Search

Eight fungal strains (F1–F8) isolate from the sediment core and degraded wood of the Pulp and Paper Mill effluent and Phanerochaete chrysosporium are tested for different cellulolytic (CMcase, FPase, Xylanases) and lignolytic (lignin peroxidase) enzyme activity in pulp. F‐3 (Cryptococcus neoformans) strain shows higher enzyme activity compare to other fungi isolated from effluent. Weight loss, cellulose loss, and organic carbon contents are found maximum in F‐3 (C. neoformans) strain. Reducing sugar, protein content, and color removing potential are also higher in C. neoformans. The culture extract of F‐3 strain grows in presence of pulp fractionated into five protein fractions has indicated two fractions of molecular weight, 38,000 and 40,000 Da, having lignin peroxidase activity. Lignin peroxidase has optimum activity at pH 2–3 and temperature 20–30 °C, maximum activity at 6–48 mM veratryl alcohol concentration and 256 mM H2O2, however, sodium azide inhibits the enzyme activity. Different metals (CoCl2, HgSO4, CaCl2, SnCl2, FeSO4, CuSO4, and ZnSO4) also affect the lignin peroxidase activity. Characterization study is performed for significant analysis. [ABSTRACT FROM AUTHOR]

Melamine-formaldehyde (MF) resins of improved environmental compatibility were synthesized at different molar ratios, temperature and pH. Five molar ratios of melamine and formaldehyde: 35:65, 36.5:63.5, 38.3:61.7, 41.1:58.9 and 42.4:58.6 were used to synthesize the corresponding resins. The prepared samples were characterized by using molecular weight determination viscometery, field emission scanning electron microscopy and thermogravimetric analysis. It was noticed that the solid content in the resin increases with an increase in pH. The maximum percentage of the solid content (51 %) was obtained for pH of 8.5 and temperature range of 95-98 oC. The refractive index of the final product was found increasing with an increase of melamine concentration in the resin. A similar trend was noticed in molecular weight of the resins with an increase in monomer yield. The maximum molecular weight of 114218 was obtained from the sample synthesized with MF molar ratio of 42.4:58.6. [ABSTRACT FROM AUTHOR]

This review provides a brief overview of the recent research efforts carried out at the CICECO laboratory of the University of Aveiro on novel materials based on chitosan within the background of previous investigations of similar counterparts. Most of this work is devoted to different modes of combining chitosans of various molecular weights and degrees of deacetylation (including appropriately modified chitosans providing either fluorescent properties or water solubility) with cellulose fibres of various sizes (standard to nanosize), morphologies (conventional papers, nanofibrillated or bacterial strands) and assemblies (composites or paper coating and impregnation). Additionally, the radical transformation of chitin and chitosan low-quality residues into viscous polyols by a straightforward oxypropylation is also discussed. The results of these investigations show the remarkable potential of chitosan as a source of promising blends and composites, among other novel materials. Copyright © 2011 Society of Chemical Industry The incorporation of cellulose nanofibres into chitosan films improves the mechanical properties of the films while preserving their transparency. The incorporation of chitosan into paper sheets improves their printability, among other positive features. [ABSTRACT FROM AUTHOR]

The light emitting layer of organic light emitting diode (OLED) is formed by uniformly mixing host and dopant. However, phase separation is often observed during fabrication of solution processed OLEDs. In particular, phase separation due to π‐π stacking is frequently observed during thermal annealing. Hence, the materials with a high glass transition temperature (Tg) are required because phase separation accelerates during annealing process if Tg is too low. To understand this phenomenon, we synthesized two host materials with similar molecular weights but different three‐dimensional connectivity which causes different rotational freedom. In both cases, when the annealing temperature rises above 120 °C, the dopant completely escaped from the EML. However, the material that does not disturb the molecular stacking order by annealing due to its limited free rotation through internal bond shows much better device characteristics even after annealing at a higher temperature than Tg. [ABSTRACT FROM AUTHOR]

We are accelerating the development of materials for the solution‐process OLEDs. High‐performance small molecules for EML and platform polymers with reduced the molecular weight for HIL/HTL have been developed as the best practice for high‐resolution printed OLED panels. Further, no‐diffusible p‐dopants have been successfully developed that are key materials for improving the performances of OLEDs produced by solution processes. [ABSTRACT FROM AUTHOR]

We demonstrate highly efficient solution-processed multilayer OLEDs, in which hole injection layer, hole transporting layer, emitting layer (EML), and electron transporting layer (ETL), are fully solution processed. The key feature of the devices is the use of the molecular hosts in the EML, which are sufficiently resistant to the orthogonal solvents such as alcohols, used for processing upper ETLs. This allows us to construct the multilayer structure through subsequent solution-processing steps, achieving high power efficiencies for solution-processed green OLEDs. We also show that the composition at the resulting interface of solution-processed layers is a critical factor in determining device performance. We perform depth-profiling measurements of the devices by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and neutron reflectometry (NR). The composition at the solution-processed EML/ETL interface is severely dependent on molecular weight of the host molecules in the EML. The mixed interface resulting from solution processing not only adversely affects the device characteristics, such as by increasing the driving voltage, but also the mixed interface beneficially affects device performance by, for example, suppressing charge accumulation at the interface. To develop highly efficient solution-processed OLEDs, precise control of the interface structure is important. [ABSTRACT FROM AUTHOR]

Polyamide 6 (PA6) is used in staple fibers and yarns in paper machine press felts due to its good mechanical properties. The crystalline modifications (α and γ forms) and the degree of crystallinity of PA6 can change under stress (compression) and heat (friction), which are present during mechanical dewatering (nip). Here, we investigate the effects of the molecular weight and crystallinity of a polymer on the mechanical properties of PA6 staple fibers such as wear resistance and compaction. The experimental part involves the ageing of felt specimens in a wet pressing simulator. The properties of the felt (air permeability), and the durability and branching of the staple fiber are examined as functions of the wear of a press felt and the crystallinity of the polymer. The changes that take place in the PA6 polymer are investigated using several techniques, and their connection with the properties of a new or aged press felt is discussed. The results indicate that the increase in molecular weight has a beneficial effect on the material's mechanical properties, and our observations also support previous studies on the crystallinity and branching of PA6. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

The article presents information on several forthcoming research papers, which will be published in the coming issues of the European Journal of Biochemistry. Some of the topics of the papers are: lipolysis, biosynthesis, electron transfer, molecular weights, etc.

