Synthesis of conducting polyaniline/TiO2 composite nanofibres by one‐step in situ polymerization method

Conducting polyaniline (PANI)/titanium dioxide (TiO₂) composite nanofibres with an average diameter of 80–100 nm were prepared by one‐step in situ polymerization method in the presence of anatase nano‐TiO₂ particles, and were characterized via Fourier‐transform infrared spectra, UV/vis spectra, wide‐angle X‐ray diffraction, thermogravimetric analysis, and transmission electron microscopy, as well as conductivity and cyclic voltammetry. The formation mechanism of PANI/TiO₂ composite nanofibres was also discussed. This composite contained ～ 65% conducting PANI by mass, with a conductivity of 1.42 S cm^?1 at 25°C, and the conductivity of control PANI was 2.4 S cm^?1 at 25°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis by in situ chemical oxidative polymerization and characterization of polyaniline/iron oxide nanoparticle composite

Polyaniline (PANI) is a well‐studied material and is the pre‐eminent electrically conducting organic polymer with the potential for a variety of applications such as in batteries, microelectronics displays, antistatic coatings, electromagnetic shielding materials, sensors and actuators. Its good environmental as well as thermal stability and electrical conductivity tunable by appropriate doping make PANI an ideal active material for several applications. In this paper, we report the synthesis of water‐dispersible colloidal PANI/iron oxide composite nanoparticles using an in situ chemical oxidation polymerization method in a micellar medium of sodium dodecylsulfate, where the cores (iron oxide) are embedded in a PANI matrix layer. Transmission electron micrographs showed evidence of the formation of an iron oxide core/PANI shell composite with a thin layer of PANI over the iron oxide cores. The results of thermogravimetric, Fourier transform infrared and UV‐visible analysis indicated that the iron oxide nanoparticles could improve the composite thermal stability possibly due to the interaction between iron oxide particles and PANI backbone. We believe that the synthetic route described can also be adapted for the assembly of hierarchical structures of other metal oxides or hydroxides onto various cores. Copyright © 2010 Society of Chemical Industry     

Surface organic modification of titanium dioxide fine particles through photo polymerization

C?C unsaturated groups were chemically inserted onto TiO₂ particles surfaces through chemical reaction of hydroxyl group on the TiO₂ fine particle surface with 2,4‐diidocyanatotoluene (TDI) first, and then with 2‐hydroxyethyl acrylate (HEA). Finally, TiO₂ fine particles with surface organic modification were made through the free radical copolymerization reaction with n‐butyl acrylate (BA) monomer under UV irradiation. The structure and properties of unmodified and modified TiO₂ were studied by FT‐IR, XPS, TGA, TEM, lipophilic rates, and adhesion properties tests. The results show that the surface of TiO₂ has been successfully introduced with the organic chains through chemical bonding linkage; the surface lipophilic rates of TiO₂ particles are increased. The dispersion and compatibility of the modified TiO₂ particles in a commercial ink 508C resin greatly improve as compared with that of unmodified TiO₂, and agglomeration of particles obviously reduces. The adhesion strength between the white printing ink made from the modified TiO₂ particles and BOPP is much better than that from the unmodified TiO₂. When the organic rate reached 24.93%, the adhesion strength reaches Grade I. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

In situ solvothermal synthesis and characterization of transparent epoxy/TiO2 nanocomposites

A solvothermal process was developed to in situ prepare epoxy (EP)/TiO₂ hybrid precursors. The chemical structure of samples was confirmed by X-ray and Fourier transformed infrared spectroscopy. Field emission scanning electron microscope micrographs of cured EP/TiO₂ hybrid composites showed that well-dispersed TiO₂ nanoparticles were successfully in situ formed in epoxy matrix through the solvothermal process. The thermogravimetic analysis, DSC, and gel content measurements showed that EP/TiO₂ hybrid precursors were fully cured with the glass transition temperature decreasing gradually. The effect of TiO₂ contents on optical and surface properties was investigated in detail. The results indicated that epoxy/TiO₂ nanocomposites exhibited excellent UV shielding effect and high visible light transparency. The contact angle of EP/TiO₂ nanocomposites, when the content of silane-coupling agent (KH560) was 5 g and the content of tetrabutyl titanate (TBT) was 3 g, can reach as high as 101°, which was 36° higher than that of pure EP, representing for the increase of hydrophobicity. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation of organic vermiculite/polymethylmethacrylate nanocomposite featuring excellent mechanical and thermal properties via ultrasonic in situ polymerisation

