Research on the preparation and characterization of chitosan grafted polyvinylpyrrolidone gel membrane with iodine

The chitosan grafted polyvinylpyrrolidone gel membrane with iodine (CS‐PVP‐I₂‐G‐M) was prepared by chitosan–polyvinylpyrrolidone–iodine complex liquid (CS‐PVP‐I₂‐L) mixed with gelatin. The intermediate product CS‐PVP‐I₂‐L was prepared by CS grafted PVP in the protection of N₂ with dimethyl 2,2′‐azobis (2‐methylpropionate) (AIBME) as initiator, then a certain amounts of iodine in ethanol solution was added. The properties of CS‐PVP‐I₂‐G‐M were characterized by IR, UV–Vis, SEM, XRD, DSC, and so forth. The iodine release results coherent with the release kinetic model—Fick diffusion laws, has a burst effect first, and then spread, and the emission of iodine was maintained within a certain range and kept at a stable level permanently, showed a sustained‐release effect of iodine. The inhibition zone diameters of CS‐PVP‐I₂‐G‐M against Staphylococcus aureus and Escherichia coli were both greater than 16 mm, it demonstrated significant antibacterial activity. Double effects sustained‐release effect of iodine and the significant antibacterial activity made CS‐PVP‐I₂‐G‐M highly potential for applications as a novel natural biomedical sterilization materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41797.     

Preparation of O‐hydroxypropyl‐N‐butyl chitosan under microwave irradiation

O‐Hydroxypropyl‐N‐butyl chitosan (C₄‐HPCS) was prepared by microwave irradiation and phase‐transfer catalysis; this consisted of two steps: (1) the synthesis of O‐hydroxypropyl chitosan (HPCS) with chitosan and propylene oxide and (2) the synthesis of C₄‐HPCS with HPCS and 1‐butyl bromide. The results of the experiment are as follows: Fourier transform infrared spectroscopy and ¹H‐NMR displayed the characteristic peaks of C₄‐HPCS, thermogravimetric analysis showed that C₄‐HPCS was stable until 240°C, the critical micelle concentration was 0.025 wt %, the surface tension was equal to 65.70 ± 0.09 mN/m, the hydrophile–lipophile balance number value was 13.55, and the emulsifying power, foaming expansion, and foaming volume stability were 73.10, 45, and 94 wt %, respectively. This indicated that C₄‐HPCS had superior surface performance and more excellent hydrophilicity. In addition, the microwave irradiation and phase‐transfer catalysis used in the experiment were considered to be more environmentally friendly and time‐saving methods. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41527.     

Preparation of amphoteric N,O‐carboxymethyl hydroxypropyl chitosan by a two‐step reaction

A novel N,O‐carboxymethyl hydroxypropyl chitosan (HPCMS) derivative was prepared by a two‐step reaction. Water‐soluble hydroxypropyl chitosan (HPCS) with a degree of substitution of hydroxypropyl higher than 0.8 was first synthesized by the reaction of chitosan (CS) with propylene oxide (PO) with alkali as a catalyst. Then, amphoteric chitosan derivatives (HPCMS) with a degree of substitution of carboxymethyl ranging from 0.42 to 1.38 were prepared by the reaction of HPCS with chloroacetic acid in an aqueous solution with alkali as a catalyst. The structures of the polymers were characterized by Fourier transform infrared spectroscopy and NMR; this showed that the hydroxypropylation mainly occurred on the ? OH groups at the C‐6 of CS in the reaction of CS with PO. In the reaction of HPCS with chloroacetic acid, both the ? OH and ? NH₂ groups of HPCS were susceptible to the carboxymethylation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40460.     

