Nicoleta Plesu

Solvent and catalyst-free synthesis of polyphosphates

Direct, efficient, solvent and catalyst-free synthesis of a series of polyphosphates was accomplished. The reaction involved a gas–liquid interfacial polycondensation between alkyl(aryl)phosphoric dichlorides and aromatic diols. The polyphosphates were characterized by IR, 1H NMR, inherent viscosity, thermal analysis, X-ray diffractions and molar mass. Yields in the range 75–90% and inherent viscosities in the range 0.24–0.45 dl g−1 were obtained. Polyphosphates were stable up to 170–250 °C, depending on phosphoric dichloride type. The X-ray diffraction patterns revealed that almost all the polymers were amorphous.

Synthesis of new phosphorus-containing (co)polyesters using solid-liquid phase transfer catalysis and product characterization.

This paper is directed towards the development of safe, and thermally stable solid polymer electrolytes. Linear phosphorus-containing (co)polyesters are described, including their synthesis, thermal analysis, conductivity, and non-flammability. Polycondensation of phenylphosphonic dichloride (PPD) with poly(ethylene glycol) (PEG 12000) with and without bisphenol A (BA) was carried out using solid-liquid phase transfer catalysis. Potassium phosphate is used as base. Yields in the range of 85.0–88.0%, and inherent viscosities in the range of 0.32–0.58 dL/g were obtained. The polymers were characterized by gel permeation chromatography, FT-IR, 1H- and 31P-NMR spectroscopy and thermal analysis. Their flammability was investigated by measuring limiting oxygen index values. The polymers are flame retardants and begin to lose weight in the 190 °C–231 °C range. Solid phosphorus- containing (co)polyesters were complexed with lithium triflate and the resulting ionic conductivity was determined. Conductivities in the range of 10−7–10−8 S cm−1 were obtained.

Polymers containing phosphorus groups and polyethers: from synthesis to application

BackgroundPhosphorus-containing high performance polymers have aroused wide interest, mainly due to good mechanical properties and their excellent fire resistance. The flexibility of synthetic polyphosphoesters allows the development of polymers in order to obtain solid polymer electrolytes for rechargeable lithium batteries based on solid films with superior fire resistance.ResultsNovel linear Phosphonate-PEG polymers were synthesized by solution polycondensation of 4-chlorophenyldichlorophosphonate as a linking agent and poly(ethylene glycol)s with different molecular weights in the presence of triethylamine or 1-methylimidazole as acid scavenger. The yields were between 54% and 88% and inherent viscosity between 0.18-0.48 dl/g. Molar masses, Mn were about 26300 g/mol for polyphosphonates with PEG 2000 and 4600 g/mol for polyphosphonates with PEG 200. The LOI values for these polymers and membranes are in the range of 26–29. The membranes based on polyphosphonate with PEG 200 and 2000 showed conductivity between 6 × 10-8 S.cm-1 and 6 × 10-7 S.cm-1 at room temperature and total ionic transference number between 0.87- 0.96. The evolution of conductivity vs. temperature is linear.Conclusions1-methylimidazole was found to be better HCl scavenger than triethylamine, and allowed higher yields and more eco-friendly synthesis of the Phosphonate-PEG polymers for SPE. These polymers and membranes based on these polymers showed good LOI values and indicate an improvement of the safety of lithium batteries. The membranes present conductivities around 6 × 10-7 S.cm-1at room temperature and total ionic transference number is higher for membranes based on polymers with high EG unit content. Best results yield 88%, inherent viscosities 0.48 dl/g and Mn 26000 were obtained with 1-methylimidazole and PEG 2000. These membranes based on these polymers showed good LOI values (in the range 26-29%) and indicate an improvement of the safety of lithium batteries.

Organic solvent-free synthesis of phosphorus- containing polymers*

Direct, efficient, organic solvent- and catalyst-free synthesis of a series of polyphosphates was accomplished. The reaction involved a gas-liquid interfacial polycondensation between arylphosphoric dichlorides and bisphenol A. The polyphosphates were characterized by IR, 1H NMR, 31P NMR, inherent viscosity, thermal analysis, and molar mass. Yields in the range 70-90 % and inherent viscosities in the range 0.30-0.40 dl/g were obtained. The thermal stability of the polyphosphates was investigated by using thermogravimetry.

