Functional polymers. XIV. Grafting of 2(2-hydroxy-5-vinylphenyl)2H-benzotriazole onto polymers with aliphatic groups

Successful grafting of 2(2-hydroxy-5-vinylphenyl)2H-benzotriazole onto saturated aliphatic C? H groups of polymers has been accomplished. When the grafting reaction was carried out in chlorobenzene at 150–160°C with di-tertiary butylperoxide as the grafting initiator, grafts as high as 20–30% at grafting efficiencies of 50 and 80% have readily been obtained. It was very important to carry out the grafting reaction in tubes sealed under high vacuum since trace amounts of oxygen cause complete inhibition of the grafting reaction by the phenolic monomer. Grafting reactions were carried out on a variety of different polymers including atactic polypropylene, ethylene/vinyl acetate copolymer, poly(methyl methacrylate), poly(butyl acrylate), and polycarbonate.     

Stereocontrol in radical polymerization

The stereospecific radical polymerization of vinyl esters, methacrylates, and alpha-substituted acrylates was studied. Fluoroalcohols, as a solvent, have remarkable effects on the stereoregularity of the radical polymerizations of vinyl acetate, vinyl pivalate, and vinyl benzoate, affording polymers rich in syndiotacticity, heterotacticity, and isotacticity, respectively. This method was successfully applied to the polymerization of methacrylates to give syndiotactic polymers. The steric repulsion between the entering monomer and the chain-end monomeric unit bound by the solvent through hydrogen bonding is important for the stereochemical control in these systems. Lewis acid catalysts, such as lanthanide trifluoromethanesulfonates and zinc salts, were also effective for the stereocontrol during the radical polymerization of methyl methacrylate, to reduce the syndiotacticity and alpha-(alkoxymethyl)acrylates to synthesize isotactic and syndiotactic polymers. Radical polymerization of the methacrylates bearing a bulky ester group, such as the triphenylmethyl methacrylate derivatives, gave highly isotactic polymers, as in the case of anionic polymerization. In addition, the control of one-handed helical conformation was attained in the radical polymerization of 1-phenyldibenzosuberyl methacrylate using chiral neomenthanethiol or cobalt(II) complexes as an additive.     

Monomer reactivity ratios in graft copolymerization

This paper discusses monomer reactivity ratios in various radiation- and redox-initiated graft copolymerizations. The polymers studied were polyethylene, cellulose acetate, poly(vinyl chloride), polytetrafluoroethylene, poly(vinyl alcohol), and poly(methyl methacrylate); the comonomer mixtures were styrene–acrylonitrile, methyl acrylate–styrene, acrylonitrile–methyl acrylate, and vinyl acetate–acrylonitrile. The polymer–comonomer mixture systems were so chosen as to permit study of both homogeneous and heterogeneous systems. The homogeneous systems included systems of low and high viscosity. The heterogeneous systems included both polymers swollen by the comonomer mixture and polymers not swollen by the comonomer mixture. None of the homogeneous grafting systems studied showed deviations from the normal copolymerization behavior under a variety of experimental conditions. Monomer reactivity ratios in graft copolymerization were the same as the values in nongraft copolymerization. The heterogeneous systems in which the polymer was swollen by the comonomer mixture yielded grafted copolymer compositions which were the same as those in nongraft copolymerization. The heterogeneous grafting system polytetrafluoroethylene/styrene–acrylonitrile showed deviations from normal copolymerization behavior at low degrees of grafting when the reaction was only on the polymer surface. The behavior became normal at higher degrees of grafting when the system approaches that in which the polymer is swollen by the comonomers. In all reaction systems, it was found that the use of radiation to initiate the reaction does not in any way affect the copolymerization behavior of the two monomers in a comonomer pair.     

