Hyperbranched poly(3-ethyl-3-hydroxymethyloxetane) via anionic polymerization

Anionic polymerization of 3-ethyl-3-hydroxymethyl oxetane was achieved using NaH with coinitiators benzyl alcohol (BA) or trimethylol propane (TMP). Pendent hydroxyls facilitate a multibranching polymerization. NMR confirmed the presence of linear, dendritic, and terminal repeat units. For TMP initiated polymerizations there was an acetone soluble portion which was more branched (DB=0.48) than the acetone insoluble portion (DB=0.20). Polymers were not soluble in water, ether or THF, but were partially soluble in acetone and completely soluble in methanol, benzene, chloroform, and DMSO. MALDI-TOF analysis showed relatively low molecular weights (around 500) and confirmed the presence of both cyclic and TMP endgroups.     

新型坡缕石/多羟基树状高分子复合材料的制备及性能研究

以NaBH4还原水杨醛席夫碱修饰坡缕石为核,采用发散法通过与三聚氯氰、4-氨甲基哌啶、水杨醛、NaBH4还原的重复反应制备了1.0~2.0 G多羟基树状高分子/坡缕石复合材料,利用红外光谱、元素分析、热重对复合材料结构进行了表征,扫描电子显微镜测定了复合材料的外部形貌。吸附实验表明：该复合材料对废水中有机酚、重金属离子的吸附能力优于坡缕石原土,10 mg第二代树状高分子/坡缕石在293K,对初始质量浓度是50 mg/L的对硝基苯酚、对苯二酚、Pb(II)的吸附量分别是35.3 mg/g、34.02 mg/g、44.8 mg/g,吸附动力学拟合结果符合拟二级动力学方程。     

纳米CaCO_3高填充ABS复合材料的制备

分别采用苯乙烯-丁二烯-苯乙烯共聚物(SBS)和乙烯-乙酸乙烯共聚物(EVA)作增韧剂,利用熔融挤出法制备纳米CaCO_3高填充丙烯腈-丁二烯-苯乙烯三元共聚物(ABS)/CaCO_3复合材料,研究了纳米CaCO_3填充量和增韧剂种类对ABS/CaCO_3复合材料力学性能和熔体流动速率的影响。结果表明:SBS对ABS/CaCO_3复合材料的增韧效果优于EVA;当ABS用量为100.0 phr、纳米CaCO_3填充量为25.0 phr、SBS用量为5.0 phr时,可得到力学性能符合GB/T 10009—1988要求的ABS/CaCO_3复合材料;当SBS和EVA用量较低时,SBS更能明显提高ABS/CaCO_3复合材料的熔体流动速率。     

Preparation of polymer/silica composite antiglare coatings on poly(ethylene terphathalate) (PET) substrates

3-(Trimethoxysilyl) propyl methacrylate and fluoroalkylsilane modified silica particles were UV-cured with the multifunctional crosslinking agent, dipentaerythritol hexaacrylate (DPHA), to prepare antiglare (AG) coatings that exhibit high hardness. Modified silica was used to impart surface roughness whereas DPHA was used to provide hardness and adhesiveness. The formed AG coatings were characterized in terms of topological, optical, and mechanical properties. It was found that with the increase of DPHA content in the coatings, the surface roughness and haze decreased while the gloss and clarity increased. For samples containing 40 and 50 wt% DPHA, the optical properties are comparable to commercial AG products for flat panel display and touch panels. These prepared coatings also demonstrate high hardness of 5?C6H and 100% adhesion on poly(ethylene terphathalate) substrates.     

Preparation of PVDF/CaCO3 composite hollow fiber membrane via a thermally induced phase separation method

The spinnabiliy of polyvinylidene fluoride (PVDF)/CaCO₃ microparticle dope solution were explored via a thermally induced phase separation process, and composite hollow fiber (CHF) membranes were prepared successfully. The experiment results showed that the self‐supporting property of CHF got improved after adding CaCO₃ at low concentration of PVDF, so the control of spinning process became easy. The effects of CaCO₃ on the structure and properties of hollow fiber membrane were investigated in terms of morphology, water flux, porosity, breakage strength, and crystallization. The results indicated that CHF presented a uniform bicontinuous structure. The permeability and porosity of CHF increased obviously when CaCO₃ was removed by acid, while the breakage strength decreased slightly. CHF presented a good drying stability. POLYM. COMPOS., 34:1204–1210, 2013. © 2013 Society of Plastics Engineers     

