Free Radical Copolymerization Research Articles

In vitro biocompatibility analysis of protein-resistant amphiphilic polysulfobetaines as coatings for surgical implants in contact with complex body fluids.

The fouling resistance of zwitterionic coatings is conventionally explained by the strong hydrophilicity of such polymers. Here, the in vitro biocompatibility of a set of systematically varied amphiphilic, zwitterionic copolymers is investigated. Photocrosslinkable, amphiphilic copolymers containing hydrophilic sulfobetaine methacrylate (SPe) and butyl methacrylate (BMA) were systematically synthesized in different ratios (50:50, 70:30, and 90:10) with a fixed content of photo-crosslinker by free radical copolymerization. The copolymers were spin-coated onto substrates and subsequently photocured by UV irradiation. Pure pBMA and pSPe as well as the prepared amphiphilic copolymers showed BMA content-dependent wettability in the dry state, but overall hydrophilic properties a fortiori in aqueous conditions. All polysulfobetaine-containing copolymers showed high resistance against non-specific adsorption (NSA) of proteins, platelet adhesion, thrombocyte activation, and bacterial accumulation. In some cases, the amphiphilic coatings even outperformed the purely hydrophilic pSPe coatings.

A preliminary study of the temperature-responsive selective extraction performance of hydrogel derived from sulfobetaine methacrylate

The limited extraction selectivity caused by the single extraction selection mechanism of solid phase extraction (SPE) technology is one of the bottlenecks restricting its development. The development of environmentally sensitive materials provides a new opportunity to solve this problem. Based on this, we developed the sulfobetaine methacrylate hydrogel with abundant pore structure, a large number of adsorption sites and especially temperature responsiveness, and used as adsorbent for the extraction of pesticide residues in lychees. The new hydrogel adsorbent was prepared by free radical copolymerization with sulfobetaine methacrylate as monomer, and used for the extraction of benzoylurea insecticides from lychees. Interestingly, the hydrogel showed an almost opposite temperature-selective extraction trend for different benzoylurea insecticides with similar structure and polarity, and opposite hydrophilicity, which may be caused by the temperature-sensitive and the special action site of the hydrogel, and the change of the diffusion of aqueous solution. In addition, the analysis method of three hydrophilic benzoylurea insecticides by sulfobetaine methacrylate hydrogel-SPE-HPLC was established. Under optimal conditions, the low limits of detection (0.030μgL-1) and quantification (0.10μgL-1), and the wide linear ranges (0.10-50.0μgL-1) were achieved. Its application in lychee samples were also tested, and the satisfactory results were obtained, with the spiked recoveries from 80.79 % to 108.31 %. This was a great breakthrough in the selective extraction of similar targets. These properties, combined with low-cost, biodegradable raw materials and convenient, green synthesis method make the sulfobetaine methacrylate hydrogel a very promising solid phase adsorbent. Temperature-responsive selective mode can greatly enrich the selective extraction mechanism and promote its development and application in complex actual samples.

Microwave‐Assisted Tragacanth Gum–Based Grafted Silver Nanocomposite Hydrogel for Sustained Release Formulations of Diclofenac Sodium and Antibacterial Assay

ABSTRACTIn this work, novel tragacanth gum‐graft‐poly(2‐acrylamido‐2‐methylpropanesulfonic acid) (TG‐g‐PAMPS) hydrogel was synthesized via free radical copolymerization of TG, 2‐acrylamido‐2‐methylpropanesulfonic acid by using ammonium peroxodisulfate and N,N‐methylene‐bis‐acrylamide under microwave radiation, resulting in the cross‐linked graft copolymer network. Silver nanoparticles (SNs) were formed and stabilized by the reduction of silver nitrate using tri‐sodium citrate. The TG‐g‐PAMPS gel and its nanocomposite were characterized and confirmed using FTIR, TGA, XRD, SEM, EDS, and TEM techniques. It is observed that the presence of SNs significantly improves the swelling ability of the TG‐g‐PAMPS gel. Degradation studies of both hydrogels were studied using the soil burial method and determining the respective weight loss. The presence of SNs is found to impart significant antibacterial properties to the gel against Pseudomonas aeruginosa and Escherichia coli bacteria. Further, the TG‐g‐PAMPS gel and TG‐g‐PAMPS‐SN were evaluated as matrix materials for the release of the drug (diclofenac sodium) and the effect of SNs on the release was examined. The in‐vitro released data were analyzed using empirical equations to understand the mechanism of release. Among the various models, the released data were well fitted into the Korsmeyer–Peppas equation and the released kinetics followed non‐Fickian diffusion.