Synthesis of double hydrophilic graft copolymer containing poly(ethylene glycol) and poly(methacrylic acid) side chains via successive ATRP

A well‐defined double hydrophilic graft copolymer, with polyacrylate as backbone, hydrophilic poly(ethylene glycol) and poly(methacrylic acid) as side chains, was synthesized via successive atom transfer radical polymerization followed by the selective hydrolysis of poly(methoxymethyl methacrylate) side chains. The grafting‐through strategy was first used to prepare poly[poly(ethylene glycol) methyl ether acrylate] comb copolymer. The obtained comb copolymer was transformed into macroinitiator by reacting with lithium diisopropylamine and 2‐bromopropionyl chloride. Afterwards, grafting‐from route was employed for the synthesis of poly[poly(ethylene glycol) methyl ether acrylate]‐g‐poly(methoxymethyl methacrylate) amphiphilic graft copolymer. The molecular weight distribution of this amphiphilic graft copolymer was narrow. Poly(methoxymethyl methacrylate) side chains were connected to polyacrylate backbone through stable C? C bonds instead of ester connections. The final product, poly[poly(ethylene glycol) methyl ether acrylate]‐g‐poly(methacrylate acid), was obtained by selective hydrolysis of poly(methoxymethyl methacrylate) side chains under mild conditions without affecting the polyacrylate backbone. This double hydrophilic graft copolymer was found be stimuli‐responsive to pH and ionic strength. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4056–4069, 2008     

Effect of fluorinated groups on photooxidative stability of polymeric protectives applied on marble

Some new protective copolymers and a commercial one have been tested on Candoglia marble, a very low porosity stone. Two of the polymers contained a partially fluorinated methacrylic monomer, 2,2,2 trifluoro ethyl methacrylate (TFEMA), in combination with either an acrylic, methyl acrylate (MA) or a vinyl ether, n-butyl vinyl ether (n-BVE) unit. Two copolymers, ethyl methacrylate/n-butyl vinyl ether and ethyl methacrylate (EMA)/methyl acrylate (Paraloid B72), were non-fluorinated and similar in compositions and molar ratio. The aim of the work is to test the copolymers and compare the performances of fluorinated new polymers with the non fluorinated one and with the largely used commercial product. The results obtained demonstrate that the introduction, even in limited amounts, of fluorine atoms in the side ester groups of methacrylic type polymers really improves their protective effect and the durability of the stone treatments. The best results were obtained with the copolymer TFEM/MA which is the fluorinated homologous of Paraloid B72.     

Polymers and Copolymers of Vinyl Monomers with Blocked Isocyanate Groups: Synthesis and Characterization

Abstract

The polymerization of vinyl monomers containing blocked isocya-nate groups is reported. The blocking agents for the isocyanate groups of 2-isocyanato methacrylate were phenol, propanone oxime, benzophe-none oxime, and ecaprolactam. The ¹H-NMR and IR spectra of these polymers are discussed. Copolymerization reactivity ratios of the vinyl monomer blocked by phenol with styrene and methyl methacrylate have been determined. Glass transition temperatures of these polymers have been determined by differential scanning calorimetry. The homo– and copolymers were crosslinked in the presence of ethylene diamine, and the gels obtained were examined by IR spectra.     

Synthesis and characterization of two new aryl cyclobutyl ketoethyl methacrylate monomers and their polymers

Two new methacrylate monomers, 2‐[3‐(6‐tetralino)‐3‐methylcyclobutyl]‐2‐ketoethyl methacrylate (TKEMA) and 2‐(3‐mesityl‐3‐methylcyclobutyl)‐2‐ketoethyl methacrylate (MKEMA), were obtained from the reaction of 1‐chloroacetyl‐3‐methyl‐3‐arylcyclobutane with sodium methacrylate. The oxime and hydrazone derivatives of poly(TKEMA) and poly(MKEMA) were prepared with hydroxylamine and 2,4‐dinitrophenyl hydrazine. Poly(TKEMA) and poly(MKEMA), their oxime and hydrazone derivatives, and the monomers were characterized with Fourier transform infrared and NMR techniques. The glass‐transition temperatures and thermal stability of the polymers and their oxime and hydrazone derivatives were compared. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4167–4173, 2001     

Copolymerization of 2-methylene-4-phenyl-1,3-dioxolane with electrophilic vinyl monomers through zwitterionic mechanism

Spontaneous copolymerization of cyclic ketene acetal, 2-methylene-4-phenyl-1,3-dioxolane ( I ) with common electrophilic vinyl monomers, such as methyl α-cyanoacrylate (MCA), acrylonitrile (AN), and methyl methacrylate (MMA) were investigated to further explore zwitterion polymerization method with cyclic ketene acetals. In the reaction of I with MCA and AN, spontaneous copolymerization took place at ambient temperature. The copolymers of I with MCA gave low molecular weight polymers, but copolymers obtained with I and AN were high molecular weight polymers. In the reaction of I and MMA, high molecular weight copolymer was obtained only at temperatures above 80°C. Thus, obtained polymers were not the alternating copolymers and possessed high I content in all the cases. From the above results, macrozwitterionic mechanism was suggested as discussed.     