Structure and conductivity of multi-walled carbon nanotube/poly(3-hexylthiophene) composite films

This work reports a structure-property investigation of a conjugated polymer nanocomposite with enhanced conductivity. Regioregular poly(3-hexylthiophene) (rrP3HT) was used to prepare composites with thin, short, multi-walled carbon nanotube (MWNT) addition over a wide range of concentrations. Scanning and transmission electron microscopies demonstrated an excellent dispersion and good wetting properties within the carbon nanotube composites. Coated MWNTs showed superstructures of P3HT self-organized on nanotube surfaces. Changes in the long range order and on the self-ordered mesophase of the bulk material were investigated by infrared and Raman spectroscopies, differential scanning calorimetry and X-ray diffraction. Interplay between charge transport through the semiconducting polymer and carbon nanotube network increased the composite's conductivity after percolation to values close to 10⁻² S cm⁻¹.     

Preparation and characterization of graphene oxide/poly(vinyl alcohol) composite nanofibers via electrospinning

Graphene oxide (GO) was well dispersed in poly(vinyl alcohol) (PVA) diluted aqueous solution, and then the mixture was electrospun into GO/PVA composite nanofibers. Electron microscopy and Raman spectroscopy on the as‐prepared and calcined samples confirm the uniform distribution of GO sheets in the nanofibers. The thermal and mechanical properties of the nanofibers vary considerably with different GO filler contents. The decomposition temperatures of the GO/PVA composite nanofiber dropped by 38–50°C compared with pure PVA. A very small loading of 0.02 wt % GO increases the tensile strength of the nanofibers by 42 times. A porous 3D structure was realized by postcalcining nanofibers in H₂. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of poly(benzylmethacrylate)-co-perfluorooctylethylmethacrylate) and electrooptical properties of the resultant polymer/liquid crystal composite films

Methacrylate copolymers of benzylmethacylate (BMA) and perfluorooctylethylmethacrylate (FMA) were synthesized and applied to the polymer/liquid crystal (LC) composite films. The copolymers were prepared by a radical solution polymerization. The high composition of FMA resulted in a precipitation during the polymerization. The contact angle of the LC on the copolymer films decreased with increasing FMA composition. Due to a small interaction between the LC and the copolymers, the copolymer/LC composite films showed low driving voltage in the range of 18–25 V_rms, corresponding to about 1/3 the value of the poly(methyl methacrylate) (PMMA)/LC composite film. © 1995 John Wiley & Sons, Inc.     

Preparation of 3-dimentional skeletal polymer via control of reaction-induced phase separation in epoxy/poly(ethylene glycol) blends

Summary  In order to prepare 3D skeletal polymer with low cross-linking density and high hydrophilicity bisphenol A epoxy was cured with diethylenetriamine in the PEG1000/PEG2000 mixing medium. The reaction-induced phase separation of this system was controlled by changing the weight ratio of PEG1000 and PEG2000. The morphology observation of the resulted polymers showed that the connectivity of epoxy phase strongly depended on the content of PEG2000 and was also influenced by the curing temperature. A 3D skeletal polymer with well-controlled macro-through-pores was prepared by using a mixture of PEG1000 and PEG2000 in 7/1 weight ratio as reaction medium and porogen. A unique light-filtrating effect was found in the prepared 3D skeletal polymer that filled with high refractive liquids. The effect most likely resulted from a total reflection mechanism of light in 3D macro-through-pores.     

Fabrication of highly refractive,transparent BaTiO3/poly(methyl methacrylate) composite films with high permittivities

Incorporation of crystalline barium titanate (BT) nanoparticles into poly(methyl methacrylate) (PMMA) was carried out to prepare highly refractive polymer nanocomposite films that have transparency and high permittivities. The BT nanoparticles were prepared by hydrolysis of a barium/titanium complex alkoxide in 2‐methoxyethanol, then surface‐modified with a silane coupling agent (3‐methacryloxypropyltrimethoxysilane) to improve their affinity for PMMA. The incorporation of the surface‐modified nanoparticles into PMMA was performed up to a nanoparticle content almost equivalent to particle close‐packing state. The refractive index of the composite films increased with nanoparticle incorporation, keeping the relative transmittance normalized with PMMA film above 90%. A high refractive index of 1.82 was reached at a nanoparticle content of 53 vol% with a dielectric constant as high as 36 and a dissipation factor as low as 0.05. The results demonstrate that the crystalline BT nanoparticles are useful fillers for effectively increasing both refractive index and dielectric constant of polymer nanocomposites. Copyright © 2011 Society of Chemical Industry     

