PCL/SiO2杂化纳米相微结构与晶态成核生长特性

The nano-phase microstructure of high molecular weight poly(ε-caprolactone) (PCL) /silica hybrid materials, in which polymeric and inorganic component are coupled by hydrogen bonding, and nucleation and growth of PCL chain in the hybrids were studied by scanning electronic microscopy, wide-angle X-ray diffraction and differential scanning calorimetry. The results show that the micro-phase separation in the hybrids occurs at the nano-meter scale. The average scale of the polymeric domain is about 70 nm. The morphological structure of the inorganic component appears as irregular particles. The uniform distribution of two phases relates to the bonding strength of hydrogen bonding between components in the hybrids. After a PCL is hybridized, the relative degree of crystallinity decreases and the corresponding scale of microlite change. In addition, with inorganic content increasing, the equilibrium melting points of the PCL in hybrids decrease. The energy that polymeric chains fold to form crystals on the surface of crystal nucleus increases. This result is due to the influence of silica and the bonding strength in hybrids.     

Coordination bonding construction, characterization and photoluminescence of ternary lanthanide (Eu(3+), Tb(3+)) hybrids with phenylphenacyl-sulfoxide modified bridge and polymer units

A novel polysilsesquioxane bridge (PPSSi) is synthesized with methylene group modification of phenylphenacyl sulfoxide by isocyanate group from 3-(triethoxysilyl)propyl isocyanate (TEPIC). Then ternary lanthanide (Eu, Tb) hybrids of polysilsesquioxane bridge (PPSSi) and four kinds of polymer chain (polyacrylamide (PAM), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA) and polyethyl methacrylate (PEMA) were assembled wth coordination bonding. To explore the influence of the different polymeric chains on the properties of lanthanide hybrids, the microstructure and photoluminescent properties of these lanthanide coordination polymer hybrids (PPSSi-Ln-PAM (PVP, PMMA, PEMA)) are compared in detail. Four organic polymer chains with different structures not only can coordinate to the lanthanide ions by their own carbonyl groups, but also can form a polymeric matrix together with the inorganic Si-O network. The results show that all the obtained hybrids could show efficient intramolecular energy transfer and lead to excellent characteristic emission of lanthanide ions. Moreover, the different structures of the polymers induce different microstructures and different photoluminescent behavior (lifetime and quantum efficiency) for these hybrid systems. The PPSSi-Ln-PMMA hybrid leads to the longest lifetime and highest quantum efficiency.     

Thermal stability and degradation kinetics of novel organic/inorganic epoxy hybrid containing nitrogen/silicon/phosphorus by sol-gel method

Hybrids containing silicon, phosphorous and nitrogen were prepared by the sol-gel method and compared with pure epoxy. The silicon, phosphorous and nitrogen components were successfully incorporated into the networks of polymer. Thermogravimetric analysis (TGA) was used for rapid evaluation of the thermal stability of different materials. The integral procedure decomposition temperature (IPDT) has been correlated the volatile parts of polymeric materials and used for estimating the inherent thermal stability of polymeric materials. The IPDT of pure epoxy was 464 °C and the IPDTs of hybrids were higher than that of pure epoxy. The thermal stability of hybrids increased with the contents of inorganic components. The inorganic components can improve the thermal stability of pure epoxy.Two methods have been used to study the degradation of hybrids containing silicon, phosphorous and nitrogen hybrid during thermal analysis. These investigated methods are Kissenger, Ozawa's methods. The activation energies (E_a) were obtained from these methods and compared. It is found that the values of E_a for modified epoxy hybrids are higher than that of pure epoxy. The hybrids of high activation energy possess high thermal stability.     

DNA multiblock copolymers

Single stranded (ss) DNA block copolymers were applied to synthesize DNA multiblock architectures by hybridization; these polymeric bioorganic hybrids were characterized by gel electrophoresis and MALDI-TOF mass spectrometry.     