The reductive amination of low-molecular-weight saccharides, uronic acids, and amino sugars, followed by a separation of the derivates by means of ion-pair chromatography or RP-HPLC, offers an interesting alternative to HPAEC-PAD for the environmental analysis of these compounds. Under this aspect various potential amination reagents, i.e., p-amino-benzoic acid (p-AMBA), p-AMBA propyl ester, 1-aminopyrene, 2-(2-aminophenyl)indole, and 4-aminoazobenzene, were tested with regard to the formation of derivates and to the chromatographic properties of the formed derivates. p-AMBA, p-AMBA propyl ester and 4-aminoazobenzene proved to be especially suited, because they facilitate the amination of all carbohydrate reference components together with a complete separation and sensible detection (detection limits < 0.5 mg/L) of the derivates. Mainly the following elution sequence was ascertained: amino sugars (hexosamines) / disaccharide(s) / monosaccharides (hexoses) / hexuronic acid(s) / N-acetyl-D-glucosamine. Detection limits down to 0.1 μmol/L were realized using p-AMBA as reagent, facilitating the determination of the target compounds in landfill leachates and lysimeter percolates. Applying the p-AMBA propyl ester for derivatization, chromatographic interferences with weakly retained derivates and the coelution of the reagent with its galactosamine derivate can be avoided, since the ester elutes after its derivates unlike p-AMBA itself. [ABSTRACT FROM AUTHOR]

Corn straw is an abundant and renewable alternative for microbial biopolymer production. In this paper, an engineered Sphingomonas sanxanigenens NXG‐P916 capable of co‐utilising glucose and xylose from corn straw total hydrolysate to produce xanthan gum was constructed. This strain was obtained by introducing the xanthan gum synthetic operon gum as a module into the genome of the constructed chassis strain NXdPE that could mass produce activated precursors of polysaccharide, and in which the transcriptional levels of gum genes were optimised by screening for a more appropriate promoter, P916. As a result, strain NXG‐P916 produced 9.48 ± 0.34 g of xanthan gum per kg of fermentation broth (g/kg) when glucose was used as a carbon source, which was 2.1 times improved over the original engineering strain NXdPE::gum. Furthermore, in batch fermentation, 12.72 ± 0.75 g/kg xanthan gum was produced from the corn straw total hydrolysate containing both glucose and xylose, and the producing xanthan gum showed an ultrahigh molecular weight (UHMW) of 6.04 × 107 Da, which was increased by 15.8 times. Therefore, the great potential of producing UHMW xanthan gum by Sphingomonas sanxanigenens was proved, and the chassis NXdPE has the prospect of becoming an attractive platform organism producing polysaccharides derived from biomass hydrolysates. [ABSTRACT FROM AUTHOR]

The article presents information on several forthcoming research papers, which will be published in the coming issues of the European Journal of Biochemistry. Some of the topics of the papers are: lipolysis, biosynthesis, electron transfer, molecular weights, etc.

: The construction of composite flooding system based on dynamic covalent bonds is one of the effective methods to improve the salt and temperature resistance of polymer flooding agents. The polymers used in most composite systems are xanthan gum and guar gum. In this paper, a novel multi‐hydroxyl polymer was synthesized, and a new composite system was constructed based on the dynamic boronic ester bonds. Firstly, the multi‐hydroxyl polymer P(AM‐DPMOH2) was prepared by aqueous solution copolymerization of acrylamide (AM) and a dihydroxy monomer 2,3‐dihydroxy‐N‐(3‐methacrylamidopropyl)‐N,N‐dimethylpropan‐1‐aminium (DPMOH2), which was obtained by quaternization reaction between 3‐chloro‐1,2‐propanediol and N‐(3‐dimethylaminopropyl). Then, the composite system was prepared by the P(AM‐DPMOH2) solution and polyboronic acid compound (BPEI). The effects of DPMOH2 content in P(AM‐DPMOH2), molecular weight of P(AM‐DPMOH2), molecular weight of BPEI, phenylboronic acid groups content in BPEI and pH on the formation of thickening composite system were investigated. The results showed that when the content of DPMOH2 in P(AM‐DPMOH2) exceeded 40 wt%, viscosity average molecular weight of P(AM‐DPMOH2) was higher than 5.0×105 g/mol, the molecular weight of PEI in BPEI was larger than 3000 g/mol, the content of phenylboronic acid groups in BPEI was more than 39.3 %, and pH was in the range of 8–9, the thickening composite system can be formed by P(AM‐DPMOH2) and BPEI. In addition, both the temperature and salt resistance of the composite system formed by 3000 mg/L P(AM‐DPMOH2) and 2000 mg/L BPEI was much better than that of 3000 mg/L P(AM‐DPMOH2). The results of this paper provide a new finding of how to construct a composite flooding system with dynamic covalent bonds. [ABSTRACT FROM AUTHOR]

Polysaccharides are a kind of biological macromolecule, which widely exists in plants, fungi, animals, microorganisms, and other organisms. Polysaccharides exhibit various biological activities such as immunological regulation, antioxidation, antitumor, antiinflammatory, regulating intestinal flora, and protecting liver. These biological activities depend on their structure and physicochemical properties including monosaccharide composition, molecular weight (Mw), spatial configuration, etc. However, biological activities of polysaccharides are hardly comparable to synthetic drugs due to their inherent physicochemical properties. Therefore, structural modification of polysaccharides is an effective way to enhance their biological activities and promote the presentation of bioactivity. At present, phosphorylation modification is a common chemical modification method, which can effectively improve the biological activities of polysaccharides. However, there are limited reports on the synthesis, structure identification, and biological activities of phosphorylated polysaccharides. In view of this, the synthesis methods, structure identification methods, and biological activities of phosphorylated polysaccharides are reviewed in this paper. The findings can provide useful guidance for the research, production, and application of phosphorylated polysaccharides in functional foods and therapeutic agents. [ABSTRACT FROM AUTHOR]

ABSTRACT In the present work, cellulose fibers were modified by grafting with poly(lauryl acrylate) and poly(octadecyl acrylate). The grafted materials were prepared by polymerization of the corresponding monomers via surface initiated atom transfer radical polymerization, starting from cellulose papers previously modified with 2-bromoisobutyryl groups. The polymerizations were carried out in the presence of ethyl-2-bromoisobutyrate, as a sacrificial initiator, added to control the molecular weight of the anchored segments, and polymerization kinetics. The grafting of both polymers was confirmed by infrared spectroscopy and elemental analysis. The effect of grafting these polymers on the thermal stability, morphology, and surface properties of cellulose fibers was studied using thermogravimetric analysis, scanning electron microscopy, and measuring water contact angle, respectively. The results reveal that grafting poly(lauryl acrylate) and poly(octadecyl acrylate) to cellulose confers the filter paper a hydrophobic character, and increases its affinity with pyrene, allowing the removal of this pollutant from water. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44482. [ABSTRACT FROM AUTHOR]