Ionic conduction of novel polymer composite films based on partially phosphorylated poly(vinyl alcohol)

New ion-conducting polymer composite films have been prepared, and their ionic conducting properties have been investigated. The polymer composite films are fabricated from partially phosphorylated poly(vinyl alcohol) with tetramethylammonium salt (P-PVA·Me₄N⁺) and poly(acrylic acid) (PAA) or poly(ethylene glycol) (PEG). For P-PVA·Me₄N⁺/PEG composite films, the ionic conductivity and carrier density sharply increased, and carrier mobility sharply decreased around [PEG]/[PO₃]_P-PVA of 2. The ionic conductivity is dominated by both carrier density and carrier mobility at [PEG]/[PO₃]_P-PVA<2 and only by carrier density at [PEG]/[PO₃]_P-PVA>2. This is attributed to the fact that the ionic conduction in P-PVA·Me₄N⁺/PEG composite films occurred through the PEG-Me₄N⁺ complex which was independent of the carrier mobility. On the other hand, the ionic conductivity in P-PVA·Me₄N⁺/PAA composite films showed a bell-shaped dependence on the PAA contents with a maximum value at [CO₂H]_PAA/[OH]_P-PVA=1. FTIR spectrum measurements demonstrated that part of the carboxylic acid residues was dissociated in the composite films. This fact implied that the ionic conduction was mediated by PAA at the low PAA content. At high PAA content, however, an excess of the carboxylic acid residues formed trapping sites for the Me₄N⁺ ion, leading to a decrease in the ionic conductivity. Furthermore, we proposed a unique mechanism of the ionic conduction.     

碳酸钙／二氧化硅纳微复合粒子的高能球磨制备

采用高能球磨法制备了碳酸钙(纳米)/二氧化硅(微米)复合粒子.用X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、能谱分析仪(EDS)和傅里叶变换红外光谱仪(FT-IR)研究了球磨过程中复合粉体的相组成和微观组织;对碳酸钙/二氧化硅复合粒子的粒径、形态、结构进行了测定与表征.结果表明随着球磨时间的延长,复合粉体在强烈的冲击、挤压作用下逐渐细化和均匀化;球磨240 min可形成结合紧密的碳酸钙/二氧化硅复合粒子,并使之球形化;纳米碳酸钙均匀复合于二氧化硅的表面及其空隙,复合过程中没有产生新物质;强烈的机械力作用,使纳米碳酸钙表面晶体结构发生畸变,颗粒表面无定形化程度增加.     

Relationship between pore structure and 1H‐NMR relaxation times in TiO2/poly(dimethylsiloxane) and CaCO3/poly(dimethylsiloxane) composite powders

Titanium(IV) oxide/polydimethylsiloxane (PDMS) and calcium carbonate/PDMS composite powders were obtained by adsorption of the polymer from a chloroform solution onto the inorganic particles followed by a thermal treatment. The composites were characterized by ¹H‐NMR relaxation and porosimetry. The composites present shorter spin–lattice (T₁) and spin–spin (T₂) proton relaxation times than silica‐reinforced PDMS, and the activation energies for the motions that cause spin–lattice relaxation are 5.8, 4.9, and 0.72 kJ mol⁻¹ for TiO₂/PDMS, CaCO₃/PDMS, and neat PDMS, respectively, revealing the greater rigidity of the polymer chains within the composite. Spin–spin relaxation (T₂) measurements of the composites showed a major component with a shorter T₂ and a minor component with a longer T₂. The intensity ratio of these two components is very close to the ratio between the amount of polymer that remains between the particles and that penetrating the particle pores as measured by Hg intrusion porosimetry. The shorter T₂ component was thus assigned to polymer interspersed among the particles, while the longer T₂ component was assigned to polymer within the particle pores. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2660–2666, 1999     

Microstructure and properties of polyimide/poly(vinylsilsesquioxane) hybrid composite films

