Synthesis and thermal properties of conjugated poly[(silylene)diacetylene silazanes]

A series of novel conjugated polymers, poly[(silylene)diacetylene silazanes] having different substituents on silicon were prepared by ammonolysis of the corresponding α,ω-dichlorodiorganosilylenediacetylene oligomers. The polymers had the number-average molecular weight between 700 and 2800, and the polydispersity index between 1.07 and 1.43. The polymers showed good solubility in common organic solvents. The structures of the poly[(silylene)diacetylene silazanes] were characterized by Fourier transform infrared, ¹H, ¹³C, ²⁹Si NMR, elemental analyses, and gel permeation chromatography. The thermal properties were measured with thermogravimetric analysis and differential scanning calorimetry. The resulting polymers had good thermal stability, and the DSC showed lower glass-transition temperature (T_g). They had good processability due to non-crystallization. Treatment of these polymers at appropriate temperature led to thermal polymerization of the acetylene unit to form a new cross-linking network system. These polymers have the potential to be used as precursors for Si/C/N-based ceramics.     

Synthesis and properties of sulfonated and crosslinked poly[(vinylidene fluoride)-graft-styrene] membranes

Crosslinked proton exchange membranes were prepared by electron beam grafting of styrene with divinylbenzene, DVB, or bis(vinyl phenyl)ethane, BVPE, on to poly(vinylidene fluoride), PVDF, followed by sulfonation. The area and thickness increase, crystallinity and mechanical properties of the membranes were investigated. All these properties were influenced by the crosslinker structure and its concentration. The crosslinkers increase the final degree of grafting. For noncrosslinked membranes it was about 80% and with 10% of BVPE crosslinker about 180% after 8 hr. The area increase with grafting is very similar for the noncrosslinked membranes and the differently crosslinked membranes, but the crosslinkers reduce swelling for sulfonated membranes swelled in boiling water. DVB reduces swelling more than BVPE. With grafting, the crystallinity of the PVDF phase decreases; with 10% BVPE the decrease is smallest and with 10% DVB largest. The mechanical properties of the sulfonated swelled membranes decrease with the degree of grafting, for a 10% DVB crosslinked membrane the strength decreases to zero at degrees of grafting higher than 75%. © 1998 John Wiley & Sons, Ltd.     

Synthesis and analytical properties of di(2-pyridyl)-N,N-di[(8-quinolyl)amino]methane

The synthesis and preliminary analytical assessment of di(2-pyridyl)-N,N-di[(8-quinolyl)-amino]methane is reported. It shows some potential as a reagent for iron(II).     

Polymeric organosilicon system VIII. Synthesis of poly[(disilanylene)diethynylene] with highly conducting properties

The reaction of bis(trimethylsilyl)butadiyne with 2 equiv. of methyllithium, followed by 1,2-dichloro-1,2-dimethyldiphenyl- or 1,2-dichloro-1,2-diethyldimethyldisilane gives poly[(1,2-dimethyldiphenyldisilanylene)diethynylene] (II) or poly[(1,2- diethyldimethyldisilanylene)diethynylene] (III), respectively. Films of II and III become conducting when treated with SbF₅ vapor.     

Synthesis and controlled photo- and biodegradabilities of poly[(hydroxybutyrate -Co-hydroxyvalerate)-G-styrene]

The graft copolymer, P(HBV-g-St), was synthesized by graft polymerization of styrene (St) onto poly(3-hydroxybutyrate-co-3-hydroxy valerate) [PHBV] under nitrogen atmosphere using benzoyl peroxide (BPO). The structure of poly[(hydroxybutyrate-co-hydroxyvalerate)-g-styrene] [P(HBV-g-St)] was identified by FT-K, ¹H-NMR, and ¹³C-NMR spectra. The effects of weight ratio of St to PHBV in feed, initiator concentration, reaction time and reaction temperature on the grafting ratio and grafting efficiency were investigated. The thermal decomposition temperature of P(HBV-g-St) was 273°C. The tensile strengths of P(HBV-g-St) before and after photo- or biodegradation were also measured. The photodegradability of P(HBV-g-St) was better than that of PHBV. The film surface of P(HBV-g-St) treated with Aspergillus nigger showed extensive grooves and pits as compared with the untreated P(HBV-g-St). It was found that the photo- and biodegradation rates of P(HBV-g-St) and tensile strength of P(HBV-g-St) can be “controlled” by changing the weight ratio of St to PHBV in feed.     

