Synthesis and characterization of linear asymmetrical poly(propylene oxide) diol

Linear asymmetrical poly(propylene oxide) was synthesized through four‐step reactions: selective benzylation, alcohol exchange reaction, propylene oxide anionic polymerization, debenzylation. One terminal of the asymmetrical polymer chains is alcohol hydroxyl and the other is phenol hydroxyl. It was characterized with infrared (IR) and ¹H Nuclear Magnetic Resonance (¹H‐NMR). Peaks at 1.11, 3.38, and 3.53 ppm were attributed to side groups (? OCH₂CH(CH₃)? ), backbone units (? OCH₂CH(CH₃)? ) and (? OCH₂CH(CH₃)? ) of poly(propylene oxide), respectively. Molecular weight and molecular weight distribution were measured with ¹H‐NMR and laser light scattering (LLS), which showed that the linear asymmetrical poly(propylene oxide) was mono‐disperse (PDI = 1.02–1.07). Then, its carbamate reaction with phenyl isocyanate was studied; the reaction rate constants for phenol hydroxyl and alcohol hydroxyl of poly(propylene oxide) were k₁ = 0.209 mol L^?1 min^?1 and k₂ = 0.051 mol L^?1 min^?1. There was a great reactivity difference for two types of hydroxyls in asymmetrical poly(propylene oxide), contrasting to the single carbamate reaction rate constant of symmetrical poly(propylene oxide) (k₃ = 0.049 mol L^?1 min^?1). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Linear segmented polyurethanes. III. Mathematical model for a two-steps polymerization

In the first article of this sequel (J. Appl. Polym. Sci., 2018, 135, 45747), an experimental and theoretical investigation was developed on the two-steps synthesis of linear segmented thermoplastic polyurethanes. The reactions were carried out at 60°C, with methylene diphenyl diisocyanate (MDI), two poly(tetramethylene oxide) macrodiols, and 1,4-butanediol (BD) as chain extender. In our second article (J. Appl. Polym. Sci., 2019, 136, 46946), a mathematical model for the prepolymerization was developed, that involved integrating a differential equation for each generated polymer species. The present article extends such model, and predicts the molecular structure along the finishing stage. In each stage, the new model first solves the molar balances at polymer topologies level (i.e.,: Disregarding the molar mass distribution [MMD] of the reacted macrodiol chains), and then calculates the MMD of the evolving polymer and its main subsets through an algebraic convolution procedure. The model reproduces the prepolymerization predictions of our previous article, but is three orders of magnitude faster. In the finishing stage, up to 156,000 polymer topologies and 4.53 × 10⁸ polymer species were calculated; and the rate constant was readjusted to (k₂ = 0.00129 L mol⁻¹ s⁻¹), in order to fit the measured MMDs.     

Comments on the reactivity of methoxy pentadecyl phenyl isocyanate isomers

The reactions of 2-methoxy-4-pentadecyl phenyl isocyanate and 4-methoxy-2-pentadecyl phenyl isocyanate with excess 2-ethyl hexanol originally reported by Ghatge and co-workers to follow zero order kinetics have been re-examined on the basis of their data and shown to follow more realistically the product catalyzed pseudo first order kinetics. The new rate constant, k_s (sec^?1) for the spontaneous reaction and k_p (li. mole^?1 sec^?1) for the product catalyzed reaction are found to be: k_s = 0.57 × 10^?6 and k_p = 34 × 10^?6 for 2-methoxy-4-pentadecyl phenyl isocyanate and k_s = 1.2 × 10^?6 and k_p = 82 × 10^?6 for 4-methoxy-2-pentadecyl phenyl isocyanate.     

NMR studies of water‐borne polyurethanes

A series of water‐borne polyurethanes were prepared by prepolymerization process. Isophorone diisocyanate, polyester diol, and dimethylol propionic acid were used to conduct the reaction. ¹H‐ and ¹³C‐NMR spectra of the raw materials and products thereof were measured with a high‐resolution spectrometer, and their chemical shifts were assigned. ¹H‐ and ¹³C‐NMR spectra of urethane group and urea group were compared. The chemical shifts of side products from the reaction between water and the isocyanate group were also analyzed. Much useful information may be obtained from the NMR analysis of this kind of polyurethanes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 257–260, 2003     

High yield synthesis of diverse well‐defined end‐functionalized polymers by combination of anionic polymerization and “click” chemistry

