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The interactions between the microbes and the surface of an anode play an important role in capturing the respiratory electrons from bacteria in a microbial fuel cell (MFC). The chemical and electrochemical characteristics of the carbon material affect biofilm growth and direct electron transfer in MFCs. This study examined the electrodeposition of polydopamine (PDA) and polypyrrole (PPY) on graphite felt electrode (GF). The MFC with the modified PDA/PPY-GF reached 920 mW/m

Cellulose acetate has a high melting temperature due to intense intermolecular hydrogen bonding and is not significantly different from the deterioration temperature, so decomposition may occur dur...

Butyl rubber was reinforced by the isoprene-modified silica. The modified silica was prepared via chemical modification by a hydrophobic and reactive oligomeric liquid isoprene rubber in a solvent....

Thermo- and pH-responsive polyrotaxane (PR)-based triblock copolymers were synthesized by atom transfer radical polymerization (ATRP) of N-isopropylacrylamide initiated with polypsudorotaxanes whic...

Biodegradable triblock copolymers based on poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) were synthesized via ring-opening polymerization of L-lactide followed by reversible addition–fragmentation chain-transfer (RAFT) polymerization of poly(methyl vinyl ketone) (PMVK) as a photodegradable block, and characterized by FT-IR and 1H NMR spectroscopy for structural analyses, and by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) for their thermal properties. Porous, biodegradable PCL-b-PLA microspheres were fabricated via the oil/water (O/W) emulsion evaporation method, followed by photodegradation of PMVK blocks by UV irradiation. The macro-chain transfer agent (CTA) synthesized by reacting a carboxylic-acid-terminated CTA—S-1-dodecyl-S′-(a,a′-dimethyl-a′′-acetic acid)trithiocarbonate (DDMAT)—with a hydroxyl-terminated PCL-b-PLA block copolymer was used to synthesize well-defined triblock copolymers with methyl vinyl ketone via RAFT polymerization with controlled molecular weights and narrow polydispersity. Gel permeation chromatography traces indicated that the molecular weight of the triblock copolymer decreased with UV irradiation time because of the photodegradation of the PMVK blocks. The morphology of the microspheres before and after UV irradiation was investigated using SEM and videos of three-dimensional confocal laser microscopy, showing a change in their surface texture from smooth to rough, with high porosity owing to the photodegradation of the PMVK blocks to become porous templates.

Butyl rubber/hydrophobized graphene oxide (HG) nanocomposites were prepared by solution mixing followed by compression molding process, and evaluated their properties using scanning electron microscope (SEM), oscillating disc rheometer (ODR), universal testing machine (UTM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The hydrophilic graphene oxide (GO) obtained through the oxidation of graphite (GP) was first hydrophobized with octadecylamine. The HG exhibit excellent dispersibility in toluene and stable under stationary condition for over 30 days. The chemical structure and functionality of HG was analyzed by fourier transform infrared (FTIR), raman spectroscopies, and wide-angle X-ray diffraction (WAXD) patterns. HG was successfully dispersed within BR matrix and result in significant reduction of curing time (around 30%), enhanced tensile strength (around 35%) as compared to the pristine butyl rubber. The air permeability of the hydrophobized graphene oxide composites was also significantly reduced by 75% compared to unfilled butyl rubber.

Being poor solubility and degradation at relatively higher pH present in the small intestine, it is very essential to develop gastro-retentive dosages for the release of curcumin. In this paper, the halloysite nanotubes (HNTs) was modified with aminopropyl trimethoxy silane (APTES) in order to increase the buoyancy of the hybrid beads through holding CO2 molecules within the pores of the beads, followed by the encapsulation of curcumin into the lumen of the HNTs. Highly porous pectin based hybrid beads were fabricated by incorporating various compositions of curcumin loaded amino silanized halloysite nanotube (MHNT) and sodium bicarbonate as CO2 generating agent. Finally, hybrid beads were crosslinked by ionotropic gelation method using calcium chloride and used to gastro retentive delivery of curcumin in sustained manner. The amino salinization of halloysite and curcumin loading into the modified halloysite were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). The highly porous nature of cross-linked hybrid beads has been confirmed with scanning electron microscopy (SEM) studies. In vitro release studies in simulated gastric fluid indicate that these new hybrid floating carriers are suitable for gastro retentive controlled release applications.

