The 50 most-cited articles in Journal of Applied Polymer Science, 2022

Abstract Polylactic acid (PLA) is a thermoplastic polyester that has received widespread attention for its environmentally friendly origin and excellent performance, and its potential to address the current problems of severe white pollution and scarcity of petroleum resources. This article focuses on the synthesis, modification, degradation and application of PLA. The main focus is on the modification of PLA with different environmentally friendly materials (natural organic materials, biodegradable polymers, inorganic minerals) in blends for defects such as the brittleness of PLA. In addition, the applications of PLA composites in the fields of construction, medical, packaging and oil and water separation are also introduced, which hopefully will provide some help to the promotion of PLA.

Abstract The article reviews the different methods of which, phytic acid (PA) can be employed as a flame retardant (FR) filler for different polymeric materials. The methods are critically discussed, based on the available literature and patents. Depending on the method used and the addition of FRs into a PA flame retarded system, different flame retarding modes of action and fire resistance performances are attained. The mechanism of action for PA‐based system remains similar to those observed in other phosphorus‐based FRs, namely, condensed and gas‐phase mechanisms.

Abstract Additive manufacturing has new revolutionary potential for carbon fiber‐reinforced polymers (CFRPs). Additive manufacturing of CFRPs combines the advantages of additive manufacturing such as customization, minimal wastage, low cost, fast prototyping and rapid manufacturing with high specific strength of carbon fiber. This article delivers a comprehensive review of additive manufacturing of short and continuous CFRPs. The article presents insight into different additive manufacturing techniques with an overview of commercially available methods for manufacturing short and continuous CFRPs. This review also includes mechanical characterization and analytical techniques discussed in the literature for CFRPs. The robust applications of short and continuous CFRPs in biomedical, electronics, and aerospace would highlight the importance of research and development in this field. In the end, drawbacks, recent innovations, and the future research directions underline the gap between research and commercialization of additive manufacturing of short and continuous CFRPs.

Abstract The advances in polymer chemistry research have revolutionized the field of smart materials and biomedical. Polyurethanes (PUs) are a versatile polymer class with diverse structure, morphology, and behavior under various conditions deemed suitable for many functional and intelligent responses. Owing to their biocompatibility, biodegradability, excellent mechanical strength, tailorable chemical, and physical forms, PU has drawn significant research attention in recent times for a wide range of applications. Herein, this review paper outlines PU's recent advances in specific applications encompassing functional textiles, intelligent functionality and medical usage. This article contains a comprehensive review of recent developments and research works concerning PU's direct involvement as coatings, 3D objects, or composite parts to add novel purpose to the textile substrates, smart objects, or medical applications. Commencing with PU's application for the waterproof breathable textiles, the review further explores recent research where PU was incorporated as a phase change…

Abstract In recent years, bio‐based polymers have emerged as an alternative to petroleum‐based polymers in various industries. The bio‐based materials are made from raw materials originating from natural sources, such as starch, cellulose, chitin, or bio‐degradable synthetic polymers (i.e., polycaprolactone and polylactic acid). In spite of several desirable properties of biodegradable polymers, for example, fully renewable, non‐toxic. Some properties like melt and impact strength, thermal stability, permeability, and so forth, still do not meet the demands for end‐use applications. One way to improve the properties of biopolymers and greatly enhance their commercial potential is to incorporate nanosized reinforcement in the polymer. The access of nano‐carriers to smart polymeric and bio‐materials are limited by polymerization methods. Bio‐polymers are considered an alternative to petroleum‐based fibers. These are directly produced by organisms. Smart nanoparticles are used in different medicines and their applications are size‐dependent. Among the different techniques used for…

Abstract Styrenic block copolymers (SBC) have been gaining attention as a specialty material in elastomer and composite industries over an extended period. Its unique segmental architecture, controllable mechanical strength, ease of processing, oxidative, and environmental stability enable versatile applications. SBCs with other unique features like ion‐containing blocks, vascular compatibility, and biostability are gaining popularity in several new‐age applications. The review mainly displays the new synthetic strategies for SBC having superior thermal and environmental resistance and how their morphologies get affected by the invention of different synthesis and molecular designing technologies. It elaborates prospects and future of SBCs in other innovative application fields like sensors for wearable devices, next‐generation proton exchange membranes for fuel cells, portable power sources for electric vehicles, shape memory polymers, and so forth. Its potential in biomedical applications like heart valves, urinary tract devices, coating for coronary stents, implants, and drug…

Abstract This article reviews the preparation strategies of dielectric polymers with high permittivity and low energy loss, as well as their applications in the field of energy storage and intelligent sensors. We discuss the dependence of dielectric properties of polymer composites on different types of dielectric polarizations, including interfacial polarization, orientational polarization, ionic polarization, and electronic polarization, as well as the improvement of dielectric properties by synergetic effects of multiple polarizations. Due to the difficulties of achieving both high dielectric polarization (hence high permittivity) and low dielectric loss, we focus on the energy loss mechanism of different polarization types and issues in the preparation process. We also discuss current applications and future prospects of dielectric polymers in the field.