Summary: Gamma irradiation is a new starch processing and modification method. In this paper, the effects of gamma irradiation on starch structure and properties were summarised and discussed. In terms of starch structure, gamma irradiation destroys glycosidic bonds and significantly reduces the average molecular weight of starch, which may be the fundamental reason for the change in starch properties after irradiation. In addition, irradiation has no effects on crystal type but decreases the crystallinity of starch. Meanwhile, gamma irradiation can increase the specific surface area of starch granules but have no significant effects on the granular morphologies, indicating the damage to starch granules caused by irradiation proceeds from inside the granules. In terms of starch properties, gamma irradiation treatment decreases the viscosity, setback, breakdown, To, Tp, Tc, the enthalpy of crystalline melting, storage modulus, loss modulus, consistency coefficient and swelling ability of starches. In addition, gamma irradiation increases the b value, water absorption capacity, oil absorption capacity and solubility of starches. However, the results of the effects of irradiation on starch digestive, retrogradation and texture properties are not consistent in different studies. It may provide a reference for the application of irradiation in starch processing and modification. [ABSTRACT FROM AUTHOR]

The deconvolution of the molecular weight distribution (MWD) of polyolefins into Schultz–Flory most probable distributions has become the standard method to identify the number of site types on multiple‐site‐type olefin polymerization catalysts such as Ziegler–Natta, Phillips, and some supported metallocenes. This method has been used to quantify the effect of polymerization conditions and catalyst formulations on polyolefin MWD and olefin polymerization kinetics. Related methods have also been developed to deconvolute other polyolefin microstructure features, such as the chemical composition and comonomer sequence length distributions. In this paper, I explain the premises behind these deconvolution models and review the publications in this area, highlighting the advantages, disadvantages, and misuses of these methods. I also propose a revised formulation on how to model the MWD of polyolefins made with multiple‐site‐type catalysts using ratio distributions for propagation and chain transfer frequencies. The main objective of this overview article is to highlight the strengths, but also show the pitfalls, of polyolefin microstructure deconvolution methods. [ABSTRACT FROM AUTHOR]

Acrylic processing aids are used widely in rigid polyvinyl chloride (PVC) applications. Key functions of processing aids in terms of processing and performance are discussed in the paper. Effect of molecular weight of acrylic processing aids on their functions are studied. Additionally, effect of processing conditions, such as temperature and shear on fusion characteristics of PVC formulations are investigated. Shear rate in the processing was varied by means of rotor speed in torque rheometer. Processing aids of comprehensive molecular weight range are evaluated in the study. It was observed that relatively lower molecular weight processing aids have different response to change in shear and temperature than higher molecular weight processing aids. Depending upon fusion conditions PVC formulations can yield either a single or double fusion peak. Generally, it was considered that ultra‐high molecular weight processing aids yield a double fusion peak, however, it was demonstrated in the studies that it is not true. Fusion conditions, temperature, and shear are the main driving forces of fusion dynamics, resulting in either a single or double fusion peak. Relatively low molecular weight acrylic processing aids can also yield double fusion peak. Melt viscosity and shear thinning properties are also examined. Relatively lower molecular weight processing aids showed higher shear thinning behavior. Effect of temperature and shear on degree of fusion was studied. It was shown that optimum processing parameters can increase the degree of fusion by ~10%. [ABSTRACT FROM AUTHOR]

The bleach plant of a pulp and paper (P&P) mill presents a major source of wastewater containing toxic organic matter characterized as chemical oxygen demand (COD). Due to their high oxidizing power, oxidoreductases hold promise to be a key solution for the removal of dissolved organic material. Here, four oxidoreductases from different enzyme families were selected to treat bleach plant effluents. Haloperoxidase treatment of the final effluent resulted in the highest levels of decolorization (71%) and reduction of aromatic compounds (36%). Using single compound analysis, 27 low molecular weight compounds were found to be persistent throughout the wastewater treatment process and, therefore, classified as hard COD. The tested enzymes efficiently removed several of the identified COD compounds. Hence, this study suggests that the application of oxidoreductases will serve as an environmental‐friendly solution for reducing waste from P&P production. [ABSTRACT FROM AUTHOR]

ABSTRACT Waterborne polyurethane (WPU) has been intensively utilized as host materials for intrinsic conducting polymers. However, the stability and compatibility between polyaniline (PANI) and WPU remain a challenge for their composites. In this research, anionic-nonionic sulfonated waterborne polyurethane (SWPU) is adopted as matrix to prepare nanosized PANI- g-SWPU dispersions through chemical graft polymerization method, and the stability mechanism is systematically investigated. The PANI- g-SWPU dispersion is endowed with much higher stability and no PANI precipitation is detected after storage for 1 year when the PEG molecular weight is 1000 and R value is 1.2. The surface resistivity reaches the minimum when the graft time is 2.5 h, pH value is 2, n(APS)/ n(aniline) is 1, and the aniline content is 20 wt %. And the resistivity of the coated paper reaches 1.39 Ω cm, indicating that the as-prepared PANI- g-SWPU dispersion can be directly used as the antistatic coatings, which is also suitable for large scalable production. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45412. [ABSTRACT FROM AUTHOR]

Anionic ring opening polymerization of ε‐caprolactam (CL) results in the formation of high molecular weight polyamide 6 (PA6) within a few minutes. The monomer conversion rate is an important characterization parameter for polymerization process as well as the end products. This paper used PA6 films with different polymerization degrees as research object for the first time, and systematically compared the performance of four methods for measuring CL conversion rate. The analytical methods were solvent extraction (methanol, ethanol, or water), vacuum removal, thermogravimetric analysis (TGA), and absorbance ratio respectively. For all PA6 products, solvent extraction based on methanol/water and vacuum removal were effective methods for determine their conversion rates. And TGA was only applicable for samples with high degree of polymerization. The CL conversion rate obtained by solvent extraction based on ethanol and absorbance ratio was slightly higher than the real value, especially the latter. Moreover, a new method was discovered and validated during the research process, namely atmospheric devolatilization. The methodology and results in this study can be employed for guiding the production and application of polymers, especially the reactive processing of PA6. [ABSTRACT FROM AUTHOR]