溶胶-凝胶法合成聚甲基丙烯酸甲酯/二氧化钛杂化聚合物材料

由共聚合在PMMA聚合物链段上引入了－Si(OR)₃功能团,通过溶胶－凝胶过程合成了PMMA/TiO₂杂化聚合物材料.溶剂抽提结果表明有化学键存在的杂化材料体系中凝胶的含量很高.通过FTIR测试对材料结构进行了分析,由TGA、DSC测试分析了杂化材料体系中无机组份的含量对材料性能的影响.     

Heavy metal removal of tri-amino-functionalized sol–gel hybrids with tailored characteristics

Adsorption of heavy metal ions from aqueous solutions on tri-amino-functionalized silica hybrids with tailored structural characteristics was investigated. The adsorbents were prepared using a controllable sol–gel method with (3-aminopropyl)trimethoxysilane or 3-[2-(2-aminoethylamino)ethylamino] propyltrimethoxysilane, polymeric polymethylhydrosilane and tetraethoxysilane as co-precursors in the absence of traditional surfactant aggregates. These as-prepared hybrids possess tailored structures with high specific surface area, large pore volumes and relatively narrow pore diameter as confirmed by transmission electron microscopy and nitrogen sorption results. The elemental analysis and FT-IR indicated that amino groups had been successfully introduced into the opened skeletons. The loadings of amino moieties of the amino-functionalized gels could be tuned from 5 to 40% by adjusting the molar ratio of organoalkoxysilane/silica in the synthesis system. The heavy metal adsorption experiments have been examined for Cu(II), Pb(II), Ni(II), Cd(II) and Zn(II) from aqueous solution employing batch method. The results showed that the adsorption capacity of the tri-amino-functionalized adsorbents was higher than that of the mono-amino-functionalized counterparts, illustrating a good potential for environmental remediation in virtue of the combination of selective adsorption performance and large-scale synthesis character.     

Rare-earth/inorganic/organic polymeric hybrid materials: molecular assembly, regular microstructure and photoluminescence

2-Hydroxynicotinic acid (HNA) was grafted by 3-(triethoxysilyl)propyl isocyanate (TEPIC) to achieve the molecular precursor HNA-Si through the hydrogen-transfer nucleophilic addition reaction between the hydroxyl group of HNA and the isocyanate group of TEPIC. Then, a chemically bonded rare-earth/inorganic polymeric hybrid material (A) was constructed using HNA-Si as a bridge molecule that can both coordinate to rare-earth ions (HNA-Si-RE) and form an inorganic Si-O network with tetraethoxysilane (TEOS) after cohydrolysis and copolycondensation processes. Further, three types of novel rare-earth/inorganic/organic polymeric hybrids (B-D) were assembled by the introduction of three different organic polymeric chains into the above system. First, methacrylic acid (MAA) [or methacrylic acid and acrylamide (ALM) in the molar ratio of 1:1] was mixed to polymerize (or copolymerize) with benzoyl peroxide (BPO) as the initiator to form poly(methacrylic acid) (PMAA) [or poly(methacrylic and acrylamide) (PMAALM)], and then PMAA or PMAALM was added to the precursor HNA-Si before the assembly of HNA-Si-RE, resulting in the hybrid materials HNA-Si-RE-PMAA (B) and HNA-Si-RE-PMAALM (C). Second, poly(vinylpyrrolidone) (PVP) was added to coordinate to the rare-earth ions by the carbonyl group in the complex HNA-Si-RE, to achieve the hybrid HNA-Si-RE-PVP (D). All of these hybrid materials exhibit homogeneous, regular, and ordered microstructures and morphologies, suggesting the occurrence of self-assembly of the inorganic network and organic chain. Measurements of the photoluminescent properties of these materials show that the ternary rare-earth/inorganic/organic polymeric hybrids present stronger luminescent intensities, longer lifetimes, and higher luminescent quantum efficiencies than the binary rare-earth/inorganic polymeric hybrids, indicating that the introduction of the organic polymer chain is a benefit for the luminescence of the overall hybrid system.     