Well‐defined poly(methyl methacrylate) (M_n = 3630 g mol^?1, PDI = 1.06) with a primary benzylic bromide prepared using anionic polymerization was successfully transformed into diverse end‐functionalities (ω‐carboxyl, ω‐hydroxy, ω‐methyl‐vinyl, ω‐trimethylsilane, and ω‐glycidyl‐ether) via “click” reaction. The bromine end‐terminated poly(methyl methacrylate) was first substituted by an azide function and sequentially was reacted with various functional alkynes (propiolic acid, propargyl alcohol, 2‐methyl‐1‐buten‐3‐yne, propargyl trimethylsilane, and propargyl glycidylether). In all the cases, ¹H‐NMR, ¹³C NMR, FT‐IR, and GPC measurements show qualitative and quantitative transformation of the chain‐end poly(methyl methacrylate) into the desired functionalities with high conversion (above 99%). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of novel urethane‐siloxane copolymers with a high content of PCL‐PDMS‐PCL segments

Novel polyurethane copolymers derived from 4,4′‐methylenediphenyl diisocyanate (MDI), 1,4‐butanediol (BD) and α,ω‐dihydroxy‐[poly(caprolactone)‐poly (dimethylsiloxane)‐poly(caprolactone)] (α,ω‐dihydroxy‐(PCL‐PDMS‐PCL); = 6100 g mol^?1) were synthesized by a two‐step polyaddition reaction in solution. In the synthesis of the polyurethanes, the PCL blocks served as a compatibilizer between the nonpolar PDMS blocks and the polar comonomers, MDI and BD. The synthesis of thermoplastic polyurethanes (TPU) with high soft segment contents was optimized in terms of the concentrations of the reactants, the molar ratio of the NCO/OH groups, and the time and temperature of the polyaddition reaction. The structure, composition, and hard MDI/BD segment length of the synthesized polyurethane copolymers were determined by ¹H, ¹³C‐NMR, and two‐dimensional correlation (COSY, HSQC, and HMBC) spectroscopy, while the hydrogen bonding interactions in the copolymers were analyzed by FT‐IR spectroscopy. The influence of the reaction conditions on the structure, molecular weight, thermal, and some physical properties was studied at constant composition of the reaction mixture. A change in the molar ratio of the NCO/OH groups and the reaction conditions modified not only the molecular weight of the synthesized polyurethanes, but also the microstructure and therefore the thermal and physical properties of the copolymers. It was demonstrated that only PCL segments with high soft segment contents crystallize, thereby showing spherulitic morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Reaction kinetics of polyureas with acetylated diamine chain extenders

Diacetyl hexamethylene‐diamine (MHAD) and diacetyl m‐phenylenediamine (Mm‐PDA) were synthesized by acetylating hexamethyene‐diamin (HAD) and m‐phenylenediamine (m‐PDA) with glacial acetic acid in presence of phosphoric acid, in order to retard the high reactivity of polyurea. Chemical structures of modified diamine chain extenders were confirmed through FTIR, the determination of the nitrogen content, High resolution ESI‐Fourier transform ion cyclotron resonance (ESI‐FTICR) mass spectrometry and ¹H‐NMR analysis. Polyureas were synthesized via two‐step solution process by reaction of 4,4′‐diphenyl diisocyanate (MDI), amine terminated polyether (Jeffamine D‐2000) with different chain extenders. The influence of modified diamine chain extenders on gel time of polyurea was investigated. The gel time was prolonged from 11s to 52s and 13s to 65s respectively. The reaction kinetics of synthesizing polyureas were studied by FTIR. The results showed that extending reaction with MHAD was second order kinetic mechanism, its apparent activation energy was 43.99 kJ·mol^?1; extending reaction with Mm‐PDA reaction was first order, its activation energy was 58.95 kJ·mol^?1. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Heavy Metal Removal and Neutralization of Acid Mine Waste Water ‐ Kinetic Study

