膨润土及改性膨润土在造纸行业中的应用

膨润土特殊的构造使其具有离子交换性、吸水性、膨胀性、触变性、粘结性、吸附性等多重性质,其常用改性方法有活化法和添加改性剂法两种。概括了近期的文献资料,对膨润土和改性膨润土在造纸行业中的应用情况进行了综述,对今后的发展提出了建议。     

Inexpensive Fabrication and Characterization of Crystalline Poly(o-Anthranilic Acid-co-o-Phenylenediamine) Emeraldine Base/Bentonite Nanocomposites

Copolymers of o-anthranilic acid and o-phenylenediamine/hydrophilic bentonite nanocomposites were synthesized by 1:1 molar ratios of the respective monomers with different percentages of nanoclay through modified in situ chemical copolymerization. The results obtained were justified by measuring the Fourier transform infrared of poly(o-anthranilic acid-co-o-phenylenediamine) emeraldine base/bentonite nanocomposites. Ultraviolet–visible spectra of poly(o-anthranilic acid-co-o-phenylenediamine) emeraldine base/bentonite nanocomposites were investigated. The thermal stability was studied, and it was found that poly(o-anthranilic acid-co-o-phenylenediamine) emeraldine base/bentonite nanocomposites were thermally more stable than pure copolymer. X-ray diffraction patterns of copolymer poly(o-anthranilic acid-co-o-phenylenediamine) emeraldine base and poly(o-anthranilic acid-co-o-phenylenediamine) emeraldine base/bentonite nanocomposites were studied.     

In Situ Polymerization and Characterization of Aniline and O-Anthranilic Acid Copolymer/Pyrogenic Silica Nanocomposites

Copolymers of aniline and o-anthranilic acid/amorphous fumed silica nanocomposite are synthesized by 5:1 molar ratios of the respective monomers with different percentages of silica nanoparticles via in situ chemical co-polymerization. The electrical conductivity and spectral characteristics upon incorporation of o-anthranilic acid units into the polyaniline backbone in presence of silica nanoparticles are investigated. The results are justified by measuring the UV-Vis absorption spectra, FT-IR for PANAA copolymer, and in situ PANAA/silica nanocomposite. Also, the thermal gravimetric analysis for the copolymer powder formed in the bulk in absence and in presence of silica nanoparticles are carried out.     

Structure,Performance and Crystallization Behavior of Poly (Lactic Acid)/Humic Acid Amide Composites

Humic acid amide (HA-amide) was prepared by amidation of HA and dodecylamine (DDA) with carbonyl diimidazole (CDI) as coupling reagent. Furthermore, HA-amide was added to poly (lactic acid) (PLA) as a nucleating agent to prepare poly (lactic acid)/humic acid amide composites (PLA/HA-amide) by melt blending. The structure and performance of PLA/HA-amide composites were investigated by thermogravimetric analysis (TG), differential scanning calorimetry (DSC), polarized optical microscopy (POM), and rheological analysis. Non-isothermal crystallization kinetics showed the HA-amide enhanced the crystallization rate of PLA. The results of crystallization behavior of PLA/HA-amide composites showed that HA-amide was an efficient nucleating agent of PLA.     

Synthesis and characterization of a novel 3D copper(I) coordination polymer with a ligand generated in situ

Hydrothermal reaction of CuCl₂ · 2H₂O, NaN₃ with 1,4-dicyanobenzene in water/ethanol yielded a novel Cu(I)-tetrazolate, {Cu(cptz)}_n, (1) (Hcptz is 5-(4-cyanophenyl)-tetrazole). The cptz ligand in the complex was generated in situ through the [2 + 3] cycloaddition reaction involving one of the two cyano-groups of the precursor 1,4-dicyanobenzene. The structure characterization shows that 1 possesses a 3D 4-connected SrAl₂ topological network. Additionally, complex 1 exhibits strong yellow fluorescence at room temperature in the solid state.     

Synthesis and Characterization of Poly(acrylic acid)/modified Bentonite Superabsorbent Polymer

A novel poly(acrylic acid)/modified bentonite superabsorbent polymer (SAP) was synthesized through chemical crosslinking by a polymerization technique in a complete aqueous environment. This SAP was fabricated effectively by dispersing modified bentonite in a monomeric solution, using N,N′-methylenebisacrylamide as crosslinker and ammonium persulfate as initiator. Fourier transform infrared (FTIR) spectral analysis showed that the XG chains had intercalated into bentonite sheets. The influence of crosslinking density and XG content were investigated. Results showed modified bentonite not only effectively increases water absorbency, but also improves water retention ability. This can be further used as a carrier matrix for the development of a drug delivery system.     

