Biomimetic design of chelating interfaces

Siderophores are naturally occurring small molecules with metal binding constants greater than many synthetic chelators. Herein, we report a two‐step process to graft a siderophore‐mimetic metal chelating polymer from a polypropylene (PP) surface. Poly(methyl acrylate) was first grafted from the PP surface by photoinitiated graft polymerization, followed by the conversion into poly(hydroxamic acid) (PHA) to obtain PP‐g‐PHA films. ATR/FTIR, contact angle, SEM, and AFM were performed to characterize surface properties of films. Iron binding kinetics and the influence of pH (3.0–5.0) on the chelating ability of films were determined. PP‐g‐PHA exhibited significant iron chelating activity (～80 nmol/cm²) with an equilibration time of 24 h. The materials retained 50% chelating ability at pH 3.0 compared with pH 5.0, almost double the retention of previously reported polycarboxylate chelating interfaces. By using siderophore‐mimetic surface chemistry, such effective metal chelating interfaces can extend the applications of metal chelating polymers in environmental remediation, water purification, and active packaging areas. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41231.     

Oxidative graft polymerization of aniline on the modified surface of polypropylene films

A novel method for preparing electrically conductive polypropylene‐graft‐polyacrylic acid/polyaniline (PP‐g‐PAA/PANI) composite films was developed. 1,4‐Phenylenediamine (PDA) was introduced on the surface of PP‐g‐PAA film, and then, chemical oxidative polymerization of aniline on PP‐g‐PAA/PDA film was carried out to prepare PP‐g‐PAA/PANI electrically conductive composite films. After each step of reaction, the PP film surface was characterized by attenuated total reflectance Fourier transform infrared spectroscopy. Static water contact angles of the PP, PP‐g‐PAA, and PP‐g‐PAA/PANI films were measured, and the results revealed that graft reactions took place as expected. The morphology of the PP‐g‐PAA film and the PP‐g‐PAA/PANI composite film were observed by atomic force microscopy. The conductivity and the thickness of the PP‐g‐PAA/PANI composite films with 1.5 wt % PANI were around 0.21 S/cm and 0.4 μm, respectively. The PANI on the PP‐g‐PAA/PANI film was reactivated and chain growing occurred to further improve the molecular weight of PANI. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2442–2450, 2007     

Polypropylene/polypropylene‐grafted acrylic acid blends for multilayer films: Preparation and characterization

Polypropylene (PP) was functionalized with acrylic acid (AA) and styrene (st) as a comonomer by means of a radical‐initiated melt‐grafting reaction. FTIR, ESCA, and ¹H‐NMR spectroscopies were used to characterize the formation of polypropylene grafted with acrylic acid (PP‐g‐AA) and polypropylene grafted with acrylic acid and styrene (PP‐g‐AAst). The content of AA grafted onto PP was determined by using volumetric titration. Blends of PP with 0–100 wt % of PP‐g‐AA were prepared by melt mixing. The effect of the modified polymer content on the surfaces of cast films was characterized through FTIR–ATR and ESCA analysis as well as contact‐angle, wetting‐tension, and ink‐adhesion measurements. The influence of the content of AA on the melting and crystallization temperature of PP was investigated by DSC. The contact angles of water on cast‐film surfaces of PP/PP‐g‐AA blends decreases with increasing modified polymer content and decreasing PP‐g‐AA molecular weight. A notorious improvement on wetting tension was observed with increasing modified polymer content and decreasing PP‐g‐AA molecular weight. From FTIR–ATR and ESCA spectra of the blends, a calculation was made of the carbonyl index on the films' surfaces. It was found that the higher the carbonyl index, the lower the contact‐angle value for the polypropylene blends. An increase in crystallization temperature of PP was observed when AA monomers were grafted into PP and with increasing PP‐g‐AA content in the blend, probably caused by a nucleation effect of AA monomers that would improve the crystallization capability of PP. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1497–1505, 2001     

Poly(N‐isopropylacrylamide) grafted to a strongly charged backbone: Thermoresponsive behavior in aqueous solution