Polyimide (PI)/poly(vinylsilsesquioxane) (PVSSQ) (PI/PVSSQ) hybrid composite films were prepared from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA)-4,4′-oxydianiline (ODA) polyamic acid and triethoxyvinylsilane (TEVS or VSSQ) via sol-gel process and thermal imidization. The presence of the PVSSQ showed a remarkable effect on the microstructure and properties of the polyimide based hybrid films. The transparency of the hybrid films decreased with increasing the content of the PVSSQ. The compatibility and interfacial interaction of the hybrid composites were evaluated by scanning electron microscope (SEM) and atomic force microscope (AFM), respectively. The PI/PVSSQ hybrids showed nanocomposite formation when the contents of PVSSQ was less than 20 wt%. It was found that the surface topography was influenced by the composition of the PVSSQ. Incorporating of the PVSSQ increased the thermal stability and T_g of hybrid composites. The dielectric constant of the hybrid composites was reduced by adding PVSSQ up to a certain content, showed a minimum and then found to be increased. The dielectric constant values of the hybrid composites ranged from 2.59 to 3.78. The presence of the PVSSQ also showed significant effects on the mechanical properties of the polyimide films.     

Preparation and morphology of electrically conductive and transparent poly(vinylchloride)-polypyrrole composite films

Summary The chemical process of preparing poly(vinylchloride)-polypyrrole composite films with high electrical conductivity and transparency has been studied. Pyrrole has been diffused into the poly(vinylchloride) matrix in the swelling medium of n-hexane and acetone mixture. The oxidative polymerization of the diffused pyrrole in the binary solvent system of acetonitrile and methanol gives high conductivity of the polypyrrole as well as the good penetration of the oxidant into the PVC polymer matrix. The analytical testing of the composite film shows the formation of homogeneous mixture of polypyrrole and poly(vinylchloride) conductive layer within the 1.0m of thickness on the film surface. The transparency of the composite film showed about 50–60% at 500 nm. The electrical conductivity of the composite was about 20 s/cm.     

多壁碳纳米管/聚(丙三醇-癸二酸-柠檬酸)酯弹性体复合材料的制备与性能研究

采用熔融共缩聚反应法合成聚(丙三醇-癸二酸-柠檬酸)酯(PGSC)弹性体,再采用半原位聚合和研磨分散的方法制备多壁碳纳米管(MWCNT)/PGSC复合材料,并对复合材料的性能进行研究.结果表明,MWCNT对PGSC的玻璃化温度影响不大;随着MWCNT用量的增大,MWCNT/PGSC复合材料的弹性模量和拉伸强度总体增大,溶胀度和吸水率逐渐减小;当MWCNT用量达到或超过1份时,与PGSC相比,MWCNT/PGSC复合材料的弹性模量和拉伸强度较大,降解速率较小.     

聚乙烯亚胺功能化Fe3O4纳米粒子的制备

以油酸包覆的Fe3O4磁性纳米粒子为原料,3,4-二羟苯基丙酸(DHCA)为表面改性剂,四氢呋喃(THF)为溶剂制备出DHCA功能化的Fe3O4纳米粒子。将制备得到的功能化Fe3O4纳米粒子偶联聚乙烯亚胺(PEI),得到稳定分散的聚乙烯亚胺功能化Fe3O4磁性复合纳米粒子。利用FTIR、TEM、VSM、Zeta电位对磁性粒子组分、形貌、粒径、磁学性能和电位性能进行表征。该法简便,反应条件温和,所制备的PEI功能化Fe3O4纳米粒子具有良好的超顺磁性和分散性。     

Preparation and characterization of a polyaniline/poly(butyl acrylate–vinyl acetate) composite as a novel conducting polymer composite

This is the first report on the preparation and characterization of a polyaniline/poly(butyl acrylate–vinyl acetate) composite. The composite was prepared by the emulsion polymerization of aniline in a medium containing poly(butyl acrylate–vinyl acetate). Films prepared from the composite (cast from an aqueous medium) had excellent mechanical properties and could be stretched up to 900%. The resultant composite was soluble in common organic solvents, and a stable water‐based dispersion could also be prepared. An electrical conductivity of 2.2 S cm^?1 was obtained. Cyclic voltammograms revealed that the composite was electroactive. It had excellent adhesion to either glass or steel plate. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2525–2531, 2003     

Immobilization of poly(ethylene imine) onto polymer films pretreated with plasma

Poly(ethylene imine) (PEI)‐immobilized surfaces have attracted much attention as interesting biomaterials in relation to cell culture, selective adsorption of endotoxins, and so on. In this study, we found that PEI could be effectively immobilized on various polymers pretreated by oxygen plasma. Surface analyses using an X‐ray photoelectron spectrometer and contents of peroxide groups determined by iodide method indicate that the hydroxy peroxides were the main functional groups that contributed to PEI immobilization covalently on the polymer surfaces treated with oxygen plasma. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 576–582, 2000