The influence of the apatite on the efficiency of neutralization and on heavy metal removal of acid mine waste water has been studied. The analysis of the treated waste water samples with apatite has shown an advanced purification, the concentration of the heavy metals after the treatment of the waste water with apatite being 25 to 1000 times less than the Maximum Concentration Limits admitted by European Norms (NTPA 001/2005). In order to establish the macro‐kinetic mechanism in the neutralization process, the activation energy, Ea, and the kinetic parameters, rate coefficient of reaction, k_r, and k_t were determined from the experimental results obtained in “ceramic ball‐mill” reactor. The obtained values of the activation energy Ea >> 42 kJ mol^?1 (e.g. Ea = 115.50 ± 7.50 kJ mol^?1 for a conversion of sulphuric acid η_H2SO4 = 0.05, Ea = 60.90 ± 9.50 kJ mol^?1 for η ^H2SO4 = 0.10 and Ea = 55.75 ± 10.45 kJ mol^‐1 for η ^H2SO4 = 0.15) suggest that up to a conversion of H2SO4 equal 0.15 the global process is controlled by the transformation process, adsorption followed by reaction, which means surface‐controlled reactions. At a conversion of sulphuric acid η ^H2SO4 > 0.15, the obtained values of activation energy Ea < 42 kJ mol^‐1 (e.g. Ea = 37.55 ± 4.05 kJ mol^‐1 for η ^H2SO4 = 0.2, Ea = 37.54 ± 2.54 kJ mol^‐1 for η ^H2SO4 = 0.3 and Ea = 37.44 ± 2.90 kJ mol^‐1 for η ^H2SO4 = 0.4) indicate diffusion‐controlled processes. This means a combined process model, which involves the transfer in the liquid phase followed by the chemical reaction at the surface of the solid. Kinetic parameters as rate coefficient of reaction, kr with values ranging from (5.02 ± 1.62) 10‐4 to (8.00 ± 1.55) 10‐4 (s^‐1) and transfer coefficient, kt, ranging from (8.40 ± 0.50) 10‐5 to (10.42 ± 0.65) 10‐5 (m s^‐1) were determined.     

Synthesis and biological activity of medium range molecular weight polymers containing exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidocaproic acid

A new monomer, exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidocaproic acid (ETCA), was prepared by reaction of maleimidocaproic acid and furan. The homopolymer of ETCA and its copolymers with acrylic acid (AA) or with vinyl acetate (VAc) were obtained by photopolymerizations using 2,2‐dimethoxy‐2‐phenylacetophenone as an initiator at 25 °C. The synthesized ETCA and its polymers were identified by FTIR, ¹H NMR and ¹³C NMR spectroscopies. The apparent average molecular weights and polydispersity indices determined by gel permeation chromatography (GPC) were as follows: M_n = 9600 g mol^?1, M_w = 9800 g mol^?1, M_w/M_n = 1.1 for poly(ETCA); M_n = 14 300 g mol^?1, M_w = 16 200 g mol^?1, M_w/M_n = 1.2 for poly(ETCA‐co‐AA); M_n = 17 900 g mol^?1, M_w = 18 300 g mol^?1, M_w/M_n = 1.1 for poly(ETCA‐co‐VAc). The in vitro cytotoxicity of the synthesized compounds against mouse mammary carcinoma and human histiocytic lymphoma cancer cell lines decreased in the following order: 5‐fluorouracil (5‐FU) ≥ ETCA > polymers. The in vivo antitumour activity of the polymers against Balb/C mice bearing sarcoma 180 tumour cells was greater than that of 5‐FU at all doses tested. © 2001 Society of Chemical Industry     

Kinetics of ylide-initiated radical copolymerization of 4-vinylpyridine and methyl methacrylate

The ylide-initiated radical copolymerization of 4-vinylpyridine (4-VP) with methyl methacrylate (MMA) at 60°C using carbon tetrachloride as inert solvent yields non-alternating copolymers. The kinetic parameters, average rate of polymerization (R_p) and orders of reaction with respect to monomers and initiator, have been evaluated and the kinetic equation is found to be R_pα[ylide]^0.94 [MMA]^1.0 [4-VP]^1.5. The values of the energy of activation and k_p²/k_t are 48 kJ mol^?1 and 6.6 × 10^?5 litre mol^?1s^?1, respectively. The copolymers have been characterized by IR and NMR spectroscopy.     