The thermoresponsive properties in aqueous solution of the graft copolymer poly(acrylic acid‐co‐2‐acrylamido‐2‐methyl propane sulfonic acid)‐g‐poly(N‐isopropylacrylamide) [P(AA‐co‐AMPSA)‐g‐PNIPAM] were studied and compared to the corresponding behavior of the poly(acrylic acid)‐g‐poly(N‐isopropylacrylamide) (PAA‐g‐PNIPAM) graft product. Both products contain about 40% (w/w) of PNIPAM, whereas the backbone, P(AA‐co‐AMPSA), of the first copolymer contains about 40% of AMPSA mole units. The strongly charged P(AA‐co‐AMPSA)‐g‐PNIPAM graft copolymer was water soluble over the whole pH range, whereas the PAA‐g‐PNIPAM copolymer precipitated out from water at pH < 4. As a result, the first product exhibited a temperature‐sensitive behavior in a wide pH range, extended in the acidic region, whereas in semidilute aqueous solutions, an important thermothickening behavior was observed, even at low pH (pH = 3.0). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3466–3470, 2004     

Preparation of biocompatible multi‐walled carbon nanotubes as potential tracers for sentinel lymph nodes

Carbon nanotubes (CNTs) are capable of traversing cellular membranes by endocytosis and are therefore promising materials for use in imaging and drug delivery. Unfortunately, pristine CNTs are practically insoluble and tend to accumulate inside cells, organs and tissues. To overcome the poor dispersibility and toxicity of pristine CNTs, hydrophilic functionalization of CNTs has been intensively investigated. Water‐soluble multi‐walled carbon nanotubes (MWCNTs) were prepared by in situ polymerization of acrylic acid in a poor solvent for poly(acrylic acid) (PAA). The solvent type influenced the grafted density and chain length of PAA. MWCNTs with a high grafted density of PAA (22 wt%) could be well dispersed in water, NaCl aqueous solution (0.9 wt%) and cell culture media. The in vitro cytotoxicity of these MWCNTs for endothelial cells is reasonably low even at high concentration of PAA‐g‐MWCNT (70 µg mL^?1). The experimental results show that the biocompatibility of these MWCNTs is sufficient for biological applications. PAA‐g‐MWCNTs were successfully utilized for lymph node tracing. Experimental results suggest that PAA‐g‐MWCNTs have potential to be used as a vital staining dye, which may simplify the identification of lymph nodes during surgery. Copyright © 2009 Society of Chemical Industry     

Improving properties of superabsorbent composite induced by using alkaline protease hydrolyzed‐sericin (APh‐sericin)

A series of superabsorbent polymer composites based on sericin hydrolyzed with alkaline protease (AP) were prepared by grafting with acrylic acid (AA) and acrylamide (AM). The properties of the superabsorbent polymers (SAP) by using hydrolyzed sericin with different amount of alkaline protease (nAPh‐sericin) were compared. It was found that the polymer prepared from 5APh‐sericin (the mass ratio of AP to sericin was 5.0 mg g⁻¹) showed the highest graft percentage and water absorbency, this phenomenon may be attributed to the change of molecular weight of resulting sericin molecules. The molecular structure of the grafted polymers was proved by thermal gravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) measurements. Comparing with PAA‐AM (poly AA‐co‐AM) and 0APh‐sericin/PAA‐AM polymer, 5APh‐sericin/PAA‐AM polymer had the most excellent water retention capacity and enzyme degradability. The morphological features of the polymers with different drying methods were evidenced by SEM images. The water absorbencies of 5APh‐sericin/PAA‐AM polymer prepared with freeze‐drying were 896 g g⁻¹ in deionized water, 424 g g⁻¹ in tap water, and 83 g g⁻¹ in 0.9 wt% aqueous NaCl solution. POLYM. COMPOS., 35:509–515, 2014. © 2013 Society of Plastics Engineers     

Starch–acrylics graft copolymers and blends: Synthesis,characterization, and applications as matrix for drug delivery

A series of acrylic monomers–starch graft copolymers were prepared by ceric ion initiation method by varying the amount of monomers. These graft copolymers were characterized by IR and ¹³C‐NMR spectroscopy. It was seen that as the concentration of monomer [acrylic acid (AA), methacrylic acid (MA), and methyl methacrylate (MMA)] increased the percent add‐on increased in all the graft copolymers, whereas grafting efficiency increased initially but showed a slight decrease with further increase in the monomer concentration (except for MMA). The release rate of paracetamol as a model drug from graft copolymers as well as their blends was studied at two different pH, 1.2 and 7.4, spectrophotometrically. The release of paracetamol in phosphate buffer solution at pH 1.2 was insignificant in the first 3 h for St‐g‐PAA‐ and St‐g‐PMA‐graft copolymers, which was attributed to the matrix compaction and stabilization through hydrogen bonding at lower pH. At pH 7.4, the release rate was seen to decrease with increase in add‐on. The tablet containing poly(methyl methacrylate) (PMMA) did not disintegrate at the end of 30–32 h, which may be attributed to the hydrophobic nature of PMMA. These results indicate that the graft copolymers may be useful to overcome the harsh environment of the stomach and can be used as excipients in colon‐targeting matrices. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of PAA‐g‐PEG/PANI polymer gel electrolyte and its application in quasi solid state dye‐sensitized solar cells