To fabricate new smart materials that can deliver both the pharmaceutically active molecules and metal nanoparticles, we have formulated chitosan-based semi-IPN hydrogels and their silver nanocompo...

New antitumor active polyrotaxanes, presynthesized from β-cyclodextrin and polypropylene glycol, were first end capped with antitumor active drug, 5-fluorouracil, and further conjugated with 5-fluo...

Porous biodegradable microspheres were fabricated by successful RAFT polymerization of methyl vinyl ketone onto polycaprolactone followed by an oil/water emulsion-evaporation method, then finally photodegradation of PMVK blocks by UV irradiation. Macro-CTA (chain transfer agent) was synthesized by reacting carboxylic acid-terminated CTA, S-1-dodecyl-S’-(α,α′-dimethyl-α’‘-acetic acid) trithiocarbonate (DDMAT) with hydroxyl terminated polycaprolactone, which was then used for the synthesis of triblock copolymer with methyl vinyl ketone (MVK). The synthesized triblock copolymers were characterized by FT-IR, 1H NMR spectroscopies. Gel permeation chromatography (GPC) was used to evaluate the molecular weight and molecular weight distribution and monitored the photodegradability of the block copolymers. The morphology of microspheres was spherical with smooth surfaces before UV irradiation. However, those from PCL-PMVK triblock copolymers had rough surfaces and porous structures after UV irradiation due to the photodegradation of PMVK blocks as a porous template. The porosity and shape of the microspheres and shape of microspheres were dependent on the PMVK contents and size of microspheres.

This study provides a route to prepare 4-arm star poly(methyl methacrylate) (4sPMMA)/PMMA grafted SiO2 (PMMA-g-SiO2) hybrid nanocomposites that can be used as 3D printing material and filler for dental materials. First, 4sPMMA was synthesized via atom transfer radical polymerization with low metal catalyst concentration. Modified colloidal silica nanoparticles (MCSPs) were synthesized by grafting 3-methoxypropyl trimethoxysilane (MPS) onto the surface of colloidal silica nanoparticles (CSPs) and then dispersed in the solution of methyl methacrylate monomer in dioxane. The mixture of 4sPMMA and MCSPs solutions was degassed and replaced in an oil bath at 70–75°C; the reaction was continued with α,α′-azobis(isobutyronitrile) as an initiator for 24 h to form 4sPMMA/PMMA-g-SiO2 hybrid nanocomposites. Viscosity measurement showed that viscosity of the hybrid was increased with increasing MPS loading used in modification of CSPs, which verified that PMMA had been grafted onto MCSPs. Fourier transform infrared spectra of the hybrid nanocomposites demonstrated the strong molecular interaction between MCSPs and polymer matrix, and 1H NMR spectra confirmed the formation of PMMA-g-SiO2. Field emission scanning electron microscopy and transmission electron microscopy images revealed that MCSPs were well dispersed in polymer matrix with the size of about 20–30 nm. Thermal stability of the hybrid nanocomposites was improved compared with PMMA made from free radical polymerization.

International audience; Highly monodispersed silica nanoparticles (SiNPs) were synthesised using a fluorinated surfactant, HOCH2CH(CF3)CO2H, and its efficiency was compared with efficiencies of five other surfactants. The size of the SiNPs (∼50–200 nm) was controlled by controlling the surfactant amount. The short alkyl-chain fluoro surfactant was found to be more efficient at producing monodispersed SiNPs than its long alkyl-chain fluoro or non-fluorinated surfactant counterparts.

Chitosan (CS) is a well-known natural polysaccharide with good biocompatibility and biodegradability. Graft copolymerization of poly (methyl vinyl ketone) (PMVK) onto chitosan was conducted by free...

Polymeric foaming agent (PFA), poly(methacryloyl toluenesulfonylhydrazide) (poly(MATSH)), was synthesized from p-toluenesulfonyl hydrazide (TSH) with methacryloyl chloride (MAC) and transformed into nanoscale material by using a method of emulsion-solvent evaporation with polyvinyl alcohol (PVA) as an emulsifier. Average particle size of poly(MATSH) nanoparticle was determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM), in comparison with TSH and MATSH monomer nanoparticles. Thermal decomposition temperature of the prepared nanoparticles was measured by using thermogravimetric analysis (TGA). A fraction of PVA remained in poly(MATSH) nanoparticle in spite of repeated washing increased decomposition temperature of the nanoparticles. The exothermic temperature of poly(MATSH) nanoparticle was examined by using differential scanning calorimetry (DSC). Furthermore, the polymer incorporated with poly(MATSH) nanoparticle according to foaming formulation based on styrene butadiene rubber (SBR) by compression molding showed higher expansion ratio due to higher surface volume and also made finer and more uniform cell structure due to smaller particle size and better compatibility with polymer and other fillers than those of poly(MATSH) in the morphology study of scanning electron microscopy (SEM).