Ion Tunneling in Polymeric Solid Electrolytes for Batery and Electrochromic Display in the Dry State

Polymeric solid electrolytes which show bi-or single-ionic tunneling were prepared, and their unique ion conduction was applied for the design of some devices. Poly [(oligooxyethylene) methacrylatel] /MX hybrids and poly [(oligooxyethylene) methacrylate-co-methacrylic acid alkali metal salts] were prepared as typical models of those tunneling systems. These showed ionic conductivities above 10^?5 and 10^?7 S/cm at room temperature, respectively. An all-solid-state electrochromic display and a dry battery were prepared with these polymeric solid electrolytes. The all-solid-state electrochromic display showed excellent coloring and bleaching response by 1–3 V. The all-solid-state battery showed V _oc = 3.1 V stability for over 2 weeks. Their characteristics as well as their mechanism are also reported.     

Structural Control in Poly(butyl acrylate)-Silica Hybrids by Modifying Polymer-Silica Interactions

Porous organic-inorganic hybrids of poly(n-butyl acrylate) (PBA) and silica were synthesized with different polymer contents via sol-gel process. With the aim of controlling interfacial properties in hybrids, the bonding agent 3-methacryloxypropyl-trimethoxysilane (MPTS) was copolymerized with n-butyl acrylate (BA) at different proportions. Copolymers P(BA-co-MPTS) and hybrids obtained were characterized by infrared spectroscopy and thermogravimetric analysis. Nitrogen sorption analyses of hybrids determined that the increase in polymer content leads to the formation of non-porous hybrids only if bonding agent content is sufficiently large. Otherwise, hybrids with large pore volumes and sizes, nearly reaching macropore range, are obtained even for polymer content as high as 45% in the absence or low content of MPTS. Scanning electron microscopy images showed that the addition of bonding agent changes the aspect of hybrid surface from rough, with loosely bound particles with a few hundreds nanometers, to relatively smooth, with particles typically smaller than 100 nm. These results were explained considering that a more homogeneous medium provided by the presence of MPTS may lead to easier condensation of PBA-silica particles due to the smaller polymeric domains. This idea is supported by the fact that, after polymer degradation, smaller uniform-sized pores arise for hybrids with larger bonding agent contents.     

Quick water-responsive shape memory hybrids with cellulose nanofibers

A type of quick water-responsive shape memory hybrids is fabricated by introducing cellulose nanofibrous mats as the filler in a polymeric matrix. Cellulose nanofibrous mats are obtained through hydrolyzing electrospun cellulose acetate (CA) nanofibers, then casted in thermoplastic polyurethane (TPU) solution to form the hybrids. The quick shape memory behavior of the formed hybrids is demonstrated using dynamic mechanical analysis (DMA) and stress–strain cyclic test. According to a predetermined protocol, the hybrids present desirable shape fixation and recovery, and the elastic modulus (E′) is shown to be responsive promptly and reversibly against drying and wetting cycle. Shape memory mechanism of the hybrids involves the reversible and competitive hydrogen bonds within cellulose before and after water immersion as well as the entropy elasticity of the TPU matrix. This study can pave a way to design novel smart materials by facile methods through incorporating natural nanomaterials as water sensitive fillers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 767–775     

Hierarchical MoS2/polyaniline binary hybrids with high performance for improving fire safety of epoxy resin

Here we report a facile strategy to fabricate phosphoric acid doped polyaniline/molybdenum disulfide (PANI/MoS₂) hybrids as high-performance nanofillers in epoxy (EP) resin for the first time. In situ growth of PANI on the surface of two-dimensional MoS₂ template resulted in the uniform dispersion and strong interfacial adhesion of PANI/MoS₂ hybrids within EP matrix, which can be confirmed by the obvious increase (13.5°C) in glass transition temperature (T_g) of EP composites. The MoS₂ nanosheets also acted as a critical component to generate synergistic effect with PANI on reducing the fire hazards of EP resin. It resulted in a remarkable removal of flammable decomposed products and a considerable reduction of toxic CO yield. The dramatical decreases in real-time smoke density and total smoke production, and high-graphitized char layer in condensed phase were obtained for EP composite with 5 wt% PANI/MoS₂ hybrids. The multiple synergistic effects (synergistic dispersion and synergistic char formation) are believed to be the primary source for these obvious enhancements of properties of EP composites. This facile strategy may achieve the potential application of functionalized MoS₂ in polymeric nanocomposites.     