Thermotropic liquid crystalline polymer (Rodrun LC5000)/polypropylene in situ composite films: rheology, morphology, molecular orientation and tensile properties

In situ composite films were prepared by a two-step method. First, polypropylene and thermotropic liquid crystalline polymer (TLCP), Rodrun LC5000 (80 mol% p-hydroxy benzoic acid (HBA)/20 mol% polyethylene terephthalate (PET)), were melt blended in a twin-screw extruder and then fabricated by extrusion through a mini-extruder as cast film. Rheological behavior of the blends, morphology of the extruded strands and films, and tensile properties of the in situ composite films were investigated. Rheological behavior of the blends at 295 °C studied using a plate-and-plate rheometer revealed a substantial reduction of the complex viscosity with increasing TLCP content, and all specimens exhibited shear thinning behavior. Over the angular frequency range of 0.6-200 rad/s, the viscosity ratio (dispersed phase to matrix phase) was found to be very low, in the range of 0.03-0.07. Morphologies of the fracture surfaces of the blend extrudates and the film surfaces etched in permanganic solution were investigated by scanning electron microscope (SEM). The TLCP droplets in the extruded strands were seen with a progressive deformation into fibrillar structure when TLCP content was increased up to 30 wt%. In the extruded films, TLCP fibrils with increasing aspect ratio (length to width) were observed with increasing TLCP concentration. Orientation functions of each component were determined by X-ray diffraction using a novel separation technique. It was observed that the Young's modulus in machine direction of the extruded film was greatly improved with increasing TLCP loading, due to the increase in fiber aspect ratio and also molecular orientation.     

Crystallization,Morphological, and Mechanical Response of Poly(Lactic Acid)/Lignin-Based Biodegradable Composites

Green/bio-based composites of poly(lactic acid) and lignin were prepared by melt blending in a twin-screw extruder. Thermal and mechanical properties, phase interaction, and morphology of the composites have been investigated. Fourier transform infrared studies elucidated the existence of intermolecular hydrogen bonding between poly(lactic acid) and lignin. Scanning electron microscopy studies revealed an extent of diffused phase boundaries between poly(lactic acid) and lignin which also indicated significant interaction between them. Tensile properties showed significant increase over neat poly(lactic acid) with lignin loading (0–0.28 volume fraction) which further justified using theoretical models. Izod impact strength decreased with lignin content.     

Facile Bulk Synthesis of Homogeneous and Transparent Nanocrystals Hybrids via In Situ Transformation of Ionomers into CdS Quantum-Dot-Polymer

We systemically report on a method for fabricating bulk CdS QD-polymer hybrids nanocomposites with tunable control photoluminescence (PL) by using as-prepared ionomers. Firstly, we rationally designed to synthesize well-dispersed PMMA/Cd(AA)₂ (cadmium acrylate) ionomers containing different concentrations of Cd²⁺ ion clusters via free-radical polymerization. And then, we introduced H₂S gas into the ionomer solutions to obtain transparent PMMA/CdS QD-polymers in situ. Subsequently, we employed PMMA/CdS QD-polymers to further produce claviform CdS/PMMA hybrid nanocomposites via in situ bulk polymerization. The properties of as-prepared QD-polymers and their hybrid nanocomposites were thoroughly investigated by Ultraviolet–visible (UV-vis), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), photoluminescence (PL), thermogravimetric analyses (TGA) measurements. We have found that these QD-polymers exhibit uniform dispersity, good optical property and an obvious advantage on thermal stability, along with facilely producing bulk nanocrystal/polymer hybrid nanocomposites with a large scale.     

巯基乙酸修饰ZnS纳米颗粒的水相合成及表征

以巯基乙酸(HSCH2COOH, RSH)为表面修饰剂,采用水相合成法制备了表面修饰巯基乙酸的ZnS纳米颗粒. 采用透射电子显微镜、粒度分布、X射线衍射和红外光谱等对ZnS纳米颗粒进行了表征,并对ZnS纳米粒子的制备条件进行了详细的考察. 结果表明,水相合成法的最佳制备条件为：反应pH值8.0, Zn2+:S2-:RSH(摩尔浓度比)为1:1.34:2. 在最佳条件下可制备粒径小(11 nm)且粒度分布窄、分散性好的ZnS纳米粒子,其晶体属面心立方b-闪锌矿结构.     