In recent years, non‐traditional intrinsic luminescence (NTIL) materials containing only ester groups in their molecules have been emerging and received extensive attention and research. Nevertheless, the existing NTIL materials still have the problems of low molecular weight and insufficient mechanical properties, which limit their further application. Isosorbide is a kind of bio‐based rigid diol monomer which is mainly used to improve the heat resistance and mechanical properties of materials all along. Besides, the ring‐opening reaction under acidic conditions makes isosorbide‐based materials exhibit some new functionalities. In this paper, a series of isosorbide‐based copolyesters with high molecular weight are synthesized by a simple and economical two‐step melt polycondensation method. It is found that, on the basis of improving the thermal and mechanical properties of the materials, copolyesters also exhibit fluorescence emission in the visible region at the excitation wavelength of 350 nm. And the fluorescence emission wavelength can be adjusted from 400 to 480. This study broadens the functional application of the isosorbide‐based materials and effectively enriches fluorescence mechanism of NTIL. [ABSTRACT FROM AUTHOR]

Shrinking resources of fossil oil prompt search for other biosphere‐present substrates to obtain polyols, which in turn are basic components to synthesize polyurethane foams (PUF). Widely available examples are biopolymers like starch, cellulose, and chitosan. It has been shown that oligomeric chitosan as well as water soluble chitosan can be applied to obtain polyols and rigid PUF of good performance properties. In this paper, the higher molecular mass chitosans, insoluble in organic solvents and water, were converted to polyols and ultimately into foamed polyurethane plastics. The polyols were characterized by the infrared spectra (IR), 1H‐NMR, and MALDI‐ToF methods. Their properties, such as density, viscosity, surface tension and hydroxyl numbers, were determined. The PUF were obtained from these polyols of various molecular mass. The biodegradable, rigid PUF of enhanced thermal resistance were obtained. Their physical parameters like apparent density, water volume absorption, dimension stability, heat conductance, compressive strength, and heat resistance at 150 and 175°C were studied and compared with those synthesized previously from oligomeric chitosan and water soluble chitosan. [ABSTRACT FROM AUTHOR]

In this paper, the influence of different material trademarks, mass ratios, the melt mass‐flow rate (MMFR) and molecular weights (MW), mold and injection temperatures, Al2O3 powder and lignin on the shape memory properties of PLA/PCL SMP material (PPSM) were then analyzed in detail by different characteristic methods. Besides, three promising applications (Origami metamaterials and variable‐stiffness grippers) are provided utilizing the PPSM doped with Al2O3/lignin. Eventually, a compensating strategy was discussed to improve the final configuration of the SMP after multi‐cycles. The shape memory recovery ratios could be improved by increasing the MMFR of PLA and the MW of PCL. The addition of 2 g‐Al2O3 could shorten the recovery time, while the addition of 2 g‐lignin could increase the thermal‐recovery force and mechanical performance. The shape memory rate under 20 g weights, initial peak forces at room and high temperatures of the origami metamaterials could reach 57%, 2027.29 N and 17.49 N, respectively. The tensile force of banding rebars could reach 150.29 N, which is promising to apply into the construction field. [ABSTRACT FROM AUTHOR]

Carbon fiber‐reinforced epoxy composites (CFECs) continue to grow in demand for aerospace, mass transportation, electric vehicle, and energy efficient architecture due to their lightweight, high strength, and high modulus. However, CFECs are susceptible to delamination upon impact which can lead to premature structural failure. This paper investigates the interlaminar fracture toughness of unidirectional CFECs based on reactive polyetherimide (rPEI) modified multifunctional epoxy matrix system. The matrices were cured formulations of tetraglycidyl diamino diphenyl methane, triglycidyl para‐amino phenol, rPEI having different molecular weights (MW) and diaminodiphenyl sulfone. Multi‐phase morphologies were observed from the resin castings and CFECs containing different MW rPEI modifiers. Results show that the mode I fracture toughness (GIC) of the rPEI‐toughened CFECs can be increased by as much as 150% over the unmodified CFECs based on the MW and type of phase morphology that promotes crack‐bridging mechanism. In addition, rPEI‐modified CFECs exhibit better property retention (~80% of GIC) after prolonged solvent exposure. Highlights: A processing‐structure–property relationship based on CFECs is established.The amine‐terminated rPEI facilitates the formation of a strong bonding.The molecular weight effect of rPEI on the phase morphology was investigated.The rPEI enhances the interlaminar fracture toughness of the composites.The rPEI particle bridging is found to be responsible for the toughening effect. [ABSTRACT FROM AUTHOR]

Ultra‐high molecular weight polyethylene (UHMWPE) is one of the most prominent high‐performance thermoplastics for biomedical, leisure, and coating applications. Large‐scale recycling of UHMWPE is extremely difficult due to the high melt viscosity of the material as well as its exceptional chemical resistance and impact strength. There is a need for a commercially scalable methodology that can process the waste feedstock for mechanical recycling while sustaining the outstanding physical properties of the material. Solid‐state shear pulverization (SSSP) is a continuous, twin‐screw extruder‐based processing technique in which the low‐temperature application of shear and compressive forces impart changes in structure at different length scales to overcome the challenges of difficult‐to‐recycle polymers. This paper investigates the use of SSSP in mechanically recycling post‐industrial scrap UHMWPE (rUHMWPE) material from a local ski and snowboard manufacturer. The SSSP‐processed particles are flat, micron‐scale flakes with enhanced surface area, which can sinter very quickly when compression molded. The molded rUHMWPE samples in turn exhibit enhanced ductility and toughness compared to the as‐received scrap material, based on the tunable mechanochemical modification of the ethylene chains. [ABSTRACT FROM AUTHOR]

Proton MR spectra of the brain, especially those measured at short and intermediate echo times, contain signals from mobile macromolecules (MM). A description of the main MM is provided in this consensus paper. These broad peaks of MM underlie the narrower peaks of metabolites and often complicate their quantification but they also may have potential importance as biomarkers in specific diseases. Thus, separation of broad MM signals from low molecular weight metabolites enables accurate determination of metabolite concentrations and is of primary interest in many studies. Other studies attempt to understand the origin of the MM spectrum, to decompose it into individual spectral regions or peaks and to use the components of the MM spectrum as markers of various physiological or pathological conditions in biomedical research or clinical practice. The aim of this consensus paper is to provide an overview and some recommendations on how to handle the MM signals in different types of studies together with a list of open issues in the field, which are all summarized at the end of the paper. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to research improvement in the flexibility of epoxy acrylate 3D printing materials so as to satisfy the requirements of clothing attachments or accessories. Tensile tests, differential scanning calorimeter, XRD, rheological and Fourier transform infrared analysis were used to measure and compare the performance and characteristics of polyethylene glycol modified bisphenol‐A epoxy acrylate 3D printed samples with different molecular weights and contents. Based on a comprehensive analysis of the experimental results, the E/PEG1000(1/0.2)‐AA sample was revealed to have an optimal composition ratio. After secondary curing, the tensile strength of the sample rose to 8 MPa, with the elongation being converged to 30%. This paper provides a reference for the modification and improvement of flexible UV‐cured 3D printed products. [ABSTRACT FROM AUTHOR]

