Synthesis of biocidal polymers containing metal NPs using an electron beam

Metal containing antibacterial polymers were prepared by the polymerization of methylmethacrylate and methacrylic acid with copper or zinc. When the thin film of the polymers coated on a glass was irradiated with an electron beam, nanoparticles were obtained. It was found that these polymers exhibited a potent antibacterial activity against the Gram-negative bacteria, Escherichia coli. The metal containing polymers showed a 99.999% (5.0 logs) reduction in E. coli at a contact time of 12 h.In addition, polymers had a good antifouling effect against marine organisms.     

Soluble blue light emitting pyridine-containing polymers prepared by oxidative-coupling copolymerization

Novel polymers containing pyridine moieties in main chains have been prepared by facile oxidative-coupling co-polymerization of pyridine N-oxide with N-alkyl carbazole and fluorene as the precursor polymers, which were reduced to the pyridine-containing polymers respectively. The polymers were characterized by FT-IR, ¹H NMR, UV-Vis, X-ray, thermo-gravimetric analysis, and fluorescence spectroscopy. The pyridine-containing polymers good solubility in convenient organic solvents, high thermal stability with the onset decomposition temperature above 310 °C. The electrochemical behaviors of the polymers were investigated by cyclic voltammetry; the HOMO and LUMO energy level of the polymers were estimated from the electrochemistry and UV-Vis spectroscopy. The fluorescence spectra of the pyridine-containing polymers display blue light emitting properties in both solution and solid-state film.     

New heat stable and processable poly(amide-ether-imide)s derived from 5-(4-trimellitimidophenoxy)-1-trimellitimido naphthalene and various diamines

New aromatic diimide-dicarboxylic acid having flexible ether linkage, 5-(4-trimellitimidophenoxy)-1-trimellitimido naphthalene, was synthesized by the reaction of trimellitic anhydride with 5-(4-aminophenoxy)-1-naphthylamine. Then, a series of novel aromatic poly(amide-ether-imide)s were prepared by the phosphorylation polycondensation of the synthesized monomer with various aromatic diamines. A model compound was synthesized by the reaction of the monomer with aniline. The resulting polymers with inherent viscosities of 0.43-0.70 dl/g were obtained in high yield. All new compounds including the naphthalene-based monomer, model compound, and the resulted polymers were characterized by FT-IR and NMR spectroscopic methods. The ultraviolet λ_max values of the poly(amide-ether-imide)s were also determined. The resulted polymers exhibited a good solubility in a variety of high polar solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), and pyridine. For some of the polymers obtained the crystallinity behavior was estimated by means of wide-angle X-ray diffraction (WXRD) method, and the resulted polymers exhibited nearly an amorphous nature. Thermal stability of the obtained polymers was determined by thermogravimetric analysis (TGA/DTG), and the 10% weight loss temperatures of the one-step degraded poly(amide-ether-imide)s were found to be in the range between 528 and 551 °C in nitrogen. From differential scanning calorimetric (DSC) analyses, the polymers showed T_gs between 276 and 307 °C. Cyclic voltammetry (CV) measurements of a typical polymer showed that they are also electrochemically stable.     

Synthesis, characterization and properties of naphthoxazine-functional poly(propyleneoxide)s

Thermally curable naphthoxazine-functionalized polymers were synthesized by the reaction of linear (diamines) and branched (triamines) poly(propyleneoxide)s (Jeffamine series) having various molecular weights, with p-formaldehyde, and 2-naphthol. The structures of the resulting polymers were characterized by using FT-IR and ¹H-NMR. In addition, curing behavior of these polymers was studied using differential scanning calorimeter (DSC). Hydrophilicity of these polymers, both in cured and non-cured states, was investigated by water contact angle measurements. The surface topographies of the polymers were also examined by atomic force microscope (AFM).     

