Water‐assisted formation of honeycomb films of poly(L‐lactic‐co‐glycolic acid)

The ordered honeycomb structures of poly(L ‐lactic‐co‐glycolic acid) and poly(D ,L ‐lactic‐co‐glycolic acid) fabricated in a humid atmosphere were reported in this paper. It was found that surfactants were important in the formation of honeycomb films of hydrophobic polymer. The affecting factors, such as the environment temperature, the atmosphere humidity, and the concentration of the polymer solution of the honeycomb porous structure, were also tested. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1013–1018, 2006     

Synthesis and structure control of l‐lactic acid–glycolic acid copolymer by homo‐copolymerization

A two‐step direct melt copolymerization process of l ‐lactic acid (L ‐LA)/glycolic acid (GA) was developed: poly(l ‐lactic acid) (PLLA) and poly(glycolic acid) (PGA) with different molecular weight was first synthesized respectively by binary catalyst (tin chloride/p‐toluenesulfonic or tin chloride); and then poly(l ‐lactic‐co‐glycolic acid) (b‐PLGA) was produced by melt polymerization of the as‐prepared PLLA and PGA, wherein the composition and chain structure of b‐PLGA copolymers could be controlled by the molecular weight of PLLA. The chain structure and thermal properties of copolymers were studied by Wide‐angle X‐ray diffraction, nuclear magnetic resonance, differential scanning calorimetry, and thermogravimetric analysis. In comparison with the random PLGA (r‐PLGA) synthesized by one‐step direct melt polymerization, the average l ‐lactic blocks length (L_LA) in b‐PLGA was longer while the average glycolic blocks length (L_GA) in b‐PLGA was shorter which further resulted in the improved crystallinity and thermostability. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41566.     

Non‐catalytic,solvent‐free synthesis of poly(tartronic‐co‐glycolic acid) as a versatile coating for different surfaces

The synthesis of poly(tartronic‐co‐glycolic acid) from tartronic acid is achieved by a simple thermal polycondensation method. This novel polyester was characterized by NMR and Fourier transform infrared spectroscopy as well as by high‐resolution electrospray ionization mass spectrometry. It contains pendent carboxyl groups at the tartronic acid units which therefore render it a more hydrophilic and more versatile analogue of poly(glycolic acid) combining the known biodegradability with the functionality of the pendent carboxyl groups. Thus, it is of interest for application in the synthesis of drug‐carrying biodegradable matrices. The copolymer was further used for coating different surfaces of magnetic nanoparticles such as magnetite, silica, titanium dioxide and exploited as a platform for further functionalization. © 2017 Society of Chemical Industry     

Swelling and hydrolytic degradation behaviour of pH‐responsive hydrogels of poly[(N‐isopropylacrylamide)‐co‐(methacrylic acid)] crosslinked by biodegradable polycaprolactone chains

BACKGROUND: Stimuli‐responsive hydrogels are typically obtained from non‐biodegradable monomers. The use of biodegradable crosslinkers can overcome this limitation. In this context, the main aim of this work was to use modified polycaprolactone as a crosslinker in the preparation of pH‐responsive hydrogels based on N‐isopropylacrylamide and methacrylic acid to give poly[(N‐isopropylacrylamide)‐co‐(methacrylic acid)] (P(N‐iPAAm‐co‐MAA)). RESULTS: Poly(caprolactone) dimethacrylate macromonomer was synthesized and successfully employed as crosslinker with various ratios in the synthesis of well‐known pH‐responsive hydrogels of P(N‐iPAAm‐co‐MAA). The swelling properties of these degradable hydrogels were investigated. They practically do not swell at pH = 2, but exhibit a very high swelling capacity in distilled water and in solutions of pH = 7. In addition, degradation studies at pH = 12 showed that the hydrolysis of the ester groups in the polycaprolactone chains produces, after a relatively short time, the total solubilization of the polymer chains. CONCLUSION: The hydrogels under study have certain characteristics that could make them good candidates for use as matrices in controlled drug delivery. On the one hand, they do not swell in acid pH solution (stomach conditions) but they swell extensively at neutral pH. On the other hand, they became rapidly water soluble following degradation. Copyright © 2009 Society of Chemical Industry     