To improve the dispersion of organically modified vermiculite (OVMT) in polymethylmethacrylate (PMMA), the method of ultrasonic in situ polymerization was introduced, and a series of OVMT/PMMA nanocomposites were successfully prepared. The structure, morphology, and mechanical and thermal properties of as-prepared sample had been investigated. Results showed that the assistance of ultrasonic irradiation could be beneficial for the good homogeneous dispersion and strong interfacial interaction of OVMT in PMMA. Consequently, the obtained nanocomposites showed better mechanical and thermal properties than those prepared without the assistance of ultrasonic irradiation. When the OVMT content was 3 wt.%, the nanocomposite prepared by ultrasonic in situ polymerization exhibited the Young's modulus, tensile strength, elongation at break and degradation temperatures for 5% and 50% weight loss of 1177 MPa, 65 MPa, 14%, 219.82ºC and 373.91ºC, respectively. These results suggested the great potential application of ultrasonic in situ polymerization for the synthesis of polymer/clay nanocomposite.     

Effect of surface modification of titanium dioxide on the UV-C aging behavior of silicone rubber

Surface modification of titanium dioxide (TiO₂) nanoparticles (NPs) by silane coupling agents and the ultraviolet-C (UV-C) aging behavior of silicone rubber (SiR) incorporated with the modified TiO₂ NPs were investigated in this work. The SiR samples incorporated with TiO₂ NPs displayed excellent stability against the UV-C radiation. In order to improve the dispersion of TiO₂ NPs in the SiR matrix, the surface of TiO₂ NPs was modified with 3-aminopropyl triethoxysilane and 3-trimethoxysilyl propyl methacrylate, respectively. The surface modification of TiO₂ NPs was characterized by thermal gravimetric analysis and Fourier transform infrared spectroscopy. The dispersion stability of the pristine TiO₂ NPs and surface silane-modified TiO₂ NPs was evaluated in an organic solvent (toluene). Effect of surface modified TiO₂ NPs on the UV-C aging behavior of SiR was evaluated in terms of the change of surface morphology, tensile properties, hardness, crosslinking density, and surface microstructure before and after the UV-C aging. The results showed that surface modification of TiO₂ NPs with silane coupling agents could improve the dispersion of TiO₂ NPs in the SiR matrix. Moreover, the SiR with modified TiO₂ NPs showed an improved aging resistance to the UV-C radiation, compared with the samples with pristine TiO₂ NPs. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47170.     

原位乳液聚合制备导电性聚苯胺/氯磺化聚乙烯复合材料及其性能

以十二烷基苯磺酸为乳化剂及掺杂剂,由二甲苯及水组成乳液,在氯磺化聚乙烯存在下,采用一步原位乳液聚合法制备了聚苯胺／氯磺化聚乙烯(PAn／CSPE)导电复合材料。研究了用熔融法(MP)或溶液法(SP)加工复合物材料的导电性及力学性能,并进行了表征。结果表明,MP法制得的复合材料在导电性及力学性能方面优于SP法制得的复合材料;当PAn质量分数为12％～18％时,MP法复合材料呈现热塑性弹性体行为,拉伸强度为6～8MPa,扯断伸长率大于400％,永久变形小于30％。当PAn质量分数小于18％时,SP法复合材料用闻甲酚二次渗杂后的导电率比原复合材料高出6个数量级,且其导电渗滤阈值由PAn质量分数22％降至3％。     

Surface modification of temperature‐responsive polymer particles by an electrically conducting polyaniline shell layer