Synthesis,characterization, conductivity,band gap,and kinetic of thermal degradation of poly‐4‐[(2‐mercaptophenyl) imino methyl] phenol

The oxidative polycondensation reaction conditions of 4‐[(2‐mercaptophenyl) imino methyl] phenol (2‐MPIMP) were studied in an aqueous acidic medium between 40 and 90°C by using oxidants such as air, H₂O₂, and NaOCl. The structures of the synthesized monomer and polymer were confirmed by FTIR, ¹H NMR, ¹³C NMR, and elemental analysis. The characterization was made by TGA‐DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly‐4‐[(2‐mercaptophenyl) imino methyl]phenol (P‐2‐MPIMP) was found to be 92% for NaOCl oxidant, 84% for H₂O₂ oxidant 54% for air oxidant. According to the SEC analysis, the number‐average molecular weight (M_n), weight‐average molecular weight (M_w), and polydispersity index values of P‐2‐MPIMP were found to be 1700 g mol^?1, 1900 g mol^?1, and 1.118, using H₂O₂; 3100 g mol^?1, 3400 g mol^?1, and 1.097, using air; and 6750 g mol^?1, 6900 g mol^?1, and 1.022, using NaOCl, respectively. According to TG analysis, the weight losses of 2‐MPIMP and P‐2‐MPIMP were found to be 95.93% and 76.41% at 1000°C, respectively. P‐2‐MPIMP showed higher stability against thermal decomposition. Also, electrical conductivity of the P‐2‐MPIMP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, and the electrochemical energy gaps (E′_g) of 2‐MPIMP and P‐2‐MPIMP were found to be ?6.13, ?6.09; ?2.65, ?2.67; and 3.48, 3.42 eV, respectively. Kinetic and thermodynamic parameters of these compounds investigated by MacCallum‐Tanner and van Krevelen methods. The values of the apparent activation energies of thermal decomposition (E_a), the reaction order (n), pre‐exponential factor (A), the entropy change (ΔS*), enthalpy change (ΔH*), and free energy change (ΔG*) were calculated from the TGA curves of compounds. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Electropolymerization of o‐phenylenediamine on Pt‐electrode from aqueous acidic solution: Kinetic,mechanism, electrochemical studies and characterization of the polymer obtained

Electropolymerization of O‐phenylenediamine (o‐PD) on Pt‐electrode from a deoxygenated aqueous acid medium was carried out using cyclic voltammetry technique. The kinetic parameters were calculated by means of electrochemical data. The experimentally obtained kinetic equation was R_P,_E = k_E [monomer]^1.19 [acid]^1.23 [electrolyte]^0.87 from the value of the anodic current density using cyclic voltammetry technique. The apparent activation energy (E_a) is found to be 28.34 kJ mol^?1. The polymer films obtained have been characterized by X‐ray diffraction, elemental analysis, scanning electron microscopy, ¹H‐NMR, ¹³C‐NMR, UV‐visible, and IR spectroscopy. The mechanism of the electrochemical polymerization reaction has been discussed. TGA is used to confirm the proposed structure and determination of the number of water molecules in the polymeric chain unit. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Development of Functional Polyurethane–ZnO Hybrid Nanocomposite Coatings from Thevetia peruviana Seed Oil

The present article reports eco‐friendly multi‐functional polyurethane–ZnO hybrid nanocomposite coatings obtained from Thevetia peruviana seed oil (TPSO). Initially, the polyols were prepared by treating TPSO with glycerol and the formation was supported by Fourier transform infrared (FT‐IR) and ¹H‐NMR studies. In the next stage, siloxane functionalized ZnO nanoparticles were added to the polyol mixture in different weight percentages (0, 1 and 2 %) and then treated with excess 4,4′‐diisocyanatodicyclohexylmethane (H₁₂MDI) in order to synthesize isocyanate terminated polyurethane nanocomposites. The polyurethane hybrids were then casted as thin films and cured under atmospheric moisture. After complete curing they were characterized by using FT‐IR, ¹H‐NMR, ¹³C‐NMR, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and dynamic mechanical thermal analysis techniques. The hybrid nanocomposites showed superior thermo‐mechanical and anti‐corrosive properties compared to pristine polyurethane. Also, due to the presence of nano ZnO in the polyurethane matrix, the composite coatings are showing excellent resistance towards various bacterial and fungal stains.     