Graft Copolymerization of Methyl Methacrylate on Poly(phenyl Vinyl Sulfide)

Graft copolymer of poly(phenyl vinyl sulfide) and methyl methacrylate was obtained. The isolation of graft copolymer was carried out by the fractional precipitation method. The isolated polymer was confirmed to be a graft copolymer by IR spectra and T determinations. Graft copolymerizations of poly(phenyl vinyl sulfide) with vinyl acetate, acrylonitrile, acrylamide, and acrylic acid were also carried out, but the separation of graft copolymer in these cases was difficult, and satisfactory results could not be obtained.     

Some Reactions of Vinyl Isocyanate and Its Copolymers∗

Linear, soluble copolymers of vinyl isocyanate with styrene and methyl methacrylate were obtained when the comonomer:vinyl isocyanate ratio in the copolymer was greater than 9:1. When the comonomer to isocyanate ratio was less than 2:1, the copolymers were insoluble. Infrared evidence indicated that spontaneous cross-linking through the isocyanate function occurred by a mechanism similar to the known reaction by which isocyanates undergo dimerization and trimerization. The soluble copolymers retained the reactive isocyanate moeity as was shown by their reactivity with n-butylamine and ethanol to produce, respectively, the corresponding polyurea and polycarbamate, and with ethylenediamine and water to produce cross-linked polymers. The intrinsic viscosity [η] for the 9:1 methyl methacrylate: vinyl isocyanate copolymer was 0.22 dl/g while that for the corresponding ethyl carbamate was 0.24 dl/g.     

Synthesis and investigation of properties of repeatedly grafted copolymers (pemosors)

Repeatedly grafted copolymers (pemosors) were obtained by grafting one and the same or different vinyl monomers onto heterochain polymers in a radical reaction. As starting polymers films of polyethylene terephthalate and poly-ε-caproamide were used. Styrene and methyl methacrylate were the grafted vinyl monomers. It has been shown that pemosors could be formed in yields of 500–1000% (of the starting sample weight) by multiple grafting on vinyl polymer. Pemosors differ in appearance both from the starting polymers and the single-graft copolymers. Investigations of pemosor samples by electron microscope showed that the morphological structure of the surface was appreciably affected, the changes being more significant with increasing content of the grafted polymer. X-Ray studies and NMR data on pemosors showed that multiple grafting of vinyl monomers does not change the crystal structure of the starting polymers, affecting only the supermolecular structure of the outer layer. Pemosors are polymers of a new type, differing in their properties from the starting polymers and the single-graft copolymers. The grafting character and penetration depth of the grafted monomer depend on the packing compactness of the supermolecular structure of the polymeric base as well as on the chemical nature of the starting polymers and monomers. Pemosors possess considerable chemical resistance and withstand prolonged boiling in 40% alkali solution.     

Chiral separation by electrokinetic capillary chromatography using newly synthesized linear polymers containing L-amino acid moieties.

Chiral linear polymers were prepared by the thermal polymerization of N-acryloyl-L-valine and N-acryloyl-L-alanine derivatives using 3-mercaptopropionic acid (3-MPA) as a radical transfer agent. C-Terminal groups of the derivatives were methyl and tert-butyl esters later removed, and N-methylamide moieties. The N'-methylamide derivative of N-acryloyl-L-valine was copolymerized with methyl ester at a molar mixing ratio of 1:1. The ester groups were removed to provide anionic linear polymers terminated with carboxylic acid of the amino acid residue. The polymers are thus shown to function as pesudostationary phases that separate enantiomeric solutes in electrokinetic capillary chromatography (EKC). Racemic 3,5-dinitrobenzoylamino isopropyl esters were separated with the polymer derived from N-acryloyl-L-valine esters and with the copolymer from N-acryloyl-L-valine methyl ester and N-acryloyl-L-valine N'-methylamide at pH 7.0. These separations could not be observed at pH 9.0 in migrating solutions containing anionic linear polymers. This pH dependence can be discussed from the standpoint of the microscopic hydrophobicity of the polymers, as assessed from the fluorescence of pyrene adsorbed onto the polymers in water.     

