Air pollution is a recently global environmental problem due to rapidly industrial and economical activities, which results of serious threats to human's living environment and natural ecosystem. Fibrous membrane is a useful method to filter air pollution particles. Therefore, this study used Taguchi method to determine factors influence, while four factors included ratio of PI and PES, flow rate, voltage, and spinning time, for testing filter efficiency of electrospinning fiber. Spinning time of 20 min was defined as the best condition to generate the fibrous membrane with filter efficiency and quality of 99.54% and 5.56, and flow rate of 0.15 ml/h was the best condition to form the fibrous membrane with filter efficiency and quality of 93.84% and 0.88. Thermogravimetry and differential scanning calorimetry were used to conduct thermal analysis of nano-fiber membrane, and decomposed temperature of PI/PES was about 500 °C. Temperature of hot gas filtration usually occurred at the temperature of above 260 °C, such as 200–350 °C for waste incineration, 150–300 °C for concrete producing, and 171–210 °C for crematorium operation, so the PI/PES acquired potential advantage on application of hot gas filtration because of its high temperature resistance and high filter efficiency.

Collagen-based biomaterials are highly effective owing to their high biocompatibility and non-immunogenicity, but their biological application is still constrained because of poor thermal stability. The greener crosslinkers devoid of aldehydes and toxic precursors have recently evoked considerable interest. In this work, biocompatible and multifunctional carboxyl polymer (MCP) has been synthesized by a simple one-step carboxylation reaction by modifying the hydroxyl group in the monomer, followed by polymerization in aqueous conditions. The synthesized polymer has been used for both collagen stabilization and leather processing. The circular dichroism studies revealed a significant change in the secondary structure of the collagen with increasing concentration of the MCP, and thermal stability of the rat tail tendon is enhanced up to 70 °C. The application of MCP as a crosslinker for collagen in the leather-making process along with metal salts increased the leather's thermal stability and improved uptake of the metal salts. The interaction mechanism of MCP and the metals during the tanning process is through complexation with carboxyl pendants available on the MCP backbone, as confirmed by UV–Visible and IR spectroscopy. The experimental leathers showed a uniform penetration of tanning agents and excellent mechanical properties compared to the control leathers. Further, biocompatibility studies using 3 T3 fibroblast cells revealed that the MCP did not induce any significant cytotoxicity with cell viability of 96%, confirming the non-toxic nature of the synthesized polymer. Thus, the current study opens a new path for sustainable alternative polymeric crosslinkers for collagen stabilization and its potential application in biomaterial and leather-making fields.

In this work, a bio-based reprocessable and degradable polybenzoxazine with acetal structures was designed and prepared. A diphenol containing acetal structures (DVEA) was reacted with stearylamine and paraformaldehyde to obtain a benzoxazine monomer (DVEA-s). The curing behavior of DVEA-s was investigated using differential scanning calorimetry and in-situ Fourier transform infrared spectroscopy, and the curing kinetics of DVEA-s were also studied. Due to the thermal exchange of acetal structures, the obtained polybenzoxazine (PDVEA-s) exhibited quick stress relaxation. Mechanically crushed PDVEA-s could be reprocessed by hot-pressing at 120 °C for 10 min. Furthermore, the degradation properties of PDVEA-s under different conditions were studied. The results showed that PDVEA-s could be completely degraded in acidic tetrahydrofuran aqueous solution at 50 °C in 4 min.

A star-shaped flame retardant containing Si/P/B (SiFAD) was synthesized and used to regulate the performance of epoxy (EP). The SiFAD modifies the flame retardancy, toughness and transparency of EP. The EP containing 6 wt% SiFAD displays a UL-94 V0 rating and a limiting oxygen index (LOI) of 34.7 vol%. The SiFAD promotes the early degradation of EP, increases the amount of char formed at high temperature, and improves the flame retardancy through the combined actions of gas phase and condensed phase. The tensile and impact strength of EP are both improved, especially the impact strength of EP containing 4 wt% SiFAD is 15.8 kJ/m2, which is 139% more than that of EP. The SiFAD in EP constructs high free volume through bridge effect, thus improves the impact strength of EP. In addition, microphase separation is produced in EP composites which is so small that the EP composites keep good transparency.