In this research an attempt was made to prepare biocompatible electrically conductive composite polymer particles in view of their wide applications in biotechnology. Temperature‐sensitive polymer particles have applications as drug carriers, bioseparators, bioreactor cell activators and diagnostic reagents. So a combination of diverse properties in a single polymer composite is expected to increase its application potential. Here temperature‐responsive poly(N‐isopropyl acrylamide‐methyl methacrylate‐N,N′‐methylene‐bis‐acrylamide) (P(NIPAM‐MMA‐MBAAm)) core particles were prepared by emulsion copolymerization without using any stabilizer. In a second step seeded chemical oxidative polymerization of different amounts of aniline was carried out in the presence of submicron‐sized core particles to obtain P(NIPAM‐MMA‐MBAAm)/polyaniline composite particles. For a comparative study, reference polyaniline particles were prepared by chemical oxidative polymerization. Fourier transform IR spectroscopy, UV?visible spectroscopy, thermal and X‐ray diffraction analyses showed that composite particles prepared with higher aniline content (0.8 g) per unit mass (g) of core particles had high surface coverage compared with lower aniline content (0.1 g). © 2013 Society of Chemical Industry     

An antibacterial submicron fiber mat with in situ synthesized silver nanoparticles

This work presents an alternative approach for fabricating electrospun submicron highly hydrophilic fiber mats loaded with silver nanoparticles. These fiber mats show a high efficient antibacterial behavior, very attractive for applications like wound healing and skin regeneration processes. The fabrication method is divided in two steps. First, poly(acrylic acid) (PAA) and β‐cyclodextrin (β‐CD) submicron fibers were electrospun and further stabilized using a thermal treatment, yielding stable hydrogel‐like fibers with diameters ranging from 100 nm up to several microns. In the second step, silver ions were loaded into the fibers and then reduced to silver nanoparticles in‐situ. The electrospinning parameters were adjusted to achieve the desired properties of the fiber mat (density, size) and afterwards, the characteristics of the silver nanoparticles (amount, size, aggregation) were tuned by controlling the silver ion loading mechanism. Highly biocide surfaces were achieved showing more than 99.99% of killing efficiency. The two‐step process improves the reproducibility and tunability of the fiber mats. To our knowledge, this is the first time that stable hydrogel fibers with a highly biocide behavior have been fabricated using electrospinning. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Photocatalysis of methylene blue on titanium dioxide nanoparticles synthesized by modified sol-hydrothermal process of TiCl4

Titanium dioxide nanoparticles were synthesized by the hydrolysis and condensation of TiCl₄, an economic titanium precursor, in a mixed solvent of iso-propyl alcohol and water. As-prepared powders were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), energy filtering transmission electron microscopy (EF-TEM). To examine the photocatalytic activity of the as-prepared TiO₂, the photodegradation of MB which is a typical dye resistant to biodegradation has been investigated on TiO₂ powders in aqueous heterogeneous suspensions. The photocatalytic activity of TiO₂ powders prepared by the hydrolysis of TiCl₄ in the mixed solutions of iso-PrOH/H₂O exceeded that of commercial TiO₂ powders. The apparent first order rate constants (k _app) for the photodegradation of methylene blue (MB) showed a good correlation with the absorbance area obtained by UV-VIS DRS on wavelength in the limits of used lamp emission 300∼420 nm.     

The carbonization of colloidal polyaniline nanoparticles to nitrogen‐containing carbon analogues

The carbonization of nanostructures afforded by conducting polymers represents a new route to the preparation of functional nanostructured carbons. The exposure of colloidal polyaniline particles stabilized with poly(N‐vinylpyrrolidone) or silica nanoparticles at 650 °C in inert atmosphere led, in both cases, to nitrogen‐containing carbonaceous materials with specific surface areas of 200 and 205 m² g^?1, respectively, and conductivities of 8.3 × 10^?7 and 1.9 × 10^?10 S cm^?1, respectively. The latter material contained 77 wt% of silica. The original particulate nanostructure of the samples was preserved after carbonization. The carbon‐to‐nitrogen atomic ratio was 7.2 and 7.9; the nitrogen content in the carbonized polyaniline–poly(N‐vinylpyrrolidone) particles was 10.8 wt%. Thermogravimetric analysis in air revealed their stability to be up to 500 °C. This is comparable with commercial multi‐wall carbon nanotubes, which have similar areas of application. The nitrogen‐containing carbons are potentially useful as supports for catalysts and in applications where carbon of higher hydrophilicity would be of benefit. Copyright © 2010 Society of Chemical Industry     