Abstract Polyimide (PI) is one of the best engineering plastics with excellent thermal, mechanical, dielectric performance and chemical stability. Among various PI products, film is one of the most dominant types. If PI films are to be applied to optical devices and display equipment, it is necessary to improve their optical transparency in the ultraviolet–visible region. However, improving the optical transparency of PI films would affect their thermal performance including thermal and dimensional stability. Therefore, how to balance optical and thermal performance to obtain highly transparent PI films with the best overall performance becomes a focus of current research field. In this review, we categorize transparent PI films into highly transparent PI, transparent PI with high glass transition temperature ( T g ) and transparent PI with low coefficient of thermal expansion (CTE) based on their optical and thermal properties. Then, we review research progress in the field of polymer molecular design including synthesis strategies and properties in recent 5 years, to inspire…

Abstract Two‐part, commercial silicone elastomers are used in a variety of fundamental soft materials research and industrial applications due to their wide availability, ease of use, low cost, and mechanical tunability. This work seeks to create a library of moduli for three common elastomer systems with varied mixing ratios: Sylgard 184, Solaris, and Ecoflex 00–30, as well as provide a comparison of their adhesive properties. Shear storage moduli are quantified using parallel plate oscillatory shear rheology. The work of debonding is measured with spherical probe adhesion testing, and the static, advancing, and receding contact angles are measured via goniometer. Sylgard 184 can have shear moduli ranging from ~0.5 kPa‐620 kPa, Solaris from ~0.6 kPa‐175 kPa, and EF from ~1.3 kPa‐35 kPa measured at a frequency of 0.01 rad/s. In general, increasing mixing ratios creates softer samples. Additionally, softer samples are universally more adhesive, regardless of the material system. When comparing the different material systems, Sylgard 184 is generally the most adhesive, followed…

Abstract Polyurethane (PU) is a well‐known synthetic polymer consisting of isocyanates, polyols, and chain extenders. The incorporation of fillers into the PU polymeric matrix, including inorganic nanomaterials, synthetic polymers, natural components, quaternary ammonium salts, and commercial drugs, bestows the end‐products with unique and improved physicochemical properties. Fillers can be used to tailor the molecular orientation, crystallinity, cross‐linking, and functional chemical groups of PU‐based composites. The bactericidal ability of PU composites highly depends on their surface composition, morphology, charge, and stability. Recent advancements highlight the potential of PU composites in combating bacterial infections. In this review, the cutting‐edge of inorganic and organic‐based PU composites for antibacterial applications is addressed. Notably, selective examples of scientific reports' key findings and their crucial information on PU composites are discussed. Furthermore, the positive impact of PU composites on the future prospects of this field is explored. This…

Abstract To attain superior fire safety epoxy resins (EP), aluminum diethylphosphonate (AlPi) and nickel alginate were incorporated to EP in different proportions. The synergistic flame retardant effects between AlPi and nickel alginate on fire safety and mechanical properties of EP were investigated in detail. EP/AlPi9.5‐Nickel Alginate0.5 acquired the UL‐94 V‐0 rating with the highest limiting oxygen index value (28.9%). Besides, the thermal decomposition behaviors of the samples were researched by thermogravimetric analysis, implying that EP/AlPi‐Nickel Alginate exhibited the better thermal stability and char‐forming ability. Compared with EP, the peak heat release rate and total heat release were declined by 58.3% and 12.8%. And the addition of nickel alginate reduced the release of smoke. In particular, the incorporation of AlPi and nickel alginate increased the impact strength, flexural strength and glass transition temperature of EP. In perspective, the synergistic effect of bio‐based nickel alginate and AlPi opens a practicable avenue in decreasing the fire risk and…

Abstract Self‐healing polymers (SHP) are the polymers that have the capability to recover the material from any physical damage by responding to the damages or cracks in the material and heal the same. This self‐healing technology gives the polymers ability to recover from the cracks at an early stage by preventing them from any catastrophic failures, which increases the scope of applications of these materials. This review article highlights the key points on extrinsic self‐healing polymer and intrinsic self‐healing polymer by comparing their healing efficiency, advantages, disadvantages, and challenges in the prospect of their future development as well as their possible applications in space industry and construction of roads.

Abstract Solid waste generation has increased enormously due to development in a fast‐moving world. Large amounts of industrial and agricultural waste are either incinerated or subject to landfilling, accounting for increasing air and water pollution. The 3 “R”s of waste management, reduce, reuse, and recycle, in most cases, deduce themselves to a theoretical topic. However, a stage has reached where the primary importance should be given to waste management and sustainable development where reprocessing the materials into new functional materials helps to reduce the consumption of fresh raw materials and reduces various forms of pollution. In this context, this review focuses on eliminating adverse environmental impacts of solid wastes by using various industrial by‐products and bio‐wastes as raw materials for EMI (Electromagnetic interference) shielding applications. In this review, we covered the sources, effects of electromagnetic radiation, mechanism, and factors affecting EMI shielding, synthesis of shielding materials derived from animal waste, agricultural waste, paper…

Abstract Fused filament fabrication process presents drawbacks in mechanical properties observed when printing in the build direction (Z‐direction). Such anisotropic properties will affect the part's performances and have to be minimized during fabrication. This study aims to evaluate the effects of nozzle temperature, printing speed and specimen state (annealed or as‐printed) on porosity percentage and tensile properties for 3D printed polyetherimide (PEI) (ULTEM 1010) parts in Z‐direction. The results demonstrated that print speed is the most influential process parameter that should be adjusted in consideration with the other printing parameters. The specimens' state did not reveal a noticeable influence, as the amorphous nature of PEI is considered less receptive to annealing. The optimization method to achieve the best results yielded values of 360°C and 30 mm s−1 as printing conditions, followed by heat treatment. This was confirmed by porosity measurements, tensile testing, and scanning electron microscopy observations. The best performances of PEI material were 3425.5 MPa,…

