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In this work, hydrogels with antimicrobial activity based on the polysaccharide maltodextrin (MD) were prepared by copolymerization with either acrylic acid (AAc) or acrylamide (AAm) to endow chemi...

Oil-in-water microemulsions (o/w MEs) were coated with chitosan to obtain new curcumin delivery systems. First, ternary phase diagrams were constructed using mixtures of Tween 20, Tween 80, ethanol...

Cotton gauzes were grafted with a hydrogel of maltodextrin (MD) and poly(acrylic acid) (PAAc) using N-maleyl chitosan as crosslinker to obtain materials with antimicrobial properties. Reaction parameters including monomer, crosslinker, and initiator concentrations were studied. The modification with the copolymer poly(acrylic acid)-co-maltodextrin (PAAc-co-MD) was corroborated by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The grafted gauzes (gauze-g-(PAAc-co-MD)) were able to load vancomycin and inhibit the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. In addition, the incorporation of chitosan as crosslinker showed a synergistic effect against these bacteria. The prepared gauze-g-(PAAc-co-MD) materials could be used in the biomedical area particularly as antimicrobial wound dressings.

Polyvinylamine-coated mesocellular silica foam (MCF) was synthesized by grafting poly(n-vinylformamide) (PNVF) followed by the acid hydrolysis of the formamide groups with hydrochloric acid (HCl) and subsequent neutralization with sodium hydroxide (NaOH). In order to graft PNVF, MCF silica was previously functionalized with the coupling agent vinyltrimehtoxysilane (VTMS). The PNVF content in the hybrid material was tailored by varying some reaction parameters such as monomer concentration, reaction time, and temperature. The grafted polymer content was determined by thermogravimetric analysis (TGA) and ranged from 27% to 50%. Additionally, small-angle X-ray scattering (SAXS), infrared spectroscopy (FT-IR), nitrogen adsorption–desorption analyses, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques confirmed the grafting of PNVF onto MCF. The N2 adsorption–desorption studies showed that the textural properties of the pristine MCF decreased as the amount of grafted PNVF increased confirming the deposition of polymer into silica. However, according to SAXS, SEM, and TEM studies, the mesostructure of MCF was maintained even after acid hydrolysis of PNVF and its subsequent neutralization to obtain PVAm.

A hybrid hydrogel (GHC-SBA15) based on spruce xylan (HC), 2-hydroxyethyl methacrylate (HEMA), and mesoporous silica (SBA15) was prepared with the intended use of fibroblast attachment and growth. Xylan was functionalized with acryloyl chloride to introduce vinyl groups and was crosslinked by radical polymerization with HEMA in presence of SBA15. Infrared spectroscopy and nuclear magnetic resonance confirmed the copolymerization of HEMA with xylan. Up to 20 wt.% addition, SBA15 was homogenously incorporated in the structured hydrogel network as observed by SEM. Moreover, nitrogen adsorption-desorption, small angle X-ray scattering and transmission electron microscopy indicated that the mesoporous SBA15 framework was maintained and that the hybrid hydrogel was a physical mixture of SBA15 with the copolymer HC/HEMA. Rheological analysis revealed that addition of 20% w/w SBA15 into hydrogel enhanced significantly the mechanical properties. In addition, we demonstrate that fibroblast L929 cells grew and spread on GHC-SBA15. Cell viability was within the expected range.

In this study, the synthesis, characterization, and application of poly(N-vinylcaprolactam)-grafted magnetite nanocomposites for magnetic hyperthermia are reported. Superparamagnetic magnetite nanoparticles (MagNPs) with sizes in the range of 10–16 nm were synthesized by the coprecipitation method and then functionalized with vinyltrimethoxysilane (VTMS). MagNPs-VTMS coated with poly(N-vinylcaprolactam) (PNVCL) were prepared by free radical polymerization. The obtained materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibration sample magnetometry (VSM), and Fourier transform infrared spectroscopy (FT-IR). The heating ability was evaluated under a magnetic field using a solid state induction heating equipment at 10.2 kA/m and 362 kHz. The MagNPs-PNVCL nanocomposites showed a behavior close to superparamagnetic materials, which is appropriated for magnetic hyperthermia treatment; in concentrations of 8 mg/mL, they were able to heat up, increasing the temperature up to 42°C in a period of time lower than 10 minutes.