Liquid crystalline and photoactive poly[4,4′-stilbeneoxy]alkylbiphenylphosphates

A series of liquid crystalline and photoactive polymers were synthesized from biphenylphosphorodichloridate with various 4,4′-bis(m-hydroxyalkyloxy)stilbenes (m = 2, 4, 6, 8, 10) in chloroform by solution polycondensation method using an acid scavenger. The resultant polymers were characterized by inherent viscosity, FT-IR, ¹H, ¹³C and ³¹P NMR spectroscopies. The liquid crystalline (LC) properties were studied using HOPM and DSC and it was inferred that out of the five polymers synthesized, higher methylene chain containing polymers (m = 6, 8, 10) exhibited LC properties. Thermogravimetric analysis revealed that all the polymers were stable in between 290 and 367 °C and underwent degradation thereafter. The thermal stability and char yield of the polymers decreased with increase in flexible methylene chain. The photochemical properties of these polymers were investigated by UV and fluorescence spectroscopy. Crosslinking proceeds via 2π-2π cycloaddition reaction of the -CHCH- of the stilbene moieties. The rate of crosslinking increases with increase in methylene chain length in the polymer backbone. The fluorescence spectra showed that the longer methylene spacer containing polymers exhibited larger red-shifts than the shorter spacer containing polymers.     

Molten salt ionic liquid-assisted synthesis of nano-structured poly(amide imide)s based on 4,4′-methylenebis(3-chloro-2,6-diethyl trimellit imidobenzene) via microwave process as an environmentally friendly methodology

In this paper, for the first time, 4,4′-methylene-bis(3-chloro-2,6-diethyl trimellit imidobenzene) was prepared by the condensation reaction of 4,4′-methylene-bis(3-chloro-2,6-diethylaniline) and trimellitic anhydride. A series of novel poly(amide imide)s was prepared by the direct polycondensation of the synthesized diimide diacid and various commercial diamines using tetra-n-butylammonium bromide and triphenyl phosphite as a condensing agent under microwave irradiation. Tetra-n-butylammonium bromide acts both as a solvent and a catalyst to mediate clean polymerization reactions to yield the desired polymers. The obtained polymers were characterized with FTIR, ¹H NMR, X-ray diffraction, field emission scanning electron microscopy, elemental and thermogravimetric analysis. The poly(amide imide)s were generally soluble in polar organic solvents, such as N,N′-dimethyl acetamide, N,N′-dimethylformamide, N-methyl-2-pyrrolidone and sulfuric acid at room temperature, and are insoluble in methylene chloride, cyclohexane and water. Morphology probes showed these macromolecules were non-crystalline and nano-structured polymers. The effect of ultrasonic irradiation on the surface morphology of polymers was studied and the results demonstrated that the morphology of macromolecules after ultrasonication became more homogenous than it is before ultrasonic radiation. On the basis of thermogravimetric analysis data, such polymers are thermally stable and can be classified as self-extinguishing polymers.     

Synthesis and in vitro antitumor activity of phthalimide polymers containing podophyllotoxin

Polymer-linked PT (podophyllotoxin) conjugates have been designed to improve the therapeutic efficacy of PT. A new PT-conjugate, 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimido-acetamidoglycinylglycine podophyllotoxin ester (ETPA-gly-gly-PT), was synthesized by covalently coupling its hydroxyl group onto the phthalimido monomer through a glycine-glycine-glycine spacer. Its homo- and copolymer with acrylic acid (AA) were prepared by photopolymerization using 2,2-dimethoxy-2-phenylacetophenone (DMP) as a photoinitiator. ETPA-gly-gly-PT and its polymers were characterized by IR and proton NMR spectra. The ETPA-gly-gly-PT content in the copolymer obtained by elemental analysis was 44 wt%. The number-average molecular weights of the polymers determined by gel permeation chromatography were as follows: M_n = 13,500 for poly(ETPA-gly-gly-PT), M_n = 17,000 for poly(ETPA-gly-gly-PT-co-AA). The in vitro antitumor activity of these conjugates and polymers were determined and used to evaluate the potential applications in antitumor drugs. The IC₅₀ values indicated that the synthesized ETPA-gly-gly-PT and its polymers against cancer cells were much better inhibitors than PT.     

Radiation-induced conductivity control in polyaniline blends/composites

Polyaniline (PANI) blends with chlorine-containing polymers and copolymers and composites with HCl-releasing compounds were prepared to investigate their radiation response in terms of induced conductivities. Blends of non-conductive PANI with poly(vinyl chloride) (PVC), poly(vinylidene chloride-co-vinyl acetate), [P(VDC-co-VAc)], poly(vinylidene chloride-co-vinyl chloride), [P(VDC-co-VC)] were prepared in the form of as-cast films. A number of blends which are different in composition were exposed to gamma radiation and accelerated electrons to various doses, and the effects of irradiation type and composition of polymers on the conductivity of films were investigated by using conductivity measurements and UV–vis and FT-IR spectroscopy. The results clearly showed that ionizing radiation is an effective tool to induce and control conductivity in the blends of PANI-base with chlorine-carrying polymers as well as its composites prepared from HCl-releasing compounds such as chloral hydrate. The main mechanism behind this radiation-induced conductivity is in situ doping of PANI-base with HCl released from partner polymers and low molecular weight compounds by the effect of radiation.     