Synthesis of chitosan derivative with dual‐antibacterial functional groups and its antibacterial activity

The O‐fumaryl ester (OFTMCS) of N,N,N‐trimethyl chitosan (TMCS) has been synthesized as a water‐soluble chitosan (CS) derivative bearing dual‐functional groups, with the aim of discovering novel CS derivatives with good water solubility and enhanced the antibacterial activity compared with unmodified CS. OFTMCS was characterized by FT‐IR, ¹³C NMR, XPS, XRD and Zeta potential analyses. The XPS results indicated that the degree of substitution (DS) on the C₂‐NH₂ group of the CS was 0.78, and that the DS on its C₆‐OH group was 0.31. The TGA results showed that the thermal stability of OFTMCS was lower than that of unmodified CS. The antibacterial activities of OFTMCS were investigated by assessing the mortality rates of the representative Gram‐positive and Gram‐negative bacteria Staphylococcus aureus and Escherichia coli, respectively. The results indicated that OFTMCS exhibited superior antibacterial activity to CS at a lower dosage. The synthesis of CS derivatives bearing dual‐functional groups could therefore be used as a promising strategy to enhance the antibacterial activity of CS. The antimicrobial mechanism of action of OFTMCS was discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42663.     

One pot blending of biopolymer‐TiO2 composite membranes with enhanced mechanical strength

A biopolymer‐TiO₂ composite membrane was prepared by blending of N‐[(2‐hydroxy‐3‐trimethylammonium) propyl] chloride chitosan and cellulose acetate with nano‐TiO₂ particles as the introduced inorganic components. It was verified that the amino groups (? NH₂) of chitosan (CTS) were partly grafted by stronger hydrophilic group ? according to the ¹H‐nuclear magnetic resonance spectra of N‐[(2‐hydroxy‐3‐trimethylammonium) propyl] chloride chitosan and attenuated total reflectance Fourier transform infrared spectroscopy. The structure, microcosmic morphology, water flux, swelling properties, and thermal stability of the composite membranes were characterized. With the mass ratio of cellulose acetate to CTS being 50 wt %, the mole ratio of CTS to glycidyl trimethylammonium chloride being 1 : 1, and drying temperature being 60°C in 70% acetic acid, the formed biopolymer‐TiO₂ composite membranes exhibited enhanced mechanical strength (84.29 MPa), lower swelling degree (101.36%), and improved antibacterial activity against Gram‐negative Escherichia coli (Rosetta and DH5α) and Gram‐positive Bacillus subtilis. The existence of nano‐TiO₂ particles and the introduction of stronger cationic group synergistically improved the antibacterial properties of the biopolymer‐TiO₂ composite membranes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42732.     

Synthesis and characterization of chitosan derivatives carrying galactose residues

A series of water‐soluble chitosan derivatives, carrying galactose residues, were synthesized by using an alternative method in which the galactose groups were introduced into amino groups of the derivatives. First, hydroxyethyl chitosan (HECS) and hydroxypropyl chitosan (HPCS) were synthesized under alkaline conditions by using chitosan and propylene or chitosan and ClCH₂CH₂OH as the starting materials, respectively. Then lactobionic acid was added into the systems so as to form galactosylated HECS (Gal‐HECS) and galactosylated HPCS (Gal‐HPCS) with substitution degrees of 53 and 47%, respectively. Lactosaminated HPCS (Lac‐HPCS) and Lactosaminated HECS (Lac‐HECS) were obtained with substitution degrees of 42 and 38%, respectively, by the reductive amination of the mixtures of lactose and HECS or lactose and HPCS with potassium borohydride present in the reaction. The chemical structures of new chitosan derivatives were characterized by FTIR, ¹H NMR, ¹³C NMR, and elemental analysis. Some physical properties were also analyzed by wide angle X‐ray diffraction (WAXD) and differential scanning calorimetry (DSC). The novel chitosan derivatives carrying galactose residues may be used as additives for hepatic targeting delivery. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2161–2167, 2005     

Studies on Electrophilic Interaction of 2,3‐Allenols with Electrophilic Halogen Reagents: Selective Synthesis of 2,5‐Dihydrofurans, 3‐Halo‐3‐alkenals,or 2‐Halo‐2‐alkenyl Ketones

