Synthesis and solid‐state properties of crosslinked alternating copolymers of phenyl vinylethylene carbonate and N‐substituted maleimides

The copolymers of phenyl vinylethylene carbonate (PVEC) and N‐phenylmaleimide were prepared with various monomer feeds by using a radical initiator. These copolymers were crosslinked by aminolysis between hexamethylenediamine (HMDA) and cyclic carbonate moiety in the side‐chain to obtain the networked polymers having the hydroxyurethane structure. Furthermore, the crosslinked copolymers having the polar cyclic carbonate in the side‐chain were synthesized from PVEC and several bifunctional maleimides, and their double networked polymers were prepared with HMDA. These copolymers and networked polymers exhibited color changes depending on their structures based on the acid–base switching in the solid‐state. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45247.     

Interaction of a new anesthetic drug richlocain with linear and weakly crosslinked poly‐N‐vinylpyrrolidone

The properties of complexes of richlocain, a new local anesthetic drug, with linear and weakly crosslinked poly‐N‐vinylpyrrolidone were investigated with changes in media properties of pH, temperature, and solvent thermodynamic quality. The kinetics and activation energy of drug release from the gel matrix were determined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2977–2981, 2003     

Synthesis and characterization of C60‐based composites of amphiphilic N‐vinylpyrrolidone/triethylene glycol dimethacrylate copolymers

It was found that under mixing of aqueous solutions of copolymers and toluene solutions of C₆₀ two types of polymer composites can be produced with different matrix structure, the fullerene content and an aggregation degree. The dimethacrylate enriched macromolecules migrate to toluene and the VP units enriched copolymer chains remain in water to form copolymer micelles and their aggregates in these media that solubilize and encapsulate the fullerene. The structure and properties of obtained polymer composites were studied by GPC with dual detection (RI and MALLS), FT‐IR, WAXS and SAXS methods. It is shown that in a composite based on N‐vinylpyrrolidone copolymer isolated from toluene the fullerene form larger particles, compare to that isolated from water. According to SAXS, the fullerene particles in a solid copolymer are organized in spherical objects with fine coil‐like structure. The stability of the composites in water, ethanol, and chloroform was shown to depend on the original polymer matrix structure and on copolymer/fullerene ratio. POLYM. COMPOS., 35:1362–1371, 2014. © 2013 Society of Plastics Engineers     

Gamma‐radiation‐induced graft copolymerization of acrylamide onto crosslinked poly(N‐vinylpyrrolidone)

Crosslinked poly(N‐vinylpyrrolidone) (PVPy) beads were irradiated with γ‐rays in air from a ⁶⁰Co source. Preirradiated beads were grafted with polyacrylamide by refluxing with acrylamide in water or dioxane. Conditions for optimum grafting were determined under a variety of reaction parameters, such as the total dose, duration, and temperature of heating, and the molar concentration of acrylamide used. The effect of the addition of methanol to the aqueous medium during grafting was also studied. The pendant carboxamide groups of PVPy‐g‐polyacrylamide were transformed into amino, aminoethylamido, and hydrazide functionalities terminating in primary amino or hydrazido groups. These provide sites for immobilizing proteins through their amino or carboxyl groups and, also, handles for attaching reagent molecules. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2163–2168, 1999     

Microbial screening of copolymers of 2,4‐dichlorophenyl methacrylate with N‐vinylpyrrolidone: synthesis and characterization

Copolymers of 2,4‐dichlorophenyl methacrylate and hydrophilic monomer (N‐vinylpyrrolidone) were synthesized with different feed ratios using dimethylformamide as solvent and 2,2′‐azobisisobutyronitrile as initiator at 70 °C. The copolymers were characterized by IR spectrometry. Copolymer compositions were determined by UV spectrometry. The monomer reactivity ratios were determined by applying the conventional linearization method of Fineman‐Ross. Gel permeation chromatography was employed for determining molecular weights and polydispersity indexes. Thermogravimetric analyses of polymers were carried out in nitrogen atmosphere. Homo‐ and copolymers were tested for their antimicrobial properties against selected microorganisms. © 2003 Society of Chemical Industry     