Synthesis,Characterization and Glass-reinforced Composites of Trimethylolmelamine-phenol Resins

Abstract

Trimethylolmelamine (TMM) has been prepared and characterized. The TMM condensed with phenol in the presence of alkali catalyst at the varying ratios of TMM: Phenol, viz. 1:1, 1:1.5 and 1:2. The resultant triazine ring containing resins (TMMP) were characterized by elemental analyses, IR spectral studies and thermogravimetry. The isothermal curing study of TMMP resin with hexamethylenetetramine (HMTA) was also carried out. Finally, the glass-reinforced composites based on TMMP-HMTA system have also been prepared and characterized for synergetic property combination of both MF and PF.     

Mechanical,Thermal, and Electrical Properties of Epoxy Matrix Composites Reinforced With Polyamide-Grafted-MWCNT/poly(azo-pyridine-benzophenone-imide)/Polyaniline Nanofibers

Friedel-Crafts acylation and in situ polymerization were adopted to graft polyamide on multi-walled carbon nanotube (MWCNT) surface to form MWCNT-PA using γ-Phenyl-?-caprolactone. Via electrospinning, MWCNT-PA/PAPBI and MWCNT-PA/PAPBI/PANI nanofibers were prepared using MWCNT-PA, poly(azo-pyridine-benzophenone-imide) (PAPBI) and polyaniline (PANI) and DGEBA as matrix. Compared with 3 wt% MWCNT-PA/PAPBI nanofibers (20.2 GPa), tensile modulus for film reinforced with 3 wt% MWCNT-PA/PAPBI/PANI nanofibers (27.6 GPa) was considerably increased. Thermal stability of MWCNT-PA/PAPBI/PANI nanofibers reinforced epoxy was higher with T₁₀ 633–654°C and T_g 283–291°C relative to DGEBAMWCNT-PA/PAPBI system. The filler loading also increased the electrical conductivity of DGEBA/MWCNT-PA/PAPBI/PANI from 3.44 to 6.01 S cm^?1.     

原位聚合法制备聚对苯二甲酸丙二醇酯／蒙脱土复合材料及其表征

采用原位聚合法制备了聚对苯二甲酸丙二醇酯(PTT)像脱土(MMT)复合材料。X射线衍射和透射电子显微镜扫描结果表明所得复合材料为剥离型或部分剥离型结构。与纯PTT、相比，由于MMT、在PTT基体中达到纳米尺寸分散，PTT／MMT复合材料的热稳定性能、结晶性能和拉伸性能都得到了明显提高。     

Synthesis, Properties, and Oxidation of Alumina-Titanium Nitride Composites

Al₂O₃-TiN composites varying from 60 to 66.6 mol% TiN were prepared by an in situ reaction between TiO₂ and AlN. N₂ or O₂ evolution takes place, depending on the composition selected. A pseudobrookite (PB) phase appears in the reaction product, the amount decreasing as the TiO₂:AlN ratio becomes poor in AlN. The in situ reaction product can be pressureless sintered to 94% to 97% theoretical density at 1600°C in N₂. The four-point flexural strength varies from 280 to 430 MPa at room temperature. The fracture toughness is 3 to 4.7 MPa.m^1/2. Oxidation of a 94% dense TiN-Al₂O₃ composite in the temperature range 710° to 1050°C was also studied. A layer of TiO₂ (rutile) protects the composite at 710°C from further oxidation with a weight gain of 0.08 mg/cm² in 90 min. In the temperature range 820° to 1050°C, the initial oxidation kinetics are parabolic, with an activation energy of 216.5 kJ/mol. Linear oxidation kinetics with an activation energy of 113.7 kJ/mol pertain at longer times.     

Synthesis and characterization of novel type poly (4-chloromethyl styrene-grft-4-vinylpyridine)/TiO2 nanocomposite via nitroxide-mediated radical polymerization

This paper describes the synthesis and characterization of novel type poly (4-chloromethyl styrene-graft-4-vinylpyridine)/TiO₂ nanocomposite. Firstly, poly (4-chloromethyl styrene)/TiO₂ nanocomposite was synthesized by in situ free radical polymerizing of 4-chloromethyl styrene monomers in the presence of 3-(trimethoxysilyl) propylmethacrylate (MPS) modified nano-TiO₂. Thereafter, 1-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO-OH) was synthesized by the reduction of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO). This functional nitroxyl compound was covalently attached to the poly (4-chloromethyl styrene)/TiO₂ with replacement of chlorine atoms in the poly (4-chloromethyl styrene) chains. The controlled graft copolymerization of 4-vinylpyridine was initiated by poly (4-chloromethyl styrene)/TiO₂ nanocomposite carrying TEMPO groups as a macroinitiators. The coupling of TEMPO with poly (4-chloromethyl styrene)/TiO₂ was verified using ¹H nuclear magnetic resonance (NMR) spectroscopy. The obtained nanocomposites were studied using transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectra, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and the optical properties of the nanocomposites were studied using ultraviolet-visible (UV-Vis) spectroscopy.     