A microporous hybrid polymer of poly(acrylic acid)‐g‐poly(ethylene glycol)/polyaniline (PAA‐g‐PEG/PANI) is synthesized by a two‐step solution polymerization method. The influence of aniline concentration on the conductivity of PAA‐g‐PEG/PANI gel electrolyte is discussed, when the concentration of aniline is 0.66 wt%, the conductivity of PAA‐g‐PEG/PANI gel electrolyte is 11.50 mS cm^?1. Using this gel electrolyte as host, a quasi solid state dye‐sensitized solar cell (QS‐DSSC) is assembled. The QS‐DSSC based on this gel electrolyte achieves a power conversion efficiency of 6.38% under a simulated solar illumination of 100 mW cm^?2 (AM 1.5). POLYM. ENG. SCI., 55:322–326, 2015. © 2014 Society of Plastics Engineers     

Polypropylene/polypropylene‐grafted acrylic acid copolymer/ethylene–Acrylic acid copolymer ternary blends for hydrophilic polypropylene

Ternary blends of polypropylene (PP), a polypropylene‐grafted acrylic acid copolymer (PP‐g‐AA), and an ethylene–acrylic acid copolymer (EAA) were prepared by melt blending. The surfaces of films with different contents of these three components were characterized with contact‐angle measurements. Scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis were used to characterize the microstructure, melting and crystalline behavior, and thermal stability of the blends. The contact angles of the PP/PP‐g‐AA blends decreased monotonically with increasing PP‐g‐AA content. With the incorporation of EAA, the contact angles of the PP/PP‐g‐AA/EAA ternary blends decreased with increasing EAA content. When the concentration of EAA was higher than 15 wt %, the contact angles of the ternary blends began to increase. Scanning electron microscopy observations confirmed that PP‐g‐AA acted as a compatibilizer and improved the compatibility between PP and EAA in the ternary blends. Differential scanning calorimetry analysis suggested that acrylic acid moieties could act as nucleating agents for PP in the polymer blends. Thermogravimetric analysis and differential thermogravimetry confirmed the optimal blend ratio for the PP/PP‐g‐AA/EAA ternary blends was 70/15/15. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 436–442, 2006     

Retention and reusability of trypsin activity by covalent immobilization onto grafted polyethylene plates

This study investigated the activity of trypsin that had been covalently immobilized onto acrylic acid (AA)– and methacrylic acid (MAA)–grafted polyethylene (PE) plates—PE–g–PAA and PE–g–PMAA—using a water‐soluble carbodiimide as a coupling agent, as a function of the immobilized amount, the grafted amount, the pH value on immobilization, and the pH value and temperature at the activity measurement. The activity of trypsin immobilized on the PE–g–PAA plates at pH 6.0 decreased with an increase in the immobilized amount because of the crowding of trypsin molecules in the vicinity of the surfaces of the grafted PAA layers. The increase in the grafted amount resulted in a decrease in the activity of immobilized trypsin because of a decrease in the diffusivity of BANA molecules caused by the formation of dense grafted PAA layers for the PE–g–PAA plates and led to the increased activity because of the increase in the hydrophilicity of the whole grafted layers for the PE–g–PMAA plates. The activity of trypsin immobilized on the PE–g–PAA and PE–g–PMAA plates at pH 6 increased with an increase in the pH value, probably because of the expansion of trypsin‐carrying grafted PAA and PMAA chains and the increased diffusivity of Nα‐benzoyl‐DL ‐arginine‐nitroanilide hydrochloride molecules in the grafted layers. The optimum temperature of the activity of immobilized trypsin shifted to 50°C from 30°C for native trypsin. Immobilized trypsin was reusable without any denaturation and isolation at temperatures ranging from 20°C to 60°C and pH values ranging from 6 to 10. Trypsin immobilized on a PE–g–PAA plate had 95% of the remaining activity in relation to native trypsin at 30°C after preservation in a pH 7.8 buffer at 4°C over 6 months. These results made clear that alkaline and thermal stability, reusability, and storage stability can be much improved by the covalent coupling of trypsin on PE–g–PAA and PE–g–PMAA plates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3574–3581, 2003     