Mesocellular silica foam (MCF) was synthesized and modified by grafting polyacrylamide (PAAm) onto its surface. Grafting process was carried out by free radical polymerization using vinyltrimethoxysilane (VTMS) as coupling agent. The dependence of the final PAAm content with respect to monomer and initiator concentrations, reaction time, and temperature was evaluated. The PAAm contents in the hybrid material were determined by thermogravimetric analysis (TGA) and ranged from 15 to 64%. Diverse characterization techniques confirmed the grafting processes including small-angle X-ray scattering (SAXS), infrared spectroscopy, (FT-IR), nitrogen adsorption-desorption analyses, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). According with SAXS and N 2 adsorption-desorption studies, the grafting of polymer may cause pore blockage of mesopores channels being more evident for MCF silica with high content of PAAm.

Radiation-grafting of pH-responsive methacrylic acid (MAA) onto poly(vinyl chloride) (PVC) was carried out by the pre-irradiation method using gamma rays, which demonstrated to be an efficient and fast procedure for obtaining PVC-g-MAA copolymers. The influence of preparation conditions, such as absorbed dose, monomer concentration, reaction time, and reaction temperature on the grafting yield was studied. The grafting of MAA onto PVC catheters was confirmed by means of Fourier transform infrared spectroscopy (FT-IR), thermogravimetry analysis (TGA), and differential scanning calorimetry (DSC). The pH-responsiveness of the grafted copolymers (critical point 8.5) was measured by swelling under cyclic changes in the pH of the medium. Interestingly, PVC-g-MAA showed enhanced capability to immobilize benzalkonium chloride and, particularly, ciprofloxacin and to sustain the release this antimicrobial agent at both acid and alkaline pH. Tests carried out with Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus point out that the developed functionalized catheters may play a role in the prevention/management of urinary tract infections.

Prevention and treatment of medical device-related infections demands novel strategies for hindering bacteria adhesion and proliferation. The aim of this work was to immobilize gold nanoparticles onto silicone rubber (SR) and then exploit the plasmon resonance properties for the photothermal killing of adhered bacteria. To obtain a good rate of gold deposition, SR films were grafted with PAAc nanobrushes (SR-g-AAc) using a 60Co gamma source. Effects of absorbed dose, monomer concentration, temperature and reaction time on the grafting percentage, swelling and mechanical properties of the films were first investigated. Gold nanoparticles were immobilized on SR and SR-g-AAc following different strategies. Immersion in gold ions (HAuCl4) solution and subsequent reduction made the films to be uniformly coated by 10–20 nm gold nanoparticles as shown by SEM-EDX and XRD. Photothermal features were evidenced as an increase in 6–7 °C in the first 5 min of irradiation with a 514 nm laser at a power density of 0.5 W/cm2. Finally, SR-g-AAc films were challenged against Staphylococcus aureus and effects of irradiation at 514 nm on bacteria survival evaluated. Overall, the gold-immobilized films were shown to be stable against autoclave sterilization and ultrasounds and exhibited outstanding ability to damage adhered bacteria after laser irradiation.

This work reports the grafting of a stimuli-responsive polymer onto the surface of gold nanoparticles (AuNPs). First, AuNPs were synthesized by reduction of chloroauric acid (HAuCl4) aqueous solution with sodium citrate. Then, AuNPs were functionalized with allyl thiol to obtain allyl-functionalized AuNPs (AuNPs-SH). A “grafting from” approach was used to graft poly(N-vinylcaprolactam) (PNVCL) by free radical polymerization to obtain nanocomposites based on AuNPs (AuNPs-g-PNVCL). Nanocomposites were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Covalent interactions between AuNPs and PNVCL were investigated by XPS and FTIR studies while the structural and morphological characteristics were studied by TEM and XRD analysis respectively. PNVCL-modified AuNPs were able to load doxorubicin (DOX) because of the presence of polymer and the in vitro drug release profiles showed a sustained release of this drug during the first 24 h at 37 °C.