Composites of hydrophilic polymers and organic nanocrystals enable enhanced robustness

We describe a new family of composite materials, polymer/organic nanocrystal (ONC) hybrids. These were prepared from soluble ONCs based on perylene diimides (PDI) and water‐soluble polymers (sodium alginate and polyvinyl alcohol). Polymer/ONC films were characterized by optical spectroscopy, electron microscopy, and tensile strength studies. The films show enhanced chemical and mechanical stability due to synergy between the constituents. The hybrid films are stable in both water and organic solvents, unlike the individual components. The ONCs we employed possess nonlinear optical activity (second harmonic generation, SHG); they showed improved photostability (stable SHG under laser light) in the hybrids. Tensile strength enhancement (as high as twofold in the film having just 2.4% ONCs by weight) was observed as revealed by mechanical measurements. Hybrids with aligned ONCs were also prepared using simple extrusion via syringe needle followed by gelation. Employing ONCs in polymeric hybrid materials enables facile fabrication in aqueous media, synergy, chemical, mechanical, and photostability as well as useful photofunction (SHG), introducing a versatile class of composite materials.     

A VERSATILE AND REGIOSELECTIVE SYNTHESIS OF VICINAL AZIDOALCOHOLS USING CROSS-LINKED POLY（4-VINYLPYRIDINE） SUPPORTED AZIDE ION UNDER SOLVENT-FREE CONDITIONS

A new polymeric reagent, cross-linked poly（4-vinylpyridine） supported azide ion, [P4-VP]N3, was introduced as polymeric reagents for efficient and regioselective conversion of epoxides to azidohydrins in the presence of cross-linked poly（4-vinylpyridine） supported sulfuric acid, [P4-VP]H2SO4, as a solid proton source and as catalyst under solvent-free conditions. The advantages of this polymeric reagent over some of those reported in the literature are easy work-up procedure and regeneration of the reagent.     

Synthesis of polymeric ionic liquid microsphere/Pt nanoparticle hybrids for electrocatalytic oxidation of methanol and catalytic oxidation of benzyl alcohol

Herein, we present a facile approach for the synthesis of polymeric ionic liquids (PILs) microspheres for metal scavenging and catalysis. Crosslinked poly(1‐butyl‐3‐vinylimidazolium bromide) microspheres with the diameter of about 200 nm were synthesized via miniemulsion polymerization, in which 1,4‐di(vinylimidazolium) butane bisbromide was added as the crosslinker. Anion exchange of PIL microspheres with Pt precursor and followed by the reduction of Pt ions produced PIL microsphere supported Pt nanoparticle hybrids. The synthesized Pt nanoparticles with a diameter of about 2 nm are uniformly dispersed and strongly bound to the surface of PIL microspheres. The catalytic performances of PIL/Pt nanoparticle hybrids were evaluated for both the electrocatalytic oxidation of methanol and oxidation of benzyl alcohol. The PIL/Pt nanoparticle hybrids show better electrocatalytic activity towards the electrooxidation of methanol than pure Pt nanoparticles. Furthermore, they are effective and easily reusable catalysts for the selective oxidation of benzyl alcohol in aqueous reaction media, demonstrating that the synthesized PIL microspheres are suitable scaffolds for heterogeneous catalysts Pt. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Lanthanide (Eu3+, Tb3+) Centered Mesoporous Hybrids with 1,3‐Diphenyl‐1,3‐Propanepione Covalently Linking SBA‐15 (SBA‐16) and Poly(methylacrylic acid)