Temperature‐induced volume change and glucose sensitivity of poly[(N‐isopropylacry‐ lamide)‐co‐acrylamide‐co‐(phenylboronic acid)] microgels

Nearly monodisperse glucose‐sensitive poly[(N‐isopropylacrylamide)‐co‐acrylamide‐co‐(phenylboronic acid)] microgels were synthesized in aqueous media by the functionalization of poly[(N‐isopropylacrylamide)‐co‐acrylamide‐co‐(acrylic acid)] microgels with 3‐aminophenylboronic acid via carbodiimide coupling. The glucose‐sensitive and thermosensitive behaviour of the microgels was investigated using a dynamic light scattering technique. The introduction of the hydrophobic phenylboronic acid (PBA) group significantly decreases the temperature at which maximum volume change of the resultant microgel particles is observed. The glucose sensitivity of the PBA‐containing microgels relies on the stabilization of the charged phenylborate ions by binding with glucose, which can convert more hydrophobic PBA groups to the hydrophilic phenylborate ions. The effect of pH, ionic strength and PBA content on temperature‐induced volume change and glucose sensitivity was systemically studied. The effect of NaCl on the glucose sensitivity was also investigated at physiological pH and ionic strength. Copyright © 2011 Society of Chemical Industry     

Synthesis and characterization of poly(L‐lactic acid)‐b‐poly(ethylene terephthalate‐co‐sebacate)‐b‐poly(L‐lactic acid) copolyesters

Random copolyester namely, poly(ethylene terephthalate‐co‐sebacate) (PETS), with relatively lower molecular weight was first synthesized, and then it was used as a macromonomer to initiate ring‐opening polymerization of l ‐lactide. ¹H NMR quantified composition and structure of triblock copolyesters [poly(l ‐lactic acid)‐b‐poly(ethylene terephthalate‐co‐sebacate)‐b‐poly(l ‐lactic acid)] (PLLA‐PETS‐PLLA). Molecular weights of copolyesters were also estimated from NMR spectra, and confirmed by GPC. Copolyesters exhibited different solubilities according to the actual content of PLLA units in the main chain. Copolymerization effected melting behaviors significantly because of the incorporation of PETS and PLLA blocks. Crystalline morphology showed a special pattern for specimen with certain composition. It was obvious that copolyesters with more content of aromatic units of PET exhibited increased values in both of stress and modulus in tensile test. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

A novel amphoteric,pH‐sensitive,biodegradable poly[chitosan‐g‐(L‐lactic‐co‐citric) acid] hydrogel

The novel amphoteric, pH‐sensitive, biodegradable poly([chitosan‐g‐(L ‐lactic‐co‐citric) acid]) hydrogel (CLC) was synthesized through the reaction of chitosan (CS) with poly(L ‐lactic‐co‐citric acid) (PLCA). The structure of CLC was characterized by Fourier transform infrared spectroscopy, elemental analysis, and wide‐angle X‐ray diffraction measurement. The degree of substitution of CS amino groups was evaluated from salicylaldehyde analysis. The swelling behavior of CLC film in an aqueous solution with various pHs and the apparent swelling kinetics were studied. The swelling mechanisms of CLC film in acidic and alkaline mediums are discussed. The results showed that CLC hydrogel had a higher degree of swelling in the pH range of 4 > pH > 8 and that the swelling rate order in different buffers was neutral > acidic > basic mediums. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3850–3854, 2003     

Synthesis and characterization of amphiphilic biodegradable poly(glutamic acid‐co‐lactic acid‐co‐glycolic acid) by direct polycondensation

Poly(glutamic acid‐co‐lactic acid‐co‐glycolic acid) (PGLG), an amphiphilic biodegradable copolymer, was synthesized by simply heating a mixture of L ‐glutamic acid (Glu), DL ‐lactic acid, and glycolic acid with the present of stannous chloride. The unique branched architecture comprising of glutarimide unit, polyester unit, and polyamide unit was confirmed by NMR spectrum. The PGLG was soluble in many organic solvents and aqueous solution of sodium hydroxide (pH ≥ 9.0). The thermal properties were evaluated using thermogravimetric analysis and differential scanning calorimetry. Molecular weights were determined by ¹H NMR end‐group analysis and GPC, respectively, and the results indicated that the higher Glu content resulted in a decrease of the molecular weight. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Evaluation of blood compatibility of MeO‐PEG‐poly (D,L‐lactic‐co‐glycolic acid)‐PEG‐OMe triblock copolymer