Polyaniline composite designed for solid polymer electrolyte

Abstract Improved ionic conductivity of solid polymer electrolytes (SPE) was achieved by adding polyaniline (PANI) in membrane formulation. SPE composite membranes contain: tris(4-hidroxybutylacrylate)-phosphate, polyphosphoester, lithium salts and small amount of PANI. The conductivity of membranes increases with PANI content and above a certain amount it decreases. The variation of the conductivity vs temperature is linear, characteristic for a thermally activated process. The activation energy for polymer matrix without PANI is 0.30 eV and 0.26 eV for polymer matrix with PANI. Conductivity enhancement in the composite polymer matrix is caused by the presence of PANI due to the increase in the concentration of free ions. PANI decreases the salt aggregation and as a consequence, the concentration of free ions was increased by improving dispersion of the lithium salt in membranes.

Electrochemical Polymerisation of Aniline on Skeleton Nickel Electrodes

The polyaniline(PAni)coating was electrochemically deposited on nickel skeleton electrode and nickel foil by potential sweep between − 0.2 V and 1.2 V/SCE, with a scan rate of 20 mV s−1; acid aqueous solutions containing 0.027 mol L−1aniline in 1 mol L−1sulphuric acid were used. The PAni film was studied by IR Spectroscopy, UV-VIS Absorption, Scanning Electron Microscopy, X-Ray Diffraction and Cyclic Voltammetry. The X-Ray studies suggest that the PAni films present a good cristalinity, as well as high molecular weight, possible high or intermediate crosslinked.

Chemical Modification of Functionalized Copolymers with Phosphonium Groups by Phase Transfer Catalysed Wittig Reactions

The interest for using polymers in Wittig reactions increased in the last years, because of their major advantages. Phase transfer catalyzed reactions are often more easily and cheaply carried out than conventional methods and they are therefore of particular interest. The phosphonium salts grafted on styrene-7%(5%)divinylbenzene copolymers used in this paper were obtained by quaternization polymer-analogous reaction. The degree of functionalization with quaternary phosphonium groups are relatively high, ranging from 1.84 to 1.98 mmoles/g of polymer. These grafted copolymers were used in liquid-liquid-solid Phase Transfer Catalysis(PTC)Wittig reaction. The yields were ranging from 1.84 to 1.98 mmoles of double bonds/gram of polymer.

Synthesis of Polyphosphates Related to Biopolymers

Polyphosphates were synthesized by base promoted liquid-vapor polycondensation of cyclohexylphosphoric dichloride with bisphenol A. The effects of temperature, reaction time, base concentration and molar ratio of reagents on yield, inherent viscosity and molecular weight of the obtained polymer were studied. A second order, central composite, rotatable experimental design was used to find domain experimental field for optimal yields and high inherent viscosities.

Interfacial polycondensation method used in the synthesis of polymers containing phosphorus in the main chain

Abstract Polyphosphoesters gained importance especially due to their use as flame retardants and as biocompatible and biodegradable materials for medicine and in the pharmaceutical industry. This paper presents the results obtained by our research group in the synthesis of polyphosphoesters by interfacial polycondensation. This reaction is rapid and irreversible polymerization at the interface between a phase containing one difunctional intermediate and another phase containing a complementary difunctional reactant. Different methods like liquid–liquid, vapor–liquid or solid<uni-2013;liquid were used in the synthesis of polyphosphates of polyphosphonates using aliphatic/aromatic phosphoric/phosphonic dichlorides and different diols. Aqueous NaOH, or tripotasium phosphate were used as bases. In almost all cases a catalyst is not needed.

Properties in aqueous solution of homo- and copolymers of vinylphosphonic acid derivatives obtained by UV-curing

Vinylphosphonic acid is homopolymerized with dimethylvinylphosphonate by radical polymerization using using UV light and photoinitiator Darocur 4265 (3 wt%). The molar ratio between vinylphosphonic acid and dimethylvinylphosphonate is varied between 1:1 and 4:1, respectively. The obtained homopolymer of vinylphosphonic acid and copolymers are characterized by Fourier transform infrared spectroscopy (FTIR), thermal analysis and size exclusion chromatography - multi angle laser light scattering. The polymerization by UV light is efficient and an average molar mass of 34,200 g/mol is obtained for poly(vinylphosphonic acid) and in the range from 12,700 to 19,120 g/mol for copolymers, which also have a good thermal stability until 320 °C. The polymers structure allows the formation of random coil conformation. The copolymers are tested as inhibitors against corrosion of iron in NaCl aqueous solution, and, as a result, it was shown that these copolymers exhibit promising anticorrosion properties.