Partial and complete hydrogenation of poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene)

Summary Poly(1-methyl-1-phenyl-1-silapentane)(II), andblock copoly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene/1-methyl-1-phenyl-1-silapentane) (block-III) have been prepared by catalytic hydrogenation of poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene)(I) over 5% palladium on carbon. These polymers have been characterized by¹H,¹³C and²⁹Si NMR as well as IR spectroscopy. Molecular weight distributions have been evaluated by gel permeation chromatography (GPC). Thermal stabilities have been measured by thermogravimetric analysis (TGA). Glass transition temperatures (T_g's) have been determined by differential scanning calorimetry (DSC).     

Synthesis of poly(1-methyl-1-phenyl-1-silapentane) by chemical reduction of poly)1-methyl-1-phenyl-1-sila-cis-pent-3-ene with diimide

Summary Poly(1-methyl-1-phenyl-1-silapentane) (I) has been prepared by the chemical reduction of the carbon-carbon double bonds of poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene (cis-II) with diimide, which was generatedin-situ by the thermal decomposition ofp-toluenesulfonhydrazide in refluxing toluene. At lower temperature (100°C),cis-II is isomerized byp-toluenesulfinic acid to lower molecular weight poly(1-methyl-1-phenyl-1-sila-cis andtrans-pent-3-ene) (cis/trans-II). Protodesilation of I with trifluoromethanesulfonic acid yields poly(1-methyl-1-trifluoromethanesulfonyl-1-silapentane) (III). The structures of I andcis/trans-II have been characterized by¹H,¹³C and²⁹Si NMR, GPC, TGA and elemental analysis. The structure of I has been characterized spectroscopically by¹H,¹³C,¹⁹F and²⁹Si NMR.     

Preparation and properties of high molecular weight poly(1-germa-) or poly(1-sila-cis-pent-3-enes)

High molecular weight poly(1,1-dimethyl-1-germa-cis-pent-3-ene), poly(1,1-diphenyl-1-germa-cis-pent-3-ene), poly(1,1-dimethyl-1-sila-cis-pent-3-ene), and poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) have been prepared. The thermal stability of these polymers is found to increase with their molecular weight.     

Synthesis and characterization of poly(1-sila-cis-pent-3-enes) substituted with pendant pyridinyl groups

Poly[1-methyl-1-[3′-(3″-pyridinyl)propyl]-1-sila-cis-pent-3-ene], poly[1-phenyl-1-[3′-(3″-pyridinyl)propyl)-1-sila-cis-pent-3-ene], and poly[1-phenyl-1-(4′-pyridinyl)-1-sila-cis-pent-3-ene] were synthesized by the anionic ring-opening polymerization of 1-methyl-1-[3′-(3″-pyridinyl)propyl]-1-silacyclopent-3-ene, 1-phenyl-1-[3′-(3″-pyridinyl)propyl]-1-silacyclopent-3-ene, and 1-phenyl-1-(4′-pyridinyl)-1-silacyclopent-3-ene, respectively. These are the first polycarbosilanes which contain heterocyclic pyridine units as side-chain substituents. These polymers were characterized by¹H,¹³C, and²⁹Si NMR as well as by IR and UV spectroscopy. The molecular weight distributions were determined by gel permeation chromatography, glass transition temperatures, by differential seanning calorimetry: (DSC) and thermal behavior, by thermogravimetric analysis. (TGA).     

Stress-strain behavior and dynamic mechanical properties of poly(1,1-dimethyl-1-sila-cis-pent-3-ene), poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) and of these polymers after crosslinking with sulfur

Mechanical properties of polymers can be described by their stress/strain curves and by their behavior under dynamic mechanical thermal analysis (DMTA). The purpose of this paper is to report such mechanical properties for two unsaturated polycarbosilanes: poly(1, 1-dimethyl-1-sila-cis-pent-3-ene) (I) and poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) (II). Tensile strength, elongation at break, modulus, bending modulus, T_g, and tan δ for I, II and for sulfur crosslinked I and II have been measured. The influence of polymer molecular weight, quantity of crosslinking agent, cure time, presence of carbon black filler, the effect of crosshead speed, and frequency on these properties was investigated.     