The "all in one" multifunctional and concentrated daily chemical products are required by the market, such as the long‐term release of anti‐bacterial, medical, or perfume agents. These functions mainly rely on the microcapsules, which could encapsulate these functional and unstable molecules, and then release them in the long term. To stabilize these functional solid particles in a high‐content surfactant, it is necessary to add a suspending rheological modifier. The poly(acrylic acid) (PAA)‐based rheology modifier is one of the most common additives in the industry of daily chemicals, for thickening or suspending. In this paper, linear PAA, and branched PAA polymers (Carbomer 941 and Carbomer 940) were selected to study the suspending ability of PAA‐based rheology modifier in high‐content surfactant and to investigate the effect of PAA polymer structure and Mw on the complex solution's rheological properties. The yield and viscosity test of the complex solutions of linear PAA and high‐content surfactant revealed that the addition of linear PAA could lead to lower yield stress and viscosity, and failed to suspend the polystyrene (PS) model microspheres due to its smaller mean square radius of gyration. The branched PAA polymer, Carbomer 940 and Carbomer 941 were more stable than the linear PAA in these two kinds of surfactant. More specifically, Carbomer 940 with a higher Mw, would exhibit higher yield stress and viscosity than Carbomer 941 with a lower Mw in nonionic surfactant alcohol polyoxyethylene ether (AEO) solvent with content less than 5 wt%. When the content was higher than 5 wt%, Carbomer 941 presented higher yield stress and viscosity than Carbomer 940, and successfully suspended PS microspheres in the 20 wt% AEO solution. This could depend on the polymer chain's elongation state of these two PAA‐based branched rheology modifiers. The same trend happened in the appearance of Carbomer 940 and Carbomer 941 in alcohol ether sulphate (AES) solution. However, the electrostatic repulsive force between the AES and PAA‐based rheology modifier could further make the polymer chain curl up and restrain the suspending ability in a lower content surfactant solution. Therefore, this fundamental research could guide the application of the anionic polyelectrolytes in the concentrated daily chemical product for stable suspending particles. [ABSTRACT FROM AUTHOR]

Stabilisers are added to gun and rocket propellants to react with species responsible for nitrate ester degradation during storage. The degradation products can be toxic and therefore harmful. There is a need to replace such stabilisers by "green" molecules and to study their degradation patterns through ageing. Propellant powders must remain chemically stable for a minimum of ten years when stored at temperatures equivalent to 25 °C [1]. α‐Tocopherol is a natural product that has been known for decades in other fields (Vitamin E) such as the pharmaceutical, food and cosmetics industries. It can act as a 'green' stabiliser" for smokeless powders because its heat flow is stable over time. In this paper, we characterise its stabilisation mechanism by identifying its main degradation products that could form within the propellant in an oxidising environment and in the presence of nitric acid. Liquid chromatography (LC) and gas chromatography (GC) separations are performed in order to dissociate the compounds formed during ageing. Compounds are then analysed by APCI‐timsTOF to obtain the molecular ion masses and then perform fragmentation spectra (MS/MS) to characterise their structure. In addition, using preparative HPLC‐UV, the degradation products are collected and analysed by NMR, with the aim of identifying the molecules. These identification methods help to unravel the stabilisation mechanism under accelerated ageing conditions. A time‐related fluctuation of the degradation products amounts is also observed, which indicates that the decomposition products also have a stabilisation effect. The three major α‐tocopherol degradation products are identified as: 2,3‐epoxy‐α‐tocopherylquinone, 5,6‐epoxy‐α‐tocopherylquinone and α‐tocored. [ABSTRACT FROM AUTHOR]

Polyacrylamide has been a hot topic of research in recent years, however, the preparation of block copolymers of polyacrylamide using ATRP method has been little studied. In this paper, polyacrylamide with reactive group bromine (PAM−Br) was synthesized by atom transfer radical polymerization (ATRP) using acrylamide (AM) as the monomer and water as the solvent, and polyacrylamide was used as the macromolecular initiator for the next reaction step. Then 9,10‐dihydro‐9‐oxa‐10‐phosphafi‐10‐oxide (DOPO) was organically modified to obtain acrylate monomers with DOPO functional groups (DOPOAA), and a mixture of water and N, N‐dimethylformamide (DMF) was used as the solvent to obtain PAM‐b‐DOPOAA block copolymers with controllable molecular mass and narrow molecular mass distribution. The effects of the molecular mass of the macromolecular initiator, polymerization time, and the molar ratio of catalyst to the ligand on the polymerization process were investigated. The structure and properties of the products were also characterized by 1H‐NMR, FTIR, XPS, DSC, TG, etc. The PAM‐b‐DOPOAA prepared by ATRP method can artificially design the length and ratio of the two chain segments, realizing one additive with two functions and the permanent existence of the function of polymer additives. [ABSTRACT FROM AUTHOR]

The focus of this paper is to report the quantitative synthesis of bis‐epoxy end functionalized polyisoprene (BETPI) macromonomers by anionic polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization. For anionic polymerization, more stable and sterically hindered living anions polyisoprene (Li+‐PIp‐Li+) react with epichlorohydrin (ECH) for the synthesis of well‐defined BETPI. For the high‐pressure RAFT polymerization, a novel bis‐epoxy end functionalized trithiocarbonate (BODAAT) is designed as RAFT agent for the polymerization of isoprene monomer to obtain well‐defined BETPI. The functionalities of the resulting BETPI are analyzed by Fourier transform infrared spectroscopy (FT‐IR), NMR, and size exclusion chromatography (SEC). Through two polymerization methods, the BETPI with 600–1000 Da of molecular weight and over 75% of epoxy end capping rate is obtained, which can be further utilized as highly reactive liquid macromonomers. [ABSTRACT FROM AUTHOR]