The aim of the present work was to assess the blood compatibility of monomethoxy (polyethylene glycol)‐poly (D ,L ‐lactic‐co‐glycolic acid)‐monomethoxy (polyethylene glycol) (MeO‐PEG‐PLGA‐PEG‐OMe, PELGE) triblock copolymer as a propriety material for intravenous use in vitro. Three different proportional triblock copolymers were synthesized. According to the International Standard Organization (ISO) and US Pharmacopoeia XXIII recommendations, siliconized glass tube was used as the negative control sample, while nonsiliconized glass tube was used as the positive control. The blood compatibility of the films of poly (D ,L ‐lactic and glycolic acid) (PLGA) was evaluated by dynamic clotting time, activated partial thromboplastin time (APTT), and plasma recalcification time (PRT) measurements, platelet adhesion investigation, and hemolytic ratio analysis. The results revealed that blood compatibility of the materials was good. Nanoparticles made by this kind of materials might be promising for intravenous use. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1019–1023, 2006     

Flurbiprofen axetil loaded coaxial electrospun poly(vinyl pyrrolidone)–nanopoly(lactic‐co‐glycolic acid) core–shell composite nanofibers: Preparation,characterization, and anti‐adhesion activity

Flurbiprofen axetil (FA)‐loaded coaxial electrospun poly(vinyl pyrrolidone) (PVP)–nanopoly(lactic‐co‐glycolic acid) core–shell composite nanofibers were successfully fabricated by a facile coaxial electrospinning, and an electrospun drug‐loaded system was formed for anti‐adhesion applications. The FA, which is a kind of lipid microsphere nonsteroidal anti‐inflammatory drug, was shown to be successfully adsorbed in the PVP, and the formed poly(lactic‐co‐glycolic acid) (PLGA)/PVP/FA composite nanofibers exhibited a uniform and smooth morphology. The cell viability assay and cell morphology observation revealed that the formed PLGA/PVP/FA composite nanofibers were cytocompatible. Importantly, the loaded FA within the PLGA/PVP coaxial nanofibers showed a sustained‐release profile and anti‐adhesion activity to inhibit the growth of the IEC‐6 and NIH3T3 model cells. With the significantly reduced burst‐release profile, good cytocompatibility, and anti‐adhesion activity, the developed PLGA/PVP/FA composite nanofibers were proposed to be a promising material in the fields of tissue engineering and pharmaceutical science. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41982.     

Anthranilic acid assisted preparation of Fe3O4–poly(aniline‐co‐o‐anthranilic acid) nanoparticles

Magnetic Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were prepared by a novel and simple method: anthranilic acid assisted polymerization. The synthetic strategy involved two steps. First, Fe₃O₄ nanoparticles capped by anthranilic acid were obtained by a chemical precipitation method, and then the aniline and oxidant were added to the modified Fe₃O₄ nanoparticles to prepare well‐dispersed Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles. Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles exhibited a superparamagnetic behavior (i.e., no hysteresis loop) and high‐saturated magnetization (M_s = 21.5 emu/g). The structure of the composite was characterized by Fourier‐transform infrared spectra, X‐ray powder diffraction patterns, and transmission electron microscopy, which proved that the Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were about 20 nm. Moreover, the thermal properties of the composite were evaluated by thermogravimetric analysis, and it showed excellent thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1666–1671, 2006     

Synthesis and characterization of fast responsive thermo‐ and pH‐sensitive poly[(N,N‐diethylacrylamide)‐co‐(acrylic acid)] hydrogels

