Surface modification of glass beads with poly(acrylic acid)

Non‐porous P₂ glass beads were etched with sodium hydroxide to increase the number of silanol groups that could be used to modify the surface. The etched glass beads were then functionalized with 3‐aminopropyltriethoxysilane (APS) and/or glycidoxypropyltrimethoxysilane (GPS). The surface of the glass beads were further modified with poly(acrylic acid) (PAA) by reacting the carboxyl groups on PAA with the amino groups of the pregrafted APS. The chemical modifications were characterized by FT‐IR spectroscopy, particle size analyzer and tensiometry for contact angle and porosity measurements. Five different molecular weight PAA polymers ranging from 2000 to 3,000,000 were grafted with less than expected increase of grafted PAA with molecular weight. The amount of APS and PAA on the surface was determined from thermogravimetric analysis and elemental analysis data. The surface properties of the surface modified glass beads were determined by measuring water and hexane penetration rate and contact angle. The surface morphology was examined by scanning electron microscopy. Copyright © 2006 John Wiley & Sons, Ltd.     

氨基硅烷/马来酸酐接枝聚丙烯界面化学反应的研究

利用溶剂萃取与红外光谱（IR）、光电子能谱（XPS）技术研究了化学键接在玻璃纤维表面的硅烷偶联剂与接枝聚丙烯间的界面化学反应。结果表明：溶剂萃取可以除去玻璃纤维/树脂界面区物理结合的聚合物基体,减少基体信号的影响,在此基础上,利用IR、XPS可以直接证明氨基硅烷（APS）与马来酸酐接枝聚丙烯（MA-g-PP）间发生了界面化学反应,生成了含酰胺基的反应产物。进一步对不同化学状态的N1s的XPS定量分析发现,尽管APS在玻纤表面以开环直链和以氢键结合的环状两种结构形式存在,但在界面上主要是无环开链结构中的氨基与酸酐发生反应。     

Synthesis of maleic anhydride grafted polyethylene and polypropylene,with controlled molecular structures

This article discusses a new chemical route to prepare maleic anhydride (MA) grafted polyethylene and polypropylene polymers with controlled molecular structure, that is, MA grafted content and polymer molecular weight and composition distributions. The chemistry involves a free radical graft reaction of maleic anhydride with poly(ethylene‐co‐p‐methylstyrene) and poly(propylene‐co‐p‐methylstyrene) copolymers. Under a suspension reaction condition, the grafting reaction takes place selectively on the p‐methylstyrene units in the copolymer, due to high reactivity of p‐methyl group and favorable mixing between p‐methylstyrene units and chemical reagents in the swollen amorphous phases. The resulting polymer shows no detectable molecular weight change during the reaction, and the MA grafted content increases with the increase of initiator and p‐methylstyrene concentrations. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1337–1343, 2000     

Synthesis and characterization of anionic graft copolymers containing poly(ethylene oxide) grafts

Anionic graft copolymers were synthesized through grafting of poly(ethylene glycol) monomethyl ether (MPEG) onto terpolymers containing succicinic anhydride groups. The backbone polymers were prepared through radical terpolymerization of maleic anhydride, styrene, and one of the following monomers: methyl methacrylate, ethylhexyl methacrylate, and diethyl fumarate. MPEG of different molecular weights were grafted onto the backbone through reactions with the cyclic anhydride groups. In this reaction one carboxylic acid group is formed together with each ester bond. The molecular weights of MPEG were found to influence the rate of the grafting reaction and the final degree of conversion. The graft copolymers were characterized by IR, GPC, and ¹H-NMR. Thermal properties were examined by DSC. Graft copolymers containing 50% w/w of MPEG 2000 grafts were found to be almost completely amorphous, presumably because of crosslinking, and hydrogen bonding between carboxylic acid groups in the backbone and the ether oxygens in MPEG grafts. © 1995 John Wiley & Sons, Inc.     