Synthesis,characterization and ionic conductivity of poly[(oligoethylene oxide) ethoxysilane] and poly[(oligoethylene oxide) ethoxysilane]/(EuCl3)0.67

Poly[(oligoethylene oxide) ethoxysilane)] ( I ) and poly[(oligoethylene oxide) ethoxysilane)]/(EuCl₃)_0.67 ( II ) were synthesized by reacting tetraethoxysilane with oligo(ethylene glycol) of molecular weight 400 and oligo(ethylene glycol)400/(EuCl₃)_0.317, respectively. The products so obtained are very transparent and rubbery. By Fourier transform infrared and Raman spectroscopy studies and by using analytical results it was concluded that these products are crosslinked macromolecular materials where the Si atom is bonded to one OEt group and to three poly(ethylene oxide) 400 chains. Scanning electronic microscopy studies showed that the presence of EuCl₃ in polymer host significantly affects the morphology of the material. Laser luminescence investigations on (II) showed that Eu³⁺ ion in the polymer host is accommodated in two different types of sites having a distorted C_2v symmetry. Moreover, the ionic conductivity of these systems was investigated and the data were satisfactorily fitted by the empirical Vogel Tamman Fulcher equation. At 70°C the conductivities of ( I ) and ( II ) were 9 × 10⁻⁶ and 14.3 × 10⁻⁶ Ω⁻¹ cm⁻¹ respectively.     

Thermal and thermomechanical properties of poly[(butylene succinate)-co-adipate] nanocomposite

In this article the thermal and thermomechanical properties of neat poly[(butylene succinate)-co-adipate] (PBSA) and its nanocomposite are reported. Nanocomposite of PBSA with organically modified synthetic fluorine mica (OSFM) has been prepared by melt-mixing in a batch mixer. The structure of nanocomposite is characterized by X-ray diffraction patterns and transmission electron microscopic (TEM) observations that reveal homogeneous dispersion of intercalated silicate layers in the PBSA matrix. The melting behavior of pure polymer and nanocomposite samples are analyzed by differential scanning calorimetry (DSC), which shows multiple melting behavior of the PBSA matrix. The multiple melting behavior of the PBSA matrix is also studied by temperature modulated DSC (TMDSC) and wide-angle XRD (WXRD) measurements. All results show that the multiple melting behavior of PBSA is due to the partial melting, re-crystallization, and re-melting phenomena. The investigation of the thermomechanical behavior is performed by dynamic mechanical thermal analysis. Results demonstrate substantial enhancement in the mechanical properties of PBS, for example, at room temperature, storage flexural modulus increased from 0.5 GPa for pure PBS to 1.2 GPa for the nanocomposite, an increase of about 120% in the value of the elastic modulus. The thermal stability of nanocomposite compared to that of neat PBSA is also examined in pyrolytic and thermo-oxidative conditions. It is then studied using kinetic analysis. It is shown that the stability of PBSA is increased moderately in the presence of OSFM.     

Mixed substituent poly[(vinyloxy)cyclotriphosphazenes]