Synthesis and characterization of some carbazole-based imine polymers

Five imine polymers, all containing 3,6-disubstituted carbazole ring in the main polymer chain, were synthesized by solution polycondensation of 3,6-diformyl (N-hexyl) carbazole with hydrazine, 1,4-diaminobenzene, 4,4′-diaminobiphenyl, 1,5-diaminonaphthalene and 3,6-(N-hexyl) diaminocarbazole. The polymers were analyzed by spectroscopic methods and compared with two imine models.     

A comparative study of interaction of ibuprofen with biocompatible polymers

In this paper we are reporting the interaction of a non-steroidal anti-inflammatory drug ibuprofen (IBF) with various biocompatible polymers. Being amphiphilic, the drug interacts with the polymers similar to the interaction of surfactants and polymers. Therefore, we have considered the polymer-amphiphile interaction approach using conductimetry. The polymers of different charges (cationic, anionic, and nonionic) have been taken for the study. It was found that the critical aggregation concentration (cac) decreases on increasing the polymer concentrations of cationic as well as nonionic polymers whereas it increases for anionic polymers. The results imply that anionic IBF interacts with cationic and nonionic polymers more strongly as compared to the anionic polymers. A possible anionic-anionic repulsion is responsible for the weak interaction of IBF with anionic polymers. On the other side, the critical micelle concentration (cmc) increases for all polymers which is a usual indication of the interaction between amphiphiles and polymers. Free energies of aggregation (ΔG_agg) and micellization (ΔG_mic) were also computed with the help of degrees of micelle ionization obtained from the specific conductivity - [IBF] isotherms.     

Structure-property relationships for novel wholly aromatic polyamide-hydrazides containing various proportions of para-phenylene and meta-phenylene units: I. Synthesis and characterization

A series of novel wholly aromatic polyamide-hydrazides was synthesized by a low temperature solution polycondensation reaction of either 4-amino-3-hydroxybenzhydrazide or 3-amino-4-hydroxybenzhydrazide with an equimolar amount of either terephthaloyl chloride (TCl), isophthaloyl chloride (ICl), or mixtures of various molar ratios of TCl and ICl in anhydrous N,N-dimethylacetamide (DMAc) as a solvent. Polymer structures were identified by elemental analysis and infrared spectroscopy. All the polymers have the same structural formula except the way of linking phenylene units inside the polymer chain. The content of para- and meta-phenylene moieties was varied within this series so that the changes in the latter were 10 mol % from polymer to polymer, starting from an overall content of 0-100 mol %. The prepared polymers were characterized for their properties in order to acquire clear understanding of the influence exerted by controlled structural variations in these polymers upon some of important properties, such as solubility, intrinsic viscosity, moisture regain, mechanical properties and thermal as well as thermo-oxidative stability. The polymers were readily soluble in several organic polar solvents such as DMAc, N,N-dimethylformamide, dimethyl sulphoxide, N-methyl-2-pyrrolidone and hexamethyl phosphoramide and could be cast into flexible films. Their solubilities were found to increase remarkably with introduction of meta-phenylene moieties into the polymer chains. Their intrinsic viscosities ranged from 0.73 to 4.83 dl g⁻¹ in DMAc at 30 °C and increased with the increase of para-phenylene units content. Mechanical properties of the films produced from these polymers are improved markedly by substitution of para-phenylene units for meta-phenylene units. Thermogravimetric studies revealed that the completely para-oriented type of polymer has better thermal and thermo-oxidative stability relative to that of the other polymers. Moreover, the results reveal that the prepared polymers have a great affinity to water sorption. The hydrophilic character increases as a function of meta-oriented phenylene rings incorporated into the polymer chains.     

Synthesis and characterization of thermally stable poly-N, N′-arylenebismaleimide

Three N,N′-arylenebismaleimides, viz. N,N′-m-phenylenebismaleimide, N,N′-p-phenylenebismaleimide and N,N′-benzidinebismaleimide, were prepared and polymerized in toluene using benzoyl peroxide (BPO) as initiator. The polymers obtained were characterized on the basis of elemental analysis and IR spectra. The polymers are insoluble in common organic solvents. The thermal behaviour of these polymers was studied by DTA and TG methods and the kinetic parameters order of reaction and activation energy were estimated.     

