A novel mucoadhesive polymer prepared by template polymerization of acrylic acid in the presence of poly (ethylene glycol)

A new mucoadhesive polymer was prepared by template polymerization of acrylic acid in the presence of poly(ethylene glycol) (PEG). FTIR results indicated that a polymer complex was formed between poly(acrylic acid) (PAA) and PEG through hydrogen bonding. The hydrogen bonding in the PAA/PEG polymer complex was stronger than that in the PAA/PEG blend, and became stronger as the molecular weight of PEG increased. Glass transition temperatures (T_g) of PAA in the PAA/PEG polymer complexes was shifted to a lower temperature than that of PAA in the PAA/PEG blend. However, they tended to become higher as the molecular weight of PEG increased. The dissolution rate of the PAA/PEG polymer complex was much slower than the PAA/PEG blend, and was dependent on pH and molecular weight of the PEG. The mucoadhesive force of the PAA/PEG polymer complexes was stronger than for the PAA/PEG blend or a commercial product, Carbopol 971P NF. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2749–2754, 1999     

A mucoadhesive polymer prepared by template polymerization of acrylic acid in the presence of poly(ethylene glycol) macromer

A new mucoadhesive polymer complex was prepared by the template polymerization of acrylic acid with poly(ethylene glycol) macromer (PEGM) as a template polymer. Fourier transform infrared results showed that the poly(acrylic acid) (PAA)/PEGM mucoadhesive polymer complex was formed by hydrogen bonding between the carboxyl groups of PAA and the ether groups of PEGM. The glass‐transition temperature of the PAA/PEGM mucoadhesive polymer complexes was shifted to a lower temperature as the repeating unit ratio of PAA/PEGM in the complex decreased. The dissolution rate of the PAA/PEGM mucoadhesive polymer complex was much slower than that of the PAA/poly(ethylene glycol) (PEG) mucoadhesive polymer complex and was dependent on the pH and molecular weight of PEGM. The mucoadhesive force of the PAA/PEGM mucoadhesive polymer complexes was stronger than that of commercial Carbopol 971P NF and almost the same as that of the PAA/PEG mucoadhesive polymer complex. The PAA/PEGM interpolymer complex seemed to be a better mucoadhesive polymer matrix than the PAA/PEG interpolymer complex. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1904–1910, 2002     

Novel mucoadhesive polymer prepared by template polymerization of acrylic acid in the presence of silk sericin

A novel mucoadhesive polymer was prepared by template polymerization of acrylic acid in the presence of sericin for a transmucosal drug‐delivery (TMD) system. FTIR results indicated that a polymer complex was formed between poly(acrylic acid) (PAA) and sericin through hydrogen bonding. The glass transition temperatures (T_g's) of sericin and PAA in the PAA/sericin polymer complex were inner‐shifted compared with the T_g's of sericin and PAA themselves. This may be due to the increased miscibility of PAA with sericin through hydrogen bonding. The dissolution rate of the PAA/sericin interpolymer complex was dependent on the pH. The mucoadhesive force of the PAA/sericin polymer complex was similar to that of a commercial product, Carbopol 971P NF. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 274–280, 2001     

A mucoadhesive polymer prepared by template polymerization of acrylic acid in the presence of poly(vinyl alcohol) for mucosal drug delivery

The interpolymer complexes composed of PVA and PAA were prepared by template polymerization of acrylic acid in the presence of PVA with different molecular weights and degrees of saponification. The carbonyl absorption band of the PAA in the PAA/PVA interpolymer complexes was shifted to a lower wavenumber due to H‐bonding between the carboxyl group of PAA and the hydroxyl group of PVA. The swelling ratio and the degree of dissolution of the PVA/PAA interpolymer complexes were dependent on the pH of the medium, the molecular weight, and the degree of saponification of the PVA. The release rate of a model drug, lidocaine, from the complexes decreased with increasing degree of saponification of the PVA due to the lower swelling degree of the complex. The adhesive force of the PVA/PAA interpolymer complexes with a plastic plate (poly propylene) was stronger than that of the commercial Carbopol 971P. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 327–331, 2004     

Kinetics and reaction mechanism of template polymerization investigated by conductimetric measurements Part 4. Radical polymerization of acrylic acid in the presence of poly(vinyl alcohol): characterization of resulting polymer blends

The radical polymerization of acrylic acid in the presence of poly(vinyl alcohol) as a template in aqueous solution has been studied using conductimetry, which shows template influences on the reaction rate. A comparison is made between data obtained by differential scanning calorimetry and infrared spectroscopy for poly(acrylic acid)–poly(vinyl alcohol) blends prepared either by template polymerization or by casting of the preformed polymers. Evidence for more significant interpolymer interactions in blends prepared by template polymerization than in those obtained by simple mixing is given. © 2001 Society of Chemical Industry     