Enhanced oxygen‐barrier and water‐resistance properties of poly(vinyl alcohol) blended with poly(acrylic acid) for packaging applications

To enhance the oxygen‐barrier and water‐resistance properties of poly(vinyl alcohol) (PVA) and expand its food packaging applicability, five crosslinked poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) blend films were prepared via esterification reactions between hydroxyl groups in PVA and carboxylic acid groups in PAA. The physical characteristics of the blends, including the thermal, barrier, mechanical and optical properties, were investigated as a function of PAA ratio. With increasing PAA content, the crosslinking density was significantly increased, resulting in changes in the chemical structure, morphology and crystallinity of the films. The oxygen transmission rate of pure PVA decreased from 5.91 to 1.59 cc m^?1 day^?1 with increasing PAA ratio. The water resistance, too, increased remarkably. All the blend films showed good optical transparency. The physical properties of the blend films were strongly correlated with the chemical structure and morphology changes, which varied with the PAA content. © 2016 Society of Chemical Industry     

Synthesis,characterization and swelling behaviors of hydroxyethyl cellulose‐g‐poly(acrylic acid)/attapulgite superabsorbent composite

In this work, a series of novel hydroxyethyl cellulose‐ g‐poly(acrylic acid)/attapulgite (HEC‐g‐PAA/APT) superabsorbent composites were prepared through the graft polymerization of hydroxyethyl cellulose (HEC), partially neutralized acrylic acid (AA), and attapulgite (APT) in aqueous solution, and the composites were characterized by means of Fourier‐transform spectroscopy, scanning electron microscopy, and transmission electronmicroscopy. The effects of polymerization variables including concentrations of the initiator and crosslinker and APT content on water absorbency were studied, and the swelling properties in various pH solutions as well as the swelling kinetics in various saline solutions were also systematically evaluated. Results showed that the introduction of 5 wt% APT into HEC‐g‐PAA polymeric network could improve both water absorbency and water absorption rate of the superabsorbent composites. In addition, the superabsorbent composites retained high water absorbency over a wide pH range of 4–10, and the swelling kinetics of the superabsorbent composites in CaCl₂ and FeCl₃ solutions exhibited a remarkable overshooting phenomenon. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Preparation and swelling properties of semi‐IPN hydrogels based on chitosan‐g‐poly(acrylic acid) and phosphorylated polyvinyl alcohol

The phosphorylated poly(vinyl alcohol) (P‐PVA) samples with various substitution degrees were prepared through the esterification reaction of PVA and phosphoric acid. By using chitosan (CTS), acrylic acid (AA) and P‐PVA as raw materials, ammonium persulphate (APS) as an initiator and N,N‐methylenebisacrylamide as a crosslinker, the CTS‐g‐PAA/P‐PVA semi‐interpenetrated polymer network (IPN) ssuperabsorbent hydrogel was prepared in aqueous solution by the graft copolymerization of CTS and AA and followed by an interpenetrating and crosslinking of P‐PVA chains. The hydrogel was characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) techniques, and the influence of reaction variables, such as the substitution degree and content of P‐PVA on water absorbency were also investigated. FTIR and DSC results confirmed that PAA had been grafted onto CTS backbone and revealed the existence of phase separation and the formation of semi‐IPN network structure. SEM observations indicate that the incorporation of P‐PVA induced highly porous structure, and P‐PVA was uniformly dispersed in the polymeric network. Swelling results showed that CTS‐g‐PAA/P‐PVA semi‐IPN superabsorbent hydrogel exhibited improved swelling capability (421 g·g^?1 in distilled water and 55 g·g^?1 in 0.9 wt % NaCl solution) and swelling rate compared with CTS‐g‐PAA/PVA hydrogel (301 g·g^?1 in distilled water and 47 g·g^?1 in 0.9 wt % NaCl solution) due to the phosphorylation of PVA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Morphological and mechanical properties of PP/ABS blends compatibilized with PP‐g‐acrylic acid