Surface modification of titanium dioxide for electrophoretic particles

To prepare stable electrophoretic ink (E Ink) needs color particles to be uniformly dispersed in the organic medium. Thus, t-he modification of inorganic particle surface is required. In this paper, Titanium dioxide modified by alumina has been studied. The surface composition and structures of modified particles have been characterized by X-ray photoelectron spectrometer (XPS), X-ray diffractometer (XRD) and Fourier transform infrared spectrometer (FT-IR). The dispersibility and electrophoretic mobility of these particles in tetrachloroethylene (TCE) have been investigated by laser particle size analyzer, static sedimentation and electrophoretic instrument. Effects of temperature, pH value and stirring rate on the dispersibility and the charge property of samples have been discussed. The results indicate the settle time of modified TiO₂ can last 120 h with the response time of 35 s under the optimized modifying conditions, in which temperature is 85°C–90°C, pH is 8–9 and stirring rate is 800 r·min⁻¹. The dispersibility and electrophoretic mobility have been significantly improved, which means that the modified TiO₂ is suitable for electrophoretic ink particles. __________ Translated from Journal of Chemical Engineering of Chinese Universities, 2006, 20(6): 893–897 [译自: 高校化学工程学报]     

纳米技术与纳米材料(X)--纳米二氧化钛的表面处理

表面处理被用来提高纳米TiO2的耐久性和分散性。介绍了纳米TiO2表面处理效果的评价和表征方法。综述了纳米TiO2的表面处理的原理、方法和研究进展。预测新表面处理剂的合成、新的表面处理方法以及表面处理剂与纳米TiO2核体之间的作用机理将是下一步研究的重点。指出在对纳米TiO2进行表面处理的规模化生产中，关键要解决分散和异相成核的技术问题。     

Characterizations on the amidized multiwalled carbon nanotubes grafted with polyaniline via in situ polymerization

A multiwalled carbon nanotubes (MWCNTs) were carboxylated after refluxing with sulfuric and nitric acids. These attached carboxylic acid groups were further condensated with o‐phenylene diamine into amide catalyzed by dicyclohexyl carbodiimide (DCC). The obtained amidized MWCNTs were in situ‐polymerized with aniline monomers to graft a conducting polyaniline (PANI) onto MWCNT (ES‐g‐MWCNTs) through the polymerization occurring in the ortho‐ and meta‐positions. The reduced conductivity of the MWCNT after carboxylation can be recovered after grafting with PANI, which owns a strong λ_max at the near infrared region due to the extended conjugation from MWCNTs to PANI. Transmission electronic microscopic pictures show a gradual broadening of the MWCNT diameter after carboxylation, amidization, and polymerization. The weight loss from the thermogravimetric thermograms due to the carboxylations of MWCNTs, amidized MWCNTs, and the PANI grafted MWCNTs into CO₂ can be used to estimate the degree of carboxylation, amidization, and grafting of PANI. The degree of carboxylation of MWCNT calculated from ESCA spectrum is around 23% close to that estimated from TGA thermogram. The doping level of redoped PANI‐grafted MWCNT is found to be 27.78% much less than the maximum 50% of neat PANI. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Electrically conductive textiles by in situ polymerization of aniline

Two methods of obtaining electrically conductive fabrics by in situ polymerization of aniline were compared. Conductive fabrics were prepared by immersing the nylon 6 fabrics in 100% aniline or an aqueous hydrochloride solution of aniline followed by initiating successive polymerization in a separate bath (DPSB) or in a mixed bath (DPMB) of oxidant and dopant solution with aniline. In each case, the polymerization conditions were optimized to obtain the maximum quality of polyaniline (PAn) on the fabrics. The higher conductivity of composite fabrics, whose value reached up to 0.6 × 10⁻¹ s/cm, was obtained by the DPMB process. Moreover, this method induced the least decrease in the degree of crystallinity as compared to the DPSB process. The serviceability of the PAn–nylon 6 composite fabrics was also evaluated. No significant changes in the conductivity were observed after abrading the composite fabrics over 50 cycles and multiple acid and alkali treatment. The stability of conductivity was slightly decreased by less than 1 order after exposure to light for 100 h, but it was significantly decreased after washing with detergent. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2094–2101, 1999     