1,3‐Diphenyl‐1,3‐propanepione (DBM)‐functionalized SBA‐15 and SBA‐16 mesoporous hybrid materials (DBM‐SBA‐15 and DBM‐SBA‐16) are synthesized by co‐condensation of modified 1,3‐diphenyl‐1,3‐propanepione (DBM‐Si) and tetraethoxysilane (TEOS) in the presence of Pluronic P123 and Pluronic F127 as a template, respectively. The as‐synthesized mesoporous hybrid material DBM‐SBA‐15 and DBM‐SBA‐16 are used as the first precursor, and the second precursor poly(methylacrylic acid) (PMAA) is synthesized through the addition polymerization reaction of the monomer methacrylic acid. These precursors then coordinate to lanthanide ions simultaneously, and the final mesoporous polymeric hybrid materials Ln(DBM‐SBA‐15)₃PMAA and Ln(DBM‐SBA‐16)₃PMAA (Ln=Eu, Tb) are obtained by a sol‐gel process. For comparison, binary lanthanide SBA‐15 and SBA‐16 mesoporous hybrid materials (denoted as Ln(DBM‐SBA‐15)₃ and Ln(DBM‐SBA‐16)₃) are also synthesized. The luminescence properties of these resulting materials are characterized in detail, and the results reveal that ternary lanthanide mesoporous polymeric hybrid materials present stronger luminescence intensities, longer lifetimes, and higher luminescence quantum efficiencies than the binary lanthanide mesoporous hybrid materials. This indicates that the introduction of the organic polymer chain is a benefit for the luminescence properties of the overall hybrid system. In addition, the SBA‐15 mesoporous hybrids show an overall increase in luminescence lifetime and quantum efficiency compared with SBA‐16 mesoporous hybrids, indicating that SBA‐15 is a better host material for the lanthanide complex than mesoporous silica SBA‐16.     

Novel polyester/SiO2 nanocomposite membranes: Synthesis,properties and morphological studies

In this paper, a new type of soluble polyester/silica (PE/SiO₂) hybrid was prepared by the ultrasonic irradiation process. The coupling agent γ-glycidyloxypropyltrimethoxysilane (GOTMS) was chosen to enhance the compatibility between the polyester (PE) and silica (SiO₂). Furthermore, the effects of the coupling agent on the morphologies and properties of the PE/SiO₂ hybrids were investigated using UV-vis and FT-IR spectroscopies and FE-SEM. The densities and solubilities of the PE/SiO₂ hybrids were also measured. The results show that the size of the silica particle was markedly reduced by the introduction of the coupling agent, which made the PE/SiO₂ hybrid films become transparent. Furthermore, thermal stability, residual solvent in the membrane film and structural ruination of membranes were analyzed by thermal gravimetric analysis (TGA). The effects of SiO₂ nanoparticles on the glass transition temperature (T_g) of the prepared nanocomposites were studied by differential scanning calorimetry (DSC). Moreover, their mechanical properties were also characterized. It can be observed that the Young's moduli (E) of the hybrid films increase linearly with the silica content. The results obtained from gas permeation experiments with a constant pressure setup showed that adding SiO₂ nanoparticles to the polymeric membrane structure increased the permeability of the membranes.     

Two series of multicomponent rare earth (Eu3+, Tb3+, Sm3+) polymeric hybrids: chemically bonded assembly and photophysical properties

In the present work, two new chemical linkages (BPDA-PAM, BPDA-DG) are synthesized through the reaction between 4,4'-biphthalic anhydride (BPDA) and acrylamide (AM), diethylene glycol (DG), respectively. Then two novel series of multicomponent rare earth (Eu(3+), Tb(3+), Sm(3+)) polymeric hybrids have been assembled through the coordination bonding: one is from the linkage BPDA-PAM to form the hybrids BPDA-PAM-RE-phen(bipy) (2,2'-bipyridine (bipy) and 1,10-penanthroline (phen)), the other is from the linkage BPDA-DG to compose the hybrids BPDA-DG-RE-PVP and PVP (PVP = poly vinylpyridine). These hybrids are characterized and especially the photophysical properties (luminescence spectra, lifetimes and quantum efficiencies) are discussed in detail.     