Polypropylene (PP) and acrylonitrile–butadiene–styrene (ABS) blends were prepared by a melt extrusion process. PP‐g‐acrylic acid was used as a compatibilizer. Blends with various compositions of PP, compatibilizer, and ABS were prepared and studied for morphological and mechanical properties. PP‐rich ternary blends showed good morphological and mechanical properties. The use of 5 wt % PP‐g‐acrylic acid as a compatibilizer resulted in a fine and homogeneous dispersion of the ABS phase in the PP phase. The experimental data of the tensile modulus showed good agreement in PP‐rich compositions with that generated from Kerner's model with perfect adhesion. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1731–1741, 2001     

Superabsorbent composite XXII: Effects of modified sepiolite on water absorbency and swelling behavior of chitosan‐g‐poly(acrylic acid)/sepiolite superabsorbent composite

In this work, a series of chitosan‐g‐poly(acrylic acid)/sepiolite (CTS‐g‐PAA/ST) superabsorbent composites containing raw sepiolite, acid‐activated sepiolite, and cation‐exchanged sepiolite were synthesized by free‐radical graft polymerization in aqueous solution, using N,N′‐methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The effects of raw sepiolite, acid‐activated sepiolite, and cation‐exchanged sepoilite on equilibrium water absorbency, swelling rate, and swelling behavior in different pH value solution of superabsorbent composites were systematically investigated. The results from FTIR spectra showed that chitosan and sepiolite participated in graft polymerization reaction with acrylic acid. The introduction of acid‐activated and cation‐exchanged sepiolite into chitosan‐g‐poly(acrylic acid) polymeric network could improve water absorbency and swelling rate compared with that of the raw sepiolite. All prepared samples have similar swelling behavior in different pH solutions and the equilibrium water absorbencies of samples keep roughly constant in the pH range from 4 to 12. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Fabrication of polymer‐gadolinium (III) complex nanomicelle from poly(ethylene glycol)‐polysuccinimide conjugate and diethylenetriaminetetraacetic acid‐gadolinium as magnetic resonance imaging contrast agents

Methoxy poly (ethylene glycol)‐graft‐α, β‐poly (aspartic acid) derivatives (mPEG‐g‐PAA‐N₃) were synthesized by sequential ring‐opening reaction of polysuccinimide (PSI) with mPEG‐NH₂ (MW: 2000 Da), and 1‐azido‐3‐aminopropane, respectively. Then N²‐(hex‐5‐yne)‐diethylenetriamine‐tetra‐t‐butylacetate (DTTA‐der) was conjugated to mPEG‐g‐PAA‐N₃ by click cycloaddition. After deprotection of carboxylic groups, mPEG‐g‐PAA‐DTTA macromolecular ligands were obtained. MPEG‐g‐PAA‐(DTTA‐Gd) complex nanomicelles were fabricated from mPEG‐g‐PAA‐DTTA and Gadolinium chloride. The formation of nanomicelles was confirmed by fluorescence spectrophotoscopy and particle size measurements. It was found that all the nanomicelles showed spherical shapes with core‐shell structures and narrow size distributions. Their sizes ranged from 50 to 80 nm, suggesting their passive targeting potential to tumor tissue. With the increase of graft degree (GD) of mPEG, the sizes of mPEG‐g‐PAA‐(DTTA‐Gd) nanomicelles showed a tendency to decrease. Compared with gadopentetate dimeglumine (Gd‐DTPA), mPEG‐g‐PAA‐(DTTA‐Gd) nanomicelles showed essential decreased cytotoxicity to KB cell line and enhanced T₁‐weighted signal intensity, especially at low concentration of gadolinium (III), suggesting their great potentials as magnetic resonance imaging contrast agents. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The effect of addition of poly(propylene‐g‐acrylic acid) on the morphology of poly(vinyl methylether) and isotactic polypropylene blend

The interfacial adhesion of blend of isotactic polypropylene/poly(vinyl methylether) (i‐PP/PVME) has been improved by the addition of poly(propylene‐g‐acrylic acid) (PP‐g‐AA) as a compatibilizing agent. The phase morphologies of the blends are investigated by optical microscopy (OM) and lateral force microscopy (LFM). The i‐PP/PVME (80/20) blend with no addition of PP‐g‐AA from extrusion process shows a coarse morphology with the dispersed domain size as large as several micrometers; After the addition of 2.5% PP‐g‐AA in the blends, the dispersed PVME domain size decreases greatly. The addition of 5% PP‐g‐AA results in a homogeneous morphology. The blending of PP‐g‐AA with PVME reduces the crystallization temperature of PP‐g‐AA, which is different from that of blending i‐PP with PVME. The increase of the interfacial adhesion is attributed to the specific intermolecular interaction between the acrylic acid group of PP‐g‐AA and the ether group of PVME. The specific interaction is studied by Fourier transform infrared spectroscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4098–4103, 2006     