Preparation and properties of high molecular weight poly(1-germa-) or poly(1-sila-cis-pent-3-enes)

High molecular weight poly(1,1-dimethyl-1-germa-cis-pent-3-ene), poly(1,1-diphenyl-1-germa-cis-pent-3-ene), poly(1,1-dimethyl-1-sila-cis-pent-3-ene), and poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) have been prepared. The thermal stability of these polymers is found to increase with their molecular weight.     

Synthesis and microstructure of poly(1-phenyl-1-sila-cis-pent-3-ene)

Summary poly(1-Phenyl-1-sila-cis-pent-3-ene) (I) has been prepared by the anionic ring opening polymerization of 1-phenyl-1-sila-cyclopent-3-ene (II). This reaction is co-catalyzed by n-butyl-lithium and HMPA in THF at low temperature. I has been characterized by ¹H, ¹³C and ²⁹Si NMR, IR, UV, GPC and TGA. The low molecular weight of l permits end group analysis. Pyrolysis of l gives significant char yields.     

Miscibility of poly(caprolactone)/chlorinated polypropylene and poly(caprolactone)/poly(chlorostyrene) blends

Poly(caprolactone) (PCL) was blended with poly(chlorostyrene) (PSCI) and chlorinated polypropylene (PPCl). A single glass transition temperature T_g was found for these mixtures, indicating their miscibility. PCL crystallizes in these blends when the chlorinated polymer content is not too high. Otherwise, T_g becomes higher than the melting point of PCL and the high viscosity of the medium hinders the crystallization. The miscibility of PCL/PPCI blends cannot be due to hydrogen bonding between the α-hydrogens of the chlorinated polymer and the carbonyl group of the polyester since PPCI does not have available a large number of α-hydrogens. It is suggested that a dipoledipole ? C?O…Cl? C? interaction is responsible for the observed miscibility phenomenon and that this interaction is probably also responsible for the miscibility between all other polyesterchlorinated polymer mixtures. Finally, it was observed that poly(α-methyl-α-n-propyl-β-propiolactone), poly(α-methyl-α-ethyl-β-propiolactone) and poly(valerolactone) are not miscible with PSCI or PPCl, despite the fact that they are miscible with poly(vinyl chloride).     

Proton conducting properties of ionically cross-linked poly(1-vinyl-1,2,4 triazole) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) electrolytes

The synthesis and thermal as well as proton conducting properties of complex polymer electrolytes based on poly(2-acrylamido-2-methyl-1-propanesulfonic acid) PAMPS and poly(1-vinyl-1,2,4-triazole) PVTri were investigated. The materials were produced by complexation of PAMPS with PVTri at various compositions to get PVTriP(AMPS) _x where x is the molar ratio of the polymer repeating units and varied from 0.25 to 4. The structure of the materials was confirmed by FT-IR spectroscopy. The TGA results verified that the polymer electrolytes are thermally stable up to approximately 200 °C. The DSC and SEM results demonstrated the homogeneity of the materials. The electrochemical stability of the materials was studied by cyclic voltammeter (CV). Proton conductivity, activation energy, and water/methanol uptake of these membranes were also measured. After humidification (RH = 50%), PVTriP(AMPS)₂ and PVTriP(AMPS)₄ showed proton conductivities of 0.30 and 0.06 S/cm at 100 °C, respectively.     

Synthesis and characterization of poly(1-sila-cis-pent-3-enes) substituted with pendant pyridinyl groups

Poly[1-methyl-1-[3-(3-pyridinyl)propyl]-1-sila-cis-pent-3-ene], poly[1-phenyl-1-[3-(3-pyridinyl)propyl)-1-sila-cis-pent-3-ene], and poly[1-phenyl-1-(4-pyridinyl)-1-sila-cis-pent-3-ene] were synthesized by the anionic ring-opening polymerization of 1-methyl-1-[3-(3-pyridinyl)propyl]-1-silacyclopent-3-ene, 1-phenyl-1-[3-(3-pyridinyl)propyl]-1-silacyclopent-3-ene, and 1-phenyl-1-(4-pyridinyl)-1-silacyclopent-3-ene, respectively. These are the first polycarbosilanes which contain heterocyclic pyridine units as side-chain substituents. These polymers were characterized by¹H,¹³C, and²⁹Si NMR as well as by IR and UV spectroscopy. The molecular weight distributions were determined by gel permeation chromatography, glass transition temperatures, by differential seanning calorimetry: (DSC) and thermal behavior, by thermogravimetric analysis. (TGA).     