Synthesis,characterization, thermal stability,conductivity, and band gap of a new aromatic polyether containing an azomethine as a side

In this study, the oxidative polycondensation reaction conditions of 4‐[(4‐methylphenyl)iminomethyl]phenol (4‐MPIMP) were studied by using oxidants such as air O₂, H₂O₂, and NaOCl in an aqueous alkaline medium between 50 and 90°C. The structures of the synthesized monomer and polymer were confirmed by FTIR, UV–vis, ¹H–¹³C‐NMR, and elemental analysis. The characterization was made by TGA‐DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of poly‐4‐[(4‐methylphenyl)iminomethyl]phenol (P‐4‐MPIMP) was found to be 28% for air O₂ oxidant, 42% for H₂O₂ oxidant, and 62% for NaOCl oxidant. According to the SEC analysis, the number–average molecular weight (M_n), weight–average molecular weight (M_w), and polydispersity index values of P‐4‐MPIMP were found to be 4400 g mol^?1, 5100 g mol^?1, and 1.159, using H₂O₂, and 4650 g mol^?1, 5200 g mol^?1, and 1.118, using air O₂, and 5100 g mol^?1, 5900 g mol^?1, and 1.157, using NaOCl, respectively. According to TG analysis, the weight losses of 4‐MPIMP and P‐4‐MPIMP were found to be 85.37% and 72.19% at 1000°C, respectively. P‐4‐MPIMP showed higher stability against thermal decomposition. Also, electrical conductivity of the P‐4‐MPIMP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels and electrochemical energy gaps (E) of 4‐MPIMP and P‐4‐MPIMP were found to be ?5.76, ?5.19; ?3.00, ?3.24; 2.76 and 1.95 eV, respectively. According to UV–vis measurements, optical band gaps (E_g) of 4‐MPIMP and P‐4‐MPIMP were found to be 3.34 and 2.82 eV, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis of new ionic crosslinked polymer hydrogel combining polystyrene and poly(4‐vinyl pyridine) and its self‐healing through a reshuffling reaction of the trithiocarbonate moiety under irradiation of ultraviolet light

A new ionic crosslinked polymer hydrogel was achieved by the strategy of ionically crosslinking α,ω‐dibromide terminated polystyrene (Br‐PS‐Br) with poly(4‐vinyl pyridine) (P4VP) which was synthesized by reversible addition‐fragmentation chain transfer polymerization using a chain transfer agent containing a trithiocarbonate moiety. The moiety of trithiocarbonate was introduced into the crosslinked network to show the self‐healing characteristics. The chain structure and components of Br‐PS‐Br and P4VP were characterized through ¹H NMR, gel permeation chromatography, Fourier transform IR spectroscopy and elemental analysis. The P4VP (M_n = 25 300 g mol^?1) chains were crosslinked with Br‐PS‐Br (M_n = 2000 g mol^?1) through the quaternization reaction to form a polymer network which was further crosslinked in acetonitrile by irradiation of UV light to fabricate a hydrogel. Such a hydrogel of P4VP/Br‐PS‐Br cut by a razor blade can be rapidly (1 h) and repeatedly (three times) healed through a reshuffling reaction of the trithiocarbonate moiety under irradiation by UV light. © 2018 Society of Chemical Industry     

Electropolymerization kinetics of o‐aminophenol and characterization of the obtained polymer films

Poly(ortho‐aminophenol) has been synthesized electrochemically from a previously deoxygenated acid medium. The initial rate of electropolymerization reaction on platinum electrode is small and the rate law is: Rate = k₂ [D]^0.50[HCl]^1.125[M]^1.29. The apparent activation energy (E_a) was found to be 68.63 kJ mol^?1. The polymer films obtained have been characterized by cyclic voltammetry, X‐ray diffraction, elemental analysis, TGA, scanning electron microscopy, ¹H NMR, UV–visible, and IR spectroscopy. The mechanism of the electrochemical polymerization reaction has been discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3093–3109, 2006     

The kinetics of reduction of selenious(IV) ions in hydrochloric acid with sulphur dioxide

The reduction of selenious ions to its elemental state has been found to be a function of selenious ion concentration, solution acidity, gas flow rate and temperature. The rate equation can be written as: where α = ?1/2, β = 1, γ = 0.9, E = ?53 411 kJ kg^?1mol^?1, R = 8314 kJ kg^?1 mol^?1 K^?1 and k₀ = 194. The reaction temperature starts to decrease when the conversion rate reaches a maximum. This observation can be used to determine the end of the reaction.     