Synthesis,characterization and properties evaluation of copolymers of 2,3,4,5,6‐pentafluorostyrene and N‐phenylmaleimide

Copolymers of 2,3,4,5,6‐pentafluorostyrene (PFS) having a combination of high hydrophobicity and high glass transition temperature (T_g) are reported here for the first time. The copolymerization was carried out using N‐phenylmaleimide (NPM) as the comonomer and azobisisobutyronitrile (AIBN) as the initiator under both conventional thermal heating and microwave heating. The initial copolymerization rate was found to be higher under microwave heating than under thermal heating. The copolymerization parameters were determined using the Fineman–Ross method and were found to be r₁ (NPM) = 0.28 and r₂ (PFS) = 0.86. Increased incorporation of NPM in the copolymers led to an increase in T_g of the copolymers without significantly affecting the hydrophobicity of poly(2,3,4,5,6‐pentafluorostyrene). Thermal stability of the copolymers is also reported. Copyright © 2005 Society of Chemical Industry     

New self‐crosslinkable copolymers based on N‐methyl‐N‐vinylbenzylpyrrolidinium halide and methyl methacrylate

Thermally‐induced self‐crosslinking behaviour has been found in copolymers containing N‐methyl‐N‐vinylbenzylpyrrolidinium chloride (MVBPC) and methyl methacrylate (MMA). NMR, IR and low molecular weight model reactions demonstrate that this crosslinking reaction occurs between the methyl ester groups of the MMA units and the quaternary ammonium salts, with the resulting benzyl esters forming chemical links between the MVBPC and MMA units with the formation of N,N‐dimethylpyrrolidinium chloride. Similar crosslinking behaviour has also been found when the Cl⁻ anion is replaced by Br⁻ and I⁻, but not in the case of BF as counter anion. © 2000 Society of Chemical Industry     

Synthesis,characterization, and blood compatibility of copolymers of polyamidoamines and n‐vinylpyrrolidone

Two new polyamidoamines derived from piperazine (Pip)/cyclohexylamine (CHA) and N,N′‐methylene bisacrylamide (MBA) were synthesized and subsequently copolymerized with N‐vinylpyrrolidone (NVP) under suitable reaction conditions to yield the respective copolymers (Pip–MBA–NVP and CHA–MBA–NVP). The synthesized materials were characterized by spectroscopic techniques. The material surface characteristics were checked by contact angle measurement, and the data established the relative hydrophilic characteristics of the synthesized copolymers with respect to the control poly(N‐vinylpyrrolidone). A thrombus‐formation study indicated less (<1.2 mg) clot formation on the heparinized material surfaces within a 30‐min contact time with the acid citrate dextrose human blood. The percentage of hemolysis of the blood by the materials was also less than 5%. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4068–4074, 2003     

Synthesis and characterization of N‐acryloylcarbazole/methyl methacrylate copolymers

Copolymers of N‐acryloylcarbazole (A) and methyl methacrylate (M) were synthesized in different in‐feed ratios. The composition of the copolymer was determined by the help of ¹H NMR spectrum. The comonomer reactivity ratios determined by Kelen‐Tudos (KT) and nonlinear error‐in‐variables methods were r_A = 1.12 ± 0.16, r_M = 0.94 ± 0.14, and r_A = 1.05, r_M = 0.90, respectively. Complete spectral assignments of the ¹H and ¹³C ¹H NMR spectra of the copolymers were done by the help of distortionless enhancement by polarization transfer (DEPT) and two‐dimensional NMR techniques, such as heteronuclear single quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple bond correlation (HMBC). The methine, α‐methyl, and carbonyl carbon resonances were found to be sequence sensitive. The signals obtained were broad because of the restricted rotation of bulky carbazole group and the quadrupolar effect of nitrogen present in carbazole moiety. Glass transition temperatures (T_g) were determined by differential scanning calorimetry and were found to be characteristic of copolymer composition. As the N‐acryloylcarbazole content increases, the T_g increases from 378.3 K for poly(methyl methacrylate) to 430.4 K for poly(N‐acryloylcarbazole). Variation in T_g with the copolymer composition were found to be in good agreement with theoretical values obtained from Johnston and Barton equations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2667–2676, 2006     