This research paper presents a hybrid modeling approach that combines mechanistic modeling and machine learning to predict the melt index (MI) of an industrial styrene–acrylonitrile (SAN) polymerization process. MI is one of the important quality variables of a thermoplastic polymer and is measured offline infrequently. The accurate prediction of MI is necessary for monitoring and quality control of the process. The proposed hybrid model consists of two parts: a white‐box submodel and a black‐box submodel. First, the white‐box submodel based on the process knowledge such as reaction kinetics predicts the polymerization‐related variables such as average molecular weights and rate of polymerization from measurement data. Then, the black‐box submodel which is a machine learning soft sensor model is trained to predict MI of the polymer product from both the output of the white‐box submodel and measurement data. The proposed approach is used to compare the MI prediction performance of hybrid models to that of data‐only machine learning soft sensor models and mechanistic models. As a result, the results indicate that the proposed hybrid model has an increased prediction accuracy and generalizability for MI prediction in an industrial polymerization process. [ABSTRACT FROM AUTHOR]

Fully conjugated polyazomethines (PAZs) exhibit large amounts of micropores among their many short branches in relatively planar structures based on their fully conjugated configuration. However, these fully conjugated structures cause insolubility and non‐processability of the PAZs because they may have strong stacking interactions due to their planar structures. In this paper, to overcome this problem, three short lengths of oligodimethylsiloxane (ODMS) grafts (x = 9, 18 and 39) were introduced by end‐capping reaction of aldehydes at the end of insoluble PAZs with amino‐terminated ODMSs as end‐capping agents. As a result, the insoluble PAZs became almost soluble (solubility > 95–100%) and their molecular weight could be estimated using gel permeation chromatography (Mw = 15.9 × 103 g mol−1). PAZ‐embedded mixed‐matrix membranes (MMMs) were fabricated using blend solutions containing only small amounts (1.0 wt%) of the solubilized PAZs with ODMS grafts and crosslinked polydimethylsiloxane (PDMS). The PAZs/PDMS MMMs showed ultrahigh permeability to oxygen which achieved 8600 barrer without a decrease of the original permselectivity of PDMS. The excellent oxygen permeability of the PAZs/PDMS MMMs may be caused by an effective increase of porosity based on the fully conjugated PAZ nanosheet. © 2022 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Polycaprolactone (PCL) is a biocompatible polymer that degrades slowly in physiological environments. Properties, including flexibility and easy processability, endow PCL with a high potential for being used in biomedical and pharmaceutical applications. Typically, PCL is synthesized by high energy‐consuming ring‐opening polymerization processes catalyzed by metallic compounds. In addition, obtaining safe PCL requires tedious purification procedures that, in turn, reduce yield and generate large amounts of toxic emissions. As an alternative, PCL can be synthesized by employing lipases as enzymatic catalysts. However, the properties of the resulting polymer are highly dependent on the experimental conditions. In this paper, we studied the effect of synthesis variables, such as solvent, temperature, the concentration of monomer and catalyst, and lipase source, on the molecular weight of PCL and the reaction yield. According to the results, the highest molecular weight and monomer conversion were obtained when ϵ‐caprolactone was polymerized by 10 % of heterogeneous catalyst that contains Candida Antarctica lipase B in toluene at 70 °C. Under these conditions, polymerization exhibited controlled characteristics and allowed obtaining a polymer with a molecular weight of 14.12 kDa while the dispersion index was 1.34. The enzymatic catalyst was stable and allowed PCL formation over five usage cycles with minor activity loss. The reported findings suggest that immobilized Candida Antarctica lipase B is a suitable catalyst for the synthesis of PCL and could be employed at a large scale with minor energy consumption and shorter reaction times compared with the conventional processes. [ABSTRACT FROM AUTHOR]

The rapid development of aerospace technology has put demands on the high tough thermosetting resins. Polytriazole (PTA) resins are a kind of high performance thermosetting resins as matrices of structural composites for aerospace parts. It is necessary to develop polytriazole resins with high toughness. In this paper, propargyl‐terminated polypropylene glycols (PtPGs) with various molecular weights (PtPG400, PtPG600, PtPG725) were synthesized and characterized. A series of PtPG‐toughened polytriazole (PPTA) resins were prepared by the "Click" reaction of PtPG and N,N,N′,N′‐tetrapropargyl‐4,4′‐diaminodiphenylmethane (TPDDM) with 1,1‐bisazidomethyl‐4,4′‐biphenyl (BAMBP). The curing behavior of the PPTA resins and the thermal, mechanical, as well as water absorption of the cured PPTA resins were investigated. The results show that the PPTA resins have excellent processing properties and can be cured and molded at 80°C. The molecular weight and the amount of PtPG have a significant influence on the mechanical properties of PPTA resins. When PtPG600 with the molar ratio of alkyne groups 1.0% is formulated, the impact strength of the cured PPTA‐600‐1.0 resin reaches 63.6 ± 8.2 kJ·m−2 and KIC 2.57 MPa·m−1/2, which are 57.4% and 41.2% higher than those of PTA resin respectively. The glass transition temperature (Tg) and water absorption of the cured PPTA‐600‐1.0 resin are 223.8°C and 0.22% respectively. [ABSTRACT FROM AUTHOR]

This paper is dedicated to improve the conversion efficiency of carboxylation for polymers of intrinsic microporous (PIM‐1). According to stable thermal properties of PIM‐1, a hydrothermal method is used for the first time to achieve the carboxylation conversion of PIM‐1 (C‐PIM), achieving a conversion rate of more than 90% at a reaction time of 10 hours, which is nearly five times more efficient than the most efficient conversion process currently available, preserving the film‐forming properties. The completion of the carboxylation conversion is verified using 1H‐NMR and 13C‐NMR, FT‐IR, and organic elemental analysis. It is found that the change in molecular weight affected the film‐forming properties of the membrane material, and the hydrophobicity of the C‐PIM membrane did not decrease compared with C‐PIM membrane reported in previous studies. The effect of C‐PIM on the selectivity of CO2 gas is explained from the microscopic to the macroscopic level by using physical characterization such as molecular structure analysis, XRD, cross‐linkage calculation, pore size and volume distribution, and fractional free volume (FFV) calculation. It verifies that the efficiency of CO2 adsorption and diffusion selectivity for PIM‐1 membranes has been improved by carboxylation, preserving excellent separation, and capture capacity of CO2. [ABSTRACT FROM AUTHOR]

