Composites of Poly(Keto-Sulfide)–Epoxy Resin Systems and Their Thermal and Mechanical Properties

A novel matrix resin system, poly(keto-sulfide)–epoxy resin, has been developed. The poly(keto-sulfide)s (PKS), based on various ketones, formaldehyde, and sodium hydrogen sulfide (NaSH), were prepared by the reported process. These (PKS) having terminal thiol (–SH) groups were used for curing commercial epoxy resin (i.e., diglycidyl ether of bisphenol A – DGEBA), to fabricate crosslinked epoxy-poly(keto-sulfide) resin glass fiber-reinforced composites (GRC). Various epoxy/hardener (PKS) mixing ratios were used, and the curing of epoxy-PKS has been monitored using differential scanning calorimetry (DSC) in dynamic mode. Based on DSC parameters the GRC of epoxy-PKS were prepared and characterized by thermal and mechanical methods. The variation in resin/hardener ratio led to variations in thermal and mechanical properties.     

Sol–Gel Synthesis and Electrochemical Sensing Properties of Brownmillerite Calcium Ferrite–Ca2Fe2O5 Nanoparticles

Journal of Inorganic and Organometallic Polymers and Materials - Nanocrystalline brownmillerite Ca2Fe2O5 (CFO) has been prepared by sol–gel technique and the samples are presented as CFO1 and...     

Morphology and Thermal Properties of Poly[bis(β-phenoxyethoxy)phosphazene]

The structure and thermal properties of poly[bis(-phenoxyethoxy)phosphazene)] (PBPEP) newly synthesized by us were investigated. The crystallization from the melt, the volumetric relaxation in the amorphous phase in the upper vicinity of the glass transition temperature (T _g) and the enthalpy of relaxation of the glass in the lower vicinity of the T _g were shown to be very slow. These slow rates may be related to the low chain mobility due to the bulky side chain. Two kinds of crystal forms, called and forms were found in the melt-crystallized sample. These forms were clearly seen as individual types of spherulites by optical microscopy. The melting temperature of these crystals were analyzed by the Hoffmann–Weeks plot. The so-called T(1) transition that had often been detected in many crystalline polyphosphazenes as the transition from the crystal phase to the mesophase was not observed by x-ray diffraction at elevated temperatures.     

Synthesis and Characterization of Lead-Free Ferroelectric 0.5[Ba(Zr0.2Ti0.8)O3]–0.5[(Ba0.7Ca0.3)TiO3]—Polyvinylidene Difluoride 0–3 Composites

0.5[Ba(Zr_0.2Ti_0.8)O₃]–0.5[(Ba_0.7Ca_0.3)TiO₃]/[BZT–BCT]–polyvinylidene difluoride/[PVDF] 0–3 composites were prepared by uniaxial hot-press method for different volume fractions of BZT–BCT ceramic powder in a PVDF polymer matrix. The structural, microstructural and dielectric properties were investigated and discussed. There was an increase in relative permittivity (ε_r) and dielectric loss (tan δ) of the composites with increase in the volume fraction of the ceramics. At room temperature and at 1 kHz frequency, 0.25[BZT–BCT]–0.75[PVDF] composite showed a highest relative permittivity (ε_r) ~41.     

Synthesis,structure and characterization of a new nonlinear optical calcium borate [Ca2B5O9]·[H(OH)2]

A new nonlinear optical crystal [Ca₂B₅O₉]·[H(OH)₂] (1) has been synthesized under hydrothermal condition. Compound 1 crystallizes in the monoclinic space group C2 with lattice constants a = 10.111(2) Å, b = 7.754(11) Å, c = 6.198(14) Å, β = 127.04(3)° and Z = 2. The fundamental building block (FBB) of 1 is a [B₅O₁₂] unit with two BO₃ triangles and three BO₄ tetrahedra. 1 was characterized by single-crystal X-ray diffraction, IR and UV–Vis spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) respectively. Also, powder second harmonic generation (SHG) measurements indicate that 1 is phase matchable and displays a SHG response of about 3.5 times that of KDP (KH₂PO₄).     