Tuned interactions of silver nanoparticles with ZSM-5 zeolite by adhesion-promoting poly(acrylic acid) deposited by electrospray ionization (ESI)

The electrospray ionization (ESI) method was used for deposition of thin films of poly(acrylic acid) (PAA) on Cu/ZSM-5 (5 wt.% Cu) and Ag–Cu/ZSM-5 (1 wt.% Ag and 4 wt.% Cu) composites. For comparative purposes, the ZSM-5 zeolite was synthesized under hydrothermal conditions and loaded with PAA under the same treating conditions as the composites. This method allowed the formation of uniform polymer films of controlled thickness on conductive substrates. The structural characteristics were characterized by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, atomic force microscopy and X-ray diffraction (XRD). The deposited PAA layer over ZSM-5 acts as a common dispersing and stabilizing agent through coordination-driven guest-templated polymer via interaction of Ag⁺ and Cu²⁺ with carboxylic acid groups, thus increasing and controlling the adhesion and the release of metallic species. A short exposure to light and temperature has reduced the metal ions to Cu⁰ and Ag⁰ metallic nanoparticles. The results of XRD analysis let suggest that the interaction of Cu and Ag with carboxylic groups of PAA inhibits the formation of large metallic silver particles. These samples were being studied for their potential as antibacterial agents toward the bacterial strains such as Staphylococcus pneumonia, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa as Gram positive and Gram negative bacteria, respectively. Aspergillus fumigatus and Candida albicans as Fungi were also evaluated. The Cu/ZSM-5 and Ag–Cu/ZSM-5 nanocomposites coated with a 10 nm thick PAA layer exhibit significant antibacterial activity.     

Study on superabsorbent composites. XXI. Synthesis,characterization and swelling behaviors of chitosan‐g‐poly(acrylic acid)/organo‐rectorite nanocomposite superabsorbents

A novel chitosan‐g‐poly(acrylic acid)/organo‐rectorite (CTS‐g‐PAA/OREC) nanocomposite superabsorbent was synthesized by aqueous polymerization using N, N′‐methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. Rectorite was organified with four different degree of hexadecyltrimethyl ammonium bromide, and the organification of rectorite was proved by FTIR and XRD. The effect of organification degree of rectorite on water absorbency of CTS‐g‐PAA/OREC with different organo‐rectorite content was investigated. The swelling behaviors in distilled water and various pH solutions were also studied. The results from IR spectroscopy and XRD data show that acrylic acid had been grafted polymerization with chitosan and organo‐rectorite and formed nanocomposite. Introducing organo‐rectorite into the CTS‐g‐PAA polymeric network can improved water absorbency and swelling rate of CTS‐g‐PAA/OREC. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Influence of carboxyl and amide groups on in vitro hemocompatibility of sulfonated polypropylene non‐woven fabric

The sulfonated polypropylene non‐woven fabric (PP_NWF) was successfully fabricated via γ‐ray simultaneous radiation‐induced graft polymerization of acrylic acid (AA)/sodium styrenesulfonate (NaSS) and acrylamide (AAm)/NaSS. The existence of graft chains in both PP‐g‐P(AA‐co‐NaSS) and PP‐g‐P(AAm‐co‐NaSS) was proved by attenuated total reflection Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. Water contact angle measurement illustrated the sulfonated PP_NWF owning good hydrophilicity. The in vitro hemocompatibility evaluation showed that both PP‐g‐P(AA‐co‐NaSS) and PP‐g‐P(AAm‐co‐NaSS) inhibited effectively the adhesion of platelets and were significantly compatible with erythrocytes. Moreover, no obvious difference was confirmed in the prevention of platelet adhesion and hemolysis ratio between carboxyl and amide groups. However, as compared with that of PP‐g‐P(AAm‐co‐NaSS), PP‐g‐P(AA‐co‐NaSS) exhibited outstanding anticoagulant activity via increased activated partial thromboplastin time and thrombin time. This result indicated that the carboxyl group but not amide group featured strong synergistic effect on the anticoagulant activity of sulfonated PP_NWF. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45915.