Fabrication of multifunctional cotton fabrics with quaternized N-halamine endowing the synergetic rechargeable antibacterial, wound healing and self-cleaning performances

Cotton has attracted considerable attention due to its functional characteristics. The focus of research on cotton has shifted in recent years towards designing multi-functional and modified media for cotton fibers, which can be firmly combined with textiles, giving them reusability and extending their service life. This study constructed a synergistic antibacterial layer of quaternary ammonium compounds (QACs) and N-halamine (Hals) using an in-situ free radical copolymerization method in water, named QACs/Hals@cotton-Cl. The route significantly increases the number of antibacterial active centers. FTIR, XPS, and SEM were used to systematically analyze the product's chemical structure, surface morphology, and other characteristics. The modified fabric's antibacterial efficiency, wound healing, renewability, and durability were also evaluated. The chlorinated modified cotton fabric could completely eradicate S. aureus and E. coli within 10min. Compared with pure cotton, it notably promoted the healing rate of infected wounds in mice. The modification method imparted excellent hydrophobicity to the cotton fabric, with a contact angle exceeding 130°, making it easy to remove surface stains. After 30days of regular storage and 24h of UV irradiation, the active chlorine concentration (Cl+%) only decreased by 25% and 39%, respectively, and the reduced Cl+% was effectively recharged via simple re-chlorination. The hydrophobicity and antimicrobial properties of QACs/Hals@cotton-Cl remained stable even after 20cycles of friction. This simple synthesis technique provides a convenient approach for the scalable fabrication of multifunctional and rechargeable antibacterial textiles, with potential applications in medical devices and personal hygiene protection.

Degradable biporous polymeric networks based on 2-methylene-1,3-dioxepane: Towards hierarchically structured materials meant for biomedical applications

Degradable biporous polymeric networks based on 2-methylene-1,3-dioxepane: Towards hierarchically structured materials meant for biomedical applications

Superabsorbent ZnO/rubber-based hydrogel composite for removal and photocatalytic degradation of methylene blue

A superabsorbent hydrogel was prepared by the free-radical copolymerization of natural rubber (NR) latex with poly(acrylic acid) (PAA) at NR loadings up to 50wt%. An NR/PAA hydrogel containing 40wt% of NR (NR-40) had a water absorption capacity of 214g/g (21,400%) of its dry weight. The compressive modulus increased 512% and sample integrity was improved due to the physical entanglement of NR chains. NR-40 hydrogel removed 97% of methylene blue (MB) from the aqueous solution in 1h (at initial concentrations of 10-1000mg/L) and produced a maximum removal of 1191mgMB/g of hydrogel at an initial MB concentration of 4500mg/L. The adsorption of MB was an endothermic process. Fourier transform infrared spectroscopy indicated that hydrogen bonding and electrostatic interaction drove the process. After the in-situ incorporation of ZnO into NR-40, absorbed energy from sunlight generated active species that could photocatalytically degrade adsorbed MB in the hydrogel matrix. The scavenger tests indicated that superoxide radical anions and hydroxyl radicals were the main species for this process. The hydrogel composite material showed good stability and could be regenerated and reused over 10cycles, degrading >80% of the adsorbed dye. This novel natural-based hydrogel provides double functions of adsorption and photodegradation of toxic dyes without the requirement of chemicals and a separation process.

Design of degradable hybrid dual-crosslinked polymer for high-efficiency profile control in high temperature reservoirs

Design of degradable hybrid dual-crosslinked polymer for high-efficiency profile control in high temperature reservoirs

Synergistic effects of covalent crosslinking and hydrophobic association on enhancing thermal and salt resistance of polymeric filtrate reducer

Synergistic effects of covalent crosslinking and hydrophobic association on enhancing thermal and salt resistance of polymeric filtrate reducer

Study on the properties of slump-retaining polycarboxylate superplasticizer synthesized by EPEG at different pH

Abstract The application of EPEG-type polycarboxylate water reducer in concrete is gradually widespread and studying its preparation process and performance comparison will help promote the EPEG market. In this study, ethylene glycol nonvinyl polyoxymethylene ether (EPEG-2400), acrylic acid (AA) and hydroxyethyl acrylate (HEA) were used as the main synthetic monomers. Under the redox initiation system of hydrogen peroxide-formaldehyde sodium bisulfite, EPEG-type water-retaining polycarboxylate water reducer was synthesized by free radical copolymerization in aqueous solution. The influence of different pH values on the dispersibility of the synthesized polycarboxylate water reducer was studied. The results show that different pH values have little influence on the molecular weight of EPEG water-retaining polycarboxylate water reducer and the work performance of EPEG-synthesized water-retaining polycarboxylate water reducer is better under neutral conditions.