To fabricate new smart materials that can deliver both the pharmaceutically active molecules and metal nanoparticles, we have formulated chitosan-based semi-IPN hydrogels and their silver nanocomposites (Ag NCs) along with amoxicillin (AMX). Semi-IPN hydrogels and their Ag NCs were synthesized from chitosan, dimethylamino ethyl methacrylate and 2-hydroxyethyl methacrylate via simple-free radical polymerization method and reducing with NaBH4. The resultant formulations were evaluated for in vitro release of AMX, anti-bacterial studies and DNA cleavage studies. The hydrogels with AMX-derived silver nanoparticles (Ag NPs) show better ability to cleave DNA and anti-microbial activity than individual AMX and Ag NPs.

Relatively narrow molecular weight distribution polyaniline/poly(4-styrene sulfonate) were synthesized by aqueous chemical oxidation polymerization using a dialysis membrane as the key to controlling the diffusion speed of the initiator. The optical, electrochemical, and electrical properties of the resulting polyaniline/poly(4-styrene sulfonate) were estimated by ultraviolet–visible–near infrared spectroscopy, cyclic voltammetry, and four-point probe. Compared to a bulk polyaniline/poly(4-styrene sulfonate), the resulting polyaniline/poly(4-styrene sulfonate) showed relatively high crystallinity according to X-ray diffraction, and their polydispersity indices ranged from 1.6 to 2.0 as a function of the reaction time. The electrical conductivities of the resulting polyaniline/poly(4-styrene sulfonates) were also enhanced gradually with increasing reaction time.

Butyl rubber (IIR)/hydrophobically modified graphene oxide (GO) (HG) nanocomposites were prepared via shear-induced compounding. Hydrophilic GO was synthesized through the chemical oxidation of graphite (GP) and modified hydrophobically by octadecylamine which has a hydrophobic long alkyl chain. The obtained HG was characterized by Fourier transform infrared and wide-angle X-ray diffraction (WAXD) patterns. It was well dispersed in toluene for more than 30 days under stationary condition. The IIR/HG nanocomposites were prepared by the shear mixing process and followed by thermal vulcanization process through compression molding. Their properties were studied using oscillating disk rheometer, universal testing machine, differential scanning calorimetry, thermogravimetric analysis, WAXD patterns, and scanning electron microscope analysis. The hydrophobic HG was dispersed at the nanoscale within IIR matrix, and the resulting nanocomposites had significantly reduced curing time. The overall tensile pr...

In this study, polyaniline/titanium oxide (PANi-TiO2) nanoweb composite was fabricated through electrochemical deposition and electrospinning techniques, and the composite was further utilized as an electrode for a supercapacitor. The PANi-TiO2 composite film showed three-dimensional hierarchical micro/nano architecture. The film was deposited on the current collector without the use of any binders. The morphology of the PANi-TiO2 composite film was confirmed by the use of field emission scanning electron microscopy (FE-SEM) analysis that polyaniline was grown in the form of nanorods with a diameter of 100 nm-200 nm on a TiO2 nanoweb. The chemical composition and quantitative analysis were determined by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The electrochemical properties were analyzed by cyclic voltammetry (CV), chronopotentiometry, and electrochemical impedance spectroscopy (EIS). The result of electrochemical tests indicated that TiO2-PANi electrode displayed a high specific capacitance of 306.5 Fg(-1) at the scan rate of 20 mVs(-1), with the capacitance retention ratio being 103% after 500 cycles at the scan rate of 50 mVs(-1).

The effects of the functionality and the single or combination of secondary bonding on the mechanical and thermo-reversible properties of the grafted ethylene propylene diene rubber (EPDM) modified with acrylic monomers including organic salt were investigated. The storage modulus of grafted EPDM containing organic salt was maintained higher than that of cross-linked EPDM by sulfur at specific temperature, but it was observed that the secondary bonding was weakened and the storage modulus was decreased sharply at elevated temperature. When the functional group for inducing secondary bonding was introduced in EPDM, it had excellent mechanical properties by formation of aggregates between grafted EPDM molecules. For those with both ionic interaction by organic salt group and the hydrogen bonding by amide group, the recycle properties were excellent maintaining 90% of their initial mechanical properties even after 5 times recycling processes.