Synthesis and characterization of polystyrene-b-tetraaniline stars from polystyrene stars with surface reactive groups prepared by RAFT polymerization

Functionalized star polymers with tetraaniline on their surface have been successfully prepared by substitution reaction of N-succinimidyl-terminated star polymers with tetraaniline. A novel functional RAFT agent bearing N-succinimidyl group was used in the RAFT polymerization of styrene, and N-succinimidyl groups-terminated polystyrenes with narrow molecular weight distribution were obtained. The star polymers with reactive N-succinimidyl groups on their surface were synthesized via RAFT polymerization of DVB. Polymerization mechanism study by gel permeation chromatography displayed that complete disappearance of linear polymers in the products is difficult. The N-succinimidyl-terminated PSt, polymer stars with surface N-succinimidyl groups and the PSt-b-tetraaniline stars were characterized by ¹H NMR spectroscopy, FT-IR and GPC.     

Isothermal crystallization kinetics of poly(ethylene terephthalate)s of different molecular weights

The isothermal crystallization kinetics and morphology of poly(ethylene terephthalate) (PET) polymers of different molecular weights have been studied by means of differential scanning calorimetry and transmission microscopy (TM). The kinetic parameters of Avrami exponent n, the rate constant k, half time t _1/2, rate at 50 % crystallinity, τ _1/2 for crystallization of different PETs were evaluated from double logarithmic plots of log {?ln[1 ? X(t)]} versus log t, where X(t) is extent of crystallinity at a given crystallization temperature. The crystallization rate of polymers with high molecular weight found to be lower than that of polymers with low molecular weight, at the same crystallization temperature. It was found that the nucleation mechanism and growth dimension of polymers with low molecular weight are different from those of polymers with high molecular weight. The results of TM and isothermal crystallization kinetics showed a consistent trend for the crystallization of all PET polymers studied, comprising a primary stage and a secondary stage. The activation energy in the PET polymers of low molecular weight was found to be lower than that of polymers with high molecular weight.     

Herstellung und polymerisation isomerer p-methylnaphthylstyrole

Two different pathways were used to synthesize p-(α-and p-(β-methylnaphthyl)styrene; polymerizations by radical as well as anionic initiation were investigated. With sodium metal in THF solution, the polymers yield the stoichiometric charge transfer complexes. These reactions proceed with crosslinking of the polymers even under extremely dry conditions.     

Novel self-dyed wholly aromatic polyamide–hydrazides covalently bonded with azo groups in their main chains

Thermal characteristics of several novel self-dyed wholly aromatic polyamide–hydrazides covalently bonded with azo groups in their main chains and containing o-hydroxy group as a substituent group in the aryl ring of the aminohydrazide part of the polymers have been investigated in nitrogen and in air atmospheres using differential scanning calorimetry, thermogravimetric analyses, infrared spectroscopy, and elemental analyses. The effect of introducing different predetermined proportions of para- and meta-phenylene moieties into the backbone chain of the polymers on their thermal characteristics has been evaluated. Azopolymers having different molecular masses of all para-oriented phenylene type units were also thermally characterized. These polymers were prepared by a low temperature solution polycondensation reaction of either 4-amino-3-hydroxybenzhydrazide or 3-amino-4-hydroxybenzhydrazide with an equimolar amount of either 4,4′-azodibenzoyl chloride (4,4′ADBC), 3,3′-azodibenzoyl chloride (3,3′ADBC), or mixtures of various molar ratios of 4,4′ADBC and 3,3′ADBC in anhydrous N,N-dimethyl acetamide containing 3 % m v^?1 LiCl as a solvent at ?10 °C. All the polymers have the same structural formula except the mode of linking phenylene units in the polymer chain. The content of para- and meta-phenylene moieties was varied within these polymers so that the changes in the latter were 10 mol% from polymer to polymer, starting from an overall content of 0–100 mol%. The results reveal that these polymers are characterized by high thermal stability and could be cyclodehydrated into linear aromatic polymers with alternating 1,3,4-oxadiazole and benzoxazole structural units within the same polymer approximately in the region of 200–480 °C, either in nitrogen or in air atmospheres by losing water from the hydrazide and o-hydroxybenzamide groups, respectively. Along with the cyclodehydration, the polymer may lose molecular nitrogen from the azo groups. This is not a true degradation, but rather a thermo-chemical transformation reaction of the evaluated polymers into the corresponding poly(1,3,4-oxadiazolyl-benzoxazoles). The resulting poly(1,3,4-oxadiazolyl-benzoxazoles) start to decompose in the temperature range above 330–560 °C, either in nitrogen or in air atmospheres without mass loss at a lower temperature. The thermal and thermo-oxidative stabilities of the polymers are affected by the nature and amount of arylene groups incorporated into their chains, being higher for polymers with greater content of para-oriented phenylene rings, which permits more interchain hydrogen bonds as a result of greater chain symmetry, packing efficiency, and rod-like structure. Increasing the content of para-oriented phenylene rings leads to a strong improvement in both the initial decomposition temperature as well as in the residual mass at a particular temperature. The stability of the polymers was found to be independent of their molecular masses. This confirms that high thermal stability is not a polymer property which would depends upon the length of its macromolecular chains, but rather upon its chemical structure in which all and every atomic group contributes by its own thermal stability to the macroscopic properties of the whole polymer.     