The reaction of primary 2,3‐allenols with iodine (I₂) afforded 2,5‐dihydrofurans while that of readily available 1‐aryl or 1‐methyl substituted 2,3‐allenols with bromine (Br₂), N‐bromosuccinimide (NBS), I₂ or N‐iodosuccinimide (NIS) formed the not easily available but synthetically useful 3‐halo‐3‐alkenals and 2‐halo‐2‐alkenyl ketones with good selectivity and yields via a sequential electrophilic interaction of X⁺ with the allene moiety, 1,2‐aryl or 1,2‐proton shift, and H⁺ elimination process.     

Synthesis of 2‐hydroxypropyl dimethylbenzylammonium N,O‐(2‐carboxyethyl) chitosan chloride and its antibacterial activity

N,O‐(2‐carboxyethyl)chitosan (N,O‐2‐CEC) was prepared from chitosan with 3‐chloropropionic acid as modifying agent and NaOH as binding‐acid agent. 2‐Hydroxypropyl dimethylbenzylammonium N,O‐(2‐carboxyethyl) chitosan chloride (HPDMBA‐CEC) was obtained by the reaction of N,O‐2‐CEC with glycidyl dimethyl benzyl ammonium chloride (GDMBA) using NaOH as catalyst. The structures of chitosan derivatives were characterized by FTIR, ¹H NMR, and gel permeation chromatography. The antimicrobial activity of HPDMBA‐CEC was evaluated against a Gram‐negative bacterium Escherichia coli (E.coli) and a Gram‐positive bacterium Staphylococcus aureus (S. aureus). Compared with CTS, N,O‐2‐CEC, and HPDMBA‐CTS, HPDMBA‐CEC had much stronger antimicrobial activity, and this activity increased with increasing substitution degree of quaternary ammonium group (DQ). When the substitution degree of carboxyethylation (DS of CE) was 0.72 and DQ was 0.60, the minimum inhibitory concentrations (MICs) of HPDMBA‐CEC were 3.1 and 6.3 μg/mL against S. aureus and E. coli, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Antimicrobial activity of some new 4‐arylazo‐3‐methylthiophene disperse dyes on polyester fabrics

A series of novel 4‐arylazo‐3‐methylthiophenes was synthesized by the heterocyclization of 2‐arylhydrazono‐2‐acetyl thioacetanilide derivatives with a variety of α‐halogenated reagents, such as chloroacetone, phenacyl bromide, ethyl chloroacetate, and chloroacetonitrile. The structures of the synthesized thiophene derivatives were confirmed by ultraviolet–visible, IR, and ¹H‐NMR spectroscopic techniques and elemental analysis. The synthesized dyes were applied to polyester fabrics as disperse dyes, and their fastness properties were evaluated. The dyed polyester fabrics displayed antibacterial efficacy against Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of 2‐hydroxyethylmethacrylate/2‐(3‐indol‐yl)ethylmethacrylamide‐based novel hydrogels as drug carrier with in vitro antibacterial properties

In this study, a new cationic monomer 2‐(3‐indol‐yl)ethylmethacrylamide (IEMA) derived from tryptamine was synthesized in a single step and characterized by Fourier transform infrared (FTIR), ¹H‐NMR, and ¹³C‐NMR. Then, one‐step preparation of novel poly[2‐hydroxyethylmethacrylate‐c‐2‐(3‐indol‐yl)ethylmethacrylamide], or p(HEMA‐c‐IEMA), copolymeric hydrogels has been performed successfully with IEMA and 2‐hydroxyethylmethacrylate (HEMA) as monomers using free radical aqueous polymerization. The hydrogels were characterized with scanning electron microscopy, FTIR, elemental analysis, thermogravimetric analysis, and texture profile analysis instruments. p(HEMA‐c‐IEMA) hydrogels were used for swelling, diffusion, drug release, and antibacterial activity studies. The drug‐release behavior of the hydrogels was determined as a function of time at 37 °C in pH 1.2 and 7.2. The swelling and drug‐release studies showed that an increased IEMA amount caused a higher increase in swelling and drug‐release values. Additionally, zero‐order, first‐order, and Higuchi equation kinetic models were applied to the drug‐release data, and the data fit well in the Higuchi model, and the Peppas power‐law model was applied to the release mechanism. Finally, the antibacterial activities of the hydrogels were screened against Gram‐positive bacteria (Bacillus cereus and Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli and Salmonella typhimurium). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45550.     

