value fillers comes true. This strategy helps to address environmental issues arising from unprocessable thermosets and may contribute to an efficient materials recycling. [ABSTRACT FROM AUTHOR]

Abstract This study explored the potential applications of three newly modified polymers [a linear polymer, a hydrophobic association of partially hydrolyzed polyacrylamide (HAHPAM), and a polymer–surfactant] as flooding agents in a specific oilfield. Rheological measurements were performed to examine the rheological performances of the three polymers under reservoir conditions. Their stability, viscoelasticity, and propagation properties were analyzed under simulated reservoir conditions. Propagation performance analyses were conducted in a sandpack model to study the propagation behavior of the three polymers in porous media. The results of the rheological study showed that the HAHPAM and polymer–surfactant exhibited high viscosity at low shear rates (deep reservoir), and all three showed acceptable viscosity with good injectivity at high shear rates (near wellbore area). In oscillatory deformation tests, the HAHPAM and polymer–surfactant showed a predominantly elastic behavior. The results of the propagation performance showed the linear polymer and polymer–surfactant could propagate well in porous media, whereas the HAHPAM showed poor propagation behavior. This finding contrasted with rheological tests in which the injectivity of HAHPAM was superior, with high viscosity at low shear rates. The results of the study provided insights either into matching the viscoelastic performance with propagation behavior in porous media, or upon analyzing the suitability of the polymers for flooding throughout a whole process under “from injectivity to propagation” considerations.

Experiments were conducted to investigate how specimen preparation (crushing and sieving) affects the swell index (SI) of bentonite-polymer (B–P) composites and the relationship between SI and hydraulic conductivity of B–P GCLs. Seven B–P and one Na–B GCLs were used in this study. Tests were conducted using DI water and synthetic municipal solid waste incineration ash leachates. Specimens were prepared using the ASTM D5890 and two alternative methods prior to SI testing. For both Na–B and B–P composites, <100% of the specimen passed through the #100 sieve regardless of the amount of crushing performed using a mortar and pestle. SIs and loss on ignitions (LOI) of the portion of the B–P composites passing #100 sieve were comparable to the Na–B, whereas the B–P specimen retained on #100 sieve had very high SIs and LOIs. These observations indicate that crushing and sieving of the B–P composites lead to segregation of polymer. A stronger correlation (R2 = 0.90) was observed between SI and hydraulic conductivity, only when SI tests were conducted with B–P without any crushing and sieving, suggesting that SI tests should conduct with B–P composites retrieved from the GCLs without sieving to provide a better prediction of hydraulic compatibility. • There are limitations in the ASTM D5890 specimen preparation procedure. • < 100% of the Na–B and B–P specimens passed through the #100 sieve after crushing. • The portion of the B–P specimens retained on the #100 sieve mainly comprised polymer. • SIs of the uncrushed B–P specimens were higher than that of the ASTM D5890 specimens. • SI of uncrushed B–P specimens correlates well with hydraulic conductivity of B–P GCLs. [ABSTRACT FROM AUTHOR]

The transport of biomolecules across bio-membranes occurs in a complex environment where the fluid on both sides of the membrane contains many inclusions. The Monte Carlo method and the hard-sphere (HS) model are used to simulate the translocation of linear polymer and ring polymer through a nanopore in a crowded environment. We compare the results of linear polymer and ring polymer and find that the ring polymer is more sensitive to the surrounding environment. Moreover, the influences of the nanopore and the inclusions to the translocation are studied and our results show that the nanopore changes the translocation time and the inclusions change the translocation tendency to the random side of the membrane. Here, the radius of gyration is described as a balance. [ABSTRACT FROM AUTHOR]

The influence of the nature of linear acrylic polymers differing in the concentration of hydroxyl groups on the spectral-luminescent properties of a hybrid compound, the molecule of which combines two different luminophore fragments, namely, hydroxy-substituted 2,4,5-triarylimidazole and 8-azomethine-7-hydroxycoumarin, and model compounds corresponding to these fragments, is studied. The optimum conditions for the preparation of acrylic polymers containing the luminophores under study by photocuring are selected. The dependence of the luminescent properties of the materials on the number of hydroxyl groups is established. [ABSTRACT FROM AUTHOR]

This paper investigates the effects of increase of reaction mixture viscosity on the kinetics of linear polymer creation in a bulk heteropolyaddition process of 2,4-toluene diisocyanate (TDI) and 1,4-butanediol (BD). The paper presents a method for solving a system of bulk polyaddition of 2,4-toluene diisocyanate and 1,4-butanediol process balance equations, allowing the determination of the process kinetic parameters. Determination of polymerisation reaction kinetic parameters was also made possible by the use of the so-called partial reaction rate constant. Such an approach enabled a significant simplification of the mathematical expressions describing the heteropolyaddition process and provided an opportunity to associate kinetic parameters with the average molar mass of the mixture and, thus, with the viscosity. The method presented herein facilitates an analysis of the linear polymers heteropolyaddition process. [ABSTRACT FROM AUTHOR]

