Showing papers in "Polymer Bulletin in 2021"

Polyaniline-TiO2-based photocatalysts for dyes degradation

Abstract: For the last few decades, photocatalysis has attracted as an emerging successful technology for purifying wastewater by dye degradation from households and industries. TiO2-based photocatalysis has gained wide attention due to its importance in energy source as well as its outstanding involvement in the reduction in environmental problems. Consequently, researchers and scientists are looking for the synthesis of polyaniline-TiO2-based photocatalysts which are widely being used for the degradation of dyes. Lately, the use of polyaniline as photosensitizers has proved that it immensely enhances photodegradation by its excellent photocatalytic activity under both ultraviolet light and natural sunlight irradiation. Considering this most unique performance of Polyaniline-TiO2-based photocatalysis, the present review provides the recent advances and trends in the development of ultraviolet and visible light-responsive polyaniline-TiO2-based photocatalysis for their potential application in environmental remediation by dye degradation.

Recent advances in dye removal from wastewater by membrane technology: a review

Abstract: Dye contamination of wastewater has become one of the most critical environmental problems these days. The most critical sources of dyes in wastewater are from industries such as textile factories, food, paper and printing products and vehicles productions. There are various techniques for the removal of dyes from wastewater such as adsorption, oxidation process, photocatalyst, biological decolorization and membrane separation technology. In this paper, the recent advances in the removal of dyes from wastewater by membrane technology as one of the most promising and effective water treatment methods have been reviewed. This review paper covers published articles mostly from 2000 to 2020. It is evident from literature survey articles that nanofiltration (NF) is the most studied type of membrane for the elimination of dyes from wastewater.

Developments in pressure-sensitive adhesives: a review

Abstract: An adhesive is a non-metallic substance used for the joining of two separate objects by applying it either on one side or both the sides of objects. One of the classifications of adhesives is based on the chemical nature, i.e. it can either be reactive or non-reactive, while the other segregates them depending upon the origin like natural or synthetic. The pressure-sensitive adhesives (PSAs) are one of the important classes following the mechanism of curing of the adhesive which do not undergo any chemical reaction or physical change during the adhesion process. PSAs are greatly replacing many conventional types of adhesive and are considered safe to use. The application of the hybrid polymers in the field of PSAs that consists of silane-curing organic compounds having wide formulation tolerance and outstanding mechanical properties is a major class in the upcoming PSA market. The present article discusses the various types of PSAs, their recent trends based on the various application properties with the structure–property relationship and their synthesis techniques.

Antimicrobial textile: recent developments and functional perspective.

Abstract: Antimicrobial textiles are functionally active textiles, which may kill the microorganisms or inhibit their growth. The present article explores the applications of different synthetic and natural antimicrobial compounds used to prepare antimicrobial textiles. Different types of antimicrobial textiles including: antibacterial, antifungal and antiviral have also been discussed. Different strategies and methods used for the detection of a textile's antimicrobial properties against bacterial and fungal pathogens as well as viral particles have also been highlighted. These antimicrobial textiles are used in a variety of applications ranging from households to commercial including air filters, food packaging, health care, hygiene, medical, sportswear, storage, ventilation and water purification systems. Public awareness on antimicrobial textiles and growth in commercial opportunities has been observed during past few years. Not only antimicrobial properties, but its durability along with the color, prints and designing are also important for fashionable clothing; thus, many commercial brands are now focusing on such type of materials. Overall, this article summarizes the scientific aspect dealing with different fabrics including natural or synthetic antimicrobial agents along with their current functional perspective and future opportunities.

Preparation and characterization of novel antibacterial blended films based on modified carboxymethyl cellulose/phenolic compounds

Abstract: The objective of this work is to re-use of agriculture waste via an environmentally friendly procedure to introduce multifunctional cellulose-based blend films using sesame seed meal extracted from agriculture wastes. The current strategy demonstrated the identification and evaluation of the bioactive compounds of sesame seed meal extracted from agricultural wastes via an ultrasonic procedure. Then, the sesame seed meal extract was loaded onto modified carboxymethyl cellulose within a matrix of a blend film. A cross-linked blend films based on the biocompatible modified carboxymethyl cellulose (m-CMC) with phenolic compounds (Ph) extracted from sesame seed meal were developed. The cross-linked m-CMC/Ph films were investigated by Fourier transform infrared spectroscopic analysis, while the surface morphology was investigated using scanning electron microscopy. Both mechanical and swelling properties were investigated. The m-CMC/Ph film exhibited excellent antioxidant performance as well as antibacterial activity against Staphylococcus aureus as Gram-positive pathogenic bacteria and Pseudomonas aeruginosa as Gram-negative pathogenic bacteria using colony-forming unit to provide further biocompatibility for prepared blend films. Additionally, molecular docking studies were carried out on effective films to evaluate their potential interaction against P. aeruginosa LolA (PDB: 2W7Q) and S. aureus metalloproteinase (PDB:1BQB) with a binding energy of − 3.7 kcal/mol and − 2.8 kcal/mol and short bond length of 2.076 A and 1.144 A, respectively. The computational calculations of the optimized monomer CMC and gallic acid were carried out to elucidate the HOMO–LUMO energy gap and interaction between them as well as the optimization of m-CMC/Ph to evaluate their interaction and film stability. As a result, the present study presents a novel simple approach to design smart biocompatible films for multifunctional healthcare and medical purposes using the biologically active extracts from sustainable plant wastes.