Solid‐phase incorporation of gaseous carbon dioxide into oxirane‐containing copolymers

Carbon dioxide was incorporated into poly(glycidyl methacrylate‐co‐methyl methacrylate) by a solid‐phase reaction, which transformed the pendent oxirane moieties into cyclic carbonate moieties, with quaternary ammonium halide catalysts. The incorporation of carbon dioxide into the copolymer led to soluble carbonate‐containing polymers, whereas the incorporation of carbon dioxide into the glycidyl methacrylate homopolymer produced an insoluble product. The copolymer composition, reaction temperature, and catalyst amount affected the incorporation efficiency and the side reaction that caused crosslinking. Effective incorporation was achieved under the following reaction conditions: the glycidyl methacrylate content was less than approximately 50%, the temperature was greater than the glass‐transition temperature, and the catalyst concentration was 1.5–6 mol %. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3812–3817, 2004     

Reaction of chlorine-containing polymers with living polymers

A graft polymer was prepared by means of the coupling reaction of chlorinated ethylene–propylene terpolymer with living polystyrene, obtained with a sodium–naphthalene complex as initiator, under various conditions; the grafting efficiency and the percentage of grafting are discussed. Poly(chloroprene), chlorinated butyl rubber, poly(vinyl chloride), poly(epichlorohydrin), and epichlorohydrin–ethylene oxide copolymer were also used as chlorine-containing polymers. The grafting efficiencies were found to be in the following order: chlorinated butyl rubber > poly(epichlorohydrin) > epichlorohydrin-ethylene oxide copolymer > chlorinated ethylene-propylene terpolymer > poly(chloroprene) > poly(vinyl chloride). A graft polymer was obtained from the reaction between chlorinated ethylene–propylene terpolymer and living poly(isoprene), with butyllithium in benzene. The undesirable metal–halogen interchange reaction was considerable.     

Photochemical modification of polymer surface by the pendant photobase generator containing oxime‐urethane groups and its application to an image‐recording material

Copolymers containing oxime‐urethane groups were prepared by the copolymerization of methyl methacrylate and benzophenoneoximinocarbonylaminoethyl methacrylate (BCM), and their photochemical properties were examined from the UV and IR absorption spectral changes. The decomposed fraction of oxime‐urethane groups in the copolymer increased with irradiation time, but it decreased with the content of BCM units in the copolymer. Changes of the surface properties of the copolymer film on irradiation were studied by measurements of the contact angle and dyeing with an acid dye. The surface of the copolymer film changed to become more hydrophilic upon irradiation with 254 nm of UV light. After the irradiated copolymer films were treated with HCl or methanol, changes of the contact angle of water on irradiation were compared. The copolymer film was dyed by acid dyes after treatment of the irradiated film with HCl. The degree of dyeing increased with irradiation time and BCM units in the copolymer, but it was unaffected by the film thickness. Various colors were developed on the irradiated area depending on the acid dye as the developer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1200–1207, 2002     

Graft polymers from poly(vinyl chloride) and chlorinated rubber

Graft polymers from poly(vinyl chloride) (PVC) and chlorinated rubber (CIR) with side chains of poly(methyl methacrylate) (PMMA), poly(methyl acrylate) (PMA), or poly(ethyl methacrylate) (PEMA) were synthesized. For this purpose, a vinyl monomer was polymerized in the presence of small quantities of PVC or CIR with benzoyl peroxide as catalyst. The graft polymers were separated from both homopolymers by precipitation with methanol from methyl ethyl ketone solutions of the reaction products and the grafting efficiency was calculated. The graft polymers were characterized by infrared spectra, elemental analysis, NMR, and osmometric or light-scattering determinations. From the results it is concluded that the PVC or CIR molecules contain side chains of PMMA, PMA, or PEMA. The graft polymers showed higher molecular weights, and the values of second virial coefficient for these polymers were much different from those of the starting polymers.     