Kinetics and reaction mechanism of template polymerization investigated by conductimetric measurements. Part 3. Radical polymerization of acrylic acid in the presence of poly(N‐vinylpyrrolidone)

Conductimetry was used for monitoring the radical polymerization of a weak electrolyte (acrylic acid) in aqueous solution and for determination of the kinetic parameters of the reaction (reaction order with respect to monomer, activation energy). The results obtained were consistent with those determined by other techniques (such as dilatometry) or expected from theory. Dilatometric and conductimetric measurements were also used to study the template polymerization of acrylic acid onto poly(N‐vinylpyrrolidone). Results indicate that the reaction proceeds according to a pick‐up mechanism. Complexes between poly(acrylic acid) and poly(N‐vinylpyrrolidone) were always isolated in equimolar composition of the two polymers, regardless of the polymerization mixture composition. Spectroscopic evidence of the existence of strong interaction and intimate mixing of the two polymers in the complexes was found. An influence of the template molecular weight on the chain length of the forming poly(acrylic acid) was detected by means of viscometry. © 2000 Society of Chemical Industry     

Template polymerization of dimethylaminoethylmethacrylate in the presence of polyacrylic acid

The occurrence of a template process in the system polyacrylic acid (PAA) as the template for the polymerization of dimethylaminoethylmethacrylate (DMAEM) has been deduced from kinetic observations. Radical photopolymerization was carried out in aqueous acetone solution (1:2 v/v) using azobisisobutyronitrile (AIBN, 1 x 10-3 mol litre-1) as the radical initiator. Polymerizations were carried out using different concentration ratios of template [T] to monomer [M]. All runs were performed in evacuated dilatometers. The rate of polymerization increased in the presence of the polymer catalyst and was found to attain a maximum value at a ratio of [T]/[M] of about 1.5 in the presence of UV light of λ = 365 nm and at a temperature of 25 /pm 0.05°C. Partial separation of the PAA from the daughter polymer PDMAEM has been achieved.     

Molecular characterization of alkyd/acrylic latexes prepared by miniemulsion polymerization

The molecular characterization of alkyd/acrylic hybrid latexes produced by miniemulsion polymerization was characterized in terms of the resin degree of grafting, acrylic degree of grafting, reacted double bonds in the alkyd, gel content, and molecular weight distribution of the sol part. A simple method based on conventional size exclusion chromatography measurements was developed to estimate the fraction of alkyd resin grafted to the acrylic polymer. The method could be applied to completely soluble hybrids and to hybrids containing gel. Also, the limits of the extraction method used in the literature to estimate the fraction of acrylic polymer grafted to the alkyd was investigated; we found that this technique only provided accurate results at high values of the acrylic degree of grafting. The combination of this information with the reacted double bonds of the alkyd (determined by iodine titration) and the molecular weight distribution of the sol polymer provided a detailed characterization of the alkyd–acrylic hybrid polymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Kinetics and reaction mechanism of template polymerization investigated by conductimetric measurements. 2. Radical polymerization of sodium methacrylate in the presence of poly(allylamine) hydrochloride

The polymerization of sodium methacrylate in water was investigated using conductimetry and dilatometry. Conductimetry was shown to be a reliable tool for the determination of the kinetic parameters of the blank polymerization (order of reaction with respect to monomer and initiator, activation energy). The conductimetric investigation of template polymerization of the acrylic monomer onto poly(allylamine) hydrochloride at low monomer concentration indicates that the reaction proceeds by a ‘zip’ mechanism. © 1999 Society of Chemical Industry     

Synthesis of methacrylic acid-styrene block copolymers by living radical polymerization in the presence of chitosan

The existence of living growing end radicals in the radical polymerization of sodium methacrylate (MAA·Na) in the presence of chitosan acetate salt has been ascertained by preparing block copolymers with styrene as secondary comonomer. When polymerization of MAA·Na eventually reached 93.4% conversion after 144 h at 30°C, secondary comonomer styrene added to the system undergoes further polymerization. Solvent extraction was performed to separate the homopolymers and block copolymers in order to determine the properties of the product. The results of the solubilities, of gel permeation chromatography and of ¹H nuclear magnetic resonance showed the characteristics of the block copolymers.     