Microwave dielectric relaxation study of poly(propylene glycol) in dilute solution

Dielectric relaxation studies of poly(propylene glycol), average molecular weight 2000 g mol⁻¹, in dilute solution of cyclohexane, decaline, benzene and carbon tetrachloride have been carried out at 10.10 GHz and 35 °C. Average relaxation time τ₀, and relaxation times corresponding to segmental motion τ₁, group rotations τ₂ and dipole moment µ have been determined. It is found that τ₀, τ₁ and µ are influenced by the solvent environment while the τ₂ value is solvent‐independent. A comparison has been made with the dielectric behaviour of poly(ethylene glycol), average molecular weight 1500 g mol⁻¹, in dilute solutions of benzene and carbon tetrachloride because both systems have an equal number of monomer units. The effect of methyl side‐groups on dielectric relaxation in poly(propylene glycol) molecules is discussed. The Kirkwood correlation factor is also evaluated in dilute solutions with concentration variation and it is found that these molecules exist in cluster form due to intermolecular hydrogen bonding. © 2000 Society of Chemical Industry     

Synthesis of poly(1‐hexene)s end‐functionalized with phenols

Electrophilic alkylations of phenol/2,6‐dimethylphenol were performed with vinylidene‐terminated poly(1‐hexene)s using BF₃·OEt₂ catalyst. Vinylidene‐terminated poly(1‐hexene)s with M_n varying from 400 to 10000 were prepared by bulk polymerization of 1‐hexene at 50 to ?20 °C using Cp₂ZrCl₂/MAO catalysts. The phenol/2,6‐dimethylphenol‐terminated poly(1‐hexene)s was characterized by NMR (¹H, ¹³C), UV, IR and vapor phase osmometer (VPO). The isomer distribution (ortho, para and ortho/para) was determined by ¹³P NMR using a phosphitylating reagent, namely 2‐chloro‐1,3,2‐dioxaphospholane. The number‐average degree of functionality (F_n) >0.9 with >95% para selectivity could be achieved using low‐molecular‐weight oligomers of poly(1‐hexene)s. Copyright © 2005 Society of Chemical Industry     

New highly proton-conducting membrane poly(vinylpyrrolidone)(PVP) modified poly(vinyl alcohol)/2-acrylamido-2-methyl-1-propanesulfonic acid (PVA-PAMPS) for low temperature direct methanol fuel cells (DMFCs)

A new type of chemically cross-linked polymer blend membranes consisting of poly(vinyl alcohol) (PVA), 2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS) and poly(vinylpyrrolidone) (PVP) have been prepared and evaluated as proton conducting polymer electrolytes. The proton conductivity (σ) of the membranes was investigated as a function of cross-linking time, blending composition, water content and ion exchange capacity (IEC). Membranes were also characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), and the differential scanning calorimetry (DSC). Membrane swelling decreased with cross-linking time, accompanied by an improvement in mechanical properties and a small decrease in proton conductivity due to the reduced water absorption. The membranes attained 0.088 S cm⁻¹ of the proton conductivity and 1.63 mequiv g⁻¹ of IEC at 25±2 °C for a polymer composition PVA-PAMPS-PVP being 1:1:0.5 in mass, and a methanol permeability of 6.1×10⁻⁷ cm² s⁻¹, which showed a comparable proton conductivity to Nafion 117, but only one third of Nafion 117 methanol permeability under the same measuring conditions. The membranes displayed a relatively high oxidative durability without weight loss of the membranes (e.g. 100 h in 3% H₂O₂ solution and 20 h in 10% H₂O₂ solution at 60 °C). PVP, as a modifier, was found to play a crucial role in improving the above membrane performances.     