Synthesis and Characterization of the Luminescent Poly[2-decyloxy-5-(2′,5′-bis(decyloxy)phenyl)-1,4-phenylenevinylene]

A new soluble luminescent poly[2-decyloxy-5-(2′,5′-bis(decyloxy)phenyl)-1,4-phenylenevinylene] (DBDP-PPV) is prepared by the dehydrohalogenation of 1,4-bis(bromomethyl)-2-decyloxy-5-(2′,5′-bis(decyloxy)phenyl) benzene (as monomer) in this study. The above monomer bearing decyloxy and 2′,5′-bis(decyloxy)phenyl substituents was prepared via such chemical reactions as alkylation, bromination, and Suzuki coupling reactions. The two asymmetric substituents on the phenylene ring make the DBDP-PPV soluble in organic solvents and eliminate the tolan-bis-benzyl (TBB) structure defects. The structure and properties of the DBDP-PPV are examined by ¹H-NMR, FT-IR, UV/Vis, TGA, photoluminescence (PL), and electroluminescence (EL) analyses. The DBDP-PPV film exhibits a PL peak at 519 nm. With the DBDP-PPV acting as a light-emitting polymer, a device is fabricated with a sequential lamination of ITO/PEDOT/DBDP-PPV/Ca/Ag. The EL spectrum of the device shows a maximum emission at 507 nm. The turn on voltage of the device is about 15.6 V. Its maximum brightness is 4.67 cd/m² at a voltage of 16.8 V.     

Poly(ε-caprolactone) Diols (HOPCLOH) and Their Poly(ester-urethanes) (PEUs): The Effect of Linear Aliphatic Diols [HO–(CH2)m–OH] as Initiators

α,ω-Hydroxy telechelic poly(ε-caprolactones) were prepared by ring-opening polymerization of the ε-caprolactone catalyzed by ammonium decamolybdate in the presence of different aliphatic diols [HO–(CH₂)_m–OH, where m?=?2, 4, 6, 8, 10, 12, 14, and 16] as initiators to obtain a family of α,ω-hydroxy telechelic poly(ε-caprolactone) [HO–PCL–O–(CH₂)_m–O–PCL–OH, m?=?2, 4, 6, 8, 10, 12, 14, and 16]. The content of the alkyl group (AG) (–(CH₂)_m–) had an important effect on the crystallinity (x_i) of α,ω-hydroxy telechelic poly(ε-caprolactone), showing a proportional relationship. In poly(ester-urethanes) derived from α,ω-hydroxy telechelic poly(ε-caprolactones) and 1,6-hexamethylene diisocyanate, the AG also showed a similar effect on the x_i and eventually on the mechanical properties, increasing the values of the modulus. Therefore, AG content was a factor to induce a plastic behavior in poly(ester-urethanes). The effect of AG on the water uptake of poly(ester-urethanes) after 1 week was negligible.     

2-[4-[2-[4-[1-(2-乙氧基)苯并咪唑-2-基]哌啶-1-基]乙基]苯基]-2-甲基丙酸的合成

以4-(2-溴乙酰基)-α,α-二甲基苯乙酸乙酯(2)为起始原料,先在酸性还原体系中还原,得到亚甲基还原产物(3)再与2-(哌啶-4-烷基)-1H-苯并咪唑(4)在有机碱的作用下进行缩合,然后在无水条件下使用氢化钠拔氢后与氯代乙基乙基醚(6)缩合得到(7),最后,将酯基水解得到2-[4-[2-[4-[1-(2-乙氧基)苯并咪唑-2-基]哌啶-1-基]乙基]苯基]-2-甲基丙酸(比拉斯汀,1)。     

Preparation and Properties of α-Cellulose Short Fiber-Reinforced Poly(lactic Acid) Composites