Monodisperse hydrophilic polymer microspheres having carboxylic acid groups prepared by distillation precipitation polymerization

Monodisperse hydrophilic polymer microspheres having carboxyl acid group with spherical shape in the range of 160 nm and 1.52 μm were prepared by distillation copolymerizations of (meth)acrylic acid with either ethyleneglycol dimethacrylate (EGDMA) or divinylbenzene (DVB) as crosslinker. Polymerization was carried out with 2,2′-azobisisobutyronitrile (AIBN) as initiator in neat acetonitrile without stirring. The polymer microspheres were formed and precipitated out from the reaction medium during the distillation of the solvent from the reaction system through an entropic precipitation polymerization manner. The effects of the crosslinker degree on the morphology and the loading capacity of the carboxylic acid group of the resultant polymer microspheres were investigated. The growth procedures of poly(DVB-co-AA) microspheres were traced by SEM characterization. The steric stabilization through the pendent chains and surface gel and the electrostatic repulsion from the carboxyl acid groups contribute to the formation of monodisperse polymer microspheres.     

Seeded emulsion polymerization of styrene: influence of acrylic acid on the particle growth process

The seeded batch emulsion copolymerization of styrene and acrylic acid was studied. The polymerization rate was investigated with pH as the main parameter. Some attempts were made to evaluate the average number of growing chains per particle during Stage II of the emulsion polymerization process. The final latex products were characterized by means of conductometric aqueous titration and potentiometric titration in an organic solvent mixture. The distribution of the acid groups over the aqueous phase, the particle surface, and the interior of the particles together with the kinetic results provided insight into important features governing the incorporation of acrylic acid. The results indicate that pH is the dominating parameter for the incorporation process. An optimal incorporation on the surface of the particles is observed for a low value of pH. In that case, all the acid groups are protonated. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1186–1196, 2000     

反相微乳液聚合荧光高分子F-PAM

通过Span80-Tween80/异辛烷/FM(4-甲氧基-N-（2-N′,N′-二甲基氨基乙基）萘二甲酰亚胺烯丙基氯化铵）-AM（丙烯酰胺）-H₂O反相微乳液聚合,制备了AM和FM的荧光高分子聚合物（F-PAM）.采用透射电镜（TEM）、原子力显微镜（AFM）、激光纳米粒度仪、荧光分光光度计等测试手段,测定了荧光高分子聚合物（F-PAM）的粒子形态、粒径和粒径分布等微观结构及其荧光性能.试验结果表明：所制备的F-PAM为单分散、球形的纳米材料,平均粒径（D）在60～145 nm之间;F-PAM的激发波长和发射波长分别为381 nm和462 nm.F-PAM激发光谱与发射光谱呈较好的镜像对称关系;F-PAM的相对荧光强度随着其质量浓度的增加而增加,且F-PAM的浓度与其荧光强度呈很好的线性关系,其线性相关系数（R）为0.9953,F-PAM的检测下限为1.83 mg·L^-1.     

Characteristics of poly(vinyl pyrrolidone)/poly(acrylic acid) interpolymer complex prepared by template polymerization of acrylic acid: Effect of reaction solvent and molecular weight of template

Poly(vinyl pyrrolidone) (PVP)/poly(acrylic acid) (PAA) interpolymer complexes were prepared, in ethanol or dimethylformamide (DMF), by template polymerization of acrylic acid in the presence of PVP (MW: 42.5 or 1100 K) used as the template. FTIR analysis showed that the complexes were formed through hydrogen bonding between the carboxyl groups of the PAA and the carbonyl groups of the PVP. The glass‐transition temperature (T_g) of the complex, prepared in ethanol, was higher than that of the component polymers, whereas the T_g of the complex, prepared in DMF, was located between that of the component polymers. The dissolution rate of the complex was affected by the molecular weight of the PVP and the reaction solvent. The release rate of ketoprofen from the complexes showed a pH dependency, and was slower at a lower pH. The ketoprofen release rate from the complex was controlled mainly by the dissolution rate of the complex above the pK_a of PAA (4.75) and by the diffusion rate below the pK_a. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2390–2394, 2004     

无机-有机纳米复合乳液的原位聚合及其应用

综述了原位乳液聚合法制备无机．有机纳米复合乳液的技术现状及其形成机理，并运用此技术合成了舍无机纳米粒子的压敏胶用无机-有机纳米复合乳液，分析了纳米粒子在制备过程中的分散性能，从纳米粒子引入方式、乳化剂用量、纳米粒子加入量3方面对压敏胶性能进行考查。     