BACKGROUND: A considerable amount of research has been focused on smart hydrogels that can respond to external environmental stimuli, especially temperature and pH. In this study, fast responsive thermo‐ and pH‐sensitive poly[(N,N‐diethylacrylamide)‐co‐(acrylic acid)] hydrogels were prepared by free radical copolymerization in aqueous solution using poly(ethylene glycol) (PEG) as a pore‐forming agent. RESULTS: Swelling studies showed that the hydrogels produced had both temperature and pH sensitivity. The deswelling kinetics at high temperature demonstrated that the shrinking rates were influenced by the addition of the pore‐forming agent and the amount of acrylic acid in the initial total monomers. The deswelling curves in low‐buffer solutions had two stages. Pulsatile swelling studies indicated that the PEG‐modified hydrogels were superior to the normal ones. These different swelling properties were further confirmed by the results of scanning electron microscopy. CONCLUSION: Such fast responsive thermo‐ and pH‐sensitive hydrogels are expected to be useful in biomedical fields for stimuli‐responsive drug delivery systems. Copyright © 2008 Society of Chemical Industry     

Cytotoxicity and hemocompatibility of a family of novel MeO‐PEG‐poly (D,L‐lactic‐co‐glycolic acid)‐PEG‐OMe triblock copolymer nanoparticles

A family of newly synthesized monomethoxy (polyethylene glycol)‐poly (D ,L ‐lactic glycolic acid)‐ monomethoxy(polyethylene glycol) (MeO‐PEG‐poly (D ,L ‐lactic‐co‐glycolic acid)‐PEG‐OMe, PELGE) biodegradable polymers are candidates for intravenous nanoparticle drug, because of their merits of biocompatibility and blood compatibility, and their capability of escaping from the endothelium system (RES) and adsorbing proteins. In the current research, relationships between composition, cytotoxicity, and hemocompatibility of a series of blank PELGE nanoparticles were investigated. Cytotoxicity on Chang cell lines was investigated using the methyl thiazolyl tetrazolium (MTT) assay. Human and rabbit blood were used in studies of red blood cell hemolysis, whole blood clotting time, plasma recalcification profiles, and red blood cell form and appearance in whole blood. The results suggested that the molecular weight of PEG used in the synthesis of polymers influenced their characteristics. Generally, as the molecular weight of PEG increased, increased cytotoxicity and hemocompatibility were observed. The RGR (relative growth rate) of PELGE nanoparticles synthesized with PEG 550 was above 70%, while that of PELGE nanoparticles synthesized with PEG 750 and PEG 2000 was in the range of 55–105% and 36–87% respectively. For PELGE nanoparticles synthesized with PEG 550, most hemolysis values were in the range of 1–3%, while for PELGE nanoparticles synthesized with PEG 750 and PEG 2000 hemolysis values were 1–2% and below 2%, respectively. None of the nanoparticles caused changes in red blood cell form or appearance. Based on the results, 12 kinds of PELGE were chosen for further studies. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 2933–2944, 2009     

Microfluidic assembly of uniform fluorescent microbeads from quantum‐dot‐loaded fluorine‐containing microemulsion

We report a facile strategy for fabricating fluorescent quantum dot (QD)‐loaded microbeads by means of microfluidic technology. First, a functional fluorine‐containing microemulsion was synthesized with poly[(2‐(N‐ethylperfluorobutanesulfonamido)ethyl acrylate)‐co‐(methyl methacrylate)‐co‐(butyl acrylate)] (poly(FBMA‐co‐MMA‐co‐BA)) as the core and glycidyl methacrylate (GMA) as the shell via differential microemulsion polymerization. Then, CdTe QDs capped with N‐acetyl‐l ‐cysteine (NAC) were assembled into the poly(FBMA‐co‐MMA‐co‐BA‐co‐GMA) microemulsion particles through the reaction of the epoxy group on the shell of the microemulsion and the carboxyl group of the NAC ligand capped on the QDs. Finally, fluorescent microbeads were fabricated using the CdTe QD‐loaded fluorine‐containing microemulsion as the discontinuous phase and methylsilicone oil as the continuous phase by means of a simple microfluidic device. By changing flow rate of methylsilicone oil and hybrid microemulsion system, fluorescent microbeads with adjustable sizes ranging from 290 to 420 µm were achieved. The morphology and fluorescent properties of the microbeads were thoroughly investigated using optical microscopy and fluorescence microscopy. Results showed that the fluorescent microbeads exhibited uniform size distribution and excellent fluorescence performance. © 2014 Society of Chemical Industry     