A biocompatible polymer composite film was prepared by casting method of the mixed solution of poly(L-lactide) (PLA) and lotus leaf powder (LLP) in chloroform. The obtained composite film showed hydrophobic properties. The surface wettability and change in the surface morphology of the film before and after degradation in the enzyme solution were analyzed by contact angle measurement and high resolution scanning electron microscopy. The degradation rate of PLA could be controlled by mixing the right composition of LLP to PLA.

A series of acrylic PSAs were synthesized by pre-emulsion addition method and characterized by FT-IR spectroscopies. Electrical and mechanical properties of antistatic waterborne acrylic PSAs containing electrically conductive fillers were investigated in this paper depending on the component of monomers, reactive emulsifiers, and the type of conductive fillers. PSA synthesized by reactive emulsifier showed higher physical properties and its composite with 1wt% of conductive fillers showed good dispersity with optimal peel strength.

The ZrO2-sol was prepared with zirconium acetate and water below 60°C followed by the modification with 0, 0.5 and 5 mol of methyltrimethoxysilane(MTMS) via sol-gel method. The epoxy system was consisted of 1,1,1-(triglycidyl-oxyphenyl) methane, (3-4-epoxycyclohexane) methyl-3-4-epoxycyclohexyl carboxylate, methyl-2,3-norbornanedicarboxylic anhybride, ethyl triphenyl phosphonium iodide and N,N-dimethylacetamide (DMAc). The epoxy system and MTMS-modified ZrO2-sols were mixed to be solid contents of 90 : 10 weight percentages. ZrO2 particles synthesized from sol-gel method were amorphous phase in XRD patterns. FE-SEM images showed MTMS-modified ZrO2 particles were dispersed with excellent homogeneity in hybrid system. The FT-IR spectra of MTMS-modified ZrO2 particle identified the methyl and silica groups formed from MTMS on the surface of ZrO2 particle. It is considered that epoxy-ZrO2 hybrid materials have the potential to be used as the hybrid thin film due to their high refractive index and excellent hy...

Biodegradable polyfumarateurethane (PFU) for use as a bupivacaine delivery vehicle, synthesized using di-(2-hydroxypropyl fumarate) (DHPF), polyethylene glycol (PEG) and 1,6-hexamethylene diisocyanate (HMDI), was designed to be degradable through the hydrolysis and enzymatic degradation of the ester bonds in its polymer backbone. Using a water-in-oil-in-water double emulsion techniques, nanoparticles encapsulating water or fluorescein isothiocyanate (FITC) were fabricated to avoid the immune system owing to the presence of PEG on their surface. The morphologies of these nanoparticles were characterized by DLS, TEM, FE-SEM, and fluorescent microscopies. The present study explored the encapsulation, loading efficiency and in vitro drug release of bupivacaine encapsulated with biodegradable PFU nanoparticles for the treatment of local anesthesia. Various concentrations of bupivacaine were encapsulated into nanoparticles and their encapsulation efficiencies and drug loading were investigated. Encapsulation efficiency was highest when 2.5% bupivacaine was encapsulated. Drug release behavior from the bupivacaine-loaded PFU nanoparticles followed a sustained release profile.

In this study, homogeneous distribution of colloidal silica nanoparticles (CSPs) was performed by modifying and stabilizing CSPs in an organic solvent at neutral pH. The surface modified CSPs were synthesized by Stober method in methanol, followed by modifying with different contents of 3-(methacryloyloxy) propyl trimethoxysilane (MPTS). Solvent exchange and dialysis process were applied to purify the modified CSPs for being stable in dioxane solvent at pH 7 ± 0.1. Both original and modified CSPs exhibited narrow particle size distribution in the range of 10–100 nm, while dynamic diameters (Z-averaged) of the CSPs were not significantly changed after modification and purification process (about 29 nm and 30 nm, respectively). Thermal Gravimetric Analysis (TGA) diagrams, Fourier Transform Infrared (FTIR), Energy Dispersive Spectroscopy (EDS) and Proton Nuclear Magnetic Resonance (1HNMR) spectra analyses showed the successful grafting of hydrolyzed MPTS on the surface of CSPs, which increased with increasing MPTS loading (0.3, 0.45, 0.6, 1.0, 1.5 g/g of SiO2). At low MPTS loadings (0.3, 0.45 g/g of SiO2), the graft amount of MPTS on the surface was not saturated, therefore hydrogen bonds between C O groups of MPTS layer and surface hydroxyl group of CSPs have been occurred, however, these ineractions were disappeared at higher MPTS loadings. Scaning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) images verified the nanoscale distribution of CSPs with 20–30 nm particle size. Based on the above results, monolayer grafting of hydrolyzed MPTS was successfully incorporated on the surface of CSPs leading to be stable in dioxane solvent. Dialysis method using dioxane solvent can be applied for purification of modified CSPs solution, which also preserved the nanoscale distribution of modified CSPs.