Preparation and properties of some water-soluble,comb-shaped,amphiphilic polymers

Water-soluble comb-shaped polymers were prepared through grafting of poly(ethylene glycol) monomethyl ethers (MPEG) onto acrylic and methacrylic ester copolymers by transesterification reactions. The grafting was alkali-catalyzed, and performed in refluxing toluene solution or in melt at 155°C. The grafting efficiency was found to be on the order of 1 graft/10 monomer units. Epoxy groups in glycidyl methacrylate copolymers were also utilized for grafting. The crude graft copolymers were purified through chromatography and characterized by NMR and IR spectroscopy. Polymers prepared from MPEG 2000 were crystalline with melting points 10–15°C lower than the MPEG used. All polymers were shown to be surface active with CMC on the order of 1.5 g/L, and surface tensions of 38–45 dyn/cm. When used as emulsifiers the graft copolymers containing bulky lipophilic ester groups (2-ethylhexyl t-butyl) gave oil-in-water (o/w) and water-in-oil (w/o) emulsions from xylene/water with higher stability than those containing straight chain ester groups (methyl nbutyl n-docecyl). The most stable emulsions were obtained by dissolving the polymers in the organic phase.     

Study of photopolymer. XIX. Novel syntheses of the polymers with pendant ester and chloromethyl groups by addition reactions of the copolymer of glycidyl methacrylate with acid chlorides

Polymer with pendant cinnamic ester and chloromethyl groups was synthesized by the addition reaction of poly(glycidyl methacrylate–co–methyl methacrylate) (PGMA) with cinnamoyl chloride. Also, polymers with pendant benzoic esters and chloromethyl groups were synthesized by reaction of PGMA with the corresponding benzoyl chlorides. Furthermore, polymers with cinnamic or benzoic esters and alkylazide groups were prepared by the substitution reaction of the obtained polymers with sodium azide.     

Diphilic Macromolecular Brushes with a Polyimide Backbone and Poly(methacrylic acid) Blocks in Side Chains

Novel macromolecular brushes with a polyimide backbone and diphilic diblock copolymer side chains consisting of a hydrophilic block of poly(methacrylic acid) adjacent to the backbone and the outer hydrophobic block of poly(methyl methacrylate) are synthesized. The synthesis includes the grafting of poly(tert-butyl methacrylate) to the polyimide chain followed by the polymerization of methyl methacrylate on the graft copolyimide as a branched multicenter macroinitiator. Brushes with diphilic side chains are obtained via the acidic hydrolysis of ester groups in the first block of side chains. The grafting polymerization of methacrylates is performed according to the “grafting from” approach by the method of pseudoliving atom transfer radical polymerization using two methodologies of polymerization activated by either copper- or iron-containing complexes. Conditions providing the controlled regime of the polymerization processes under study are found, and pathways for the targeted regulation of the degree of polymerization of methacrylate blocks and their grafting density are determined. As is shown by dynamic light scattering and transmission electron microscopy, the macromolecules of brushes with diphilic side chains form in ethanol homotypic, obviously spherical, supramolecular micellar structures with hydrodynamic radii in the range from 40 to 120 nm depending on the length and grafting density of the two blocks in diphilic side chains.     

Grafting of poly(ethylene oxide) on poly(methyl methacrylate) by transesterification

The grafting of the potassium alkoxide derivative of poly(ethylene oxide) on poly(methyl methacrylate) in homogeneous solution in toluene was studied. The alkoxide was prepared by reaction with potassium metal with methanolic potassium methoxide, or with potassium naphthalene. The last was the most suitable for the systematic investigation of the grafting process. Soluble graft polymers were formed, and essentially the initial poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) participated in the production of graft polymer. The composition of the graft polymers and the frequency of grafting of the side chains were determined by NMR. The solubility of the graft polymers in methanol and water increased with increasing PEO contents, while the melting ranges decreased. Fractionation of the crude graft polymers showed that the grafting reaction was random, and graft polymers containing one PEO side chain per about 10–170 MMA units were obtained.