New poly(amide–imide)s syntheses. 17. Preparation and properties of poly(amide–imide)s derived from N-phenyl-3,3-bis[4-(4-aminophenoxy)-phenyl]phthalimidine,trimellitic anhydride,and various aromatic diamines

A dicarboxylic acid ( 1 ) bearing two phthalimide rings was prepared by the condensation of N-phenyl-3,3-bis[4-(4-aminophenoxy)phenyl]phthalimidine and trimellitic anhydride. A new family of poly(amide–imide)s having inherent viscosities of 0.65–1.65 dl/g was prepared by the triphenyl phosphite activated polycondensation of the diimide–diacid 1 with various aromatic diamines in a medium consisting of N-methyl-2-pyrrolidone (NMP), pyridine, and calcium chloride. All the resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N-dimethylacetamide. The soluble poly(amide–imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these polymers were in the range 249–340°C and the 10% weight loss temperatures were above 545°C in nitrogen.     

4-ACYLBIS(1-PHENYL-3-METHYL-5-PYRAZOLONES) AS EXTRACTANTS FOR f-ELEMENTS

ABSTRACT

The liquid-liquid extraction of early actinides such as thorium(IV) and uranium(VI) and trivalent lanthanoids such as neodymium(lll), europium(lll) and lutetium(lll) from nitrate solutions was studied using 4-sebacoylbis(1-phenyl-3-methyl-5-pyrazolone) (H₂SP) and 4-dodecandioyl-bis(1-phenyl-3-methyl-5-pyrazolone) (H₂DdP) in chloroform as extractants. The results demonstrate that these metal ions are extracted into chloroform as Th(SP)₂, Th(DdP)₂, UO₂(HSP)₂, UO₂(HDdP)₂, Ln(SP)(HSP) and Ln(DdP)(HDdP) with H₂SP or H₂DdP. The equilibrium constants of the above species were deduced by non-linear regression analysis. The results clearly highlight that thorium(IV) can be selectively separated from uranium(Vl) and trivalent lanthanoids when extracted from 0.2 mol/dm³ nitric acid solutions using 4-acylbis(1-phenyl-3-methyl- 5-pyrazolones). Thorium(IV), uranium(VI) and lutetium(lll) complexes of H₂SP were synthesised and characterised by IR and ¹H NMR spectral data to further clarify the nature of the complexes.     

Miscibility of conductive blends of poly(o-anisidine) with poly(2-alkyl-2-oxazoline)s

HCl-doped poly(o-anisidine) (PANIS–HCl) and undoped poly(o-anisidine) (PANIS-base) were blended with poly(2-methyl-2-oxazoline) (PMOx) or poly(2-ethyl-2-oxazoline) (PEOx) by solution casting from dimethyl sulfoxide. Blends containing 50 wt % or less of PANIS–HCl or PANIS-base were flexible and homogeneous. The glass transition temperature of the blend continuously shifted away from that of PMOx or PEOx with increasing PANIS–HCl or PANIS-base content, indicating miscibility. The shift in the T_g value was larger for the PMOx blend than for the corresponding PEOx blend, suggesting a stronger interpolymer interaction in the former blend. Fourier transform infrared spectroscopic studies indicated the presence of specific interactions in the blends as evidenced by the changes of C=O and NH bands. Blends containing 50 wt % of PANIS–HCl showed conductivity of about 10^-4 S/cm. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:391–397, 1997     

Synthesis and properties of poly(diphenylacetylenes) having ether linkages

Summary Polymerization of 1-phenyl-2-(p-phenoxyphenyl)acetylene (p-PhODPA), 1-phenyl-2-(p-methoxyphenyl)acetylene, and 1-phenyl-2-(p-n-butoxyphenyl)acetylene was examined. These monomers polymerized with TaCl₅-n-Bu₄Sn to give methanol-insoluble polymers in over 60% yields. Poly(p-PhODPA) was a yellow solid completely soluble in toluene, CHCl₃, etc., and its weight-average molecular weight was about 1.0x10⁶ or higher. This polymer was thermally very stable (the onset temperature of weight loss in TGA in air was 420 °C). Its oxygen permeability coefficient (P o ₂) was 37 barrers (P o ₂/P n ₂ 2.2) and similar to that of natural rubber. In contrast, the other two polymers did not completely dissolve in any organic solvent, and their thermal stability was lower.     