Adhesion mechanisms of grafted polyolefins

By comparing surface properties assessed by wettability measurements with polymer-metal adhesion strength determined by peeling for different grafted polyolefins (acrylic acid grafted polyethylene, acrylic acid and maleic anhydride grafted poly(ethylene-vinyl acetate), maleic anhydride grafted polypropylene), a general adhesion mechanism can be proposed. The surface polarity is not the main determining parameter for adhesion. Polyolefin-aluminium adhesion is obtained through chemical bonding of acid groups grafted in the polymer bulk and basic groups present on the aluminium.     

The effect of compatibilizing and coupling agents on the mechanical properties of glass bead filled PP/PET blends

PP/PET blends (95/5) filled with 50% by weight of glass beads were prepared and studied at morphological and mechanical level, and compared with its analogous samples of glass bead-filled PP. The influence of a compatibilizing agent (maleic anhydride grafted polypropylene) and different silane coupling agents was analysed. It has been found that PET embeds glass bead surface independently on the silane coupling agent employed. Addition of MAPP in PP/PET blends leaded to tensile strength values similar to those of unfilled PP, but rupture takes place in a brittle manner.     

Preparation of thin surface layers by grafting of PEO

We have developed a two‐stage process to graft poly(ethylene oxide) (PEO) onto a silica surface. In the first stage the adsorption of an anchor reactive polymer to the surface is carried out, and in the second stage the grafting of compatibilizing macromolecular tails is performed via the reactions of functional groups of the polymer anchored. Random copolymers of styrene and maleic anhydride (SM) were chosen as reactive anchoring polymers. The kinetics of adsorption of SM from dilute solutions onto the silica surface as well as the grafting of PEO to SM macromolecules adsorbed was experimentally investigated by null ellipsometry. A model of the structure at the surface is proposed.     

The preparation and characterization of carboxylic acid‐coated silica nanoparticles

The preparation of carboxylic acid‐coated silica nanoparticles was investigated. A monolayer of carboxylic acid residues with controllable graft density was anchored to the nanoparticle by a ring‐opening reaction with succinic anhydride. Poly(methacrylic acid) [poly(MAA)] grafted nanoparticles were prepared via a polymerization–deprotection strategy. Tert‐butyl methacrylate was polymerized from the surface of silica nanoparticles in a predictable manner and with excellent control over the molecular weight distribution. Subsequent removal of the tert‐butyl group resulted in poly (MAA) grafted nanoparticles. The polymer nanoparticles were also functionalized with dyes, which may be useful in tracking the particles in biological systems. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Thermo‐responsive glycopolymer chains grafted onto honeycomb structured porous films via RAFT polymerization as a thermo‐dependent switcher for lectin Concanavalin a conjugation

Stable and surface‐modified films with regular porous arrays were created by crosslinking honeycomb structured porous films prepared via breath figures from poly(styrene‐co‐maleic anhydride). The formation of open or closed pores of the films was controlled by the addition of a polyion complex. Subsequent crosslinking of the films with 1,8‐diaminooctane led to films, which maintain their structure in solvents. In addition, excess amino functionality after crosslinking allowed the attachment of RAFT agent, 3‐benzylsulfanyl thiocarbonyl sulfanylpropionic acid, for the controlled surface polymerization of N‐isopropyl acrylamide (NIPAAm) and N‐acryloyl glucosamine (AGA). The attachment of thermo‐responsive glycopolymers onto the honeycomb structured porous films was confirmed using contact angle measurements and confocal fluorescence microscopy. Cleavage of surface anchored polymers via aminolysis revealed that the molecular weights of the surface grafted chains are significantly larger than the molecular weight of the chains generated in solution. The honeycomb structured porous films with their grafted PNIPAAm‐ran‐PAGA polymer chains showed selective recognition of Concanavalin A (ConA). Below the lower critical solution temperature (LCST) of the surface, the conjugation is switched off, while above the LCST the surface grafted glucose moieties bind strongly to ConA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3440–3455, 2010     

Synthesis and characterization of poly[(3,4-dihydro-2h-pyran)-alt-(maleic anhydride)] and its derivatives: Biologically active polymers