The objective of this study is to fabricate the PLA/α-cellulose composites and to investigate the effect of α-cellulose short fibers on the toughness improvement of PLA. To homogeneously disperse the polar α-cellulose in the non-polar PLA matrix, the as-received α-cellulose was subjected to surface modification using stearic acid to impart the hydrophobic characteristics to the short fibers. The α-cellulose fibers dispersed more homogeneously in PLA through this modification, and consequently, the fiber pull-out and longer micro-crack length could improve the toughness and damping property of the resulting PLA composites. The inclusion of α-cellulose short fibers considerably decreased the spherulite dimension of the PLA/α-cellulose composites to accommodate larger deformation through grain boundary sliding. The PLA/α-cellulose composite improved its toughness by three times that of the neat PLA with low α-cellulose content (～4 wt.%), and maintained its transparency.     

Phase Equilibria in the Sections of the Ca(NO3)2–CO(NH2)2–H2O System and Deicing Properties of Nitrate–Urea Mixtures

Theoretical Foundations of Chemical Engineering - Phase equilibria in the sections of the Ca(NO3)2–CO(NH2)2–H2O system and the deicing properties of calcium nitrate and carbamide...     

Anionic Ring-Opening Polymerization (ROP) of a Phosphorus-Bridged [1]Ferrocenophane Initiated by Living Polystyrene and Polyisoprene: Synthesis of Novel Organic–Poly(ferrocenylphosphine) Block Copolymers

The novel block copolymers, polystyrene-b-poly(ferrocenylphosphine) and polyisoprene-b-poly(ferrocenylphosphine), were synthesized by anionic polymerization, utilizing the living organic anions to initiate the ring-opening polymerization of a phosphorus-bridged [1]ferrocenophane. The resulting block copolymers possess narrow polydispersities and have potentially coordinating phosphorus sites in the polymer backbone. These materials are of interest as precursors to metallized self-assembled nanoscale architectures.     

Synthesis,crystal structure and magnetic properties of one-dimensional cyano-bridged bimetallic complex of [Mn(Me2-bipy)2]3[W(CN)8]2·9H2O

An octacyanotungstate(V)-manganese(II) bimetallic assembly [Mn(Me₂-bipy)₂]₃[W(CN)₈]₂·9H₂O (1) (Me₂-bipy = 4,4′-dimethyl-2,2′-bipyridine) was synthesized in methanol and characterized by X-ray crystallography. X-ray analysis shows that complex 1 is a neutral, one-dimensional (1D) infinite chain polymer. Magnetic data analysis demonstrates a long-range magnetic interaction and two different antiferromagnetic coupling constants obtained by fitting between Mn and W ions in 1.     

1-[2-(2-羟基乙氧基)乙基]哌嗪的合成研究进展

简述了6种常见的1-[2-(2-羟基乙氧基)乙基]哌嗪的合成路线,并对其优缺点进行了比较。     

Synthesis and Characterizations of Poly(aniline)–Natural Clay Nanocomposites

Aniline (ANI) was polymerized under inert atmosphere in the presence and absence of natural clay initiated by peroxydisulphate (PDS) in an aqueous acidic medium. While increasing the amount of clay the rate of polymerization (R_p) was decreased and showed first order dependence with respect to amount of clay. The % yield was also decreased while increasing the amount of clay due to the confinement of monomer radical cation by the clay. The FTIR spectrum confirmed the presence of benzenoid and quinoid units in the polyaniline (PANI) structure. DSC inferred the absence of T_m due to cross-linking reaction of PANI because of de-doping process. AFM showed the distorted spherical morphology of uniformly dispersed clay platelets in the PANI. The % weight residue remain above 700°C is increased with the increase of amount of clay, which was confirmed by TGA method. Due to confinement effect the intrinsic viscosity value of PANI—nanocomposites were decreased with the increase of amount of clay in the system. PANI-nanocomposites showed improved d.c. conductivity value than the pristine PANI. Suitable mechanism was proposed to explain the experimental results obtained.