The new thermally stable acrylic pressure sensitive adhesives (PSAs) were synthesized by pre-emulsion addition method, characterized by FT-IR spectra and differential scanning calorimetry (DSC), and evaluated their physical properties based on reactive emulsifiers and tackifiers. Experimental Tg of PSAs with different monomer compositions was similar to its theoretical values. The PSAs with reactive emulsifier showed higher mechanical and thermal properties than those with conventional emulsifier. The novel thermally stable acrylic PSA synthesized from 2-ethylhexyl acrylate (2-EHA) and butyl acrylate (BA) as main monomers, and methylmethacrylate (MMA) and acrylic acid (AAc) a cohesive monomer, and reactive emulsifier and tackifier, showed excellent physical properties such as initial, moisture and heat resistant peel strengths, which are considered to be one of the most important properties to be applied for liquid crystalline display (LCD) devices.

Surface-modified colloidal silica (M-CS) nanoparticles were successfully synthesized from colloidal silica (CS) and methyltrimethoxysilane using sol–gel method and characterized by Fourier transform-infrared spectroscopy. Both CS and M-CS were then incorporated into acrylic adhesives. M-CS particles in 2-ethoxyethanol had similar particle size to pure CS based on the characterization by DLS. The morphologies of M-CS particles in acrylic adhesives examined by TEM showed more homogeneous dispersities than that of pure CS which were aggregated and phase separated in acrylic adhesives. In addition, the thermal properties of the nanocomposite acrylic adhesives determined by thermogravimetric analyses and differential scanning calorimetry showed higher glass transition temperature and thermal properties than pure acrylic adhesives. Finally, the 180° peel strength of nanocomposite acrylic adhesives was higher than pure adhesives with improved durabilities.

A series of terpolymers based on stearyl methacrylate (SMA), n-methyol acrylamide (n-MAM), and 2-(perfluorooctyl) ethyl acrylate (PFOEA) were synthesized by changing PFOEA contents up to 8 wt% in order to obtain optimal water-repellent properties. In addition, various contents of m-isopropenyl-α,α’-dimethylben-zyl isocyanate (TMI) from 1 to 4 wt% were added to the above terpolymers with 4 wt% of PFOEA content. The emulsion polymerization was carried out using tridecyl alcohol (EO) 7 (TDA-7) as a nonionic surfactant, alkyl dimethyl amine derivatives (ADAD) as a cationic surfactant, and 2,2’-azobis(2-amidinopropane dihy-drochoride) (AAPDL) as an initiator. The synthesized copolymers were characterized by FT-IR spectroscopies, contact angle, surface energy, and water-repellency. Surface and thermal properties were analyzed by SEM, TGA, and DSC. It was found that water repellency increased with increasing the contents of PFOEA and TMI. Keywords: emulsion polymerization, water-repellency, surface modification, thermal property

Mn3O4/multi-walled carbon nanotube (MWCNT) composites are prepared by chemically synthesizing Mn3O4 nanoparticles on a MWCNT film at room temperature. Structural and morphological characterization has been carried out using X-ray diffraction (XRD) and scanning and transmission electron microscopies (SEM and TEM). These reveal that polycrystalline Mn3O4 nanoparticles, with sizes of about 10-20 nm, aggregate to form larger nanoparticles (50-200 nm), and the Mn3O4 nanoparticles are attached inhomogeneously on MWCNTs. The electrochemical behavior of the composites is analyzed by cyclic voltammetry experiment. The Mn3O4/ MWCNT composite exhibits a specific capacitance of 257 Fg �1 at a scan rate of 5 mVs �1 , which is about 3.5 times higher than that of the pure Mn3O4. Cycle-life tests show that the specific capacitance of the Mn3O4/ MWCNT composite is stable up to 1000 cycles with about 85% capacitance retention, which is better than the pure Mn3O4 electrode. The improved supercapacitive performance of the Mn3O4/MWCNT composite electrode can be attributed to the synergistic effects of the Mn3O4 nanoparticles and the MWCNTs, which arises not only from the combination of pseudocapacitance from Mn3O4 nanoparticles and electric double layer capacitance from the MWCNTs but also from the increased surface area, pore volume and conducting property of the MWCNT network.