Abstract The materials with low dielectric constant and low dielectric loss are vital for high integration degree of the circuit board. Although many polymers like epoxy resin exhibit excellent comprehensive performance, their dielectric constant is unable to satisfy high electronic packaging application. In this work, we present a simple grafting strategy via reaction between the hollow glass microsphere and polyhedral oligomeric silsesquioxane followed by blending epoxy resin to fabricate epoxy resin hollow glass microspheres composite materials. The superior heat resistance of hollow glass microspheres (HGM) can improve the thermal performance of composites. Due to the addition of Ge‐POSS, P‐HGM exhibited a good interfacial compatibility with epoxy resin matrix and forms an interfacial adhesion region. With the P‐HGM loading of 20 wt%, the fabricated composite materials exhibited the low dielectric constant of 2.59 and low dielectric loss of 0.0145. At the same time, the tensile strength, impact strength and flexural strength were 42.15 MPa, 24.33 kJ/m2 and 90.82 MPa,…

Abstract Direct ethanol fuel cells (DEFCs) offer a high degree of design flexibility, ranging from a single cell to a massive multi‐cell that can be used in various applications, including portable devices, transportation, and stationary applications. Unfortunately, the most significant barrier to the commercialization of DEFCs is getting low‐cost and ethanol permeability, high conductivity performance, and extended durability of polymer electrolyte membranes, as key components that highly influence the overall performance. In this paper, the recent progress in developing the polymer electrolyte membrane for the application of DEFCs has been comprehensively reviewed. Focusing on an updated modification of polymeric materials in the last 5 years, including Nafion‐based membrane, polyvinyl alcohol‐based membrane, polybenzimidazoles‐based membrane, chitosan‐based membrane, and sodium alginate‐based membrane, as well as factors and challenges that affected the performance of polymer electrolyte membranes have been discussed, including the main characterization, catalyst selection, cell…

Abstract The need for flexible energy storage devices for advanced technologies has encouraged researchers to focus on environmental‐friendly biopolymers. In this work, chitosan (CS) and potato starch (PS) biopolymers are blended to prepare proton conducting solid electrolytes. Based on the X‐ray diffraction (XRD) inspection, the most amorphous blended film with the lowest crystallinity degree was selected to prepare polymer electrolytes. The variation in Fourier‐transform infrared spectroscopy (FTIR) bands were used to investigate the occurrence of interactions among the ammonium thiocyanate (NH 4 SCN) salt and CS:PS polymer blends. The experimental results of electrochemical impedance spectroscopy (EIS) were simulated with electrical equivalent circuit (EEC) modeling to determine the circuit elements. The highest value of S cm −1 was recorded for the sample included 40 wt.% of dopant salt. The dielectric analyses were helpful in separating the regions ascribed to electrode and molecular polarizations. The combination of circuit elements achieved from the EEC modeling and Koops…

Abstract With the advancement of applications in biomedicines and bioelectronics, conducting polymers have attained huge significant attention. For such applications, poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is considered a potential conducting polymer because of its low cost, considerable stability, high conductivity and mechanical strength. Most importantly, its easy aqueous solution processability makes it more attractive. Over the last few years, PEDOT:PSS has been predominantly explored and investigated for different optoelectronic flexible devices, and recently it has been studied for biomedical applications. PEDOT:PSS based materials have made progress in biomedicines due to their properties such as biocompatibility, cell proliferation, antibacterial, nontoxicity and so forth. To adjust the desirable properties, special attention is required for altering the structure of PEDOT:PSS material. PEDOT:PSS offers excellent antibacterial properties against both gram‐positive and gram‐negative bacteria. Moreover, PEDOT:PSS demonstrates an important role in…

Abstract Limited investigations are available on the influence of chloride and sulfate solutions on pozzolana‐based cement rubberized concrete after crumb rubber treatment. Mechanical and durability characteristics of rubberized concrete are assessed and compared to conventional concrete. Five contents of crumb rubber (10%–30% at 5% of increment) are utilized for partially replacing fine aggregate in concrete. The optimum amount of crumb rubber in concrete is revealed at a replacement level of 15%. The specimens remained in the crystalline form after being immersed in NaCl (sodium chloride), Na2SO4 (sodium sulfate), and MgSO4 (magnesium sulfate) solution, according to structural analyses by XRD (X‐ray diffraction). When rubberized concrete is submerged in both sulfate solutions with the same concentrations and for the same amount of time, the specimens immersed in Na2SO4 solution lose less weight and compressive strength than specimens submerged in MgSO4 solution. The losses in compressive strength of conventional concrete are 1.86%, 3.57%, and 4.82% when immersed in NaCl, Na2SO4,…

Abstract There has been significant interest in the recent past to develop injectable hydrogel scaffolds that follow minimally invasive implantation procedures towards efficient healing and regeneration of defective bone tissues. Such scaffolds offer several advantages, as they can be injected into the irregularly shaped defect and can act as a low‐density aqueous reservoir, incorporating necessary components for bone tissue repair and augmentation. Considering that bone is a biocomposite of natural biopolymer and bioapatite nanofiller, there has been a growing trend to develop nanocomposite scaffolds by combining biopolymers and inorganic nanofillers to biomimic the hierarchical nanostructure and composition of natural bone. Furthermore, the nanocomposite scaffolds can be tailored to have patient‐specific bone properties, which can lead to better biological responses. The present article begins with the introduction, followed by an overview of polymer matrices, property requirements, and crosslinking techniques employed for injectable hydrogels. Various strategies to develop…