Cross-linking polymerization of acrylic acid in supercritical carbon dioxide

Cross-linking polymerization of acrylic acid in supercritical carbon dioxide (scCO₂) was studied in a batch reactor at 50 °C and 207 bar with either triallyl pentaerythritol ether or tetraallyl pentaerythritol ether as the cross-linker and with 2,2′-azobis(2,4-dimethyl-valeronitrile) as the free radical initiator. All polymers were white, dry, fine powders. Scanning electron microscopy showed that the morphology of the polymer particles was not affected by cross-linking. As the cross-linker concentration was increased, the polymer glass transition temperature first decreased, then increased. Water-soluble and water-insoluble polymers were synthesized by adjusting the cross-linker concentration. Viscosity measurements showed that the polymer thickening effect strongly depended on the degree of cross-linking. Finally, cross-linking polymerization of acrylic acid in scCO₂ was carried out in a continuous stirred tank reactor. The use of cross-linker decreased the monomer conversion in this system.     

New crosslinked polymer from a rapid polymerization of acrylic acid with triaziridine‐containing compound

A triaziridine containing compound, trimethylolpropane tris(1‐aziridinepropionate) (TMPTA‐AZ), is prepared from a Michael addition of aziridine (AZ) with trimethylolpropane triacrylate (TMPTA). A rapid polymerization of acrylic acid (AA) with TMPTA‐AZ occurred at ambient temperature without catalyst. This polymerization process involves three subsequent reactions are proposed: (1) An exothermic neutralization takes place between AA and TMPTA‐AZ. (2) That neutralization heat triggers AZ ring‐opening reaction and that carboxyl group (of AA) plays as a nucleophile and results in an amino ester bond formation. (3) A final crosslinked polymer is obtained from that amino group reacts with its acrylic double bond via an intermolecular Michael addition reaction. These new crosslinked polymers with various performance properties are obtained from a mixture of AA and TMPTA‐AZ in different ratios and post‐heating. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 809–815, 2007     

Electroinduced dispersion polymerization of acrylonitrile in the presence of poly(acrylic acid) and catalytic amount of CE(IV)

Electroinduced dispersion polymerization of acrylonitrile initiated by Ce(IV) was performed in an electrolytic cell in the presence of poly(acrylic acid) (PAA). Micron‐size polyacrylonitrile (PAN) particles were stabilized with PAA by electrostatic interaction or by a PAA–Ce(III)–PAN ternary complex formation. A PAA–PAN stable polymer was formed in the cathodic compartment, and the reduced initiator was reoxidized in the anode, thus allowing for the continuation of the process. A possible mechanism of polymerization is suggested. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 723–728, 2002; DOI 10.1002/app.10076     

Graft polymerization of acrylic acid onto polypropylene monofilament by RF plasma

Plasma‐induced graft polymerization of acrylic acid onto polypropylene monofilament was carried out to introduce carboxyl groups on its surface. The monofilament was treated with oxygen plasma to create hydroperoxide groups and subsequent graft polymerization of acrylic acid on exposed filament was carried out. An increase in the plasma power led to higher graft levels. It was observed that the hydroperoxide build up on PP surface follows linear increase with the increase in the plasma treatment time only up to 180 s beyond which it slowed down significantly. The formation of oxygenated species was ascertained by X‐ray photoelectron spectroscopy, and the peroxide content was measured by the 2′‐diphenylpicrylhydrazyl (DPPH) estimation. The grafting was observed to be considerably influenced by the plasma exposure time, plasma power, reaction temperature, monomer concentration and the storage temperature. A maximum in the degree of grafting was observed at 40% monomer concentration beyond which grafting tended to decrease very fast. The grafting was also found to be maximum at 50°C followed by a sharp decrease, subsequently. The storage of the exposed filament at ?80°C led to the identical grafting all along the 16 days. However, the storage at 25°C showed significant reduction in the degree of grafting. The atomic force microscopy showed that surface morphology is transformed into a nonhomogeneous one after the plasma exposure, but tends to flatten out after the grafting process in the form of globular structures. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Mechanical properties of cross-linked polymer particles prepared by nitroxide-mediated radical polymerization in aqueous micro-suspension

The compressive strengths of micron-sized, cross-linked poly(styrene-divinylbenzene) particles synthesized by conventional radical copolymerization (70 °C) and nitroxide (TEMPO)-mediated radical copolymerization (125 °C) in aqueous micro-suspension have been measured. In the conventional system, the breaking energies and the compressive strengths of the particles (after removal of unreacted monomer) remained approximately constant from low to high conversion, whereas in the NMP system, both quantities increased close to linearly with conversion. The results suggest that the network formation is more homogeneous in the NMP system than in the conventional system.