In our previous paper, we showed that the molecular weight of linear, trimethyl‐terminated polydimethyl siloxane (PDMS) can be estimated using a standard curve by measuring PDMS endgroup‐related signal normalized to backbone‐related signal for PDMS films that are thick relative to the information depth of SIMS. Within industrial surface analysis laboratories, it is more likely that PDMS fluid is encountered as a thin film, perhaps as a contaminant or an additive that has exuded from a bulk material. This paper explores the influence of PDMS film thickness, substrate type, and primary ion projectile type (cluster vs. monoatomic) on the ratio of measured endgroup:backbone peak area ratio. These factors are shown to have a significant influence on the measured spectra, and these effects should be carefully considered before making molecular weight estimates of PDMS based on SIMS peak ratios. [ABSTRACT FROM AUTHOR]

Ring‐opening metathesis polymerization (ROMP) of strained macrocycles is a key method to prepare diverse polymers. However, lack of ring strain in most macrocycles is an impediment to polymerization. In this paper, the polymerization/oligomerization of unstrained macrocycles was achieved using a supramolecular approach, leading selectively to cyclic products. Diphenyl thiourea and other guest molecules were used as additives to the ROMP reaction of unstrained macrocycles. An intermediate host‐guest complex leads to the stabilization of the open form of the macrocycle after treatment with Grubbs catalysts, thereby favoring polymerization by inhibiting the ring‐closing reaction back to the monomer. This proof‐of‐concept enables ring‐expansion polymerization of unstrained macrocycles leading to cyclic polymers with molecular weights up to 6700 Da. [ABSTRACT FROM AUTHOR]

This paper deals with the development of polymeric nanocarriers based on amphiphilic copolymers of N‐vinyl‐2‐pyrrolidone and acrylic acid of various molecular weights synthesized through the AIBN‐initiated radical copolymerization of N‐vinyl‐2‐pyrrolidone and acrylic acid in the presence of n‐octadecyl mercaptan. The structure of the copolymers is characterized by 1Н NMR, 13С NMR, IR and MALDI‐TOF MS spectroscopy. It is shown that the length of the hydrophilic block defines the size of the nanoaggregates while impacting the steric stabilization efficiency and the probability of the interchain hydrogen bond formation. The hydrogen bonds formation between the residues of N‐vinyl‐2‐pyrrolidone and acrylic acid is in agreement with the reduction of the ζ‐potential of the nanoaggregates and the critical aggregation concentrations upon increasing the molecular weight. The presence of acrylic acid residues in the amphiphilic macromolecules leads to a higher affinity for doxorubicin and slow partial release of doxorubicin bonded with the aggregates' corona, which is helpful for reducing its cardiac toxicity. Nanoaggregates with a paclitaxel‐loaded hydrophobic core are obtained, showing the possibility of dual loading. The amphiphilic copolymers of N‐vinyl‐2‐pyrrolidone and acrylic acid containing an n‐octadecyl thio end group are thus promising candidates for combination cancer therapy with immobilized anti‐cancer drugs, paclitaxel, and doxorubicin. [ABSTRACT FROM AUTHOR]

High‐throughput screening (HTS) approaches are commonly used to accelerate downstream process development. Although most HTS approaches use batch isothermal data (KP screen) or bind and elute mode as screening procedure, different or new process designs are rarely investigated. In this paper, a mechanistic model case study for the separation of two different two‐component solutions was conducted and confirmed prior evidence. With these outcomes, a novel HTS screening procedure was developed including the determination of competitive adsorption‐based displacement effects and key parameter identification. The screening procedure employing an overload bind and elute (OBE) mode is presented in a case study dealing with IgG aggregate removal in a typical monoclonal antibody purification step, applying a Sartobind® S membrane adsorber (MA). Based on a MA scale down device, the OBE mode allows the determination of classical process parameters and dynamic effects, such as displacement effects. Competitive adsorption‐based displacement effects are visualized by introducing a displacement identifier leading to a displacement process map. Based on this map, the approach is transferred to and confirmed by the OBE recycle experiments with 4.6 and 8.2 ml benchtop scsale devices resulting in 45% reduced IgG monomer and 88% increased higher molecular weight species binding capacities. [ABSTRACT FROM AUTHOR]

In 2019 Ferreira et al. observed for the first time the influence of the superlubricity phenomenon of platelet‐like fillers on the properties of high molecular weight polyethylene (HMWPE) in the molten state. At the time, the study was carried out in the solid state of the polymer, analyzing the influence of the superlubricity phenomenon of oxide graphene and oxide graphite (GrO) agglomerates on the mechanical properties of the HMWPE. It was observed that the agglomerates, due to their superlubricity state, toughen the HMWPE polymer matrix. Here, mechanical tests (tensile), X‐ray microtomography, and scanning electron microscopy are carried out to elucidate this phenomenon. The same is observed for polystyrene containing very poorly dispersed GrO. The results presented here are a paradigm shift, as it has always been thought that the presence of agglomerates is harmful, but the opposite is proven here. In general, this paper can contribute a lot to the development of new composites and nanocomposites based on fillers that present the superlubricity phenomenon. [ABSTRACT FROM AUTHOR]

Complete heparin digestion with heparin lyase I and II results in a mixture of hexasaccharides and tetrasaccharides with 3‐O‐sulfo group‐containing glucosamine residues at their reducing ends. Because these tetrasaccharides are derived from antithrombin III‐binding sites of heparin, we examined whether this method could be applied to estimate the anticoagulant activity of heparin. Therefore, this paper presents a new low molecular weight heparin sample preparation method–chemical depolymerization. Qualitative analysis of the studied compounds and a comparison of their composition are an important contribution to the structural analysis of low molecular weight heparins, which has not been fully conducted so far. Qualitative on‐line liquid chromatography–mass spectrometric analysis of these resistant oligosaccharides is also described in this paper. [ABSTRACT FROM AUTHOR]

In this paper, a robust short‐chain branching (SCB) determination technique recently developed using IR5‐detected GPC (GPC‐IR5) for polyethylene resins is reported, wherein the IR5 detector is an infrared detector equipped with five filters set at different frequency ranges and a mercury‐cadmium‐telluride detector with thermoelectric cooling capability. Both intensity ratios of methyl/methylene and methyl/all C─H groups have very good linear relationship with the SCB content. Based on these relationships, an excel spreadsheet method is developed to deduce the SCB distribution across the molecular weight distribution using in‐house developed algorithms. The uncertainty of SCB determination using the GPC‐IR5 technique is found to be chromatographic signal‐to‐noise ratio dependent and can be explicitly expressed and calculated slice by slice. The SCB uncertainty is also found to be a function of experimental conditions and environment, which can affect not only the signals but also the noise levels at different IR bands. At a given polymer concentration, the higher the SCB content, the smaller the relative error bars. The SCB detection limit of this GPC‐IR5 technique is found to be at ≈0.5–1.0 SCB per 1000 TC for all samples tested. Some practical aspects for application of this technique are also discussed in this paper. [ABSTRACT FROM AUTHOR]