Impact of acid type and glutaraldehyde crosslinking in the physicochemical and mechanical properties and biodegradability of chitosan films

Abstract: Biodegradable chitosan films were produced using lactic and acetic acid solutions and glutaraldehyde as crosslinking agent by casting technique. The aim of this study was to evaluate the influence of different acids and the crosslinking on the characteristics and biodegradability of chitosan films. The films were analyzed through thickness, swelling degree, mechanical and thermal properties, chemical structure and biodegradability. The glutaraldehyde release was also evaluated. All films’ properties are deeply affected by the acid type and glutaraldehyde crosslinking. Crosslinking reduced the swelling degree of films, also increasing their fragility. The glutaraldehyde release from the films to the simulant solutions was not observed after the incubation period. Through biodegradation tests, it was observed that the crosslinking does not prevent films’ degradability but longer time is required. The qualitative analysis of ecotoxicity of the films suggests the possibility of composting the developed films. The films presented potential for application as membranes and in packaging, and different formulations can be used according to the desired final characteristics.

Electrochemical characteristics of solid state double-layer capacitor constructed from proton conducting chitosan-based polymer blend electrolytes

Abstract: This research is about the preparation of polymer blend electrolytes based on chitosan using solution cast technique Field emission scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR) routes were utilized for studying morphological and structural properties, respectively Electrical impedance spectroscopy (EIS) was engaged for determining the direct current electrical conductivity of the films The ion association at the highest salt concentration was actually present as confirmed by EIS and FTIR achievements The sample surface displays the protrude salts at the highest salt concentration Proton conducting polymer electrolyte with NH4Br as H+ (proton) provider has been used in electric double-layer capacitor (EDLC) applications The highest conducting sample was used to fabricate EDLC The transference number measurement indicated that the sample is mostly includes ion charge carriers which are vital for application in electrochemical devices The linear sweep voltammetry study revealed that the decomposition of the sample takes place above 154 V The fabricated EDLC device was performed capacitive behavior, as it can be seen from the cyclic voltammetry (CV) plot Since no redox peaks have appeared, it can be concluded that the EDLC did not undergo either oxidation or reduction The acquired value of specific capacitance (1325 Fg−1) is considered to be of great interest from the application viewpoints

Formulation and evaluation of interpenetrating network of xanthan gum and polyvinylpyrrolidone as a hydrophilic matrix for controlled drug delivery system

Abstract: The prime objective of the present study was to develop novel colon targeting xanthan gum/polyvinylpyrrolidone-co-poly acrylic acid hydrogels for controlled delivery of 5-fluorouracil at colon-specific site by combining the properties of natural and synthetic polymers. Xanthan gum (XG) and polyvinylpyrrolidone (PVP) polymer have been chemically cross-linked with acrylic acid (AA) monomer using ethylene glycol dimethacrylate and ammonium per sulfate/sodium hydrogen sulfite as a cross-linker and initiator, respectively. Different proportions of XG, PVP, acrylic acid and ethylene glycol dimethacrylate were blended with each other to fabricate pH-sensitive hydrogels by free radical polymerization. SEM, FTIR, TGA, DSC, XRD and sol−gel fraction analysis were carried out for characterization and structural analysis of polymeric system. pH-responsive behavior of fabricated hydrogels was investigated by performing swelling studies and in vitro drug release studies at both pH 1.2 and pH 7.4. Toxicity studies were performed on rabbits to evaluate cytotoxicity and biocompatibility. TGA and DSC confirmed that formulations were thermodynamically stable, while FTIR, SEM and XRD revealed the successful grafting of components. By increasing the content of polymer, monomer and cross-linker, gel fraction was found to be increased. Swelling capacity of hydrogels increases with the increase in concentration of monomer, while swelling capacity tends to decreases with the increase in concentration of cross-linker and polymer in hydrogel composition. pH sensitivity of hydrogels was confirmed by swelling dynamic and drug release behavior in simulated gastrointestinal fluids. Toxicity studies confirmed that hydrogels were non-toxic. Drug release kinetics revealed the controlled release pattern of 5-fluorouracil in developed polymeric network. Cross-linked XG/PVP-co-poly (AA) hydrogels can be used as promising candidate for controlled delivery of 5-FU for prolonged treatment period at colon-specific site.