This study was carried out to confirm the effects of functional groups that could derive secondary bonding and silica contents on mechanical properties and thermo-reversible characteristics of grafted EPDM-silica composites, which was produced by blending silica or introducing silica hybrid through ionic bonding after grafting methacrylic acid onto EPDM. The storage modulus of graft copolymer had appeared to be higher than cross-linked EPDM vulcanizate at room temperature, and decreased by a gentle slope as temperature increased, and then began to decrease more sharply as secondary bonding force became weaker at higher temperature. When silica hybrid was introduced through ionic interaction, storage modulus and mechanical properties were found to be higher due to not only hydrogen and ionic bonding, but also nanosized silica particles, which were bonded to the elastomer structure in uniformed distribution. When the graft copolymer had only hydrogen bonding, recycling of the elastomer caused mechanical pro...

Recently, carbon fiber composites have been widely used as structural reinforcement materials of buildings, replacing reinforcing bars or concrete. And the increase in use of super fibers such as aramid and high strength PE, which is aimed at improving the reinforcement properties, has resulted in a demand for a resin system with excellent mechanical and thermal properties. In this research, a fiber-reinforced composite has been produced by using the super fibers such as carbon fiber or aramid fiber, reinforcement resin and the silica hybrid compound containing epoxy group. This study was carried out to confirm the effect of the silica hybrid on mechanical properties, heat resistance and adhesion strength of a fiber-reinforced epoxy composite, which was produced by blending silica or introducing silica hybrid through covalent bonds. And the silica hybrid containing epoxy group, which may be introduced to the structure of fiber-reinforced epoxy composite through covalent bonds caused by reaction with a hardener, has been used, so that the heat resistance and adhesion strength could be improved.

A series of thermoresponsive sodium alginate-g-poly(vinyl caprolactam) (NaAlg-g-PNVCL) beads were prepared as drug delivery matrices of 5-flurouracil (5-FU) crosslinked by glutaraldehyde (GA) in the hydrochloric acid catalyst. Graft copolymers of sodium alginate with vinyl caprolactam were synthesized using azobisisobutyronitrile as an initiator, and characterized by Fourier infrared spectroscopy, differential scanning calrimetry and X-ray diffraction for analysis of the amorphous nature drug in the beads, and by scanning electron microscopy for the spherical nature of the beads. Preparation condition of the beads was optimized by considering the percentage of encapsulation efficiency, swelling behavior of beads and their release data. Effects of variables such as GA concentration, drug/polymer ratio and catalyst concentration on the release of 5-FU were carried out at two different temperatures (25 and 37 °C) in simulated intestinal fluid for 12 h. It was observed that, drug release from the beads decreased with increasing drug/polymer (d/p) ratio, extent of crosslinking agent and catalyst concentration. The swelling degree of graft copolymer beads was found to be increased with decreasing of environmental temperature. In vitro release studies were performed at 25 and 37 °C for 12 h, and showed that thermoresponsive graft copolymer beads had higher drug release behavior at 25 °C than that at 37 °C, following Fickian diffusion transport mechanism with slight deviation.

Poly(N′-isopropylacrylamide-co–methacryl amide) has been prepared by free-radical emulsion polymerization. The copolymer was transformed into thermoresponsive microspheres by chemical crosslinking with N′, N′ Methylenebis-acrylamide (NNMBA). Enalpril maleate (ENAM), an anti-hypertensive drug, was successfully loaded into these microspheres during in-situ polymerization. DSC and X-RD analysis of the drug-loaded and plain microspheres have confirmed partial dispersion of ENAM in the microspheres. SEM confirmed the spherical nature of the particles with a mean particle size of 100 µm. Drug release profiles of these microspheres exhibited a prolonged release of ENAM for more than 12 h.