Hemocompatibility of electrospun halloysite nanotube‐ and carbon nanotube‐doped composite poly(lactic‐co‐glycolic acid) nanofibers

One of the major problems of nanofiber scaffold or other devices like cardiovascular or blood‐contacting medical devices is their weak mechanical properties and the lack of hemocompatibility of their surfaces. In this study, halloysite nanotubes (HNTs) and carbon nanotubes (CNTs) were incorporated within poly(lactic‐co‐glycolic acid) (PLGA) nanofibers and the mechanical property and hemocompatibility of both types of composite nanofibers with different doping levels were thoroughly investigated. The morphology and internal distribution of the doped nanotubes within the nanofibers were characterized using scanning electron microscopy and transmission electron microscopy. Mechanical properties of the electrospun nanofibers were tested using a material testing machine. The hemocompatibility of the composite nanofibers was examined through hemolytic and anticoagulant assay, respectively. We show that the doped HNTs or CNTs are distributed in the nanofibers with a coaxial manner and the incorporation of HNTs or CNTs does not significantly change the morphology of the PLGA nanofibers. Importantly, the incorporation of HNTs or CNTs within PLGA nanofibers significantly improves the mechanical property of PLGA nanofibers, and PLGA nanofibers with or without doping of the HNTs and CNTs display good anticoagulant property and negligible hemolytic effect to human red blood cells. With the enhanced mechanical property, great hemocompatibility, and previously demonstrated biocompatibility of both HNTs‐ and CNTs‐doped composite PLGA nanofibers, these composite nanofibers may be used as therapeutic artificial tissue/organ substitutes for tissue engineering applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Polymer nanocomposites containing carbon nanotubes and miscible polymer blends based on poly[ethylene‐co‐(acrylic acid)]

Four binary polymer blends containing poly [ethylene‐co‐(acrylic acid)] (PEAA) as one component, and poly(4‐vinyl phenol‐co‐2‐hydroxy ethyl methacrylate) (P4VPh‐co‐2HEMA) or poly(2‐ethyl‐2‐oxazoline) (PEOx) or poly(vinyl acetate‐co‐vinyl alcohol) (PVAc‐co‐VA) or poly (vinylpyrrolidone‐co‐vinyl acetate) (PVP‐co‐VAc) as the other component were prepared and used as a matrix of a series of composite materials. These binary mixtures were either partially or completely miscible within the composition range studied and were characterized by differential scanning calorimetry (DSC) and Fourier transformed infrared spectroscopy (FTIR). Carbon nanotubes (CNTs) were prepared by a thermal treatment of polyester synthesized through the chemical reaction between ethylene glycol and citric acid over an alumina boat. High resolution transmission electron microscopy (HRTEM) was used to characterize the synthesized CNTs. Films of composite materials containing CNTs were obtained after evaporation of the solvent used to prepare solutions of the four types of binary polymer blends. Young's moduli of the composites were obtained by thermomechanical analysis at room temperature. Only one glass transition temperature was detected for several compositions on both binary blends and the composite material matrices. Evidence of hydrogen bond formation was recorded for both miscible blends and composite materials. The degree of crystallinity and Young's moduli of the CNT‐polymer composites increased compared to the single polymer blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

One‐Step Immobilization of Protein‐Encapsulated Core/Shell Particles onto Nanofibers

A novel method is described to functionalize nanofibers to form a nanocomposite with core/shell particles in order to control protein release. The nanocomposite is produced by electrically neutralizing negatively charged poly(lactic acid) nanofibers with positively charged poly[(lactic acid)‐co‐(glycolic acid)] particles via a one‐step electrohydrodynamic jetting process. The protein‐encapsulated core/shell particles exhibited no significant initial burst release or denaturation. The protein release profile was controlled by porosity and protein/polymer interactions. The method may be promising to engineer intelligent scaffolds that can fulfill the needs of biomimetic materials.