Synthesis of polyaniline/clay nanocomposites by in situ polymerization and its application for the removal of Acid Green 25 dye from wastewater

Abstract: Synthesis, characterization and adsorption studies of polyaniline (PANI) and polyaniline/montmorillonite clay (PANI/MMT) nanocomposites have been carried out. In situ polymerization method was used to synthesize PANI/MMT nanocomposites using HCl as a catalyst and ammonium persulfate as an oxidizing agent. The molar ratio of monomer/oxidant was 1:1, and the polymerization was done at two different temperatures, i.e.,. 0° and 20 °C. Complete removal of Acid Green 25 (AG25) dye was achieved with PANI/MMT adsorbent. The kinetic adsorption data of AG25 dye were found to fit pseudo-second-order kinetic model. Since the removal of this dye takes place efficiently at a very fast rate, PANI/MMT nanocomposites will be excellent adsorbents in continuous adsorption systems.

Rheological investigation of the viscoelastic thixotropic behavior of synthesized polyethylene glycol-modified polyacrylamide hydrogels using different accelerators

Abstract: The present work is mainly focused on the synthesis and comprehensive rheological investigation of uniform and large macroporous polyethylene glycol-modified polyacrylamide hydrogels [PEG-m-P(AAm)] through free radical polymerization using different accelerators (ascorbic acid (AsA), thermal activation (60 °C) and N,N′,N″,N‴-tetramethyl ethylenediamine (TEMED)). The synthesis and surface morphology of the hydrogels were confirmed by FTIR and SEM techniques. Rheological investigation was carried out to determine the effect of accelerator nature on the rheological parameters and pseudo-plastic behavior of polymer hydrogels. A decline in viscosity with the increase in shear rate confirms the non-Newtonian pseudo-plastic behavior of hydrogels. From the creep-recovery study, the least strain (0.2) and creep compliance (2 × 10−2 Pa−1) for the thermally activated synthesized polymer hydrogel show more elastic property than the hydrogels synthesized by AsA and TEMED having strain values of 0.6 and 2.2, respectively. The thixotropic character of the hydrogels was found by the hysteresis loop test. The hydrogels prepared via AsA (998.825 Pa s−1) showed greater thixotropic behavior, followed by thermal activation (652.857 Pa s−1), and TEMED (531.9 Pa s−1) respectively. The hydrogels synthesized by different routes attained a completely different morphology, which can be applicable for specific applications. The obtained results verify that these materials may be used for the removal of potentially toxic materials, as a carrier for bioactive compounds and in cosmetic industry.

The effect of silica nanoparticles on polysulfone–polyethylene glycol (PSF/PEG) composite membrane on gas separation and rheological properties of nanocomposites

Abstract: Currently, composite membranes play a significant role in the separation of acidic gases Inorganic nanoparticles are used in these composite membranes to enhance the thermal and chemical properties of composites In this study, polysulfone–polyethylene glycol/silica (PSF–PEG/silica) nanocomposite membranes were investigated for the purpose of improvement of the N2, O2, CH4 and CO2 separation properties The results of gas permeability in nanocomposite membranes showed that the PSF/PEG 10,000 membrane, with 20 wt% of silica, provided the best gas separation properties CO2 permeability in the nanocomposite membrane with 20 wt% of silica was 1336 Barrer In addition, the ideal selectivity for CO2/N2 paired gases in this membrane was 4576, which was higher than the values obtained in the pure PSF membrane and the composite membrane with 20 wt% PEG 10,000 In addition, scanning electron microscopy, infrared spectroscopy, thermal gravimetric analysis, X-ray diffraction, differential scanning calorimetry and a tensile strength test were all used to examine the membrane structure and morphology of the nanocomposite Finally, mechanical rheometry was used to study the rheological properties of hybrid nanosized composites and the effect of nanoparticle percentage on them

Review on preparation and adsorption properties of chitosan and chitosan composites

Abstract: Compared with traditional polymers, biopolymers are more environmentally friendly due to their sustainable sources, easy decomposition and naturally recycled by biological processes. Among all biopolymers, chitosan (CS) proves attractive for several adsorption-related applications such as in gas capture and removal of dyes or heavy metal ions. However, there are considerable drawbacks such as unstable yield, non-uniform sizes, lack of process repeatability, low mechanical strength and chemical resistance. Thus, physical and chemical modifications have been proposed to obtain stable size and improved mechanical property of CS beads, microspheres, film or fiber. This paper introduces the research background of CS and modified CS as an adsorbent and analyzes the modification, application and adsorption mechanism of CS and CS composite materials. The research progress of the adsorption of metal ions, dyes and anions by CS and CS composite materials is reviewed, and the main factors affecting their adsorption performance are summarized. Finally, the development trend of CS as adsorbents is prospected.