Abstract Developing thermosets with inherent recyclability and flame retardancy is a great importance from the views of fire safety, resource conservation and environmental protection. Owing to their superior mechanical properties, versatility, outstanding adhesion‐ability, durability, thermal, and solvent stability comparable to conventional thermosets while demonstrating end‐of‐life reuse, recyclable thermosetting materials have gained much interest as an attractive class of sustainable thermosets. The chemical structure of thermosets includes dynamic covalent networks that provide durability and reprocessability. However, these recyclable thermosets possess significant flammability, limiting their application in automobiles, railways, aircraft, buildings, and electronic items. Thus, it is urgent to include them with flame retardants. The goal of this review paper is to give a broad understanding of the study by highlighting and discussing recent advances as well as future prospects for inherently recyclable flame retardant thermosets (RFRs). Moreover, synthesis methods have been…

Abstract Demand for electronic materials with improved dielectric properties are increasing. One of the ways to reduce the dielectric constant is to incorporate fluorine atoms. In this article, a novel fluorinated epoxy resin (diglycidol ether of 2,4‐bis (1,1,1,3,3,3‐hexafluoroisopropyl) fluorobenzene (FB‐EP)) with 45.7 wt% fluorine content was synthesized from fluorobenzene, epichlorohydrin and hexafluoroacetone. The structures of desired monomers were characterized by NMR and FTIR. The epoxy resin FB‐EP was cured by copolymerization with hexahydrophthalic anhydride (HHPA) and by homopolymerization catalyzed with boron trifluoride ethylamine (BF3MEA), respectively. The curing reaction kinetics of the fluorinated epoxy and the properties of the cured materials were studied in comparison with those of common diglycidol ether epoxy resin (BADGE). The results of curing activation energy indicate that FB‐EP is reactive as the BADGE, and the four‐trifluoromethyl groups on FB‐EP do not negatively affect the cationic polymerization reactivity of the epoxy groups. The cured FB‐EP materials…

Abstract Superoleophilic and high‐strength electrospun membranes are promising materials for oil/water separation applications. Here we report the fabrication of a mechanically robust, hydrophobic polyurethane/multi‐walled carbon nanotube (PU/MWCNT) electrospun composite membrane for gravity‐driven oil/water separation. Various electrospun composite membranes with different MWCNT loadings were developed. Spinning parameters such as polymer concentration, solvent ratio, applied voltage, flow rate, and working distance were systematically optimized. The incorporation of MWCNT has increased the thermal stability, hydrophobicity, mechanical properties, and dye adsorption capacity of the PU membrane. The optimized composite fibrous membrane (PU/0.2‐MWCNT) exhibited a percentage elongation of 502%. All the PU/MWCNT composite membranes were found to be superoleophilic in nature. The optimized composite membrane showed the highest oil sorption capacity and lab‐scale oil flux of 14.21–24.07 gg −1 and 425.44 Lm −2 h −1 , respectively. In the oil sorption process, all electrospun membranes…

Abstract A series of self‐healing waterborne polyurethane (WPU) films utilizing reversible covalent bond acylhydrazones diol (PA) as chain extender were successfully synthesized. The self‐healing performance of WPU with different content of chain extender PA has been systemically characterized via cut‐and‐healing tests and mechanical quantitative evaluation. The film can repair cracks through acylhydrazone exchange reactions within 12 h. When the content of PA is 1.5 wt%, the WPU has the highest self‐healing efficiency of 90.5%. Meanwhile, the effect of PA mass fraction on the particle size distribution, mechanical ability, crystallization, water resistance properties, and thermal stability of WPU were evaluated. With the introduction of acylhydrazone bonds, the hydrophobicity of the WPU material was enhanced, while achieving self‐healing performance, which solves the problem of aging and replacement of materials. These results indicated that the self‐healing WPU exhibited great application prospect as a versatile material.

Abstract Epoxy resin is an attractive traditional thermoset that is widely used in a variety of applications. And its flammable problem has drawn an increasing number of researchers to solve it. As flame retardants, ammonium polyphosphate (APP) and aluminum hydroxide (ATH) were mixed in the epoxy matrix to create composites with an interesting synergistic flame retardant effect, and its mechanism were thoroughly investigated. When 10 wt% APP and ATH were added at a mass ratio of 3/1, the peak of heat release rate and total heat release were reduced by 48% and 38%, with a LOI of 28.9% and a UL‐94 of V‐0 rating. During the combustion process, polyphosphoric acid formed by the decomposition of APP could catalyze matrix decomposition to form a charring barrier and react with alumina formed by the decomposition of ATH to produce extremely stable aluminum metaphosphate, which covered the surface of burning matrix and hampered further combustion.

Abstract To prepare a fully organic polylactic acid (PLA)‐based bio‐nanocomposite, cellulose nanocrystals (CNCs) were grafted by PLA through ring‐opening polymerization (ROP) of L‐lactide monomers onto CNCs. The grafting process was evaluated by 1 HNMR and FTIR spectroscopic methods. The effect of surface‐modified CNCs (M‐CNCs) was investigated on thermal, mechanical, rheological, and dynamic mechanical thermal properties of PLA. The M‐CNCs were successfully dispersed in the PLA matrix. Isothermal and non‐isothermal DSC studies revealed that M‐CNCs caused an intensive increase in crystallization kinetics and therefore nucleation density and crystallization extent. DSC, XRD, and DMTA analyses indicated the formation of different crystal structures [α, α', β] in PLA after addition of M‐CNCs. Rheological analysis was carried out for microstructural investigation of the nanocomposites. Interestingly, after the addition of M‐CNCs not only the tensile strength and modulus of the samples increased but also the toughness of PLA was considerably improved.