Synthesis and characterization of hyperbranched poly(silyl ester)s

Hyperbranched poly(silyl ester)s were synthesized via the A₂ + B₄ route by the polycondensation reaction. The solid poly(silyl ester) was obtained by the reaction of di‐tert‐butyl adipate and 1,3‐tetramethyl‐1,3‐bis‐β(methyl‐dicholorosilyl)ethyl disiloxane. The oligomers with tert‐butyl terminal groups were obtained via the A₂ + B₂ route by the reaction of 1,5‐dichloro‐1,1,5,5‐tetramethyl‐3,3‐diphenyl‐trisi1oxane with excess amount of di‐tert‐butyl adipate. The viscous fluid and soft solid poly(silyl ester)s were obtained by the reaction of the oligomers as big monomers with 1,3‐tetramethyl‐1,3‐bis‐β(methyl‐dicholorosilyl)ethyl disiloxane. The polymers were characterized by ¹H NMR, IR, and UV spectroscopies, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The ¹H NMR and IR analysis proved the existence of the branched structures in the polymers. The glass transition temperatures (T_g's) of the viscous fluid and soft solid polymers were below room temperature. The T_g of the solid poly(silyl ester) was not found below room temperature but a temperature for the transition in the liquid crystalline phase was found at 42°C. Thermal decomposition of the soft solid and solid poly(silyl ester)s started at about 130°C and for the others it started at about 200°C. The obtained hyperbranched polymers did not decompose completely at 700°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3430–3436, 2006     

Synthesis of poly(N,N-dimethylcarbamoylmethylene) as a polymer homolog of N,N-dimethylacetamide

Summary A novel polymer homolog of N,N-dimethylacetamide (DMAc) having amide groups on all main chain carbons, poly(N,N-dimethylcarbamoylmethylene) 1, was prepared by heating poly(di-t-butyl fumarate) 2 at 180 °C for 2 hours followed by treatment with hexamethylphosphoramide at 180 °C for 5 hours. The structure of the obtained polymer 1 was confirmed by ¹H-, ¹³C-NMR and IR spectroscopy. The polymer 1 actually showed the properties based on its repeating structures. 1 had the amphiphilicity and was soluble both in protic and aprotic solvents. Furthermore, 1 showed the miscibility with commodity polymers such as poly(N-vinylpyrrolidone), poly(vinyl alcohol) and poly(vinyl chloride). In comparison with another polymer homolog of DMAc, poly(2-methyl-2-oxazoline), the polymer 1 exhibited better miscibility with poly(N-vinylpyrrolidone). Received: 24 June 1999/Accepted: 19 July 1999     

Synthesis and evaluation of interaction parameters of synthetic elastin‐derived polypentapeptide with poly(vinylpyrrolidone) in solution and solid phase

The parent repeating sequence of elastin, poly(GVGVP) has been synthesized by solution phase method and characterized by 13C and ¹H‐NMR spectroscopy. The poly(GVGVP) and poly(vinyl pyrrolidone) (PVP) interactions have been examined in solution phase by the viscometric method at 24 °C. The interaction parameters such as α, β, µ, and Δ[η]_m indicated the miscible nature of poly(GVGVP)/PVP blends. Immiscibility occurred when the quantity of poly(GVGVP) is lesser than 60%. In the solid phase, Fourier transform infrared spectroscopic scrutiny of the thin films of poly(GVGVP)/PVP blends indicated the presence of strong intermolecular interaction such as hydrogen bonds linking the blend components. This result was further supported by glass transition temperature (T_g), scanning electron microscopic, and X‐ray diffraction studies. The blending of poly(GVGVP) with PVP may provide an opportunity to produce new materials for potential biomedical applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46699.