Synthesis of novel bentonite/pectin-grafted-poly(crotonic acid-co-acrylic acid) hydrogel nanocomposite for adsorptive removal of safranin O dye from aqueous solution

ABSTRACT This novel work is devoted to the synthesis of the bentonite/pectin-grafted-poly(crotonic acid-co-acrylic acid (AA-co-CA) hydrogel nanocomposite by free-radical copolymerisation method for exploring its potential towards safranin O dye removal. The prepared nanocomposite was characterised by different techniques revealing the presence of numerous functionalities, porous nature and greater swelling % at basic pH. The pHpzc of the nanocomposite was determined to be 4. Maximum of 97.09% of safranin O dye removal take place under optimised conditions, that is, 0.03 g of bentonite dose (bentonite to net hydrogel weight ratio (1.295%), with pH of 7, nanocomposite dose of 5 g/l for 120 min. The dye concentration was 500 mg/l at the temperature of 25°C. Effect of ionic strength confirmed the greatest decrease in adsorption capacity in the presence of divalent cations. The highest R2 and the lowest error margins of the Freundlich isotherm and pseudo-second-order kinetic models make these models well fitted to the experimental data. Further, the spontaneous and exothermic nature of the process was confirmed by the negative values of ΔG and ΔH, respectively. The enhanced adsorption of safranin O dye by the prepared nanocomposite was informed by several mechanisms, including electrostatic, pore filling and H-bonding. A comparison of the adsorption capacity of the prepared nanocomposite with various other adsorbents was also studied. Stability of the prepared adsorbent was revealed from its recovery upto five cycles in different desorption media. Finally, the treatment of the adsorbent with real textile wastewater showed its removal efficiency as 95.8% highlighting its promising nature for treating large industrial wastewater.

A superabsorbent and pH-responsive copolymer-hydrogel based on acemannan from Aloe vera (Aloe barbadensis M.): A smart material for drug delivery

Combining natural polysaccharides with synthetic materials improves their functional properties which are essential for designing sustained-release drug delivery systems. In this context, the Aloe vera leaf mucilage/hydrogel (ALH) was reacted with acrylic acid (AA) to synthesize a copolymerized hydrogel, i.e., ALH-grafted-Polyacrylic acid (ALH-g-PAA) through free radical copolymerization. Concentrations of the crosslinker N,N'-methylene-bis-acrylamide (MBA), and the initiator potassium persulfate (KPS) were optimized to study their effects on ALH-g-PAA swelling. The FTIR and solid-state NMR (CP/MAS 13C NMR) spectra witnessed the formation of ALH-g-PAA. Scanning electron microscopy (SEM) analysis revealed superporous nature of ALH-g-PAA. The gel fraction (%) of ALH-g-PAA was directly related to the concentrations of AA and MBA whereas the sol fraction was inversely related to the concentrations of AA and MBA. The porosity (%) of ALH-g-PAA directly depends on the concentration of AA and MBA. The ALH-g-PAA swelled admirably at pH7.4 and insignificantly at pH1.2. The ALH-g-PAA offered on/off switching properties at pH7.4/1.2. The metoprolol tartrate was loaded on different formulations of ALH-g-PAA. The ALH-g-PAA showed pH, time, and swelling-dependent release of metoprolol tartrate (MT) for 24h following the first-order kinetic and Korsmeyer-Peppas model. Haemocompatibility studies ascertained the non-thrombogenic and non-hemolytic behavior of ALH-g-PAA.