Biodegradable amphiphiles of grafted poly(lactide) onto 2‐hydroxyethyl methacrylate‐co‐N‐vinylpyrrolidone copolymers as drug carriers

This article describes the synthesis and characterization of 2‐hydroxylethyl methacrylate‐co‐N‐vinylpyrrolidone copolymers, (HEMA‐co‐NVP), via free radical polymerization followed by grafting of poly(lactide) onto (HEMA‐co‐NVP) copolymers, via ring opening polymerization using tin octoate as a catalyst. The copolymers and the grafted copolymers (i.e., amphiphiles) were subjected to sustained release studies using salicylic acid, as a model drug. Characterization of the formed copolymers was performed using ¹H‐NMR, ¹³C‐NMR, FTIR, TGA, DSC, and SEM techniques. Derivative of TGA thermogram was used to determine %hydrophilicity and %hydrophobicity in the grafted and ungrafted copolymers. The SEM morphology revealed porous layers with crispy structure that were most likely due to the presence of poly(lactide) chains. At lower content of poly(lactide) moiety, grafted copolymers showed non‐Fickian diffusion release rate, whereas Fickian diffusion release rate at higher content of poly(lactide) was observed. The increase of poly(lactide) content (i.e., larger %hydrophobicity) in the copolymer increased the drug‐sustainability, due to the consistent but porous amphiphilic degradable structures that allow controllable release of drug in time interval. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polyamide‐6‐b‐polybutadiene block copolymers: Synthesis and properties

Polyamide‐6 (PA6)/polybutadiene (PB) block copolymers were synthesized with macroactivators (MAs) based on hydroxyl‐terminated polybutadiene functionalized with diisocyanates and having three N‐acyllactam chain‐growing centers per molecule. Two different diisocyanates, hexamethylene diisocyanate and isophorone diisocyanate, were applied as precursors for the MAs. The sodium salt of ε‐caprolactam was chosen as an initiator. The influence of the MA type and concentration on the anionic ring‐opening polymerization of ε‐caprolactam at 180°C was studied. A large percentage of the gel fraction in the copolymers was estimated, indicating crosslinked macromolecules. The structure and phase behavior of the copolymers were investigated with differential scanning calorimetry, wide‐angle X‐ray scattering, thermogravimetric analysis, and dynamic mechanical thermal analysis. In the copolymers, only the PA6 chains crystallized, and the crystallinity depended on the PB content. Different glass‐transition temperatures for the PB blocks and PA6 blocks were observed, indicating microphase separation in the copolymers. The mechanical properties of the copolymers were studied by notched impact testing and hardness measurements. The impact strength increased linearly with the soft component concentration up to 10 wt % and reached values six times higher than those of the PA6 homopolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 711–717, 2003     

Semi‐interpenetrating networks based on poly(N‐isopropyl acrylamide) and poly(N‐vinylpyrrolidone)