     

Synthesis,characterization and polychelatogenic properties of poly[(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid)‐co‐(methacrylic acid)]

Poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid), poly(methacrylic acid), and five copolymers of poly[(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid)‐co‐(methacrylic acid)] were synthesized by radical polymerization and obtained in yields >97%. The polymers were characterized by FT‐IR, [¹H]NMR, and [¹³C]NMR and studied by means of the Liquid‐phase Polymer‐based Retention (LPR) technique. The metal ion retention ability of the copolymers for Cu(II), Cd(II), Co(II), Hg(II), Ni(II), Zn(II), Cr(III) and Ag(I) was investigated at different pH values because of their environmental and analytical interest. The retention profiles of the copolymers were compared with those of the corresponding homopolymers and retention of metal ions was found to increase with increasing pH. © 2001 Society of Chemical Industry     

Swelling characteristics of thermo‐ sensitive poly[(2‐diethylaminoethyl methacrylate)‐co‐(N,N‐dimethylacrylamide)] porous hydrogels

Temperature‐sensitive poly[(2‐diethylaminoethyl methacrylate)‐co‐(N,N‐dimethylacrylamide)] [P(DEAEMA‐co‐DMAAm)] hydrogels with five different DMAAm contents were synthesized with and without the addition of sodium carbonate as porosity generator. The synthesized hydrogels were characterized with dry gel density measurements, scanning electron microscopy observation and the determination of swelling ratio. The influence of the pore‐forming agent and content of DMAAm on swelling ratio and network parameters such as polymer–solvent interaction parameter (χ), average molecular mass between crosslinks (M?_c) and mesh size (ζ) of the cryogels are reported and discussed. The swelling and deswelling rates of the porous hydrogels are much faster than for the same type of hydrogels prepared via conventional methods. At a temperature below the volume phase transition temperature, the macroporous hydrogels also absorbed larger amounts water compared to that of conventional hydrogels and showed obviously higher equilibrated swelling ratios in aqueous medium. In particular, the unique macroporous structure provided numerous water channels for water diffusion in or out of the matrix and, therefore, an improved response rate to the external temperature changes during the deswelling and swelling processes. These properties are attributed to the macroporous and regularly arranged network of the porous hydrogels. Scanning electron micrographs reveal that the macroporous network structure of the hydrogels can be adjusted by applying porosity generation methods during the polymerization reaction. Copyright © 2007 Society of Chemical Industry     

Synthesis,characterization and application of poly[(1‐vinyl‐2‐pyrrolidone)‐co‐(2‐hydroxyethyl methacrylate)] as controlled‐release polymeric system for 2,4‐dichlorophenoxyacetic chloride using an ultrafiltration technique

BACKGROUND: Polymers supporting chemicals used in agriculture have recently been developed to overcome the serious environmental problems of conventional agrochemicals. The success of these formulations is based on a suitable choice of polymer support. Degradable polymeric hydrogels are of particular interest. The gradual release of the bioactive agent can be achieved by hydrolytic or enzymatic cleavage of the linking bond. RESULTS: In this context, poly[(1‐vinyl‐2‐pyrrolidone)‐co‐(2‐hydroxyethyl methacrylate)] [poly(NVP‐co‐HEMA)] has been used as a bioactive carrier reagent. Herein, we report a controlled‐release system with the herbicide 2,4‐dichlorophenoxyacetic acid (2,4‐D) using an ultrafiltration system. Hydrolysis was studied by testing the release at various pH values. A high release with poly(NVP‐co‐HEMA)–2,4‐D was observed at pH = 7 and 10 after two days (Z = 2). The release percentage of copolymer–herbicide increased at pH = 10. It showed release values between 79.0 and 94.5%. Poly(NVP‐co‐HEMA)–herbicide can release a bioactive compound in aqueous solution at pH = 3, 7 and 10. CONCLUSION: Based on the results of homogeneous hydrolysis, it is argued that the herbicide release rate depends on the pH of the reaction environment. This functional polymer could be employed as a biodegradable material for applications in agrichemical release. Copyright © 2008 Society of Chemical Industry