The syntheses of several monomers, bioactive poly[(3, 4-dihydro-2H-pyran)-alt-(maleic anhydride)] and its derivatives, which have different substituents (e.g., acetoxy, methoxy, ethoxy, methoxycarbonyl, formyl, acetoxymethyl, and tosyloxymethyl groups) in the 2-position of the tetrahydropyran ring of the copolymer backbone, are described. The alternating sequences in copolymers of the dihydropyran derivatives and maleic anhydride were obtained from the equimolar and larger ratios of maleic anhydride to dihydropyran derivative at the onset of the copolymerization. The molecular weights of the copolymers were found to be low (M_n = 1000–7500) due to a transfer reaction of the dihydropyran derivatives. Hydrolyses of the anhydride groups in the copolymers without catalyst afforded poly[(dihydropyran)-alt-(maleic acid)] and its derivatives, whereas an additional three copolymers having substituents, e.g., hydroxy, hydroxymethyl, and carboxyl groups were obtained by hydrolyses of the pendent groups (acetoxy, acetoxymethyl, and methoxycarbonyl) with the aid of a hydroxide catalyst. Carbamoyl groups on the polymers were obtained from ammonolysis of methoxycarbonyl groups. The polymers having mercaptomethyl or aminomethyl groups were obtained by substitution of hydrogen sulfide or ammonia for tosyloxylmethyl groups.     

Modification of porous silica particles with poly(acrylic acid)

The surface of porous silica particles was modified with poly(acrylic acid) by reacting the carboxyl groups on poly(acrylic acid) with the amino groups of pregrafted aminopropyltriethoxysilane (APS). The chemical modifications by APS and polymer were characterized by infrared spectroscopy and the amount of APS and poly(acrylic acid) grafted to the surface were determined by thermal gravimetric analyses. The wettability of the modified silica particles, based on the rate of water penetration, was pH‐dependent with PAA; at pH 1.5 the wettability increased but at pH 5.5 it decreased dramatically. The pore size and size distribution of the silica particles decreased with APS and polymer grafting. Copyright © 2000 John Wiley & Sons, Ltd.     

Synthesis of end‐functionalized AB copolymers. II. Synthesis and characterization of carboxyl‐terminated poly(ethylene glycol)–poly(amino acid) block copolymers

AB block copolymers composed of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(amino acid) with a carboxyl group at the end of PEG were synthesized with α‐carboxylic sodium‐ω‐amino‐PEG as a macroinitiator for the ring‐opening polymerization of N‐carboxy anhydride. Characterizations by ¹H NMR, IR, and gel permeation chromatography were carried out to confirm that the diblock copolymers were formed. In aqueous media this copolymer formed self‐associated polymer micelles that have a carboxyl group on the surface. The carboxyl groups located at the outer shell of the polymeric micelle were expected to combine with ligands to target specific cell populations. The diameter of the polymer micelles was in the range of 30–80 nm. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3527–3536, 2004     

Tuning salicylate‐based polymers to overcome lag time and extend release via copolymers and polymer blends

This work describes how physicochemical properties of salicylate‐based poly(anhydride‐esters) (PAEs) can be tuned for drug delivery and optimized by comparing copolymerization with polymer blending. These alterations reduced the lag time of drug release, while still maintaining a long‐term drug release profile. The chemical composition of the copolymers and polymer blends was determined by proton nuclear magnetic resonance and additional properties such as molecular weight, glass transition temperature and contact angle measurements were obtained. In vitro salicylic acid release from the copolymers and blends is studied in an environment mimicking physiological conditions. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 685–689     

Preparation of poly(vinylphenylboronic acid) chain grafted poly(glycidylmethacrylate‐co‐ethylenedimethacrylate) beads for the selective enrichment of glycoprotein

Surface‐initiated atom transfer radical polymerization was successfully used to prepare 4‐vinylphenylboronic acid functionalized poly(glycidylmethacrylate‐co‐ethylenedimethacrylate) beads for the selective enrichment of glycoprotein from complex biological samples in this study. The modified bead surfaces were characterized using Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The sorption behaviors, including adsorption isotherms, incubation time, and pH effect, were investigated. The results demonstrated that the boronated beads have a high affinity for glycoprotein, which is due to the well‐defined boronic acid brushes on the beads surfaces. Furthermore, the polyvinylphenylboronic acid grafted poly(glycidylmethacrylate‐co‐ethylenedimethacrylate) beads were used to efficiently enrich and purify glycoprotein from real egg white samples and α‐fetoprotein from human serum samples. The mass spectrometry results demonstrated that the polyvinylphenylboronic acid grafted poly(glycidylmethacrylate‐co‐ethylenedimethacrylate) beads are a suitable material for the enrichment of glycosylated protein from complex biological samples.     