Nonconventional luminogens, represented by clustering-triggered emission (CTE) materials, have attracted increasing attention owing to their unique intrinsic emission and promising applications. However, the influencing factors of clustering-triggered emission and gelation behavior remain poorly understood. Herein, a series of poly(thioether)s with different pendant groups were synthesized and their unique properties were studied. Owing to the similar molecular structure, all five poly(thioether)s exhibited visible photoluminescence, but the intensity varied when the pendant group or solvent changed, which could be attributed to different clustering degree between polymer chains. Moreover, poly(thioether)s with different pendant groups showed the diverse gelation behavior during polymerization process. The impact of pendant group on the clustering-triggered emission property and gelation behavior of poly(thioether) derivatives were investigated in detail, which might be of great fundamental value for the rational design of functional nonconventional luminogens for biological and medical applications.

Hydrogels have received widespread attention as flexible strain sensors in the fields of human motion detection and health monitoring. However, the presence of large amounts of water in traditional hydrogels leads to poor mechanical properties and low anti-freezing, which severely limits their applications. Herein, a novel PVA/DMSO/CMC/AlCl3/TA/LiCl (PDCATL) composite organo-hydrogel was developed by freeze-thaw and salt solution immersion methods, using polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), aluminum chloride hexahydrate (AlCl3·6H2O) and tannic acid (TA) dissolved in a dimethyl sulfoxide (DMSO)/water binary solvent. The PDCATL organohydrogel exhibited high tensile strength and elongation at break (up to 1.90 MPa and 587%), which can withstand >6000 times its own weight, good anti-freezing and excellent transparency (>90% light transmission). The PDCATL organohydrogel still maintained excellent transparency, flexibility, recyclability and signal sensing capability at low temperatures (−20 °C). The PDCATL organohydrogel also had good strain sensitivity (GF = 1.82) as a wearable strain sensor and can be used to detect motion and physiological activity signals in various parts of the human body. This study will provide a viable avenue for the application of hydrogel sensors in the fields of visual human-computer interaction, wearable sensors, visual optical detection and medical health detection.

The use of immobilized enzymes as biocatalysts in industrial bioprocesses has gained attention due to their catalytic efficiency and environmental benefits. Despite showing significant potential in numerous experiments, their practical applicability remains a challenge due to various factors such as the separation of materials after use, production costs, and resistance to stirring. In response, a polyacrylamide (PAM) bead was developed to support the enzyme utilizing the high hydrophilicity of PAM to promote enzyme activity. This study demonstrated a novel and straightforward technique for developing a PAM bead with wrinkles and a rough surface that can be filtered out easily. Instead of typical entrapment, the bead was chemically modified, achieving amine functionality at 3.8 mmol/g, then covalently coupled with xylanase, resulting in significant improvement in stability. The activity of PAM-xylanase was maintained at approximately 90% on day 30 of 30 °C incubation, which was at least 10 times more stable than the free enzyme. Moreover, the bead could be reused 5 times with a conversion of approximately 91% compared to its initial hydrolysis, making it a promising alternative to immobilized biocatalysts currently in use., making it a promising alternative to immobilized biocatalysts currently in use.

Recently, temperature-sensitive hydrogels have gained great interest as rectal gels. In this study, we selected temperature-sensitive hydroxybutyl chitosan gel (HBC) cross-linked with graphene oxide (GO) to improve biocompatibility. First, modified Hummer and ultrasonic stripping methods were used to synthesize stable GO dispersions. Pingyangmycin (PYM) as the model drug, the optimal drug loading process of GO@PYM was determined by the BBD model using encapsulation rate as the index of investigation. Then, HBC hydrogel was prepared by homogeneous etherification reaction. The 5%(wt) HBC hydrogel's gel time (Tgel) was 36.5 °C and gelation time was 30s. Finally, GO was cross-linked with HBC by hydrogen bonding to form HBC/GO composite hydrogel. Tgel was reduced to 31.7 °C. GO substantially enhanced the mechanical strength of HBC and the stability of HBC/GO structure. HBC/GO@PYM drug loading rate was approximately 8 times higher than HBC@PYM. The results of pharmacokinetic experiments showed that compared with HBC@PYM group, t1/2, MRT0-∞ (mean retention time) and AUC0-∞ (area under the curve) of HBC/GO@PYM group was 1.44, 1.51 and 2.31 times, respectively. HBC/GO effectively prolonged action time of the drug in-vivo by rectal administration, showed good sustained release effect, and significantly improved the bioavailability of PYM. HBC/GO@PYM can be further investigated by rectal administration.