Synthesis and characterization of ZnO NPs-doped PMMA-BDK-MR polymer-coated thin films with UV curing for optical data storage applications

Abstract: Hybrid material of poly-methyle-methacrylate (PMMA)-benzyl-dimethyl-ketal-azo dye methyl red (MR) thin film composites doped by various concentrations of ZnO NPs have been dip coated on glass substrates. The existence of azo dye (MR) in the composite was intentional to give the solution the desired pH level and to induce the cis ↔ trans cycles through illumination ↔ thermal relaxation. The optical and structural properties of the as-prepared thin films are investigated in relevance to ZnO NPs contents and the period of UV light illumination (short- and long-wavelength UV light). We found that the PMMA-BDK-MR doped by 1% ZnO NPs could be successfully used in optical data storage by implementing this composite in the WRITE/READ/ERASE cycle repeatedly. Specifically, it was found that the absorption band of the PMMA-BDK-MR doped by 1% ZnO NPs thin film lies between 350 and 600 nm upon illumination with 366 nm UV light for 10 s. Thermogravimetric analysis (TGA) was used to investigate the thermal stability of PMMA-BDK-MR/ZnO NPs. The TGA results are presented and interpreted. Furthermore, we investigated annealed poly-methyle-methacrylate-benzyl-dimethyl-ketal-methyl-red (PMMA-BDK-MR) doped by 1% ZnO NPs thin films. The trans–cis cycle has been repeated sequentially to confirm the hysteresis behavior for possible data READ/WRITE or ERASE memory applications.

A review featuring the fundamentals and advancements of polymer/CNT nanocomposite application in aerospace industry

Abstract: Carbon nanotubes (CNTs) have enormous application in various fields such as sensors, aerospace, super capacitors and photovoltaic devices, etc., and they are extensively exploited for number of other energy and environmental applications nowadays. With the rapid development and evolution in the field of aerospace industry, the existing developed technologies do not have adequate potential to overpower the requirements and demands of the new era. Nanocomposites based on CNT have procured significant attention in recent years for their applications in aircrafts, military crafts, missile and spacecraft due to advanced properties such as thermal stability, chemical stability, huge surface area, etc. In this review, the fundamentals in the field on CNT nanocomposites with reference to nanoparticles and conducting polymers such as DGEBA, polyaniline, polythiophene and polypyrrole are discussed. The main objective of the review is to study the advancement in aerospace applications of polymer/CNT nanocomposites.

Formulation and characterization of crosslinked polyvinyl alcohol (PVA) membranes: effects of the crosslinking agents

Abstract: The article addresses the formulation and characterization of the polyvinyl alcohol membrane (PVA) with citric acid, succinic acid and their mixing as crosslinking agents. PVA is highly hydrophilic and has excellent film (membrane) properties. Chemical crosslinking is the most common approach to stabilize and produce PVA membranes with enhanced mechanical resistance. Thus, we prepared membranes with variable PVA and crosslinking agents. The thermal properties of the membranes were analyzed using thermogravimetric method (TGA), while the functional groups formed in the membrane were determined using Fourier-transform infrared spectroscopy. The water absorption of the membranes was determined by the degree of swelling. The oxidative stability was obtained using the Fenton test. The ion exchange capacity was also evaluated. Membrane structure, morphology and surface properties were analyzed by topography and adhesion force using atomic force microscopy. The scanning electron microscopy was used to elucidate the fractures. The results indicated that the membranes exhibited roughness uniformly distributed, indicating homogeneous films and excellent crosslinking features allied to enhanced adhesion and strength properties with good stability.

Extraction of pectin from albedo of lemon peels for preparation of tissue engineering scaffolds

Abstract: Pectin is a type of anionic polysaccharide naturally found in a number of fruits and vegetables. Although pectin is widely used for food industry, its biomedical applications such as wound dressing, drug delivery and cancer targeting have also been investigated. In our study, we combined extracted pectin (from albedo of lemon peels) with chitosan (as a natural polymer) to synthesize chitosan/pectin cryogels. The extracted pectin was subjected to qualitative and quantitative analyses. Chitosan/pectin spongy supermacroporous cryogels were produced by cryogelation method at different combinations (100:0, 80:20, 60:40 and 40:60, w/w). Polyelectrolyte interactions between pectin and chitosan and crosslinking of chitosan with glutaraldehyde were verified by using FTIR. The porosity, swelling ratio, degradation behaviors and mechanical properties of cryogels were determined. SEM analysis demonstrated the pore morphology and average pore diameters of cryogels. After all analysis, 40:60 chitosan/pectin cryogel was selected for cytotoxicity studies. Glioblastoma (U-87 MG) cell line was used to evaluate the in vitro cytotoxicity of scaffolds. MTT assay and SEM analyses demonstrated the scaffolds were nontoxic, and supported cell attachment and viability.