Preparation of new dendrimer‐like star‐shaped amphiphilic poly(ethylene glycol)–poly(ϵ‐caprolactone) copolymers for biocompatible and high‐efficiency curcumin delivery

Novel amphiphilic star‐shaped terpolymers comprised of hydrophobic poly(?‐caprolactone), pH‐sensitive polyaminoester block and hydrophilic poly(ethylene glycol) (M_n = 1100, 2000 g mol^?1) were synthesized using symmetric pentaerythritol as the core initiator for ring‐opening polymerization (ROP) reaction of ?‐caprolactone functionalized with amino ester dendrimer structure at all chain ends. Subsequently, a second ROP reaction was performed by means of four‐arm star‐shaped poly(?‐caprolactone) macromer with eight ‐OH end groups as the macro‐initiator followed by the attachment of a poly(ethylene glycol) block at the end of each chain via a macromolecular coupling reaction. The molecular structures were verified using Fourier transform infrared and ¹H NMR spectroscopies and gel permeation chromatography. The terpolymers easily formed core–shell structural nanoparticles as micelles in aqueous solution which enhanced drug solubility. The hydrodynamic diameter of these agglomerates was found to be 91–104 nm, as measured using dynamic light scattering. The hydrophobic anticancer drug curcumin was loaded effectively into the polymeric micelles. The drug‐loaded nanoparticles were characterized for drug loading content, encapsulation efficiency, drug–polymer interaction and in vitro drug release profiles. Drug release studies showed an initial burst followed by a sustained release of the entrapped drug over a period of 7days at pH = 7.4 and 5.5. The release behaviours from the obtained drug‐loaded nanoparticles indicated that the rate of drug release could be effectively controlled by pH value. Altogether, these results demonstrate that the designed nanoparticles have great potential as hydrophobic drug delivery carriers for cancer therapy. © 2015 Society of Chemical Industry     

Synthesis and characterization of poly(ester ether siloxane)s

A series of novel thermoplastic elastomers based on ABA‐type triblock prepolymers, poly[(propylene oxide)–(dimethylsiloxane)–(propylene oxide)] (PPO‐PDMS‐PPO), as the soft segments, and poly(butylene terephthalate) (PBT), as the hard segments, was synthesized by catalyzed two‐step melt transesterification of dimethyl terephthalate (DMT) with 1,4‐butanediol (BD) and α,ω‐dihydroxy‐(PPO‐PDMS‐PPO) (M?_n = 2930 g mol^?1). Several copolymers with a content of hard PBT segments between 40 and 60 mass% and a constant length of the soft PPO‐PDMS‐PPO segments were prepared. The siloxane‐containing triblock prepolymer with hydrophilic terminal PPO blocks was used to improve the compatibility between the polar comonomers, i.e. DMT and BD, and the non‐polar PDMS segments. The structure and composition of the copolymers were examined using ¹H NMR spectroscopy, while the effectiveness of the incorporation of α,ω‐dihydroxy‐(PPO‐PDMS‐PPO) prepolymer into the copolyester chains was controlled by chloroform extraction. The effect of the structure and composition of the copolymers on the transition temperatures (T_m and T_g) and the thermal and thermo‐oxidative degradation stability, as well as on the degree of crystallinity, and some rheological properties, were studied. Copyright © 2006 Society of Chemical Industry     

Electroreductive block copolymerization of dichlorosilanes in the presence of disilane additives

The electroreductive polymerization of dichloromethylphenylsilane in the presence of triphenylsilyl group‐containing disilanes such as hexaphenyldisilane followed by the electroreductive termination with chlorotriphenylsilane afforded triphenylsilyl group‐terminated polymethylphenylsilane in 15–32% yield. The isolated polymethylphenylsilane (M_n = 3350 g mol^?1, M_w/M_n = 1.4) was found to react as a macroinitiator to copolymerize with dibutyldichlorosilane under electroreductive conditions producing the corresponding block copolymer (M_n = 4730 g mol^?1, M_w/M_n = 1.2) in 38% yield. The ratio of monomer units (? MeSiPh? to? BuSiBu? ) of the copolymer was determined to be 75:25 using ¹H NMR analysis, which was in good agreement with the calculated ratio (74:26) on the assumption that molecular weight of the macroinitiator was not changed. The block structure of the resulting copolymer, poly(methylphenylsilane)‐block‐poly(dibutylsilane), was also confirmed by comparing its ¹H NMR and UV absorption spectra with those of polymethylphenylsilane, polydibutylsilane and a statistical copolymer prepared by electroreductive polymerization of dichloromethylphenylsilane with dibutyldichlorosilane. This method is applicable to the preparation of other types of macroinitiator such as triphenylsilyl group‐terminated polydibutylsilane, and polydibutylsilane‐block‐polymethylphenylsilane was also obtained using this macroinitiator. Copyright © 2011 Society of Chemical Industry