Methacryloyl gelatin (GelMA) was blended with dextran methacrylate (DexMA) to produce polymer networks with interconnected macropores via cryostructuring and radical crosslinking of the polymers at subzero temperatures. The experimental set-up was optimized to allow the formation of monolithic networks characterized by highly uniform structure with interconnected macropores. The total polymers mass, the amount of the gel-forming reagents and particularly the rheological properties of GelMA resulted the most critical factors for the fabrication of homogeneous and not collapsed scaffolds. Indeed, only the use of GelMA with very low gelation temperature resulted in the formation of uniform monolithic cryogels. However, blending with DexMA produced general worsening of the mechanical properties of the scaffolds, due to DexMA interference with secondary structuring of GelMA during the cryogelation process. DexMA also had negative effect on the ability of the cryogel to support growth and proliferation of HaCat cells, bringing to slower cell adhesion to the scaffold.

Emerging incidences of microbial diseases have imposed an alarming condition leading to the greatest threats to global health. The development of antimicrobial resistance among the pathogenic strains has further provided a recent surge in this issue. Polyurethane is a widely recognized synthetic polymer comprising isocyanates, polyols, and chain extenders. Owing to its extraordinarily unique physicochemical properties it finds a broad spectrum prospective in biomedical and clinical applications. Further incorporation of additional fillers into the polymeric matrix imparts the fabricated composite with improved physicochemical properties. Most prominently among them is the evolution of antimicrobial ability into the synthesized composite. The present review explores the antimicrobial activity of polyurethane-based composites and their applicability in wound infection prevention, antimicrobial coatings, water, and air disinfection as well as in therapeutics. We have also provided a deep insight into the shape memory behavior of the polymers with impetus on their shape, structure, and features. Furthermore, a brief discussion on the mechanistic overview of the antimicrobial activity of polyurethane-based composites is deciphered, an understanding of which is essential for the development of effective antimicrobials.

It is a challenge to simultaneously achieve a high selectivity and permeance for the glassy polymeric membranes. Herein, the asymmetric Kapton membrane fabricated by pyromellitic dianhydride and 4,4′-oxydiphenylenediamine was prepared by the phase inversion method and characterized by rheometer, SEM, TGA, FT-IR and tensile testing. The aim of this work is to enhance gas separation performance of the membrane and its application value via optimizing the concentration of acetone additive, coagulation bath composition and evaporation time. After optimizing, results showed that the transition from the instantaneous coagulation to the delayed coagulation, and the inner membrane structure is gradually transferred from the finger-like shape to the sponge-like shape. The optimized gas separation performance of the resulting Kapton membrane has the permeance of 2.49 GPU and 1.10 GPU for H2 and CO2, respectively, as well as selectivity of 57.07 and 25.27 for H2/CH4 and CO2/CH4, respectively.

Nanocomposites for Additive Manufacturing (AM) featuring enhanced mechanical properties and antibacterial performance are desirable in the medical and culinary fields. Silver nitrate was introduced as a reinforcement and antibacterial agent in a medical-grade polyamide 12 (PA12) for the preparation of PA12/Ag nanocomposites for the material extrusion (MEX) AM method, with a reactive melt mixing process. Polyethylene glycol and polyvinylpyrrolidone were introduced into the mixture as reduction agents. The chemical reaction occurred during the filament extrusion. Samples compatible with the corresponding international standards were 3D printed and sixteen tests were performed to characterize the nanocomposites for their rheological, thermal, mechanical, and antibacterial properties. The mechanical reinforcement reached 26% in the tensile test, 24.2% in the compression test, and 26.1% in the flexural test, with similar improvement in the stiffness of the material in all tests. These results were achieved by the PA12/ 5.0% AgNO3 / 2.5% PEG nanocomposite. The biocidal activity of Ag was induced in the nanocomposites, as the tests against Escherichia coli and Staphylococcus aureus showed. The process followed can be easily scaled up for industrial use.