The mixed substituent cyclophosphazene monomers N₃P₃Cl₄(OCH?CH₂)(OCH₂CF₃) ( 2 ) and N₃P₃Cl₃(OCH?CH₂) (OCH₂CF₃)₂ ( 3 ) undergo polymerization under radical initiation conditions to yield the mixed substituent poly[(vinyloxy)cyclotriphosphazenes] [CH₂CH(ON₃P₃Cl₄(OCH₂CF₃))]_n( 5 ) and [CH₂CH(ON₃P₃Cl₃(OCH₂CF₃)₂)]_n ( 6 ), respectively. A significant, progressive reduction in molecular weight compared to the parent polymer of the series [CH₂CH(ON₃P₃Cl₅)]_n ( 4 ) was observed and attributed to increased chain transfer. The thermal decomposition of 5 and 6 is similar to that observed for 4 with an exothermic elimination of HCl at modest temperatures. An alternative synthetic pathway involving nucleophilic substitution reactions of 4 provided [CH₂CH(ON₃P₃(OCH₂CF₃)₅)]_n ( 7 ), [CH₂CH(N₃P₃Cl₂(OC₆H₅)₃)]_n ( 8A) , [CH₂CH(ON₃P₃Cl_1.7(OC₆H₅)_3.3)]_n ( 8B ), [CH₂CH(ON₃P₃Cl_1.5(NHCH₃)_3.5)]_n ( 9 ), [CH₂CH(ON₃P₃Cl_3.8 (N(CH₂CH₃)₂)_1.2]_n ( 10A ), [CH₂CH(ON₃P₃Cl_3.4(N(CH₂CH₃)₂)_1.6)]_n ( 10B ), and [N₃P₃Cl₂(OCHCH₂)(N(CH₃)₂)]_n, ( 11 ). The thermal behaviors of all of the new polymers were examined by TGA, DTA, DSC, and pyrolysis mass spectrometry. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013     

Thermal degradation of poly[(tetramethyl-p-silphenylene) siloxane]

For the purpose of studying the mechanism of thermal degradation of poly[(tetramethyl-p-silphenylene) Siloxane] (poly TMPS) a series of polymers with silphenylene and siloxane bonds in the main chain were prepared and subjected to thermogravimetry (TG) and pyrolysis study. Analyses of products from poly TMPS degradation (in vacuum at a constant temperature) by gas chromatography (GC), infrared (IR), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry (GC–MS) revealed that degradation occurs at the silphenylene bonds. The TG curves obtained in He for heating rates of 1,2,2.5,7.5, and 10°C/min were analyzed by the Ozawa method; activation energies of 39 ± 1 and 45 ± 2 kcal/mol were obtained respectively for the initial cleavage of the methyl side group and the later-stage scission of the main-chain silphenylene bond which leads to a major weight loss. The results agree with those obtained for other structurally similar polymers.     

Bis[(tetraphenylporphyrinato)zinc]-calix[4]pyrrole. Synthesis and receptor properties

A new bis[(tetraphenylporphyrinato)zinc]-calix[4]pyrrole conjugate has been synthesized from monoacetyl-substituted tetraphenylporphyrin, and its complexing ability toward 1,4-diazabicyclo[2.2.2]octane has been evaluated by spectrophotometric titration and 1H NMR spectroscopy.     

Poly[(2-chloroethyl)oxirane], poly[(3-chloropropyl)-oxirane] and poly[(4-chlorobutyl)oxirane]: New polyether elastomers of improved chemical reactivity

(2-Chloroethyl)oxirane, (3-chloropropyl)oxirane, and (4-chlorobutyl)oxirane were prepared from the corresponding alkenols and polymerized using a triethylaluminum-water-acetylacetone initiator system. Copolymerizations with propylene oxide and epichlorohydrin were also accomplished; the copolymerization activities of the (chloroalkyl)oxiranes were similar to the activity of epichlorohydrin. Poly[(2-chloroethyl)oxirane], poly[(3-chloropropyl)oxirane], and poly[(4-chlorobutyl)oxirane] exhibit elastomeric properties and are highly reactive in nucleophilic substitution reactions.     

Synthesis,reactivity, and optoelectronic properties of poly(3‐alkenylthiophene) diblock copolymers

Poly(3‐hexylthiophene)‐b‐poly(3‐pentenylthiophene) and poly(3‐hexylthiophene)‐b‐poly(3‐undecenylthiophene) diblock copolymers have been synthesized by McCullough method. X‐ray diffraction analysis of the diblock copolymers displayed all the reflection peaks specific to regioregular poly(3‐hexylthiophene), indicating that the presence of poly(3‐alkenylthiophene) block does not affect the packing of the polymer in the solid state. The synthesized diblock copolymers were subjected to hydroboration/oxidation and hydrosilation to demonstrate the reactivity of the alkenyl substituents. Furthermore, poly(3‐hexylthiophene)‐b‐poly(3‐pentenylthiophene) was used as a chain transfer agent for the ruthenium‐catalyzed ring‐opening metathesis polymerization of cyclooctene to generate a polycyclooctene graft copolymer, which was hydrogenated to give poly(3‐hexylthiophene)‐b‐poly(3‐pentenylthiophene‐g‐polyethylene). The opto‐electronic properties and the morphology of the synthesized polymers have been investigated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis of regiospecifically meta-substituted poly(phenylacetylene)s and some of their electrical properties