Abstract Electrospinning is a facile technique to create porous nanofiber scaffolds with a high capability of natural environment mimicking. Here, co‐electrospinning of gelatin:TiO2, polycaprolactone:silk fibroin (G:T/P:F) was investigated with the aim of wound healing. Polycaprolactone improved the mechanical properties and gelatin:TiO2enhanced cellular interactions. Silk fibroin was extracted from theBombyx morisilkworm and increased the cellular and mechanical properties of the designed scaffolds. The morphology of the scaffolds was observed with field emission scanning electron microscopy (FESEM) and confirmed bead free porous nanofibrous structure. The fiber diameter rose after silk fibroin and TiO2addition but it was in the favorable fiber range. The contact angle, swelling, and mechanical properties of the G:T/P:F scaffolds supplied the requirements for skin tissue engineering. The designed scaffold showed over 80% cell viability with filopodia formation after 48 h according to cell adhesion observations and MTT assay results. The DAPI and LIVE/DEAD staining results confirmed…

Abstract Development of new adsorbent based on anionic silica precursor, cellulose nanofiber (CNF), and graphene oxide (GO) has prepared via ionic reaction followed by a sol–gel process. Different instruments were used for the characterization of the nanocomposite: Fourier transform infrared spectrometer (FTIR), X‐ray diffraction (XRD), scanning electronic microscope (SEM), Thermal gravimetric analysis (TGA), and transmission electron microscope (TEM). Methylene blue (MB) adsorption on CNF/GO and CNF/GO/silica nanocomposites achieved during 60 min. A pseudo‐second‐order kinetic model was fitted to the adsorption process, with a maximum adsorption capacity of 588.23 and 625 mg/g in a slightly alkaline solution, respectively. It was found that the adsorption capacity of CNF/GO and CNF/GO/silica could regenerate the MB up to four cycles with slight decrease from 98 to 93%. This study showed that CNF/GO and CNF/GO/silica nanocomposites are effective adsorbents for organic pollutants in wastewater.

Abstract Graphene agglomeration tends to develop with the increase of graphene loading. In this article, we present a unified model that first considers the evolution of graphene agglomeration and then incorporates it into the calculation of electrical and mechanical properties of agglomerated graphene/polymer nanocomposites. In the evolution of graphene agglomerates, a modified nanoparticle distance in terms of yield strength is introduced, while in the calculation of composite properties, a two‐scale framework that consists of the graphene‐rich agglomerates and the remainder as the graphene‐poor region is constructed. In electrical conduction, electron tunneling is modeled through Simmons formula and its difference with the widely used Cauchy function is compared. We highlight that both Simmons and Cauchy functions could well describe the interfacial tunneling activity, but the former is physics‐based while the latter is statistics‐based. In the calculation of nonlinear elastoplastic response, a field‐fluctuation method is adopted. We also demonstrated how the presented model…

Abstract In order to synchronously improve dielectric permittivity (ε′), breakdown strength (Eb), and thermal conductivity (TC) while inhibiting dissipation factor (tan δ) of raw Zn (Zinc)/PVDF (poly[vinylidene fluoride]) composites, two kinds of core‐shell structured particles of Zn@ZnO (zinc oxide) and Zn@ZnO@PS (polystyrene) were synthesized by high‐temperature oxidation followed by suspension polymerization, then they were composited with PVDF to elaborately generate morphology‐controllable high‐ε′ but low loss, and high TC composites. The results confirm that both the Zn@ZnO/PVDF and Zn@ZnO@PS/PVDF composites show markedly improved ε′, suppressed tan δ and conductivity over the original Zn/PVDF because of the induced multiple polarizations in the Zn@ZnO and Zn@ZnO@PS configurations and the barrier effect of constructed shells on direct contact of Zn particles. The second organic PS shell inhibits the loss and conductivity due to its high‐electrical resistivity, and further boosts the Eb and TC of the composites owing to enhanced interfacial compatibility between the Zn@ZnO and…

Abstract The objective of this study was to develop an eco‐friendly, cost‐effective, and efficient adsorbent using kappa‐carrageenan (KCG) and tamarind kernel powder (TKP) based cross‐linked 3‐D network hydrogel. The equilibrium swelling capacity of 1429% was achieved by optimization studies. The KCG/TKP hydrogel was characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, field emission scanning electron microscopy, energy dispersive spectroscopy, and thermogravimetric analysis. This hydrogel was employed for the efficient removal of brilliant green (BG) and rose bengal (RB) dye from wastewater. BG and RB were used as a cationic and anionic model dye, respectively. The adsorption capacity of model dyes on KCG/TKP was investigated under different parameters like dye concentration, pH, temperature, and adsorbent amount. With remarkable adsorption capacity, the hydrogel demonstrated a strong dependence on the pH of the medium. The kinetics, adsorption isotherm, thermodynamic studies, and reusability were investigated. The KCG/TKP hydrogel follows…

Abstract Bio‐based epoxy resins with low‐dielectric constant, low viscosity and excellent mechanical properties have great significance for the future of advanced electronic and microelectronic industries. Cyclosiloxane segment possesses low polarity, high‐dissociation energy, and elevated molecular volume, thereby making it useful for the synthesis of materials with low dielectric constant and viscosity. Herein, a tetrafunctional eugenol‐based epoxy resin (DEP) based on a cyclosiloxane structure was designed and prepared through a hydrosilylation reaction. Allyl glycidyl ether (AGE) was selected as a reference compound and generated a silylation epoxy resin (AGDEP). The viscosity of these silicone‐containing tetrafunctional epoxy monomers (< 0.315 Pa·s) was significantly lower than that of the conventional oil‐based epoxy resin (14.320 Pa·s). After curing with methyl hexahydrophthalic anhydride (MHHPA), the dielectric constant of DEP‐MHHPA was as low as 2.8 (10 MHz), which was superior to that of EP‐MHHPA. Notably, the glass transition temperature (Tg) of DEP‐MHHPA was as high as…