Mesoporous type-MCM-48 silica was grafted with polyacrylamide (PAAm) by using an azo-type initiator. The effect of monomer and initiator concentrations, reaction time, and temperature were evaluated to determine the optimal grafting conditions. Functionalized MCM-48 silicas were characterized by X-ray diffraction (XRD), infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption–desorption analyses, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) which confirmed the grafting process. According to XRD, SEM and TEM results, PAAm-modified MCM-48 silica did not show changes in its morphology and mesostructure by comparing with pristine MCM-48. Also, modified silicas were tested as delivery system using nalidixic acid as drug model. MCM-48-PAAm silicas were able to load more significant amounts of nalidixic acid than the unmodified MCM-48, and showed a sustained delivery behaviour, releasing about 80% of drug.

Mesoporous silica MCM-41 was grafted with a thermoresponsive terpolymer composed of triethoxyvinylsilane, N-isopropylacrylamide, and β-cyclodextrin (TEVS/NIPAAm/βCD). The terpolymer was grafted to the surface of MCM-41 (MCM-T) by coupling TEVS via silane chemistry. Grafting was a function of the NIPAAm/βCD molar ratio. MCM-T samples showed sensitivity to temperature (lower critical solution temperature, LCST) close to that of NIPAAm. The new material was capable of easily adsorbing ibuprofen and released it above its LCST.

MCM-41 mesoporous silicas were covalently modified with polyacrylamide (PAAm) by a novel grafting strategy. The effect of various parameters such as monomer concentration, reaction time, and temperature on the content of PAAm onto MCM-41 silicas were studied. Modified silicas were characterized by X-ray diffraction (XRD), infrared spectroscopy, FT-IR, thermogravimetric analysis, nitrogen adsorption–desorption analyses, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy which confirmed the grafting process. According to XRD, SEM and TEM results, PAAm-modified MCM-41 silica did not show changes in its morphology and mesostructure by comparing with pristine MCM-41. Nitrogen adsorption–desorption studies showed that the attaching of PAAm onto MCM-41 silica decreased the values of pore size, pore volume and surface area.

In this work, several normal, oil-in-water (o/w) microemulsions (MEs) were prepared using peppermint essential oil, jojoba oil, trans-anethole, and vitamin E as oil phases to test their capacity to load paclitaxel (PTX). Initially, pseudo-ternary partial phase diagrams were constructed in order to find the normal microemulsion region using d-α-tocopherol polyethylene glycol 1000 succinate (TPGS-1000) as surfactant and isobutanol (iso-BuOH) as co-surfactant. Selected ME formulations were loaded with PTX reaching concentrations of 0.6 mg mL−1 for the peppermint oil and trans-anethole MEs, while for the vitamin E and jojoba oil MEs, the maximum concentration was 0.3 mg mL−1. The PTX-loaded MEs were stable according to the results of heating–cooling cycles and mechanical force (centrifugation) test. Particularly, drug release profile for the PTX-loaded peppermint oil ME (MEPP) showed that ∼ 90% of drug was released in the first 48 h. Also, MEPP formulation showed 70% and 90% viability reduction on human cervical cancer (HeLa) cells after 24 and 48 h of exposure, respectively. In addition, HeLa cell apoptosis was confirmed by measuring caspase activity and DNA fragmentation. Results showed that the MEPP sample presented a major pro-apoptotic capability by comparing with the unloaded PTX ME sample.

This chapter discusses the state of the art of stimuli-responsive nanomaterials including nanocomposites, metallic nanomaterials, sensors, biosensors, nanomedicine, and mesoporous materials with potential biomedical applications and focuses on the interest of nanomaterials. Nanomaterials are multifunctional due to the incorporation of both therapeutic and bioimaging agents. The different types of nanomaterials are fabricated using several approaches ranging from conventional chemical methods to more sophisticated processes such as surface modification by synthesis of inorganic and organic nanomaterials to obtain layers free of pollutant without purification and isolation processes, among other advantages for obtaining new materials of special physical-chemical properties.

In this work, the preparation of inclusion complexes by functionalizing mesocellular silica foam (MCF) with β-cyclodextrin (β-CD) is reported. Likewise, the effect of the grafted β-CD amount on the loading and release of doxorubicin (Dox) at simulated physiological and lysosomal pH was studied. First, MCF silica was functionalized with β-CD under different conditions by means of reflux in toluene. The materials obtained were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By means of TGA, the grafting percentage of β-CD onto MCF was determined, obtaining a grafting range from 10 to 40%. The drug was loaded into the inclusion complexes by immersion in an aqueous Dox solution and then the release was studied at different pH values (7.4, 5.0) at 37 ​°C. The results suggested that the silica materials modified with β-CD could act as drug carriers in the sustained and directed administration of this anticancer agent, loading up to 1.17 ​× ​10−1 mg Dox/mg MCF-(β-CD) in 72 ​h and releasing up to 70%. Kinetically, the release profiles of the inclusion complexes were better adjusted to the Higuchi model, suggesting that release was carried by diffusion of drug from the inclusion complex to the simulated pH medium.