聚合物中纳米粒子气泡膨胀分散方法

提出了一种聚合物中纳米粒子气泡膨胀分散方法,并应用该方法制备了环氧树脂/SiO₂纳米复合材料。该方法将纳米粒子团聚体和压缩气体一同注射到聚合物熔体（溶液）中,形成内含纳米粒子的微气泡,并利用气泡急速膨胀时引起的高速拉伸作用实现纳米粒子在聚合物中的均匀分散。在对分散机理进行分析的基础上,通过数值仿真计算对其分散能力进行了分析。对气泡膨胀分散法制备的环氧树脂/SiO₂纳米复合材料进行了透射电镜（TEM）分析和DSC分析,结果表明,样品中SiO₂粒子粒径在15～30 nm之间,其玻璃化温度比高速搅拌法制备的对比样品高18℃。     

Surface modification of graphite encapsulated iron nanoparticles by plasma processing

The graphite encapsulated iron nanoparticles were fabricated by using arc discharge method. The synthesized nanoparticles were pre-treated by an inductively-coupled RF Ar plasma and then post-treated by NH₃ plasma under various gas pressures and treatment times. Analyses of XPS spectra have been carried out to study the effect of the plasma treatment on the surface modification of nitrogen-containing groups. The morphological changes of the particles surface by plasma treatment have also been analyzed by using HR-TEM. Present results show that the highest values of N/C atomic ratio of 5.4 % is obtained by applying 10 min of Ar plasma pre-treatment and 2 min of NH₃ plasma post-treatment conducted in RF power of 80 W and gas pressure of 50 Pa.     

Interfacial agent effect on rheological response and crystallite characteristics in germicidal polypropylene/titanium dioxide nanocomposites

Germicidal nanocomposites based on metallocene isotactic polypropylene (iPP) and titanium dioxide (TiO₂) nanoparticles have been prepared at a constant TiO₂ content of 2 wt%. Different quantities of a polypropylene wax partially grafted with maleic anhydride (PP‐g‐MAH) are employed to improve the polymer‐nanoparticle compatibility. Remarkable biocidal capabilities of these TiO₂ nanocomposites have been found and their crystalline structure and thermal and rheological responses explored. Several very interesting features have been found in these germicidal nanocomposites. On the one hand, rheological parameters do not change significantly with respect to those exhibited by pure iPP. This is extremely advantageous for the processing of these compounds since they can be transformed under similar conditions to those employed for iPP. On the other hand, the existence of two polymorphs is observed independent of the amount of compatibilizer used. The enhancement in polymer‐nanoparticle interactions by effect of the interfacial (PP‐g‐MAH) component is appraised looking at dynamical mechanical relaxations as a function of temperature and at crystallization processes of the various nanocomposites. Copyright © 2012 Society of Chemical Industry     

二氧化钛柱撑膨润土催化合成四氢呋喃

通过水热法制备了TiO2-PILC,用XRD、FT-IR、BET等对催化剂进行表征,考察了催化剂制备条件及催化1,4-丁二醇液相环化脱水合成四氢呋喃工艺条件,结果显示：钛/土比为0.025 mol/g,焙烧温度650 K,反应温度190～200 ℃,每克催化剂可处理1,4-丁二醇98 kg以上,原料转化率≥99%,四氢呋喃的选择性≥99.4%,羰基含量≤0.19%,精馏后产品四氢呋喃纯度≥99.7%。     

Effect of acids on in situ polyaniline film formation

The chemical oxidation of aniline with ammonium persulfate (APS) to form polyaniline (PANI) films has been studied in different aqueous acid media such as sulfuric, nitric, phosphoric and acetic acids. A comparison was made between the yields of PANI film deposition during the polymerization from these media with the corresponding one obtained previously from aqueous HCl solution. The degradation of the formed PANI films at the beginning of polymerization obtained at the higher concentrations of HCl is absent when the other acids under consideration were used. The effect of acid concentration on the yield and growth rate of the PANI film was studied. The variation in the yield and growth rate of the polymer films at different acid concentrations was explained on the basis of the electrostatic repulsion and the screening effects. Copyright © 2004 Society of Chemical Industry