Abstract Development of the non‐halogenated flame retardants (FRs) is an emerging research area as halogenated FRs are prone to produce carcinogenic and persistent organic pollutants. In this context, 1,2,3‐triazole synergized FR polymeric materials noticeably attained great interest in the last decade. The mini‐review highlights the role of azide‐alkyne click chemistry with specific reference to 1,2,3‐triazole moiety covalently grafted FR for various polymeric systems. In particular, the intumescent FR mechanism of 1,2,3‐triazole has been reviewed and the technical evidence for the mechanism is provided by fourier transform infrared spectroscopy (FTIR), energy‐dispersive X‐ray spectroscopy (EDX), and X‐ray photoelectron spectroscopy (XPS) analysis. 1,2,3‐triazole moiety is increasingly proving itself to be a potent non‐halogenated FR and it has the potential to be adopted by the industry in near future.

Abstract Photoresponse of the Au/(Er2O3:PVC)/n‐Si diode was executed in a wide range of illumination intensity (P). Its basic electrical parameters such as ideality factor (n), barrier height (ΦB0), series and shunt resistances (Rs, Rsh), photocurrent (Iph), energy‐dependence of interface states (Nss), and photosensitivity (S) were calculated from the results of the current–voltage (I–V) measurements. At the negative‐bias region, an increase in Iph is observed due to the e−‐h+ pairs that occur as a result of increasing P and their drift in opposite directions under the internal electric field. The ln(Iph)–ln(P) plot shows a good linear behavior under various applied voltages. Their slopes vary from 1.47 to 1.64, indicating that empty trap levels, that is, levels not occupied by charges, are of low density. The values n, ΦB0, and Rs were obtained using the thermionic emission theory, Cheung, and Norde functions. The value of ΦB0 decreases with increasing n and P as linearly with ΦB0(n) = (−0.143n + 1.118) eV and ΦB0(P) = (−2 × 10−4P + 0.831) eV, respectively. This illumination…

Abstract Waterborne polyurethane (WPU) is an environmentally friendly material using water as dispersion medium. However, it is significantly restricted that most of the soft segments in WPUs come from oil. In this work, environmentally friendly and low‐cost castor oil is used as the soft segment of polyurethane, and KH550 modification could improve the thermal stability and flexibility of CWPU. The results show that the particle size of the modified CWPU nano‐emulsion gradually increased to 60.48 nm. Through FTIR and XPS analysis, KH550 is successfully introduced into the castor oil‐based waterborne polyurethane system. After the CWPU‐3% film is treated with NaCl, NaOH, HCl solution and high temperature, the groups in the system remain unchanged which shows CWPU‐3% film having good chemical resistance and high temperature resistance. When the addition amount of KH550 is 3%, the maximum contact angle of the CWPU film was 92.39° which reveals good hydrophobic property. The tensile strength of the films increased from 10.2 MPa to 12.8 MPa, and the elongation at break decreased from…

Abstract Natural fibers are a powerful competitor in the polymer composite market due to their availability, sustainability, obtainability, cost, and biodegradability. The surface of natural fibers was changed to increase mechanical qualities, hydrophobicity, and bonding with polymer matrix. This study exposes the influence of several surface treatments of coconut tree peduncle fibers (CTPFs) on the thermomechanical and water absorption properties of CTPF‐reinforced polymer composites. The CTPFs were treated with sodium hydroxide, benzoyl peroxide, potassium permanganate and stearic acid at a constant 40 wt% and individually reinforced in an unsaturated polyester resin matrix containing 60 wt% CTPFs. Chemically treated CTPFs improved reinforcement‐matrix adhesion and enhanced composite mechanical characteristics. In addition, the scanning electron microscope fractographical study of stressed composite specimens shows improved reinforcement‐matrix bonding. Moreover, the treated CTPFs have a higher cellulose wt%, which improves the composites crystalline nature, hydrophobicity and…

Abstract The present work aims to investigate the potentiality of reinforcing coconut tree peduncle fiber an agro‐waste with unsaturated polyester resin, optimizing its mechanical properties and promote as an alternative reinforcement to harmful synthetic fiber polymer composites. It was found that polymer composites with 40 wt% fiber content exhibited maximum mechanical properties and started to decline on further addition of fibers due to lack of sufficient resin to wet the fibers leading to fiber pull‐out and debonding under applied loads. This was also evidenced from the observed micrograph of specimen undergone tensile failure. In addition, the chemical bonding between the fiber and matrix was confirmed through Fourier transform infrared analysis. Also, the thermal stability was ascertained by the degradation temperature obtained through thermo‐gravimetric analysis. Moreover, the water absorption study in fresh and seawater exposed the pseudo‐Fickian behavior and aquatic properties of the developed composite, which was further confirmed by the crystalline size obtained through…

Abstract This research investigates the physical and mechanical properties of hybrid composites made of epoxy reinforced by kenaf and flax natural fibers to investigate the hybridization influences of the composites. Pure and hybrid composites were fabricated using bi‐directional kenaf and flax fabrics at different stacking sequences utilizing the vacuum‐assisted resin infusion method. The pure and hybrid composites' physical properties, such as density, fiber volume fraction (FVF), water absorption capacity, and dimensional stability, were measured. The tests of tensile, flexural, interlaminar shear and fracture toughness (Mode II) were examined to determine the mechanical properties. The results revealed that density remained unchanged for the hybrid compared to pure kenaf/epoxy composites. The tensile, flexural, and interlaminar shear performance of flax/epoxy composite is improved by an increment of kenaf FVF in hybrid composites. The stacking sequence significantly affected the mechanical properties of hybrid composites. The highest tensile strength (59.8 MPa) was obtained for…