Bioengineering functional copolymers. III. Synthesis of biocompatible poly[(N‐isopropylacrylamide‐co‐maleic anhydride)‐g‐poly(ethylene oxide)]/poly(ethylene imine) macrocomplexes and their thermostabilization effect on the activity of the enzyme penicillin G acylase

Stimuli‐responsive poly[(N‐isopropylacrylamide‐co‐maleic anhydride)‐g‐poly(ethylene oxide)]/poly(ethylene imine) macrobranched macrocomplexes were synthesized by (1) the radical copolymerization of N‐isopropylacrylamide and maleic anhydride with α,α′‐azobisisobutyronitrile as an initiator in 1,4‐dioxane at 65 °C under a nitrogen atmosphere, (2) the polyesterification (grafting) of prepared poly(N‐isopropylacrylamide‐co‐maleic anhydride) containing less than 20 mol % anhydride units with α‐hydroxy‐ω‐methoxy‐poly(ethylene oxide)s having different number‐average molecular weights (M_n = 4000, 10,000, or 20,000), and (3) the incorporation of macrobranched copolymers with poly(ethylene imine) (M_n = 60,000). The composition and structure of the synthesized copolymer systems were determined by Fourier transform infrared, ¹H and ¹³C NMR spectroscopy, and chemical and elemental analyses. The important properties of the copolymer systems (e.g., the viscosity, thermal and pH sensitivities, and lower critical solution temperature behavior) changed with increases in the molecular weight, composition, and length of the macrobranched hydrophobic domains. These copolymers with reactive anhydride and carboxylic groups were used for the stabilization of penicillin G acylase (PGA). The conjugation of the enzyme with the copolymers significantly increased the thermal stability of PGA (three times at 45 °C and two times at 65 °C). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1580–1593, 2003     

Waterborne polyesters partially based on renewable resources

A new experimental approach for preparing biobased, water‐soluble polyesters (PEs) via titanium(IV) n‐butoxide‐catalyzed bulk polycondensation is presented. In the described method polymers were obtained from isosorbide, maleic anhydride and poly(ethylene glycol) (PEG). The chemical structure of the synthesized PEs was confirmed using 2D NMR spectroscopy and by titration methods. Careful analysis of 2D NMR spectra viz. correlation spectra (COSY), heteronuclear single quantum correlation spectra (HSQC) and heteronuclear multiple‐bond correlation spectra (HMBC) allowed to accomplish the complete proton assignment of isosorbide, PEG, and unsaturated acid residues in the PEs. Moreover, by using NMR spectroscopy the transformation of maleic anhydride into fumaric acid ester and the absence of maleic acid ester units in the final polymer were proven. However, during polycondensation part of the unsaturated bonds has reacted in a Michael addition with isosorbide or PEG. Gel permeation chromatography measurements revealed that the unsaturated PEs have M_n values in the range 3000–5000 g/mol. These PEs, with a low content of carboxylic acid end groups, exhibited sufficient thermal resistance for practical applications, for example, as free radical curable coatings. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Surface modification of silicate glass using 3-(mercaptopropyl)trimethoxysilane for thiol-ene polymerization

A thiol-ene polymerization was accomplished on silicate glass slides to graft a series of homopolymers and copolymers using 3-(mercaptopropyl)trimethoxysilane (MTS) as both a silane coupling agent and initiator. MTS was initially covalently bonded to an acid cleaned glass surface via a classical sol-gel reaction. Poly(acrylic acid) (PAA), poly(acrylamide) (PAAm), poly(methyl acrylate) (PMA), poly(acrylamido-2-methyl-propanesulfonic acid) (PAMPS), and the copolymer poly(AA-co-AAm-co-MA-co-AMPS) were grafted from the thiol group of MTS. The surface chemistry of the MTS modified slides and polymer grafts was characterized with attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Surface texture was evaluated with tapping mode atomic force microscopy (TM-AFM). The Owens-Wendt-Kaelble (OWK) and Lifshitz-van der Waals acid-base (LW-AB) methods were used to evaluate surface energies by sessile drop contact angle method. The synthetic approach demonstrated a facile, rapid method for grafting to glass surfaces.     