Synthesis of (R)‐ and (S)‐Ricinoleic Acid Amides and Evaluation of Their Antimicrobial Activity

A series of fatty acid amides derived from (R)‐ and (S)‐ricinoleic acid and 4 cyclic and acyclic amines were synthesized in a proecological solvent‐free process with yields ranging from 43 to 88%. All S‐configured compounds and both enantiomers of amide with 2‐amino‐2‐methyl‐1‐propanol were obtained and studied in terms of biological activity for the first time. The evaluation of antimicrobial activity of (R)‐ and (S)‐ricinoleic acid derivatives against 13 different microorganisms representing Gram‐negative and Gram‐positive bacteria, yeast, and molds showed significant inhibitory activity against Gram‐positive bacteria, especially Micrococcus luteus and Bacillus subtilis, and against selected molds. Ethanolamine‐ and pyrrolidine‐derived amides showed the most promising antibacterial and antimold potential. Derivatives from ricinoleic acid and pyrrolidine were the most active against both selected molds, Aspergillus brasiliensis and Penicillium expansum. Moreover, the R‐configured analog was the most potent against B. subtilis. The amides of ricinoleic acid with ethanolamine exhibited significant potential to Staphylococcus aureus, which distinguished them from the rest of tested derivatives to which this bacterium was very resistant.     

Cure behavior and antimicrobial performance of sulfur‐cured natural rubber vulcanizates containing 2‐hydroxypropyl‐3‐piperazinylquinolinecarboxylic acid methacrylate or silver‐substituted zeolite

This work used 2‐hydroxypropyl‐3‐piperazinylquinolinecarboxylic acid methacrylate (HPQM) or silver‐substituted zeolite (SSZ) as antibacterial agents for natural rubber (NR) compounds vulcanized by conventional vulcanization (CV), semi‐efficient vulcanization, and efficient vulcanization (EV) systems. The cure behavior and antibacterial performance of the NR vulcanizates were studied by varying the loadings of HPQM or SSZ, contact times, and vulcanization systems. The antibacterial performance of the rubber compounds was examined by halo test and plate‐count‐agar methods against Escherichia coli (E. coli, ATCC 25922) and Staphylococcus aureus (S. aureus, ATCC 25923) as the testing bacteria. The cure time and crosslink density were dependent on the vulcanization recipe used but were not affected by the addition of HPQM or SSZ. Diphenylguanidine at the level of 1.0 phr (parts by weight per hundred parts of resin) in NR vulcanized by the EV system had the ability to kill the E. coli and S. aureus bacteria. The NR vulcanized by the CV system showed the most pronounced antibacterial performance, as compared with the other two vulcanization systems, via migration and diffusion of HPQM or SSZ onto the NR surfaces, this being identified by the relatively large reduction of contact angle values. The HPQM showed the most preference for NR compounds vulcanized with the CV system with a contact time of 120 min or longer to achieve a bacteria‐killing efficacy of 99.0–99.9%, the efficacy being more pronounced for E. coli bacteria. J. VINYL ADDIT. TECHNOL., 19:123–131, 2013. © 2013 Society of Plastics Engineers     