Abstract Sensors based on electronic textiles (e‐textiles) have become increasingly prominent in the field of biomechanical monitoring technology due to multiple properties such as being lightweight, flexible, and comfortable, with increasing potential in incorporating into long‐term monitoring devices. Previous research has been conducted into textile strain sensors based on graphene for human motion monitoring, however most graphene e‐textile strain sensors exhibit poor sensitivity and stretchability. To our knowledge, no previous research has looked at knitted graphene‐based fabrics in regards to the fabric composition of the substrate. In this paper, we propose a graphene/fabric composite sensor using a cost‐effective dip coating method of an acrylic/Spandex knit fabric, and further explores its mechanical, electrical, and sensing properties. The developed graphene/textile composite sensor has a wide sensing range (up to 344%) and exhibits a good sensitivity with a high gauge factor of up to 16. As a wearable sensor, our sensing fabric can detect both large and subtle human…

Abstract Biobased flame retardant (FR) has attracted great interest owing to its green and degradable properties similar to polylactic acid (PLA). In this work, with ammonium polyphosphate (APP) as the core, chitosan (CS) and halloysite (HNT) as the shell, a biobased FR (APP@CS@HNT) with a core‐shell structure was prepared through the self‐assembly method. The flame retardancy of PLA composites has been improved with the addition of the FR (APP@CS@HNT). With the loading of 17 wt% APP@CS@HNT, the PLA composite shows a high limiting oxygen index value (29.4%) and achieves vertical burning (UL‐94) test V0 rating. Compared with pure PLA, the cone calorimetry test indicates that the peak heat release rate (PHRR) and total heat release decrease from 299.88 to 152.29 kW/m 2 and from 102.0 to 71.2 MJ/m 2 , respectively. The addition of APP@CS@HNT can also improve the smoke suppression performance of PLA composites. Such enhanced flame retardancy is mainly attributed to APP@CS@HNT prompting the PLA matrix to produce more continuous and denser carbon layers at a lower temperature to form…

Abstract Enhanced heat and moisture management has become highly urgent to clothing systems due to the global need to personalize the ventilation process. As a significant sector of apparel industries, membrane‐based clothing systems offer protection and ventilation functionalities. This review aims at providing a new viewpoint on efforts to improve heat and moisture management in membrane‐based clothing systems according to the latest advances in this field. The study terminates with presenting a perspective on current challenges and opportunities for future research directions in personal thermal and moisture management technologies. In fact, membranes with different functionalities used in clothing systems such as photonic membranes with heating and cooling performances, unidirectional liquid transport membranes, waterproof‐breathable membranes, shape‐memory membranes, thermoregulating membranes, thermal conductive membranes and finally protective membranes are investigated. The essential functions associated to different categories of the investigated membranes along with the…

Abstract This study describes a soft‐actuator grade thermoplastic polyurethane (TPU) with 73 ~ 86 shore A, the method of its fabrication and selected properties. The TPU was produced using bio‐based synthesized TPU (HP 2.5, HP 3.0, HB 2.5, and HB 3.0) pellets with bio‐based polyether‐biol (PO3G‐1000), and dicyclohexylmethane diisocyanate (H12MDI) and bio‐based 1,3 propanediol (PDO) and 1,4 butanediol (BDO) as a chain extender. The TPU was formed into a filament for fused deposition modeling (FDM) 3D printers during a melt‐extrusion process at 180 ~ 220°C. The manufactured TPU filaments were characterized by rheological, chemical, thermal, and mechanical analyses. The equivalence ratio 3.0 with a relatively large amount of HS with BDO as a chain extender, more hydrogen‐bonding peaks occurred. The transition temperature and mechanical properties increased depending on the [NCO]:[OH] ratio, and for BDO as the chain extender. However, it was found that when PDO derived from natural material was used, the thermal stability was better. From these results, samples of auxetic re‐entrant TPU…

Abstract There is an urgent requirement of replacing the environmentally hazardous petroleum‐based plastics with sustainable and efficient starch‐based bioplastics. Development and detailed characterization of the biodegradable bioplastics from plant‐based polysaccharides such as starch is essential to reduce plastic pollution in the environment. In this research, bioplastics were developed from an equivalent blend of starch from two different sources namely rice and potato (1:1, w/w), crosslinked with different concentrations of citric acid (CA). The effect of CA cross‐linking of starch‐based bioplastics was investigated on its physicochemical and functional properties. The X‐ray diffraction (XRD) spectra revealed that the synthesized bioplastics were amorphous in nature with broad diffraction peaks. Further, the peak at 1716 cm−1 in Fourier transform infrared (FTIR) spectra indicated the formation of ester bonds in CA cross‐linked bioplastics. Atomic force microscopy (AFM) revealed the surface roughness of the bioplastics decreased with increasing concentration of CA. Mechanical…