Chemical oxidative polymerization of m-phenylenediamine and its derivatives using aluminium triflate as a co-catalyst

Aromatic diamine monomers, including m-phenylenediamine (mPD), 2-methyl-m-phenylenediamine (2Me-mPD), 4-methyl-m-phenylenediamine (4Me-mPD) and trimethyl-m-phenylenediamine (tMe-mPD), were polymerized by chemical oxidation using ammonium persulfate as an oxidant. Aluminium triflate (Al(OTf)₃) was also used for the first time as a co-catalyst under various polymerization conditions. The polymerization yield was improved when Al(OTf)₃ was introduced to the polymerization reaction for most polymers. The poly(2-methyl-m-phenylenediamine) (P(2Me-mPD)), poly(4-methyl-m-phenylenediamine) (P(4Me-mPD)) and poly(trimethyl-m-phenylenediamine) (P(tMe-mPD)) polymers exhibited better solubility than poly(m-phenylenediamine) (P(mPD)) polymers in most common solvents. The homopolymers obtained were characterized by FT-IR, ¹H and ¹³C NMR, WAXD and TGA. The results showed that the yield, solubility and structure of the polymers are significantly dependent on the polymerization conditions. TGA measurements indicated that the polymers have good thermal stability and decompose above 400 °C in nitrogen.     

Preparation of phosphorus-containing polymers—XV. Preparation of phosphorus-containing polyamide-imides from N,N′-bis(4-carboxyphthalimido)-3,3′-diphenylalkylphosphine oxide and aromatic diacetamides

Phosphorus-containing polyamide-imides were prepared from N,N′-bis(4-carboxyphthalimido)-3,3′-diphenylalkylphosphine oxide and aromatic diacetamido derivatives by acidolysis; the reaction conditions are discussed. The resulting polymers were fairly soluble in DMA, DMF and conc. H₂SO₄; the reduced viscosities of polymers in DMA or cone. H₂SO₄ (0.2 g/dl) at 30° were 0.19–0.32. The phosphorus-containing polymers have good thermal stability, and are self-extinguished immediately after the flame is removed. Most of the i.r. absorption bands of polymers vanished on heating at above 600°.     

Synthesis and characterization of new ointment-like poly(ortho esters)

Ointment-like poly(ortho esters) were synthesized for the first time from the reaction of 3,9-bis(methylene)-2,4,8,10-tetraoxaspiro[5. 5] undecane with poly(ethylene glycol)-400, N,N-bis(2-hydroxyethyl)-n-hexadecylamine and N,N-bis(2-hydroxyethyl) palmitamide, respectively. The obtained polymers were characterized by 1H NMR spectra, 13C NMR spectra, elemental analyses, light scattering, and measurements of intrinsic viscosity. The influence of catalyst on the intrinsic viscosity of polymers was investigated. The 9-[(1,3-dihydroxy-2-propoxy) methyl] guanine controlled release profiles of hydrophobic ointment-like polymers such as polymer P_II in vitro were also discussed.     

Synthesis and characterization of water-soluble PEGylated lignin-based polymers by macromolecular azo coupling reaction

Water-soluble PEGylated lignin polymers were efficiently synthesized by macromolecular azo coupling reaction between alkali lignin and PEG based macromolecular diazonium salts in alkaline water.