Materials exhibiting reversible changes of their photoluminescence properties upon exposure to heat have an immense potential in various advanced photonic applications. Particularly, the control over an on‐demand response of thermochromic luminescent materials (TLMs) similar to a chameleon is of great importance. However, it is still difficult and challenging to achieve it. Therefore, this paper reports a simple and effective way to construct TLMs, which involves the incorporation of the metal–ligand complexes into polyethylene glycol (PEG). Ratiometric or off–on response modes of these TLMs can be tuned by incorporating metal complexes based on either Zn2+ or Co2+ into PEG and by taking advantage of reversible metal–ligand coordination, dissociation, or excited‐state conformation changes of the resulting materials. Moreover, by choosing PEG matrices with different molecular weights, the thermochromic transition temperatures of these TLMs can be tuned. It is also demonstrated that the controllable response behavior of these chameleon‐like TLMs can be used in applications related to real‐life anti‐counterfeiting and security printing. This work opens novel opportunities for the development of smart materials with controllable responses useful for advanced photonic applications. [ABSTRACT FROM AUTHOR]

Herein, near‐infrared (NIR) photocontrolled iodide‐mediated reversible‐deactivation radical polymerization (RDRP) of methacrylates, without an external photocatalyst, was developed using an alkyl iodide (e.g. 2‐iodo‐2‐methylpropionitrile) as the initiator at room temperature. This example is the first use of a series of special solvents containing carbonyl groups (e.g. 1,3‐dimethyl‐2‐imidazolidinone) as both solvent and catalyst for photocontrolled RDRP using long‐wavelength (λmax=730 nm) irradiation. The polymerization system comprises monomer, alkyl iodide initiator, and solvent. Well‐defined polymers were synthesized with excellent control over the molecular weights and molecular weight distributions (Mw/Mn<1.21). The living features of this system were confirmed by polymerization kinetics, multiple controlled "on‐off" light switching cycles, and chain extension experiments. Importantly, the polymerizations proceeded successfully with various barriers (pork skin and A4 paper), demonstrating the advantage of high‐penetration NIR light. [ABSTRACT FROM AUTHOR]

Xylo‐oligosaccharide (XOS) can stimulate the growth of Bifidobacterium, it is widely used in functional food, nutritional products and other aspects. At present, XOS is mainly prepared by hydrolysis of the hemicellulose in plant materials by enzyme catalyzing, resulting the high cost. In order to find an efficient method to reduce the cost, XOS was prepared by synthesis from D‐xylose through oxalate acid catalyzing in this paper, getting the results as following: a light‐yellow product of XOS was obtained with the max yield of 53.75±3.48 %. Its molecular weight is in the range of 459–1306 g/mol, being oligomers contain 3–9 units of D‐xylose units. In addition, the XOS contains both of the basic units of α‐D‐xylose and β‐D‐xylose, mainly connected by both α1‐β4 and β1‐α4 glycosidic bonds. Therefore, this study develops a new method of XOS generation, doing benefit to the high value‐added utilization of xylose. [ABSTRACT FROM AUTHOR]

Thermoplastic polyurethane (TPU) has become the focus of attention in the green and sustainable materials field because of its superior processability and recyclability. In this paper, a series of polylactic acid (PLA) and polycaprolactone (PCL)‐based TPUs were successfully prepared by selecting PLA glycol, PCL glycol, isophorone diisocyanate (IPDI) and 1,4‐butanediol (BDO) through a one‐step polymerization method. The properties of the PLA and PCL‐based TPUs are comprehensively characterized by Fourier transform infrared spectroscopy, 1H NMR spectra, gel permeation chromatography, differential scanning calorimetry, thermalgravimetric analyzer, tensile test, dynamic mechanical analysis, scanning electron microscope, and so forth. The effect of hard segments content and PLA glycol molecular weight on the properties of PLA and PCL‐based TPUs was systematically studied. Notably, their performance shows a certain degree of regularity and can be controlled by adjusting the hard segments content or the molecular weight of the PLA glycol. The prepared PLA and PCL‐based TPUs have a tensile strength of 24.71 MPa, excellent thermal stability and out‐standing damping performance. Its tan δ max of 1.40 and an effective damping temperature range of 50°C also make it a green damping material with great potential. [ABSTRACT FROM AUTHOR]

Tactile sensing is considered essential for effective object handling by robots. To this end, flexible smart materials are being extensively researched for application as soft pressure sensors. This paper proposes a soft pressure sensor featuring a ferroelectric‐polymer sensing layer for dynamic pressure detection during robotic grasping operations. The solution‐processed sensing layer is optimized in terms of the molecular weight of the ferroelectric polymer and the processing solvent. The proposed sensor exhibits high sensitivity to pressure with minimal response delay. Furthermore, these sensors successfully sensitize a robotic hand, enabling the real‐time detection of pressure signals during object handling, thus demonstrating the potential of the proposed sensor for novel robotic interface applications such as biomimetic electronic skin. [ABSTRACT FROM AUTHOR]

The search for novel efficient antibacterial agents is attracting a great attention due to the unregulated use of common antibiotics and development of multidrug‐resistant bacteria strains. This paper proposes an eco‐friendly approach to obtain stable chitosan‐capped silver nanoparticles with controlled physicochemical and biological properties using reducing and stabilizing capacity of chitosan. The study of the influence of chitosan characteristics on the kinetic of Ag+ reduction showed that an increase in polysaccharide molecular weight led to a decrease in their reducing ability. The synthesized silver nanoparticles were characterized by UV and FTIR spectroscopy, TEM, XRD, DLS. The relationships between physicochemical characteristics of the formed silver nanoparticles and the type of used chitosan, as well as synthesis temperature, were determined. It has been demonstrated that spherically‐shaped (13–27 nm) and positively‐charged (zeta‐potential 26.1–29.5 mV) silver nanoparticles with a single symmetric SPR band at 408–418 nm are stable during 6 months in a colloidal form, and can be produced with the assistance of low‐molecular weight chitosan (20–30 kDa) at 95°C. The synthesized silver nanoparticles enhanced the antibacterial activity of kanamycin and ampicillin against both gram‐negative and gram‐positive bacteria. These results revealed the prospects for the application of chitosan‐capped silver nanoparticles to create new effective antibacterial systems (gels, films, etc). [ABSTRACT FROM AUTHOR]