In this work, magnetite nanoparticles (Fe3O4 NPs) were grafted with poly (N-vinylcaprolactam) (PNVCL) chains via free radical polymerization for being used as carrier of doxorubicin (DOX). Grafting of PNVCL on these magnetic NPs was corroborated by studies of X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The in vitro DOX release was studied at physiological temperature in phosphate buffer solution 7.4. Also, hemolysis assays were carried out in order to investigate the biocompatibility of the magnetic nanocomposites. Composite nanoparticles exhibited a spherical morphology with a magnetic core and a polymer layer. The polymer-grafted magnetite NPs showed a high hemobiocompatibility with DOX encapsulation efficiency of about 35–47% and a maximum DOX cumulative in vitro release of 42% which depended of the polymer content in the nanocomposite. These results show that obtained magnetic functional nanocomposites could have the potential to be used as nanocarriers of DOX.

The aim of the present work was to functionalize poly(vinyl chloride) (PVC) urinary catheters with grafted copolymers that can improve the biocompatibility and serve as binding points of lysozyme. PVC catheters were modified by grafting a mixture of N-vinylcaprolactam (NVCL) and 2-hydroxyethylmethacrylate (HEMA) applying a gamma-ray pre-irradiation method. The effect of absorbed dose, monomer concentration, temperature, and reaction time on the grafting percentage was evaluated. The grafted catheters were characterized regarding surface composition (FTIR-ATR spectroscopy), thermal properties (DSC and TGA) and swelling in aqueous medium. Lysozyme was directly coupled onto PVC-g-(NVCL/HEMA) previously activated using carbonyldiimidazole. Antimicrobial lytic activity of the modified catheters over time was tested against Micrococcus lysodeikticus. Lysozyme diminished the adhesion of Staphylococcus aureus onto the functionalized catheters, which may be suitable to prevent biofilm formation.

The structural order and stability of spherical SBA-15 silicas synthesized under acid conditions were evaluated as a function of surfactant Pluronic 123 (P123), tetraethyl orthosilicate (TEOS), and hydrochloric acid (HCl) concentrations in the initial gel composition. Also, the effect of temperature and reaction time was studied. Samples were characterized by small angle X-ray diffraction (SAXS), nitrogen adsorption–desorption analyses, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that synthesis conditions affect the structural order and stability of the SBA-15 silicas. These silicas exhibited an ordered pore structure and regular spherical morphology with size from 2 to 5 µm.

N-vinylimidazole (VIm) was grafted onto medical-grade poly(vinyl chloride) (PVC) catheters in order to provide a bactericidal surface that make them less susceptible to microbial colonization. The grafting of VIm was carried out by means of gamma rays using the direct method, which demonstrated to be an efficient and fast procedure for obtaining PVC-g-VIm copolymers. These copolymers could be quaternized in a second step using methyl iodide (CH 3 I). The effects of solvent nature, absorbed dose, and monomer concentration on the grafting yield were investigated. Modified PVC catheters were characterized by means of Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TGA), and swelling studies. PVC-g-VIm copolymers both before and after quaternization showed good hemocompatibility, while quaternization was required to inhibit the growth of Staphylococcus aureus .

The major challenge for tissue engineering is the development of biomaterials that possess suitable chemical, mechanical, and topographical properties for cell culture. Functional polymers have shown promising results. This work showed a different methodology to synthesize a new functional polymer rich in primary amines on surface, using as substrate polytetrafluoroethylene (PTFE), which is a biocompatible polymer. For this purpose, PTFE was grafted with glycidyl methacrylate (GMA) by gamma radiation for its further functionalization with polyallylamine (PAA) to evaluate its hydrophilicity, roughness, thermal properties and amine content, using atomic force microscopy (AFM), contact angle and thermogravimetric analysis (TGA), respectively. The presence of amine groups onto surface was confirmed by Fourier transform infrared spectroscopy (FTIR) and quantified by X-ray photoelectron spectroscopy (XPS). Grafting yields (≈50%) of GMA onto PTFE were obtained using the pre-irradiation oxidative method at dose of 10 kGy, reaction time of 10 h, and 50 °C. Further chemical functionalization of the grafted films with PAA yielded 3.8% surface nitrogen content, a root mean square roughness (RMS) value of 465 nm, and contact angle of 57.5°. The results suggest that the developed material may have potential applications as substrate for cell adhesion.