The physical properties, antioxidant and antimicrobial activity of chitosan–gelatin edible films incorporated with the extract from hop plant

Abstract: The aim of this study was to develop active films based on blends of gelatin and/or chitosan containing different bioactive agents (hop extract, hop α-acids, or hop β-acids) The physical, mechanical, optical, structural, and barrier properties, as well as antioxidant and antibacterial activity of the resulting films were characterized and investigated The results indicate that films based on blends of gelatin and/or chitosan have extremely good mechanical properties, which are further improved upon the addition of bioactive agents All films with bioactive agents showed better ultraviolet light barrier properties than those without bioactive agents, conferring an advantage in protecting food against oxidizing reactions Fourier transform infrared spectroscopy analysis confirmed that there were interactions between bioactive agents and the biopolymers In addition, chitosan and/or gelatin edible films containing bioactive agents demonstrated strong antioxidant activities They were also shown to have antimicrobial activity and to be more effective against Gram-positive than against Gram-negative bacteria

Studies on favorable ionic conduction and structural properties of biopolymer electrolytes system-based alginate

Abstract: In this present work, the investigation of solid biopolymer electrolytes (SBEs)-based alginate-doped NH4Br was carried out and prepared via casting technique. The SBEs system was characterized using Fourier transform infrared, thermal gravimetric analysis, differential scanning calorimetry, X-ray diffraction, scanning electron microscope, and electrical impedance spectroscopy. Based on IR-analysis, it was shown that the complexation between alginate and NH4Br has occurred based on the changes of peak at COO− group of alginate. The interaction led to the improvement in amorphous phase and thermal stability of SBEs system when NH4Br was added. The ionic conductivity of SBEs system was found to achieve maximum value at 4.41 × 10−5 S/cm when 20 wt. % of NH4Br was added and the value was comparable with other types of polymer electrolytes system. The temperature-dependence ionic conductivity of entire SBEs system obeys Arrhenius behavior where the R2 ~ 1 and present system are thermally assisted. From IR-deconvolution approach, it can be found that the ionic conductivity of alginate-NH4Br SBEs system was governed by ions mobility, μ and diffusion coefficient, D. All these findings imply that present alginate-based SBEs system is potential to be applied in electrochemical devices, i.e., proton battery, supercapacitor and fuel cell.

Synthesis and characterization of chitosan nanoparticles containing teicoplanin using sol–gel

Abstract: Chitosan, as a natural polysaccharide, has a unique structure and multi-functional properties. One of the most prominent specifications of chitosan is high biocompatibility, good biodegradability, low toxicity and antibacterial and antiallergenicity properties. Chitosan has a high potential for controlled drug delivery. Therefore, investigating the loading capacity and release rate of chitosan at different conditions is important. By reducing particle size, chitosan has shown a high ability of teicoplanin loading due to its cationic property, which is important in this research. The aim of this study was to investigate chitosan nanoparticle potential for use in biomedical devices for drug delivery systems. Nanoparticles were prepared by ionic gelation with tripolyphosphate (TPP) ion, and the factors that affected chitosan nanoparticle size were investigated. The prepared samples were characterized using DLS, FTIR, TGA, DSC and XRD techniques. It is found at best condition with CS/TPP ratio of 2:1 nanoparticles were obtained at an average size of about 100 nm. The results confirmed that the drug (teicoplanin) loaded on the TPP cross-linked chitosan nanoparticles causes an increase in nanochitosan size and there was no interaction between teicoplanin and chitosan. Also, it is observed that 28.2% of teicoplanin was released in the first 10 h and the release is continued gradually to receive 37.4% in 100 h. Thus, it seems that chitosan nanoparticles mitigate the drug release and are suitable for sustained drug release.

Bridging the gap between rubbers and plastics: a review on thermoplastic polyolefin elastomers

Abstract: Thermoplastic elastomers (TPE) are studied for their unique properties of being easily processes and recycled. This paper focuses on the wide scope of thermoplastic polyolefin elastomers (TPO/TPE-O) which is one of the major classes of TPE. The performance of TPO is the cumulative effect of polyolefins and rubbers with the ease of processing due to the presence of thermoplastics. The study focuses on the classification of TPO, their routes of synthesis, composites, applications, and its impact on environment. The mechanical blending of polyolefins and conventional rubber was carried out to manufacture TPO. In further developments, the polyolefin elastomers (POE) were synthesized by copolymerization techniques to overcome the drawback of mechanical blending techniques. Environment-friendly blends of TPO are synthesized using industrial and municipal waste which includes scrap rubber tires, marble waste-filled polypropylene, computer body waste, etc. This technology will help in reducing the issue of landfills. The composites of TPO have been studied using different types of fillers which may be synthetic or bio-based. These include talc, carbon black, carbon nanotubes (CNT), Kenaf fiber, pineapple leaf fiber, etc. TPO have found their use in encapsulation, in electrical insulation, roofing, medical devices, and the automobile industry. Also, impact of using TPOs on environment is discussed here qualitatively.