Three series of novel semi‐interpenetrating polymer networks, based on crosslinked poly(N‐isopropylacrylamide), PNIPA, and different amounts of the linear poly(N‐vinylpyrrolidone), PVP, were synthesized to improve the mechanical properties and thermal response of PNIPA gels. The effect of the incorporation of the linear PVP into the temperature responsive networks on the temperature‐induced transition, swelling/deswelling behavior, and mechanical properties was studied. Polymer networks with four different crosslinking densities were prepared with varying molar ratios (25/1 to 100/1) of the monomer (N‐isopropylacrylamide) to the crosslinker (N,N′‐methylenebisacrylamide). The hydrogels were characterized by determination of the equilibrium degree of swelling, the dynamic shear modulus and the effective crosslinking density, as well as tensile strength and elongation at break. Furthermore, the deswelling kinetics of the hydrogels was studied by measuring their water retention capacity. The inclusion of the linear hydrophilic PVP in the PNIPA networks increased the equilibrium degree of swelling. The tensile strength of the semi‐interpenetrating networks (SIPNs) reinforced with linear PVP was higher than that of the PNIPA networks. The elongation at break of these SIPNs varied between 22% and 55%, which are 22 – 41% larger than those for pure PNIPA networks. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and properties of ethylene‐substituted styrene copolymers

The copolymerization of ethylene and substituted styrenes [RSt's; p‐methylstyrene (MSt), p‐tert‐butylstyrene (BSt), 2‐vinylnaphthalene (VN), and p‐(tert‐butyldimethylsilyloxy)styrene (BMSiOSt)] were investigated with dimethylsilylene(tetramethylcyclopentadienyl)(N‐tert‐butyl)titanium dichloride to yield the corresponding ethylene–RSt copolymers. The substituent on the styrene (St) monomers did not affect the monomer reactivity ratio. The effect of the substituent structure of RSt on the thermal and mechanical properties was studied with differential scanning calorimetry, dynamic mechanical thermal spectroscopy, and elongation testing. The glass‐transition temperature (T_g) of the copolymers increased with increasing RSt content, and the order of T_g was as follows: BSt > VN > MSt = St. A copolymer with p‐hydroxystyrene (HOSt) was successively synthesized by means of deprotection of the copolymer with BMSiOSt. The copolymer showed a much higher T_g than the other copolymers because of the hydrogen connection of its OH groups. The mechanical properties of the copolymer in the glass state, at a lower temperature than T_g, were almost independent of the nature of the RSt. The substituent of the St monomers affected the pattern of the stress–strain curve in the elongation testing in the amorphous state. An improvement in the shape memory effect was observed in poly(ethylene‐co‐BSt). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and flocculation properties of N‐oxide polymers

N‐oxide polymers possess strong zwitterionic character, high solubility in water, and high chelating properties with various cations. In this work, N‐oxide polymers were synthesized following various routes and their solution properties were determined. Molecular properties of the polymers (molecular weight, square root of the mean‐squared radius, and virial coefficients) were related to their chain expansion in solution by determining the intrinsic viscosity as a function of pH. Viscosity results were correlated with the flocculation ability of the polymers for suspending solids removal. These polymers exhibit dramatic conformation changes as the solution pH is varied, especially at low pH values. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2693–2700, 2002     

Drug complexation and physicochemical properties of vinylpyrrolidone‐N,N′‐dimethylacrylamide copolymers

Solid dispersions of the nonsteriodal antiinflammatory drug (NSAID) 2′,4′‐difluoro‐4‐hydroxy‐(1,1′‐biphenyl)‐3‐carboxylic acid (DIF) with the water‐soluble random copolymer poly(N‐vinyl‐2‐pyrrolidone‐co‐N,N′‐dimethylacrylamide) (VP‐co‐DMAm) were prepared by the solvent method (coevaporates) and melting DIF/VP‐co‐DMAm (cofused) physical mixtures. Differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), and X‐ray diffraction (XRD) were used to elucidate the possible interaction between the NSAID drug and VP‐co‐DMAm in cofused and coevaporated polymer–drug solid dispersions. The XRD and FTIR studies suggest the presence of physical interactions with formation of a charge transfer complex between DIF and the VP‐co‐DMAm copolymers as a consequence of the coevaporation or cofusion processes. In solution, dynamic and equilibrium solubility studies were determined to elucidate the mechanism of interaction between DIF and VP‐co‐DMAm copolymers. Thermodynamics data about the DIF: VP‐co‐DMAm dissolution process indicate that the coevaporated systems are more stable that the cofused systems. The dissolution of the cofused and coevaporated systems was diffusion controlled and the dissolution kinetics followed the Noyes–Whitney and the Levich equations. Molecular simulations using semiempirical quantum chemical calculations reinforce the experimental results, suggesting that the improvement in the DIF solubility could be attributed to the charge transfer complex formation between the drug and VP‐co‐DMAm copolymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1337–1347, 2004     