Synthesis of quaternary ammonium ion‐grafted polyolefins via activation of inert C?H bonds and nitroxide mediated radical polymerization

A TEMPO‐functionalized isotactic poly(1‐butene) macroinitiator was synthesized via rhodium‐catalyzed activation of the alkane C? H bonds in polyolefin side chain using a boron reagent and subsequent transformations of the boronate ester group in the polymer. These functionalization processes did not induce cross‐linking or degradation of the polymer chains. Nitroxide mediated radical polymerization of dipropyl(4‐vinylphenyl)amine with the macroinitiator produced high‐molecular weight amine‐grafted copolymers of the polyolefin. Adjusting the ratio of polar monomer concentration to macroinitiator concentration controlled the concentrations of amine blocks in the graft copolymers up to 10 mol %. Quaternization of the amine‐grafted copolymers with methyl triflate generated ammonium ion blocks along the side chain of the graft copolymers. A systematic decrease of contact angle in a series of ammonium ion‐grafted copolymers was observed through water contact angle measurements, suggesting that the graft polymerization and the quaternization led to increased hydrophilicity in the polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4519–4531, 2009     

Characterization of maleic acid/anhydride copolymer films by low-rate dynamic liquid-fluid contact angle measurements using axisymmetric drop shape analysis

Thin films of alternating maleic acid/anhydride copolymers (poly(octadecene-alt-maleic acid/anhydride), POMA; poly(propene-alt-maleic acid/anhydride), PPMA; poly(styrene-alt-maleic acid/anhydride), PSMA) were studied to unravel the influence of the comonomer characteristics in the backbone on the surface-energetic properties of the copolymer films in the dry state and in contact with aqueous solutions. Water contact angle measurements revealed a graduation of the wettability of the dry hydrolyzed and annealed copolymer films that was dependent on the comonomer unit. It ranged from moderately hydrophilic (PPMA, annealed gamma(sv) = 39.9 mJ/m2) to very hydrophobic (POMA, annealed, gamma(sv) = 18.4 mJ/m2) surfaces. Liquid-fluid contact angle measurements using captive air bubbles were performed in different aqueous media (pure water, phosphate-buffered saline, and 10(-)(3) M KCl of two different pH values (pH = 3 and pH = 10) to study the copolymer films in their hydrated states relevant for biointerfacial phenomena. It was found that the graduation of the wettability of the copolymer films in the dry state is overall maintained upon immersion in aqueous solutions. The dependence of the wettability on the pH value of the aqueous medium could be related to the (de)protonation of the carboxylic groups.     

Synthesis of water‐soluble conductive copolymer based on polyaniline

Synthesis and characterization of polyaniline‐grafted poly(styrene‐alt‐maleic anhydride) (PANI‐g‐PSMA) was carried out to obtain conductive comb copolymers with highly improved processability. First, polyaniline (PANI) was prepared in nano‐scale by chemical synthesis under ultrasonic irradiation. Then the poly(styrene‐alt‐maleic anhydride) (PSMA) was synthesized by free radical polymerization. Moreover, the PANI was grafted on the PSMA backbone to prepare a comb‐like conductive copolymer for improving its processability as a new method. The products were characterized by Fourier transform infrared, ultraviolet–visible spectroscopy and X‐ray diffraction patterns. Morphology of the samples was also investigated by scanning electron microscopy images. Finally, the solubility and conductivity of the products were studied, and it resulted in high solubility of the products in water and other common organic solvents in comparison to the pure PANI. Copyright © 2015 John Wiley & Sons, Ltd.