Synthesis, characterization and absorption study of chitosan-g-poly(acrylamide-co-itaconic acid) hydrogel

Abstract: Hydrogels are hydrophilic cross-linked polymers that can absorb water several times their weight. In this study, synthesis of hydrogel based on chitosan, acrylamide and itaconic acid is prepared via radical copolymerization studied. To study the effect of initiator concentration, time, temperature, cross-linker concentration, monomer amount and itaconic percentage on the water absorption and grafting percentage of copolymerization reaction, experimental design was performed using response surface method. The determined R2 for the quadratic models for both grafting percentage and water absorption showed values greater than 0.9, which confirm that the model is properly fitted the obtained experimental data. The optimum conditions for maximum water absorption determined by RSM are: initiator concentration 9.51 mMol/L, time 5.27 h, temperature 79.97 °C, cross-linker concentration 42.77 mMol/L and itaconic percentage 18.42%. Synthesized hydrogel is characterized using FTIR and thermogravimetric analysis and scanning electron microscopy. The results indicate the porous structure of the hydrogel; thus, this porous natural-based hydrogel can be used in variety of applications such as medical and environmental fields as a drug carrier or water treatment application.

Antibacterial nanocomposite films of poly(vinyl alcohol) modified with zinc oxide-doped multiwalled carbon nanotubes as food packaging

Abstract: Poly(vinyl alcohol) (PVA) is a synthetic and promising film-forming polymer that is usually used in packaging applications In this study, PVA nanocomposite films with varying amounts of zinc oxide-doped multiwalled carbon nanotubes (MWCNTs-ZnO) were prepared The tensile strength of the nanocomposite films was 116% higher than that of the PVA film The thermal stability, water vapor transmission rate, hydrophobicity, and antibacterial activity of the nanocomposite films were better than those of pure PVA Tests on water loss in vegetables at room temperature revealed that the vegetable wrapped in packaging films could keep more water for more than 4 days Tests on the shelf life of chicken meat packed in films suggested that the growth of natural microorganisms in raw chicken kept in the preservation storage of the refrigerator could be inhibited for at least 36 h The findings of this study indicated that nanocomposite MWCNTs-ZnO/PVA films with good transparency had great potential applications in food packaging

Plasticized solid polymer electrolyte based on triblock copolymer poly(vinylidene chloride-co-acrylonitrile-co-methyl methacrylate) for magnesium ion batteries

Abstract: Limited global resources of lithium lead to the consideration of magnesium ion batteries as potential energy storage devices. Magnesium ion batteries have potential for high energy density but require new types of electrode and electrolytes for practical applications. Solid polymer electrolytes offer the opportunity for increased safety and broader electrochemical stability relative to traditional electrolytes. Herein, we report the development of solid polymer electrolyte for magnesium ion batteries based on triblock copolymer poly(vinylidene chloride-co-acrylonitrile-co-methyl methacrylate) (poly(VdCl-co-AN-co-MMA)). The polymer electrolytes are prepared by solution-casting technique using poly(VdCl-co-AN-co-MMA) with various concentrations (10 wt%, 20 wt%, 30 wt%, and 40 wt%) of magnesium chloride (MgCl2) salt. Among the prepared polymer electrolytes, the highest magnesium-ion-conducting polymer electrolyte is 70 wt% poly(VdCl-co-AN-co-MMA):30 wt% MgCl2 polymer–salt composition by electrochemical impedance measurements, and the obtained value of ionic conductivity is found to be in the order of 10−5 S cm−1. Addition of plasticizer succinonitrile in various concentrations (0.1 wt%, 0.2 wt%, 0.3 wt% and 0.4 wt%) with the identified polymer electrolyte of highest conductivity shows increased values of conductivity up to the order of 10−3 S cm−1. Observable changes in crystalline/amorphous nature of the polymer are analyzed using X-ray diffraction pattern. Glass transition temperature of polymer electrolytes has been found using differential scanning calorimetric studies. Transference number measurements have been made to confirm the ionic conductivity. The electrochemical stability for highest conducting plasticized polymer electrolyte is obtained from linear sweep voltammetry as 3.3 V. A primary magnesium ion battery has been constructed with prepared electrolyte of highest conductivity, and its performance and discharge characteristics are also analyzed. The open-circuit voltage of 2.18 V is obtained with the constructed primary magnesium ion battery.