Polyvinylidene fluoride (PVDF) is an excellent material for porous membranes due to its outstanding chemical resistance, thermal stability, and film formability. However, the lower surface energy and the hydrophobicity of PVDF, result in poor wettability and organic fouling. In the present work, polyethyleneimine (PEI) was covalently bound on PVDF through the amination reaction in the casting solution. After converting the solution into membranes by phase inversion, the PEI-aminated PVDF membrane was further modified with poly (methyl vinyl ether-alt-maleic anhydride) (PEOSMA). The PEOSMA-modified membranes possess super hydrophilicity and antifouling performance. The protein adsorption capacity of the modified membrane was extremely low, only 5.65 μg/cm2. The pure water recovery rate (FRR) reached 97%, with BSA rejection over 97%. The presented protocol offers an effective in-situ covalent modification method for PDVF membranes with a high potential in large-scale applications.

Dispersion photopolymerization was carried out under green LED irradiation to rapidly prepare monodisperse poly(methyl methacrylate) (PMMA) microspheres with small size by using a high-efficient three-component initiating system. The polymerization parameters including exposure time, MMA content, stirring speed, water ratio and PVP content were systematically investigated. Crucial parameters were further optimized by response surface method (RSM), and a corresponding polymerization mechanism was proposed. Finally, PMMA microspheres with 375.6 nm of size and 0.101 of PDI were prepared. This study provides a facile method for the rapid fabrication of PMMA microspheres.

With the specialization and diversification of the use environment of composite products, composite materials should have good comprehensive properties. Abiding by this target, we successfully prepared a transparent epoxy resin (EP) composite with flame retardancy, low smoke, enhanced toughness, high glass transition temperature by blending the flame-retardant POI synthesized in this work. POI was synthesized from phosphophenanthrene, vanillin and histidine, and the combination of these three raw meticulously selected endowed POI molecule with excellent versatility. EP composite modified with 10 wt% POI (EP/POI-10) obtained a limiting oxygen index (LOI) of 30.5% and received the V-0 grade (UL-94). The reduction of total smoke production by 78.1% via cone calorimeter tests was obtained. The impact strength of EP/POI-7 increased by 48.2% due to the energy dissipation of cracks from POI. The comprehensive analysis of the dual-phase revealed that the improvement of flame retardance was attributed to the joint action of the gaseous phosphorus free radicals quenching and the protecting of condensed coke. Moreover, EP/POI obtained high glass transition temperature as well as good transparency.

Allyl benzoxazine resin (BOZ-A) synthesized from 2,2′-diallyl bisphenol A (DABPA), aniline and paraformaldehyde has been used to improve the mechanical and processing properties of bismaleimide resin. However, the lower heat resistance and the unsatisfactory dielectric properties cannot satisfy the requirements of high-performance composites in aerospace fields. Introducing nonpolar materials into the resin matrix effectively improves the dielectric properties. Inspired by the designability of benzoxazine, a novel allyl benzoxazine resin grafted with trifluoromethyl (BOZ-F) or methyl (BOZ-C) was synthesized and blended with BD-type bismaleimide resin (BDM-C and BDM-F) to explore the effect of substituent groups on the comprehensive performance. Due to the different electronic effects of the substituents, BDM-C possesses higher reactivity with a polymerization temperature of 212.7 °C, which is lower than that of BDM-A (217.8 °C) and BDM-F (226.6 °C). Their respective reactivity also leads to differences in rheological properties. Specifically, BDM-F exhibited the excellent thermal stability with a Tg of 308.3 °C, which is 17.2 °C higher than that of BDM-A. Furthermore, the dielectric constant (Dk) and dielectric loss (Df) of BDM-F at 10.5 GHz decreased to 3.06 and 0.0078 from 3.13 and 0.0114 when compared with BDM-A. In addition, BDM-C demonstrated the highest bending strength of 136.02 MPa. The current study delivers an effective approach to balance the performance of thermosetting resins by regulating substituents, which is valuable for potential application in wave-transparent fields.