Abstract Linz‐Donawintz (LD) slag is a solid waste produced during the basic oxygen furnace process of steel making and is more often disposed of on nearby land causing a disturbance in vegetation and human health. Hence, judicial management of LD slag is a need for an hour. For this purpose, the usability of LD slags as a reinforcement material in epoxy composites was investigated in the present work. In this investigation, the physical properties (density, void content, water absorption rate), mechanical properties (tensile properties, flexural properties, compressive strength, hardness), and tribological properties (sliding wear behavior) are reported. From the experimental investigation, it is found that the density, void content, and water intake capacity increase with LD slag loading. The maximum voids present in the composite is 1.92% for epoxy/40 wt. % LD slag composite. Similarly, maximum water uptake of only 0.6% is observed for composite with maximum filler content and for maximum immersion time. Further, it is observed that the strength of composite under tensile and…

Abstract In the process of drilling with water‐based drilling fluid, polymer plugging agent is very important to solve the problem of wellbore instability in the formation with micropores and microfractures. In this study, N ‐isopropyl acrylamide and 2‐acrylamide‐2‐methylpropanesulfonic acid were grafted onto the surface of SiO 2 modified by vinyl trimethoxysilane by reverse suspension polymerization reaction, and a heat‐sensitive polymer plugging agent was synthesized. The structure analysis showed that the synthetic material was the target product, with a particle size of 49.665 μm, high‐temperature resistance and sensitive temperature response behavior. According to laboratory evaluation experiments, it can be seen that the addition of the polymer increased the electrostatic stability of bentonite particles and had a chemical inhibition effect. Under the action of temperature and pressure, the synthesized temperature sensitive plugging agent formed a dense hydrophobic membrane on the surface of mud cake, which physically sealed the microcracks and pores, and reduced the…

Abstract High‐performance thermoplastic composites are gaining attention as potential replacement for thermoset composites in high‐end structural applications owing to their superior fracture toughness and recyclability. In this study, polyaryletherketone (PAEK) and carbon fabric (CF) reinforced PAEK are compared with epoxy and epoxy‐CF composites. PAEK‐CF composites are prepared by film stacking method followed by compression molding while hand lay‐up technique was used for epoxy‐CF composites. PAEK and PAEK‐CF composites possess superior tensile properties, flexural strength and fracture toughness compared to those prepared from epoxy. The incorporation of CF improved the wear resistance in both PAEK and epoxy and PAEK‐CF exhibited the lowest wear rate. The investigation of interlaminar shear strength of the composites was conducted and the highest value observed for PAEK‐CF composite. Wear and fracture surface analysis suggested ductile failure for PAEK and PAEK‐CF composites and brittle failure in epoxy composites, as indicated by interfacial bonding/debonding and fiber pullout,…

Abstract The introduction of dynamic covalent chemistry into the field of polymer chemistry has resulted in a new class of network polymer materials named covalent adaptable networks (CANs). These new materials have effectively bridged two antagonistic materials, that is, conventional thermoplastic and thermoset polymers together, thanks to these dynamic exchangeable covalent bonds, making them recyclable. In this work, we report a catalyst‐free reprocessable polybenzoxazine‐polyurethane thermosetting system with activation of carbamate dynamic bond exchange. The curing characteristics and properties of this biobased polybenzoxazine‐polyurethane network have been determined by Fourier transform infra‐red (FTIR), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMA). Moreover, the tests of the recyclability of the material were successfully achieved under mild reprocess conditions (130°C, 10 min) thanks to the formation of abundant free phenolic hydroxyl groups. This work provides a promising potential for industrial applications as a new recyclable…

Abstract Polymers and their composites have played an important role in industrial development. Polymer composites are becoming much stronger and more competitive than other materials as a result of ongoing research and development. This was made possible by newly developed techniques that could alter the physical and chemical properties of constituents. One of them is the self‐reinforcement technique, which allows for the fabrication of high‐strength thermoplastic polymer composites with reserved degradability, which is not possible with glass fiber/carbon fiber reinforcement. A self‐reinforced polymer composite is made of a single polymeric material, which serves as both the matrix and the reinforcement. This review article discusses the use of self‐reinforcement in various polymers and its impact on mechanical, thermal, and fire properties. Furthermore, the effects of process parameters (such as temperature and time, an), reinforcement structure, and mechanical property variation on the structure of self‐reinforced composites are reviewed and presented in detail. In addition, the…

Abstract Stone cultural relics are widely distributed globally and have significant historical and cultural significance and research value. However, most of them have suffered severe weathering and erosion due to the physical and chemical effects of different climatic conditions. Herein, a series of nano‐silica/fluorinated polyacrylate composites as surface protective coatings to protect simulated stone cultural relics were prepared with dodecafluoroheptyl methacrylate (DFMA), acrylates, and different contents of nano‐silica. The storage stability, mechanical stability, coagulum rate, and surface tension of the composite coatings were measured. The UV absorption, chemical structure, surface morphology, and thermal properties of composite films were characterized. When the nano‐silica content was 6 wt%, the optimal nano‐silica/fluorinated polyacrylate (Si‐F‐3) composite with excellent comprehensive properties was applied in the protection of simulated stone cultural relics. Compared with the uncoated original stone samples, the simulated stone cultural relics treated with Si‐F‐3…

Abstract This review focuses on the optimization of the optical performance of polymer/dye blends in which dyes are physically dispersed in polymer matrices. The optimization of the optical performance of polymer/dye blends is discussed in terms of: (i) the preparation procedure of polymer/dye blends (melt processing is considered particularly effective for producing polymer/dye blends with optimal dye distribution); (ii) mechanical and thermal solicitations after polymer/dye blend preparation; (iii) the polymer matrix, whose affinity for the dye and crystallinity affects the optical performance the polymer/dye blend; and (iv) the dye, whose chemical structure and concentration are significant determinants of the optical properties of polymer/dye blends.