Ultrasound-Triggered Release of Ibuprofen from a Chitosan-Mesoporous Silica Composite- a Novel Approach for Controlled Drug Release

Summary: In this work, an attempt was made to synthesize a novel Chitosan-Mesoporous silica (CS-MS) hybrid composite to design a drug delivery system based on ultrasound triggered stimuli-responsive smart release. The in-vitro drug release properties of both the Mesoporous Silica (MS) and Chitosan (CS) hybrids were investigated. Ibuprofen (Ibu) was used as a model drug. The results from powder X-Ray diffraction (XRD) patterns, and BET N₂ adsorption isotherms exhibited that MS can accommodate drug molecules into the lumen of the channels and pores. Drug release, stimulated by temperature and pH of the release media was also investigated. We studied the Ultrasound (US) triggered release of Ibu in a simulated body fluid (pH 7.4). The results exhibited that US can be used as a non-invasive technique for drug release from polymeric materials. The enhancing effect of ultrasound on drug release is due to the Cavitation effect, without causing any significant destruction on the polymer morphology.     

Drying Study of Siloxane-PPG Nanocomposites

This is a study of the structural transformations occurring in hybrid siloxane-polypropyleneglycol (PPG) nanocomposites, with different PPG molecular weight, along the drying process. The starting materials are wet gels obtained by the sol-gel procedure using as precursor the 3-(trietoxysilyl)propylisocyanate (IsoTrEOS) and polypropylenglycol bis(2-amino-propyl-ether) (NH₂-PPG-NH₂). The shrinkage and mass loss measurements were performed using a temperature-controlled chamber at 50°C. The nanostructural evolution of samples during drying was studied in situ by small angle x-ray scattering (SAXS). The experimental results demonstrate that the drying process is highly dependent on the molecular weight of polymer. After the initial drying stage, the progressive emptying of pores leads to the formation of a irregular drying front in gels prepared from PPG of high molecular weight, like 4000 g/mol. As a consequence, an increase of the SAXS intensity due to the increase of electronic density contrast between siloxane clusters and polymeric matrix is observed. For hybrids containing PPG of low molecular weight, the pore emptying process is fast, leading to a regular drying front, without isolated nanopockets of solvents. SAXS intensity curves exhibit a maximum, which was associated to the existence of spatial correlation of the silica clusters embedded in the polymeric matrix. The spatial correlation is preserved during drying. These results also reveal that the structural transformation during drying is governed by capillary forces and depends on the entanglement of polymer chains.     

Effect of the silica content on the physico-chemical and relaxation properties of hybrid polymer/silica nanocomposites of P(EMA-co-HEA)

Poly(ethyl methacrylate-co-hydroxyethyl acrylate) 70/30 %wt/silica, P(EMA-co-HEA)/SiO₂, nanocomposites, with silica contents ranging from 0 to 30 %wt, were synthesized and studied as promising candidate materials for the synthetic matrix of scaffolds for bone substitutes or dentin regeneration. The physico-chemical properties of the hybrids were studied by calorimetry and by contact angle measurements on the surfaces. The dynamic-mechanical and compression properties were analysed. Intermediate silica contents in the range from 10 to 20 %wt of silica rendered co-continuous interpenetrated structures, in which silica produced a reinforcing effect in the polymeric matrix and at the same time conferred bioactivity to the surfaces by improving surface wettability, making these hybrids appropriate for the proposed application. On the contrary, silica percentages below 10 %wt formed disconnected inorganic aggregates at the nanoscale dispersed in the copolymer matrix, which did not modify significantly the copolymer properties. Silica contents above 20 %wt formed denser inorganic networks with few terminal silanol groups available at the surfaces, much more rigid and hardly manageable samples.