To enhance the applicability of alginate hydrogel in tissue engineering, we attempted to fabricate oxidized sodium alginate/polyacrylamide-gelatin (OSA/PAM-GT) composite hydrogels by interpenetrating network approach with the hydroxyapatite/D-glucono-δ-lactone (HAP/GDL) as the endogenous ionic cross-linking agent for oxidized sodium alginate (OSA) and N, N′-methylenebisacrylamide (MBAA) as the chemical cross-linking agent for polyacrylamide (PAM), followed by their surface coverage with gelatin. Then TiO2 nanoparticles as the reinforcing agent were added to the OSA/PAM-GT hydrogel matrix to construct organic/inorganic hybrid OSA/TiO2/PAM-GT composite hydrogels. In particular, the effects of the amount of TiO2 nanoparticles on the microscopic morphology, mechanical properties, swellability, biodegradability, bio-mineralization and biocompatibility of the composite hydrogels were studied. Experimental results indicated that the addition of TiO2 nanoparticles into the matrix of OSA/TiO2/PAM-GT composite hydrogels could effectively regulate the porosity, mechanical properties, swelling ratio, in vitro biodegradability and bio-mineralization of OSA/TiO2/PAM-GT composite. Moreover, OSA/TiO2/PAM-GT composite hydrogels had the best biocompatibility when the content of TiO2 nanoparticles was 0.5% (w/v), indicating that an appropriate amount of TiO2 nanoparticles could effectively promote cell adhesion, proliferation and differentiation. Consequently, the combined method of the interpenetrating network technology, the incorporation of TiO2 nanoparticles with the surface coverage of gelatin could overcome the defects of alginate hydrogels to some extent, making OSA/TiO2/PAM-GT composite hydrogels suitable for tissue engineering applications.

Shape memory polymers and composites have potential in many application fields as a kind of smart materials with excellent shape memory properties. Herein, two shape memory polyimides (SMPIs) were prepared via thermal imidization process. Furthermore, shape memory composites (SMPCs) were obtained via solution impregnation and compression molding methods using SMPI as the polymer matrix and carbon plain weave fabric as the reinforcement. These polyimides and composites possessed superior shape memory behavior (shape memory recovery ratio, Rr, of SMPI 1 and HO-SMPC-40%: 99.1% and 90.6%). Remarkably, both of these samples maintained stable cyclic and bending shape memory performances. In addition, the composites were endowed with electrical-induced shape memory characteristics owing to their great conductivity. The SMPCs work effectively as deformable lightweight devices, which they could produce shape memory effect in different degrees reflecting to different applied power levels (Rr of HO-SMPC-40% under the power of 10 W and 20 W: 33% and 72%, respectively). These smart SMPIs and SMPCs exhibit flexible deformation properties that extend the potential use of polyimides and their composites to applications such as lightweight deformable sensors for the exploration industry.

The quantitative trace determination and separation from individual rare earths is a difficult task, with this view a new synthesized and functionalised Calix[4]resorcinarene polyhydroxamic acid is used for sorption, speciation, sequential separation and trace determination of La (II), Ce (III), Ce (IV), Nd (III) and Gd (III). The rare earths are quantitatively separated and trace determination in the range of 2–15 ng with the selectivity order La (III) > Ce (III) > Nd (III) > Gd (III). The column parameters like pH, flow rate and distribution were evaluated. The effect of various electrolytes and diverse metal ions in separation are studied. The present method is applied for estimation of rare earths in monazite and other geological specimens. Suitable eluents were used to effectuate the separations of the binary and ternary combinations.

Corrosion inhibitors (CIs) are cost-effective and efficient solutions to mitigate the corrosion and to protect the relevant assets in the oil & gas sector. The corrosion inhibitors have however the potential to dramatically impair the effectiveness of the kinetic hydrate inhibitor (KHIs) because of compatibility issues. Creating a copolymer with both CI and KHI qualities for a sour environment is a challenge. This study proposes a new copolymer with CI and KHI moieties: 3-acrylamidopropyl trimethyl ammonium chloride (AMPTMA) block copolymers with acryloyl and acrylamide type comonomers. The corrosion studies were carried out utilizing high-pressure high temperature (HPHT) rotating cage autoclave and electrochemical measurements under different laboratory (standard 3.5 wt% NaCl brine) and field simulated conditions. These copolymers provided corrosion inhibition efficiency of up to 90%, owing to their strong adsorption on the carbon steel surface. The type of comonomer used in copolymers appears to play a significant role in corrosion prevention and adsorption capabilities on the metal surface. Additionally, one of the copolymers demonstrated the effectiveness as KHI by holding a subcooling of 5.6 °C at 96 bar in a sour (H2S) environment. These findings provide evidence that AMPTMA based copolymers have the potential to work as dual-purpose inhibitors (KHCI) to mitigate corrosion and gas hydrate formation.