Optoelectronically suitable graphene oxide-decorated titanium oxide/polyaniline hybrid nanocomposites and their enhanced photocatalytic activity with methylene blue and rhodamine B dye

Abstract: Organic–inorganic photocatalytic hybrid nanocomposites based on titanium oxide nanoparticle and polyaniline decorated with graphene oxide were synthesized via in situ chemical oxidative method using ammonium persulphate as an initiator and different weight percentages of TiO2 nanoparticles. The materials were characterized by using conventional techniques like UV–vis spectroscopy, FT-IR spectroscopy and X-ray diffraction. The electrical conductivity of the nanocomposites was found in the range of semiconducting materials. The nanocomposites possess broad application prospects covering the field of semiconducting devices, solar cells, sensors, microwave-absorbing materials and so on. The nanocomposites also exhibit promising photocatalytic activity towards degradation of methylene blue (MB) and rhodamine B dye in the presence of UV-light radiation. Compared to pure PANI and TiO2 nanoparticles, the GO/PANI/TiO2 nanocomposite showed much improvement in degradation efficiency. Significant photodegradation was observed with the molecules where 98.9% degradation was noted with 20% of TiO2 nanoparticles within 1 h under short-wavelength UV-light.

Study and modeling of thermomechanical properties of jute and Alfa fiber-reinforced polymer matrix hybrid biocomposite materials

Abstract: In this paper, we have investigated and studied the effect of thermal stress on the fiber–matrix interface damage of three new hybrid biocomposite and biocomposite materials. Our genetic simulation based on Weibull probabilistic models showed that the jute–Alfa/PEEK (PEEK: thermoplastic matrix—polyetheretherketone) hybrid biocomposite material is more resistant to the mechanical and thermal stress applied comparing with the other biocomposites such as jute/PEEK and Alfa/PEEK with the same volume fraction used in our genetic model. Our results also show that natural fibers improve the physical properties of biocomposite materials, especially hybrid biocomposite materials. This finding is similar to that found by Antoine Le Duigou et al. where they have shown experimentally that the natural reinforcements greatly improve the properties of composite materials and also they have a very low environmental impact.

Enhancing the dielectric properties of compatibilized high-density polyethylene/calcium carbonate nanocomposites using high-density polyethylene-g-maleic anhydride

Abstract: High-density polyethylene (HDPE) and nanoparticles of calcium carbonate (NCC) have been mixed via melt blending technique using different ratios of NCC as nanofiller and high-density polyethylene-g-maleic anhydride (HDPE-g-MA) as a compatibilizer. The combined effect of NCC as well as HDPE-g-MA concentrations on the breakdown strength and dielectric spectroscopy performance of HDPE was investigated. According to the American Society for Testing and Materials (ASTM) standard, the ac breakdown voltage of such nanocomposites was measured at constant 500 V/s ramp. The ac breakdown voltage was enhanced by 8.2% for HDPE/ 2wt% NCC and reached 21% in the presence of 1 wt% HDPE-g-MA which increases the efficiency of NCC dispersion. The surface morphology of synthesized HDPE/NCC and HDPE/NCC/HDPE-g-MA nanocomposites was characterized by field-emission scanning electron microscopy (FE-SEM). FE-SEM images showed an enhanced dispersion of NCC that may be due to good adhesion between NCC and HDPE under the compatibilization effect of HDPE-g-MA. Fourier-transform infrared (FTIR) analysis showed chemical interaction between HDPE-g-MA and stearic acid on the surface of NCC and physical entanglement among HDPE and HDPE-g-MA. Dielectric constant (e′) and tangent loss (tan δ) were measured under different applied frequency values from 1 kHz to 1 MHz.

Investigation of chemical bonding and electronic network of rGO/PANI/PVA electrospun nanofiber

Abstract: Reduced graphene oxide-reinforced polyaniline and poly(vinyl alcohol) (PVA/PANI/rGO) nanofibers were synthesized by electrospinning method with different rGO content varying from 1 to 5wt%. The PVA/PANI/rGO nanofibers were characterized by SEM, FTIR, Raman, XPS and UV–visible spectroscopy to investigate the morphology, vibrational bonding, elemental composition and optical properties, respectively. The XRD results reveal the broad peak at 2θ = 25° corresponding to (002) for rGO and three peaks at 2θ = 14°, 20° and 25° corresponding to (011), (020) and (200), respectively for PANI. The FTIR signatures at 1088, 1245, 1359, 1411, 1717, 2930 and 3305 cm−1 correspond to ν-(C–O), ν-(N–H), ν-(C–OH), ν-(C=O), ν-(C–H) and ν-(O–H), respectively. The optical bandgap of PVA/PANI/rGO nanofibers was decreased from 4.20 to 4.07 eV as the rGO wt% increased. The structural and electronic network of carbon was analyzed by semiempirical Gaussian peaks to predict various binding energy of core orbital binding energy spectra in PVA/PANI/rGO nanofibers.