Self‐assembled amphiphilic poly‐N‐vinylpyrrolidone nanoparticles as carriers for hydrophobic drugs: Stability aspects

Nanoparticles can experience numerous impacts during storage or after intravenous administration resulting in disassembly and/or drug leakage and affecting their efficiency as drug delivery systems. In this study, this crucial issue was addressed by investigating the stability of amphiphilic poly‐N‐vinylpyrrolidone derivative nanocarriers in blood serum, against destabilizing agents and during long‐term storage. All amphiphilic poly‐N‐vinylpyrrolidone derivative nanoparticles prepared in this study were found to possess sizes less than 150 nm, narrow size distribution, spherical morphology, and a slightly negative surface charge. These nanoparticles could efficiently entrap hydrophobic substances (pyrene and curcumin) while retaining excellent compatibility with red blood cells. Moreover, our studies demonstrate the stability of the nanoparticles during long‐term storage and upon dilution with body liquids enhancing their potential as stable in vivo carriers, which is critically important for intravenous drug delivery applications. All properties were found to strongly depend on the ratio between the hydrophobic and the hydrophilic moiety of the polymers under study. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45637.     

Synthesis and properties of PVC‐bound N,N‐dialkylaminopyridine

A linear poly(vinyl chloride) (PVC)‐supported dialkylaminopyridine was prepared through PVC treated with N‐methylaminopyridine and NaH in tetrahydrofuran. The properties of this PVC‐bound catalyst were examined by acetylation of linalool and 5‐FU. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1067–1069, 2002; DOI 10.1002/app.10391     

Effect of the nature and degree of crosslinking on Rose Bengal binding by DVB‐, NNMBA‐, HDODA‐ and TTEGDA‐crosslinked poly(N‐vinylpyrrolidone)s

Poly(N‐vinylpyrrolidone)s with 2–20 mol% DVB, NNMBA, HDODA and TTEGDA crosslinkings were prepared by suspension polymerisation. The binding of Rose Bengal by these poly(N‐vinylpyrrolidone)s was followed by a batch equilibration method. In order to optimise the conditions of dye binding, the effect of the concentration of Rose Bengal solutions, temperature and pH were followed. Kinetic studies showed that the binding of Rose Bengal by poly(N‐vinylpyrrolidone)s is a phase boundary process followed by a three‐dimensional diffusion. Copyright © 2003 Society of Chemical Industry     

Effect of inorganic salts on viscosity of acrylonitrile‐N‐vinylpyrrolidone copolymer solutions

Effects of inorganic salts on viscosities of dimethyl sulphoxide (DMSO) solutions of acrylonitrile(AN)/N‐vinylpyrrolidone(N‐VP) copolymer are discussed. Viscosity was determined by the rotary viscosimeter. It was shown that the solution viscosity decreases quickly with addition of KCl and NaCl and the effect of NaCl is more prominent than that of KCl. As concentration of KCl and NaCl went beyond 0.025 mol/L, the viscosity showed a trend of increase. The viscosity increased considerably with addition of FeCl₃ and CuCl₂. Changes in solution viscosity became less obvious with addition of ZnCl₂. As temperature increased, the viscosity of the copolymer solution containing NaCl decreased most quickly and the copolymer solution consisting of FeCl₃ showed the slowest decrease. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3492–3495, 2003