Catheter-associated infections still represent a challenging thread because of the likelihood of biofilm formation. The aim of this work was the surface modification of catheters to immobilize lysozyme and acylase under mild conditions while preserving antimicrobial and anti-quorum sensing performances. Glycidyl methacrylate (GMA) was grafted onto poly(vinyl chloride) (PVC) catheters by a pre-irradiation method. The effects of monomer concentration, pre-irradiation dose, reaction time, monomer concentration and reaction temperature were investigated. The grafting process was monitored using FTIR-ATR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and swelling data. Lysozyme was directly immobilized onto PVC-g-GMA maintaining the hydrolytic activity, which hindered Staphylococcus aureus adhesion. For acylase immobilization, the PVC-g-GMA catheters were reacted with ethylenediamine and glutaraldehyde in order to facilitate acylase covalent binding. Free acylase in solution demonstrated notably capability to act as quorum sensing inhibitor, as observed using Chromobacterium violaceum as biosensor, by degrading a wide variety of acylated homoserine lactones (AHLs), including those produced by Pseudomonas aeruginosa and Acinetobacter baumannii. Acylase-immobilized PVC-g-GMA catheters were challenged against degradation of AHLs and the activity monitored using both the biosensor and HPLC-MS. Relevantly, the functionalized catheters completely degraded all tested AHL signals, opening new ways of preventing biofilm formation on medical devices.

Medical cotton gauzes were modified by grafting poly(methacrylic acid) (PMAA) via free radical polymerization to obtain wound dressings with antimicrobial and drug delivery properties. The effect of several reaction parameters including monomer and initiator concentrations, reaction time, and temperature was studied. The grafting was confirmed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), swelling studies, and scanning electron microscopy (SEM). The grafted cotton gauzes (gauze-g-PMAA) samples were loaded with ZnO nanoparticles to endow with antibacterial properties. Also, they were tested as drug eluting systems using nalidixic acid as antimicrobial agent. The antibacterial activity of the ZnO-loaded gauze-g-PMAA samples was evaluated against Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis). The PMAA-grafted gauzes showed antibacterial activity and inhibited the growth of both microorganisms. These results suggest that the PMAA-grafted cotton gauzes could be used in the biomedical area particularly as antimicrobial and drug-eluting wound dressings.

Safety and biocompatibility assessment of biomaterials are themes of constant concern as advanced materials enter the market as well as products manufactured by new techniques emerge. Within this context, this review provides an up-to-date approach on current methods for the characterization and safety assessment of biomaterials and biomedical devices from a physical-chemical to a biological perspective, including a description of the alternative methods in accordance with current and established international standards.

This chapter discusses the state of the art of biopolymers and synthetic polymers with potential biomedical applications and focuses on the interest of the gamma ray, for controlling polymerization during grafting of polymers onto biocompatible substrates. Biopolymers have attracted attention because they have their own biological activity. They come from renewable resources and fossil fuels, are nontoxic for the human body, are biocompatible, and many of them are biodegradable. Graft modification is a very interesting alternative to modifying synthetic and natural polymers. Particularly, radiation-induced graft polymerization has shown interesting advantages over other techniques, including the possibility to carry grafting at room temperature without the use of additives such as catalyst or chemical initiators. Some biomedical applications of the grafted biopolymers are also described.

Poly(N-vinylimidazole) (PVIm) was grafted $numbers onto silicone rubber (SR) with the aim of providing antimicrobial properties. The grafting was carried out by means of gamma rays using the direct method. The influence on the grafting yield of absorbed dose, monomer concentration, addition of FeSO4 salt, composition and type of solvent (H2O, MeOH, THF, and acetone) was investigated. Grafts onto SR between 10% and 90% were obtained at doses from 20 to 100kGy and a dose rate 10.9kGyh-1; grafting yield increased with monomer concentration and dose. The new graft copolymers were confirmed by Fourier transform infrared spectroscopy (FT-IR). Differential scanning calorimeter (DSC) showed glass transition at 149 and 159°C for 38% and 88% grafting respectively. Thermogravimetry analysis (TGA) presented two decomposition temperatures for SR-g-VIm at 380 (PVIm) and 440°C (SR). SR-g-VIm showed antibacterial activity against Pseudomonas aeruginosa.