This study explored the potential applications of three newly modified polymers [a linear polymer, a hydrophobic association of partially hydrolyzed polyacrylamide (HAHPAM), and a polymer-surfactant] as flooding agents in a specific oilfield. Rheological measurements were performed to examine the rheological performances of the three polymers under reservoir conditions. Their stability, viscoelasticity, and propagation properties were analyzed under simulated reservoir conditions. Propagation performance analyses were conducted in a sandpack model to study the propagation behavior of the three polymers in porous media. The results of the rheological study showed that the HAHPAM and polymer-surfactant exhibited high viscosity at low shear rates (deep reservoir), and all three showed acceptable viscosity with good injectivity at high shear rates (near wellbore area). In oscillatory deformation tests, the HAHPAM and polymer-surfactant showed a predominantly elastic behavior. The results of the propagation performance showed the linear polymer and polymer-surfactant could propagate well in porous media, whereas the HAHPAM showed poor propagation behavior. This finding contrasted with rheological tests in which the injectivity of HAHPAM was superior, with high viscosity at low shear rates. The results of the study provided insights either into matching the viscoelastic performance with propagation behavior in porous media, or upon analyzing the suitability of the polymers for flooding throughout a whole process under "from injectivity to propagation" considerations. [ABSTRACT FROM AUTHOR]

Abstract In this study, Acid Soluble Collagen-g-P(methyl methacrylate- co -ethyl acrylate) (CME) was synthesized to take advantage of the flexibility of the resulted branched polymer chains and the high density of their chain entanglement. The coaxial electrospinning technique was applied to study the effect of electrically and structurally varied materials on fiber formation and fiber morphology when CME and Nylon 66 were electrospun as core and shell respectively. By tailoring the electrostatic field, different fiber content was achieved. The effect of chain orientation and intermolecular forces between the polymeric chains was investigated in the formed fibers by measuring thermal and mechanical properties, hydration degree and degradability. This approach to in situ fiber formation is not restricted to biomedical but has potential end-uses in a variety of multi-functional applications. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) was prepared by incorporating 1.5% wt. of chain extender to control the thermal stability of PLA during processing. PLA films were processed with three-selected residence times: 4, 8 and 16 min. The PLA film with highest molecular weight was processed with a residence time of 8 min; therefore, films processed at those conditions were selected for hydrolysis experiments. Results showed that the addition of the chain extender significantly increased the dynamic moduli of PLA, and the onset decomposition temperature decreased by 1 °C. These results were attributed to the different structures obtained after processing PLA with the chain extender, resulting in long-chain branching. The hydrolytic degradation of PLA films at accelerated conditions was decreased by the presence of the chain extender, reducing the rate constant from 0.206 to 0.065 h −1 . This reduction was associated with differences in the degradation mechanism from bulk to surface erosion. [ABSTRACT FROM AUTHOR]

The strain hardening behavior of polymers has important roles in processing such as foaming, film formation, and fiber spinning. The most common method to enhance strain hardening is to introduce a long-chain branching structure on the backbone of a linear polymer, but this method is costly and challenging to tailor the behavior. We hypothesized that in situ shrinking fibers can increase the strain hardening of linear polymers, and the degree can be efficiently controlled. In this study, we show that heat-activated shrinking fibers compounded in linear polypropylene enhance strain hardening and foamability. Moreover, changing processing conditions, such as temperature, can amplify the degree of enhancement. Rheological measurements and physical foaming tests are shown to support our hypothesis. [ABSTRACT FROM AUTHOR]

Suppose G is a graph with vertex set V (G). The Graovac--Pisanski index of G is defined as GP(G) = 1/2 |V (G)|²δ(G), where δ(G) = 1/|Γ||V(G)| Σ Σ u ∈V(G) g∈Γ d(u,g(u)). This is a type of graph invariant that is combined distance and symmetry of molecules under consideration. The aim of this paper is to compute the symmetry groups and Graovac--Pisanski index of some linear polymers. [ABSTRACT FROM AUTHOR]

Preferential solvation of polymer chains by the thermodynamically better component in mixed solvent is a general phenomenon which has been amply studied in systems of miscible solvent components. In strongly endothermic mixtures of partially miscible solvent components, it provokes transient contraction of polymer chains and can lead to cononsolvency, which consists in the fact that a mixture of two good solvents becomes a poor solvent. It has been studied for a few polymers and solvent mixtures, but so far, there is not a consensus concerning the principles of this behavior at the molecular level. We performed a series of coarse-grained dissipative particle dynamic simulations aimed at broadening the knowledge of preferential solvation in endothermic mixtures. The study shows that the cononsolvency can be partially explained by general thermodynamic arguments at coarse-grained the mean-field level, but the model ignoring specific interactions fails to describe all details correctly. [ABSTRACT FROM AUTHOR]

This paper investigates the effects of increased reaction mixture viscosity on the kinetics of linear polymer creation in a bulk polyaddition process of diphenyl carbonate and bisphenol A diglycidyl ether. The paper presents a method for solving a system of bulk polyaddition of diphenyl carbonate and bisphenol A diglycidyl ether process balance equations, allowing the determinatiof the process kinetic parameters. Determination of polymerisation reaction kinetic parameters was also made possible by the use of the so-called partial reaction rate constant. Such an approach enabled a significant simplification of the mathematical expressions describing the heteropolyaddition process and provided an opportunity to associate kinetic parameters with the average molar mass of the mixture and, thus, with the viscosity. The method presented herein facilitates an analysis of the linear polymers heteropolyaddition process. [ABSTRACT FROM AUTHOR]