Synthesis and characterization of neem (Azadirachta indica) seed oil-based alkyd resins for efficient anticorrosive coating application

Abstract: Neem (Azadirachta indica) is a fast-growing and evergreen tree with various medicinal values. During a severe drought, it sheds off its leaves and also produces fruits. The available literature revealed that the seeds from neem fruits contained oil varying in the range of 25–45% oil load. Neem oil was extracted from the dried neem seeds by the soxhlet extraction method using petroleum ether as an efficient solvent. Neem seed oil-based alkyd resins were synthesized by the alcoholysis–polyesterification process. The progress of the reaction was examined by determining the acid value at various time intervals. Further characterization of the oil and resins for the determination of molecular weight, structure, fatty acid composition, surface morphology and thermal stability was carried out by gel permeation chromatography, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, gas chromatography–mass spectrometry, scanning electron microscopy, thermogravimetry and differential scanning calorimetry, respectively. Attempts were made to study the effect of maleic anhydride content in the resins that changed the curing, anticorrosion, wettability and thermal properties of the resins and cured films. The curing of the alkyd resins was done by blending it with epoxy resin by gradually increasing the temperature from 60 to 210 °C. The coating of the alkyd resins over mild steel plates showed superior corrosion protection for several days. The wettability of the cured films was evaluated by measuring the water contact angle (WCA). The resin with the higher percentage of maleic anhydride showed better performance in different paints and surface coating applications. The synthesized alkyd resins from the neem seed oil possessed great application potential in beneath water marine vessel finish that opposed salt corrosion.

Shape memory polymer nanocomposite: a review on structure–property relationship

Abstract: Shape memory polymers (SMPs) are among the main groups of smart materials widely used in smart textiles and apparels, intelligent medical devices, sensors & actuators, high-performance water–vapor permeability materials, morphing applications, and self-deployable structures in spacecraft. However, SMPs have some limitations: comparatively low tensile strength and stiffness, relatively low recovery stress, low thermal conductivity, inertness to electrical, light, and electromagnetic stimuli accompanied by slow responsibility and low recovery time during actuation, which often limits SMPs potential applications in high-performance field. In recent years, researchers have focused more on shape memory polymer nanocomposites (SMPNCs) than the classical composites to overcome this limitation of the SMPs, as nanofillers have a large surface area and strong interaction with polymers. This review thoroughly examines the progress in SMPNCs, including the very recent past, with a particular focus on their structure–property relationship. Considering all the SMPs, the most commonly used SMPs like polyurethane, epoxy, polycaprolactam, polylactic acid, and polyvinyl alcohol along with carbon-based (i.e., CNTs, carbon black, graphene oxide, graphene nanoplatelets, graphene quantum dots, nano-diamonds), metal oxide-based (i.e., Fe3O4, TiO2), cellulose-based (i.e., cellulose nanocrystals, nano-cellulose gel), and other nanomaterials like nano-clay, TiN, AuNRs, organic nanoparticles, silica, sepiolite, silsesquioxane, and hydroxyapatite nanofillers are discussed. The future development of SMPNCs may enhance their performance under thermal, electric, light (UV/NIR), magnetic, and solvent (pH/water) stimuli, which may open the door to more advanced applications in the field of aerospace, robotics, sensing and actuation, and biomedical.

Fabrication and evaluation of structural, thermal, mechanical and optical behavior of epoxy–TEOS/MWCNTs composites for solar cell covering

Abstract: In the present study, hybrid organic–inorganic composites were fabricated from epoxy–TEOS (tetraethyl orthosilicate, Si(OC2H5)4) with various ratios (0–10 wt%) of multiwall carbon nanotubes (MWCNTs) as reinforcing nanofillers by the sol–gel method. The effect of the MWCNTs ratios on the structural, optical and mechanical characteristics and the thermal conductivity of the epoxy–TEOS/MWCNTs composites is investigated. The X-ray diffraction (XRD) analysis reveals that the pure epoxy-TEOS is amorphous, while epoxy–TEOS/MWCNTs composites are crystalline with an orthorhombic crystal structure that has an average crystallite size of 3.9 ± 0.15 nm. In addition, thermal stability and thermal conductivity were improved by adding TEOS and MWCNTs, whereas the exothermic peak temperature decreases compared with pure epoxy-TEOS. Similarly, the hardness Shore-D and tensile strength reach the optimum value at 4 wt% MWCNTs content. The significant improvement in the mechanical and thermal properties of the prepared composites could be attributed to the synergistic effect of MWCNTs and epoxy–TEOS which was emphasized by Fourier transform infrared (FTIR) spectroscopy. Moreover, epoxy-TEOS sample has high optical transmittance (T) within the visible region, but the composites samples are transparent at λ < 800 nm and have a lower value of T. The indirect optical band gap decreases from 3.59 to 2.91 eV with an increase in MWCNTs fractions from 0 to 10 wt%, respectively. However, the glass transition reflects the onset of decomposition temperatures was also considerably increased. The acquired outcomes such as a large increase in thermal conductivity and tensile stress coupled with reduced T make the composites readily applicable for a variety of applications.