Gamma radiation has been shown particularly useful for the functionalization of surfaces with stimuli-responsive polymers. This method involves the formation of active sites (free radicals) onto the polymeric backbone as a result of the exposition to high-energy radiation, in which a proper microenvironment for the reaction among monomer and/or polymer and the active sites takes place, thus leading to propagation which forms side chain grafts. The modification of polymers using high-energy irradiation may be performed by the following methods: direct or simultaneous, pre-irradiation oxidative and pre-irradiation. The most frequent ones correspond to the pre-irradiation oxidative method and the direct one. Radiation-grafting has many advantages over conventional methods considering that it does not require catalyst nor additives to initiate the reaction, and in general, no changes on the mechanical properties with respect to the pristine polymeric matrix are observed. This chapter focused on the synthesis of smart polymers and coatings obtained by the use of gamma radiation. In addition, diverse applications of these materials in the biomedical field are also reported.

Silicone rubber (SR) was γ-ray grafted with poly(methacrylic acid) (PMAA) to improve its ability to host antimicrobial drugs. Dependence of grafting yield on monomer concentration, pre-irradiation dose, temperature and reaction time was evaluated. Modified SR films were characterized by means of FT-IR, DSC, TGA, SEM, contact angle measurements, and swelling studies. SR-g-MAA showed pH sensitivity (critical pH ∼6) and good cytocompatibility. Soaking of SR-g-MAA in benzalkonium chloride and vancomycin aqueous solutions led to high loadings; up to 5.8 and 15.2 mg cm-2, respectively. SR-g-MAA released 100% vancomycin after 24 h in buffer pH 7.4 at 37 °C, but only 20% benzalkonium chloride due to strong ionic interactions. Drug-loaded SR-g-MAA prevented in vitro growth of Staphylococcus aureus. Overall, grafting of PMAA may improve the performance of SR for biomedical applications.

(PP-g-DMAEMA)-g-NIPAAm was synthesized using gamma radiation from a 60Co source. Graft polymerization of N,N’-dimethylaminoethylmethacrylate (DMAEMA) onto polypropylene (PP) was accomplished in about 100 percent yield by the mutual irradiation technique at a dose of 10 kGy. Grafting of N-isopropylacrylamide (NIPAAm) onto PP-g-DMAEMA was carried out by the pre-irradiation method with doses from 20 to 100 kGy. The influence of temperature, reaction time, and monomer concentration on grafting yield was studied. Grafting processes were confirmed by infrared spectroscopy (FTIR-ATR). (PP-g-DMAEMA)-g-NIPAAm films were characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The lower critical solution temperature (LCST) and critical pH point of the films were obtained by water contact angle and percent swelling measurements. The LCST was also determined by DSC. We report here hare a new binary graft copolymer which shows two LCST values, synthesized in two steps.

Poly(ether-block-amide) (PEBA) films were grafted with acrylic acid (AAc) by gamma radiation, using the oxidative pre-irradiation technique. The effect of dose, monomer concentration, temperature, and reaction time on the graft percentage of AAc onto PEBA was studied. The modified material PEBA-g-AAc was characterized by Fourier infrared spectroscopy (FTIR), scanning electron microscopy, and water contact angle. It was found that PEBA films did not suffer degradation at low doses (

Mixed matrix membranes (MMM) based on polysulfone and chemically modified clinoptilolite were prepared. Clinoptilolite enriched with Ca2+, K+, and Na+ by ion exchange at two test temperatures was prepared. Chemical composition was monitored by energy dispersive X-ray spectroscopy. X-ray diffraction, thermogravimetric analysis, and N2 adsorption–desorption isotherms were also performed. Thermal and morphological properties of MMM were evaluated. CH4/CO2 gas mixture permeability tests at different upstream pressure were carried out. Type of exchanged cation in modified clinoptilolite affected the CO2 permeability. An improvement on the CO2/CH4 selectivity values in the MMM compared to the polymeric membrane was appreciated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45659.