The syntheses, characterizations, and electrical properties of four regiospecifically substituted poly(phenylacetylene)s are described. Tungsten(VI) chloride/tetra-n-butyltin (WCl₆/n-Bu₄Sn) catalyst system (Higashimura–Masuda, H.–M. catalyst) was used to polymerize 3-bromo-, 3-chloro-, 3-trimethylsilyl-, and 3-trimethylstannylphenylacetylenes in order to obtain high-molecular-weight and soluble materials. Characterizations of these polymers were done by IR and UV spectroscopic methods, GPC, DSC, and elemental analysis. The electrical conductivities of the polymers were measured on the surface of pressed pellets by a four-point probe.     

Poly[(3-hydroxypropyl) oxirane] and poly[(4-hydroxybutyl)oxirane]: New hydrophilic polyether elastomers

Preparations of poly[(3-hydroxypropyl)oxirane] and poly[(4-hydroxybutyl)oxirane] are described. Three routes to poly[(3-hydroxypropyl)oxirane] are discussed, each of which involves the methanolysis of a polymeric ester. (3-Acetoxypropyl)oxirane, [3-(m-chlorobenzoyloxy)propyl]oxirane, and (3-chloropropyl)oxirane were polymerized using the AIEt₃/H₂O/AcAc initiator system. Poly[(3-acetoxypropyl)oxirane] and poly{[3-(m-chlorobenzoyloxy)propyl]oxirane} were converted directly to poly[(3-hydroxypropyl)oxirane] by methanolysis, the former under either acidic or basic conditions only. Poly[(3-chloropropyl)oxirane] was first converted to poly[(3-benzoyloxypropyl)oxirane] by treatment with tetrabutylammonium benzoate; subsequent basic methanolysis then afforded poly[(3-hydroxypropyl)oxirane]. Poly[(3-hydroxypropyl)oxirane] is a colorless elastomer which can be cast into tough, clear films from water or methanol. Poly[(4-hydroxybutyl)oxirane] was prepared from poly[(4-chlorobutyl)oxirane] by benzoyloxylation and subsequent methanolysis. Poly[(4-hydroxybutyl)oxirane] is insoluble in water, but is hydrophilic and can be cast into tough films from methanol or dimethylsulfoxide.     

Synthesis,magnetic, and optoelectronic properties of poly(triphenylamine‐alt‐phenylenevinylene)s

Conjugated polymers alternatively involving m‐phenylenevinylene or p‐phenylenevinylene and a triphenylamine moiety in the main chain were synthesized via a Wittig–Horner‐type polycondensation of 4‐diformyl‐4′,4″‐dimethyl‐triphenylamine or 4‐diformyl‐4′,4″‐dimethoxy‐triphenylamine with m‐xylene‐bis(diethylphosphonate) or p‐xylene‐bis(diethylphosphonate). A high glass‐transition temperature (ca. 120 °C) and thermal stability (5% weight loss at temperatures greater than 450 °C) were observed for all polymers. These polymers, especially poly(methyltriphenylamine‐alt‐p‐phenylenevinylene), fluoresced a strong green color under UV irradiation, with a quantum efficiency of 50% for their chloroform solutions. Cyclic voltammetry showed a relatively low ionization potential (5.18–5.44 eV) for the polymers. These results suggest that these polymers satisfied the requisites of polymer materials for a single‐layer light‐emitting diode. The aminium radical derived from the oxidation of poly(triphenylamine‐alt‐m‐phenylenevinylene) satisfied both non‐Kekulé‐type π conjugation and ferromagnetic connectivity of the unpaired electrons and displayed a multiplet ground state. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4119–4127, 2000     