稀土改性SO_4~(2-)/TiO_2对合成莰烯的催化作用研究

筛选出三种稀土改性催化剂SO2-4/TiO2-La2O3、SO2-4/TiO2-CeO2、SO2-4/TiO2-Nd2O3催化α-蒎烯合成莰烯的反应。考察了La3+、Ce4+、Nd3+浓度、反应温度、反应时间对转化率和产物分布的影响。确定在130℃反应均为一级反应,反应速率常数分别为3.964×10-1h-1、5.262×10-1h-1和5.313×10-1h-1。     

Curing Characteristics,Morphological, Tensile and Thermal Properties of Bentonite-Filled Ethylene-Propylene-Diene Monomer (EPDM) Composites

Bentonite (Bt) with irregular shape and surface morphology was used as a new type of filler in EPDM. EPDM/Bt composites were prepared using a laboratory size two-roll mill by adding 0 to 70 phr Bt. The effects of Bt loading on curing characteristics, morphology, tensile and thermal properties of EPDM/Bt composite were studied. Scorch and curing time were decreased with 0 to 30 phr loading and increased subsequently at 50 and 70 phr. Tensile strength and elongation at break (E_b) were increased with increasing Bt loading from 0 to 50 phr and decreased at 70 phr, whereas the tensile modulus (M100%) shows an increasing trend with increasing Bt loading. Thermogravimetric analysis shows the enhancements of thermal properties with increasing Bt loading. Morphological studies of tensile fracture surfaces of EPDM/Bt composite proves good interaction between Bt particles and EPDM at 50 phr and formation of Bt agglomerates at 70 phr.     

Pervaporation‐Assisted Esterification of Caproic Acid with Isobutanol in Conventional,In Situ,and Ex Situ Reactors

The factors that affect the pervaporation‐assisted esterification of caproic acid and isobutanol have been investigated in a batch reactor and compared with two different pervaporation reactors, in situ and ex situ reactors, with different configurations. The operating process parameters of the pervaporation modules can be adjusted to optimize the performance, which improves the conversion of reactants and reduces the operating costs. The performances of the reactors have been extensively studied and the membrane selectivity has been investigated in terms of the flux of individual reaction species. The mass transfer limitation of both pervaporation reactors was studied and suitably eliminated. In addition, the performance of the pervaporation reactors was investigated by evaluating the ratio of water removal rate to the water production rate.     

Crystalline,Thermal, and Biodegradable Properties of Poly(L-Lactic Acid)/Poly(D-Lactic Acid)/POSS Melt Blends

A ternary nanocomposite consisting of poly(L-lactic acid) (PLLA), poly(D-lactic acid) (PDLA), and epoxy cyclohexyl polyhedral oligomeric silsesquioxane (e-POSS) was prepared by reactive blending method. Scanning electron microscopy revealed that the feeding of three compositions in batches, i.e., PDLA incorporation at different times, was more beneficial for the even dispersion of POSS in matrix. POSS introduction improved the homocrystallinity and stereocomplex of the blends. Rheological properties and heat resistance were enhanced, which indicated potential extensive application of PLLA-based materials. The optimization of degradation stability in saline buffer was attributed to the various hydrophobic properties of blends caused by POSS structure.     

Synthesis,characterization, and properties of cashew gum graft poly(acrylamide)/magnetite nanocomposites

Graft copolymer nanocomposites based on cashew gum and poly(acrylamide) with different concentrations of nano‐iron‐oxide particles (Fe₃O₄) have been prepared by an in situ polymerization method. The characterization of graft copolymer composite was carried out by FTIR, UV, XRD, SEM, DSC, and TGA, electrical conductivity, and magnetic property [vibrational sample magnetometer (VSM)] measurements. The shift in the spectrum of UV and FTIR peaks shows the intermolecular interaction between metal oxide nanoparticles and the graft copolymer system. The spherically shaped particles observed from the SEM images clearly indicating the uniform dispersion of nanoparticles within the graft copolymer chain. The XRD studies revealed that the amorphous nature of the graft copolymer decreases by the addition of Fe₃O₄ nanoparticles. The glass transition temperature studied from DSC increases with increase in concentration of metal oxide nanoparticles. Thermal stability of composite was higher than the pure graft copolymer and thermal stability increases with increase in content of nanoparticles. Electrical properties such as AC conductivity and dielectric properties of the composites increased with increase in concentration of metal oxide nanoparticles. The magnetic property of graft copolymer nanocomposites shows ferromagnetic and supermagnetism and the saturation of magnetism linearly increased with increasing the Fe₃O₄ content in the polymer composite. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43496.