Cationic starch iodophores

Cross‐linked cationic starches N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium starch chloride (CQS chloride), N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium starch iodide (CQS iodide), and N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium starch iodide–iodine (CQS triiodide) with the degree of substitution (DS) according to cationic groups from 0.04 to 0.62, as well as cross‐linked starch–iodine complexes were synthesized and tested as potential antibacterial agents. Cationic starch iodine derivatives were obtained during ion exchange reaction between CQS chloride and iodide or iodide–iodine anions in aqueous solutions. CQS_DS≤0.3 chloride can form several types of iodine complexes, such as the blue amylose–iodine inclusion complex and ionic CQS⁺I^?·(I₂)_m complex (m ≥ 1). The antibacterial activity of modified starches–iodine samples against different pathogenic bacterial cultures and contaminated water microorganisms was evaluated. CQS chloride and CQS iodide were found to be bacteriostatic. A strong antibacterial activity was characteristic of CQS triiodides in which molecular iodine is present in both ionic and inclusion complexes. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Microbiocidal activity of chitosan‐N‐2‐hydroxypropyl trimethyl ammonium chloride

Chitosan‐N‐2‐hydroxypropyl trimethyl ammonium chloride (QTS) was prepared by reaction of chitosan with glycidyl trimethylammonium chloride, which was characterized by FTIR. QTS with different molecular weights (M_w 41.55 × 10⁴, 9.02 × 10⁴, 3.57 × 10⁴, and 0.17 × 10⁴) showed biocidal activity on Staphylococcua aureus, Bacillus subtilis, Staphylococcua epidermidis, and Candida albicans. QTS with high molecular weight had high biocidal activity on the gram‐positive bacteria, and the biocidal effect of QTS decreased with decreasing molecular weight from 9.02 × 10⁴ to 0.17 × 10⁴. QTS with M_w 41.55 × 10⁴ exhibits slightly lower biocidal activity on Candida albicans than other QTS samples. However, no remarkable biocidal activity of QTS was found on gram‐negative bacteria Escherichia coli and Pseudomonas aeruginosa at the concentration up to 10 g L^?1. Existence of cationic surfactant, amphoteric surfactant, nonionic surfactant, Ca²⁺ and Mg²⁺ had no remarkable effect on microbiocidal activity of these QTS samples. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3851–3856, 2007     

Antimicrobial properties of bio‐inspired poly(4‐vinyl‐2‐pyridone) and its N‐alkylated cationic derivatives

Developing new antimicrobial polymers and designing new antimicrobial materials are important research areas for overcoming bacterial resistance. In the present study a new polymer, poly(4‐vinyl‐2‐pyridone), having bioactive structure analogous to that of naturally occurring heterocyclic compounds, was synthesized from 4‐vinylpyridine following a simple protocol. To augment the antibacterial properties of the synthesized polymer, N ‐alkylation of the heterocyclic pyridone moieties was achieved with ethylene chlorohydrin (2‐chloroethanol) to generate choline analogous structure. Also, its N ‐butylated analogue was synthesized as a reference compound to study structure–activity relationship. Structures of the polymers were confirmed using various characterization techniques. Antimicrobial efficacy of the polymers was determined using the minimum inhibitory concentration method in parallel experiments. The test microorganisms used were a Gram (+) bacterium (Staphylococcus epidermidis ), Gram (?) bacteria (Salmonella typhi , Pseudomonas aeruginosa and Escherichia coli ) and a fungus (Candida albicans ). Both the polymer derivatives are far more effective antimicrobial agents than the pristine polymer. Trends in the antimicrobial efficacy of these polymers correlate with their zeta potential values. © 2016 Society of Chemical Industry     

Preparation,characterization, and antibacterial activities of quaternarized N‐halamine‐grafted cellulose fibers

A viable method for coating of cellulose fiber with quaternarized N‐halamine is reported in this article. The use of quaternary ammonium salt group in combination with N‐halamine group can reinforce the antibacterial activity. The chemical structure of as‐synthesized N‐halamine precursor 4‐(Bromo‐acetic acid methylester)‐4‐ethyl‐2‐ oxazolidinone (BEO) was characterized by ¹H‐NMR. The cellulose fibers were characterized by Fourier transform infrared spectra and X‐ray photoelectron spectra. The spectra data confirmed that the quaternarized N‐halamine‐grafted cellulose fibers were successfully obtained. The antibacterial properties of functional fibers were challenged with both Gram positive and Gram negative bacteria. The antibacterial tests and showed that the as‐prepared antibacterial cellulose fibers exhibited powerful and rapid bactericidal performance against both Gram negative E. coli and Gram positive S. aureus. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42702.     