The crystal and molecular structure of tris[(triphenylstannyl)methyl]methane

The title compound, C₅₈H₅₂Sn₃, belongs to the triclinic space group P$\text{1}$, with a 10.165, b 13.365, c 18.670 Å, α 96.28, β 93.88, γ 103.15°, V = 2443.8 ų, f_w = 1105.1, Z = 2, D_calc 1.501 g cm^?3, m.p. 206.5–208°C, λ(Mo-K_$\text{α}$) 0.71069 Å. The structure was refined on 2684 nonzero reflections to an R factor of 0.044. The crystal contains molecules in which the (SnCH₂)₃CH core possesses an approximate C₃ symmetry. The three SnC(H₂) bonds are gauche to the C(4)-H bond. Repulsive interactions involving the bulky Ph₃Sn substituents lead to large SnC(H₂)C(H) angles (av. 117.3°), whereas the C(H₂)C(H)C(H₂) angles at the tertiary carbon average 111.3°. Little distortion of the Ph₃Sn groups themselves is present, since the PhSnPh angles (av. 109.8°) are almost equal to the C(H₂)SnPh angles (av. 109.9°). The molecule as a whole has no symmetry because the aromatic rings in the three Ph₃Sn groups have different orientations. The phenyl groups create a pocket in the middle of the molecule which encloses and shields the tertiary hydrogen atom. The resulting inaccessibility of this hydrogen accounts in part for the low reactivity of the title compound in redox reactions.     

Synthesis and characterization of poly[(4-vinylphenyl)dimethyl- silane]-b-polybutadiene-b-poly[(4-vinylphenyl)dimethylsilane] (PVPDMS-b-PBd-b-PVPDMS)

The novel functionalized triblock copolymers,poly[(4-vinylphenyl)dimethylsilane]-b-polybutadiene-b-poly[(4-vinylphenyl)-dimethylsilane] (PVPDMS-b-PBd-b-PVPDMS),were synthesized by anionic polymerization method using high vacuum technique. The hydrocarbon-soluble dilithium initiator synthesized from l,3-di[l-(methylphenyl)ethenyl]benzene(MPEB) was used to synthesize polybutadiene(PBd) precursors and the triblock copolymers in the presence of sec-BuOLi.The precursors and copolymers were characterized by size exclusion chromatography(SEC),~1HNMR and DSC techniques.     

可溶性聚吡咯甲烷的制备与光学性能研究

以3-酰基吡咯和对二甲氨基苯甲醛为原料,采用均相聚合法和非均相聚合法分别制备了两种可溶性的聚吡咯甲烷衍生物(聚合物A和B)。利用红外光谱、紫外-可见吸收光谱、荧光光谱和X射线衍射谱对产物的分子结构、光学性能和聚集态结构进行了表征和分析。紫外-可见吸收光谱显示,所制备的产物在430~650nm可见光范围内均有明显的吸收。荧光光谱表明,两种聚合产物均为蓝色荧光材料。X射线衍射谱表明,两种聚合物的聚集态结构均为完全非晶态。     

Synthesis,hydrophilicity, and oxygen permeability of poly[(trimethylsilyl)propyne]-gr-poly(N,N-dimethylacrylamide)

N,N-dimethylacrylamide (DMAA) was graft copolymerized on poly[(trimethylsilyl)propyne] (PTMSP) by single electron reduction of PTMSP with potassium naphthalenide (K-Naph), followed by anion polymerization of DMAA from the carbanion formed in the reduction. A hard and practically non-water-swelling PTMSP-gr-poly(DMAA) was obtained under the conditions using controlled amount of K-Naph and DMAA. The graft copolymer was characterized with regard to structure, number-averaged molecular weight, and the amount of grafting poly(DMAA) determined by the relative absorbance of the IR absorption band assigned to the CO and SiC H functionalities (A_CO/A_{SiC H}). The oxygen permeability and water contact angle (θ) of the graft copolymer were evaluated while varying the amount of grafting poly(DMAA). The graft copolymer proved to be highly oxygen permeable (165 Barrers) and hydrophilic (θ = 27°). Its transparency was also elucidated with UV–vis spectra. This graft copolymer was proposed as a promising candidate for use as a hard contact lens material. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 603–610, 1998