Facile synthesis of an acrylic acid-co-2-acrylamide-2-methylpropanesulfonic acid copolymer / polyvinylpyrrolidone semi-IPN hydrogel with excellent swelling and anti-leakage properties

Facile synthesis of an acrylic acid-co-2-acrylamide-2-methylpropanesulfonic acid copolymer / polyvinylpyrrolidone semi-IPN hydrogel with excellent swelling and anti-leakage properties

Preparation and properties of a metal-organic frameworks polymer material based on Sa-son seed gum capable of simultaneously absorbing liquid water and water vapor

Atmospheric water harvesting (AWH) technology has attracted significant attention as an effective strategy to tackle the global shortage of freshwater resources. Work has focused on the use of hydrogel-based composite adsorbents in water harvesting and water conservation. The approaches adopted to make use of hygroscopic inorganic salts which subject to a "salting out" effect. In this study, we report the first use of modified UIO-66-NH2 as a functional steric cross-linker and Sa-son seed gum was used as polymeric substrate to construct super hygroscopic hydrogels by free radical copolymerization. The maximum water uptake on SMAGs (572cm3·g-1) outperforms pure UIO-66-NH2 (317cm3·g-1). Simultaneously, our first attempt to use it for anti-evaporation applications in an arid environment (Lanzhou, China) simulating sandy areas. The evaporation rate of the anti-evaporation material treated with 0.20% super moisture-absorbent gels (SMAGs) decreased by 6.1% over 64h period under natural condition in Lanzhou, China. The prepared material can not only absorb liquid water but also water vapor, which can provide a new way for water collection and conservation technology. The design strategy of this material has wide applications ranging from atmospheric water harvesting materials to anti-evaporation technology.

Utilizing methacrylated lignin as a sustainable macro-crosslinker for synthesizing innovative PVA/AMPS composites crosslinked hydrogel nanofibers: A potential application for lithium-ion battery separators

Utilizing methacrylated lignin as a sustainable macro-crosslinker for synthesizing innovative PVA/AMPS composites crosslinked hydrogel nanofibers: A potential application for lithium-ion battery separators

Flexible and thermoresponsive AEMR-pNIPAM/Cs0.33WO3 composite hydrogel film with NIR shielding potential for smart windows and smart curtains

Flexible and thermoresponsive AEMR-pNIPAM/Cs0.33WO3 composite hydrogel film with NIR shielding potential for smart windows and smart curtains

Supramolecular self‐assembled nanoparticles for targeted therapy of myocardial infarction by enhancing cardiomyocyte mitophagy

AbstractMyocardial infarction accompanied by diabetes mellitus is accepted as the most serious type of coronary heart disease, and among the current treatment strategies, the precise delivery of protective drugs for inhibiting cardiomyocyte apoptosis is still a challenge. In this study, we developed a biodegradable nanoparticles‐based delivery system with excellent macrophage escape, cardiac targeting, and drug release properties to achieve targeted therapy of myocardial infarction. Specifically, a copolymer of p(DMA–MPC–CD) combining self‐adhesion, hydration lubrication, and targeting peptide binding site was successfully prepared by free radical copolymerization, and it was self‐assembled on the surface of melatonin‐loaded dendritic mesoporous silica nanoparticles (bMSNs) following the integration of adamantane‐modified cardiac homing peptide (CHP) based on supramolecular host–guest interaction. Importantly, a hydration layer formed around the zwitterionic phosphorylcholine groups of the multifunctional nanoparticles, which was confirmed by the enhancement in hydration lubrication and reduction in coefficient of friction, prevented the nanoparticles from phagocytosis by the macrophages. The in vivo bioluminescence imaging test indicated that the nanoparticles were endowed with satisfied cardiac targeting capability, and the in vivo mice study demonstrated that the intravenous injection of drug‐loaded nanoparticles (namely bMSNs–Mel@PDMC–CHP) effectively reduced cardiomyocyte apoptosis, alleviated myocardial interstitial fibrosis, and enhanced cardiac function.

Hydrophilic Modification of Polytetrafluoroethylene (PTFE) Capillary Membranes with Chemical Resistance by Constructing Three-Dimensional Hydrophilic Networks.