Low‐temperature conversion of spent adsorbent to iodine sodalite by a mechanochemical route

The focus on a ball milling induced conversion as a possible synthesis route of iodine sodalite (Na₈Al₆Si₆O₂₄I₂) from zeolite‐based iodine adsorbents in order to treat a radioactive iodine filter for the off‐gas cleaning during nuclear facilities is presented. A mixture of silver iodide and zeolite 13X as a simulated adsorbent was mechanochemically milled using a laboratory‐scale planetary ball mill. The obtained powders were characterized by X‐ray diffraction to determine the effect of milling time on the conversion of the iodine sodalite. The crystal grain size and the lattice strain of the grounded phases were evaluated. After the ball milling, the milled samples were hydrothermally crystallized to form a sodalite phase with a sodium hydroxide solution for 48 h in an autoclave maintained at 150^°C. The iodine sodalite was successfully obtained after hydrothermal crystallization. A leaching test was carried out for the assessment of the order of iodine leachability and chemical durability under reducing conditions. The leaching amount was found to be low on the orders of 10^?4 ～10^?5 mol dm^?3 in sodium thiosulfate solution. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2441–2447, 2012     

In situ thermal polymerization of an ionic liquid monomer for quasi‐solid‐state dye‐sensitized solar cells

In situ thermal polymerization of a model ionic liquid monomer and ionic liquids mixture to form gel electrolytes is developed for quasi‐solid‐state dye‐sensitized solar cells (Q‐DSSCs). The chemical structures and thermal property of the monomers and polymer are investigated in detail. The effect of iodine concentration on the conductivity and triiodide diffusion of the gel electrolytes is also investigated in detail. The conductivity and triiodide diffusion of the gel electrolytes increase with the increasing I₂ concentration, while excessive I₂ contents will decrease the electrical performances. Based on the in situ thermal polymeric gel electrolytes for Q‐DSSCs, highest power conversion efficiency of 5.01% has been obtained. The superior long‐term stability of fabricated DSSCs indicates that the cells based on in situ thermal polymeric gel electrolytes can overcome the drawbacks of the volatile liquid electrolyte. These results offer us a feasible method to explore new gel electrolytes for high‐performance Q‐DSSCs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42802.     

Modification of narrow‐spectrum peptidomimetic polyurethanes with fatty acid chains confers broad‐spectrum antibacterial activity

Each year, thousands of patients die from antimicrobial‐resistant bacterial infections that fail to respond to conventional antibiotic treatment. Antimicrobial polymers are a promising new method of combating antibiotic‐resistant bacterial infections. We have previously reported the synthesis of a series of narrow‐spectrum peptidomimetic antimicrobial polyurethanes that are effective against Gram‐negative bacteria, such as Escherichia coli; however, these polymers are not effective against Gram‐positive bacteria, such as Staphylococcus aureus. With the aim of understanding the correlation between chemical structure and antibacterial activity, we have subsequently developed three structural variants of these antimicrobial polyurethanes using post‐polymerization modification with decanoic acid and oleic acid. Our results show that such modifications converted the narrow‐spectrum antibacterial activity of these polymers into broad‐spectrum activity against Gram‐positive species such as S. aureus, however, also increasing their toxicity to mammalian cells. Mechanistic studies of bacterial membrane disruption illustrate the differences in antibacterial action between the various polymers. The results demonstrate the challenge of balancing antimicrobial activity and mammalian cell compatibility in the design of antimicrobial polymer compositions. © 2019 Society of Chemical Industry