Polytetrafluoroethylene (PTFE) capillary membranes, known for the great chemical resistance and thermal stability, are commonly used in membrane separation technologies. However, the strong hydrophobic property of PTFE limits its application in water filtration. This study introduces a method whereby acrylamide (AM), N, N-methylene bisacrylamide (MBA), and vinyltriethoxysilane (VTES) undergo free radical copolymerization, followed by the hydrolysis-condensation of silane bonds, resulting in the formation of hydrophilic three-dimensional networks physically intertwined with the PTFE capillary membranes. The modified PTFE capillary membranes prepared through this method exhibit excellent hydrophilic properties, whose water contact angles are decreased by 24.3-61.2%, and increasing pure water flux from 0 to 1732.7-2666.0 L/m2·h. The enhancement in hydrophilicity of the modified PTFE capillary membranes is attributed to the introduction of hydrophilic groups such as amide bonds and siloxane bonds, along with an increase in surface roughness. Moreover, the modified PTFE capillary membranes exhibit chemical resistance, maintaining the hydrophilicity even after immersion in strong acidic (3 wt% HCl), alkaline (3 wt% NaOH), and oxidative (3 wt% NaClO) solutions for 2 weeks. In conclusion, this promising method yields modified PTFE capillary membranes with great hydrophilicity and chemical resistance, presenting substantial potential for applications in the field of water filtration.

Mucoadhesive, antioxidant, and lubricant catechol-functionalized poly(phosphobetaine) as biomaterial nanotherapeutics for treating ocular dryness.

Dry eye disease (DED) is associated with ocular hyperosmolarity and inflammation. The marketed topical eye drops for DED treatment often lack bioavailability and precorneal residence time. In this study, we investigated catechol-functionalized polyzwitterion p(MPC-co-DMA), composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) and dopamine methacrylamide (DMA) monomers, as potential topical nanotherapeutics for DED. The copolymers were synthesized via random free-radical copolymerization, producing different proportions of catecholic functionalization. All as-prepared polymer compositions displayed good ocular biocompatibility. At a feeding ratio of 1:1, p(MPC1-co-DMA1) can facilitate a robust mucoadhesion via Michael addition and/or Schiff base reaction, thus prolonging ocular residence time after 4 days of topical instillation. The hydration lubrication of MPC and radical-scavenging DMA endow the nano-agent to ease tear-film hyperosmolarity and corneal inflammation. A single dose of p(MPC1-co-DMA1) (1mg/mL) after 4 days post-instillation can protect the cornea against reactive oxygen species, inhibiting cell apoptosis and the over-expression of pro-inflammatory factors (IL-6 and TNF-α). In clinical assessment, DED-induced rabbit eyes receiving p(MPC1-co-DMA1) could increase lacrimal fluid secretion by 5-fold higher than cyclosporine A. The catechol-functionalized polyzwitterion with enhanced lubricity, mucoadhesion, and anti-oxidation/anti-inflammation properties has shown high promise as a bioactive eye drop formulation for treating DED.

Synthesis, performance and mechanism of shrinkage-reducing agents with water-reducing function for cement-based materials

Synthesis, performance and mechanism of shrinkage-reducing agents with water-reducing function for cement-based materials

Mechanism-Guided Discovery of Cleavable Comonomers for Backbone Deconstructable Poly(methyl methacrylate).

The development of cleavable comonomers (CCs) with suitable copolymerization reactivity paves the way for the introduction of backbone deconstructability into polymers. Recent advancements in thionolactone-based CCs, exemplified by dibenzo[c,e]-oxepine-5(7H)-thione (DOT), have opened promising avenues for the selective deconstruction of multiple classes of vinyl polymers, including polyacrylates, polyacrylamides, and polystyrenics. To date, however, no thionolactone CC has been shown to copolymerize with methacrylates to an appreciable extent to enable polymer deconstruction. Here, we overcome this challenge through the design of a new class of benzyl-functionalized thionolactones (bDOTs). Guided by detailed mechanistic analyses, we find that the introduction of radical-stabilizing substituents to bDOTs enables markedly increased and tunable copolymerization reactivity with methyl methacrylate (MMA). Through iterative optimizations of the molecular structure, a specific bDOT, F-p-CF3PhDOT, is discovered to copolymerize efficiently with MMA. High molar mass deconstructable PMMA-based copolymers (dPMMA, Mn > 120 kDa) with low percentages of F-p-CF3PhDOT (1.8 and 3.8 mol%) are prepared using industrially relevant bulk free radical copolymerization conditions. The thermomechanical properties of dPMMA are similar to PMMA; however, the former is shown to degrade into low molar mass fragments (<6.5 kDa) under mild aminolysis conditions. This work presents the first example of a radical ring-opening CC capable of nearly random copolymerization with MMA without the possibility of cross-linking and provides a workflow for the mechanism-guided design of deconstructable copolymers in the future.