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1.
The sol–gel reaction of a polycarbonate (PC) oligomer having triethoxysilyl groups at both ends of the PC chain (PCS) with a tetraethoxysilane or tetramethoxysilane oligomer provided transparent or semitransparent films of higher silica containing organic–inorganic hybrid materials (HSPC‐HMs). The films were superior to those from PC and from PCS in terms of the morphological homogeneity, heat resistance, and surface hardness. The HSPC‐HM films had minimum oxygen permeability at a PCS/tetraethoxysilane ratio of 3/7. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4273–4279, 2006 相似文献
2.
Yingqian Gao Lifu Zhang Jian Chen Xiangwei Wang Haifeng Cheng 《International Journal of Applied Ceramic Technology》2017,14(6):1041-1048
Oxide (Nextel? 440) fiber‐reinforced silica composites, with the density and porosity of 1.97 g/cm3 and 21.8%, were prepared through sol‐gel. Their average flexure strength, elastic modulus, shear strength, and fracture toughness at room temperature were 119.7 MPa, 25.6 GPa, 10.8 MPa, and 4.0 MPa·m1/2, respectively. The composites showed typical toughened fracture behavior, and distinct pullout fibers were observed at the fracture surface. Their mechanical properties were performant up to 1000°C, with the maximum flexural strength of 132.2 MPa at 900°C. Moreover, the composites showed good thermal stability, even after thermal aging and thermal shock at elevated temperatures. 相似文献
3.
Novel intercrosslinked networks of siliconized epoxy‐1,2‐bis(maleimido)ethane matrix systems are developed. The siliconization of epoxy resin is carried out by using 5–15% hydroxyl‐terminated poly(dimethylsiloxane) with γ‐aminopropyltriethoxysilane as a crosslinking agent and dibutyltin dilaurate as a catalyst. The siliconized epoxy systems are further modified with 5–15% 1,2‐bis(maleimido)ethane and cured by using diaminodiphenylmethane. The prepared neat resin castings are characterized for their mechanical properties. Mechanical studies indicate that the introduction of siloxane into these epoxy resins improves the toughness with a reduction in the stress–strain values, whereas incorporation of bismaleimide (BMI) into the epoxy resin improves the stress–strain properties with a lowering of the toughness. The introduction of both siloxane and BMI into the epoxy resin influences the mechanical properties according to their content percentages. Differential scanning calorimetry (DSC), thermogravimetry, and heat distortion temperature analyses are also carried out to assess the thermal behavior of the matrix materials that are developed. DSC thermograms of the BMI modified epoxy systems show unimodal reaction exotherms. The glass‐transition temperature, thermal degradation temperature, and heat distortion temperature of the cured BMI modified epoxy and siliconized epoxy systems increase with increasing BMI content. The water absorption behavior of the matrix materials is also studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3808–3817, 2003 相似文献
4.
Encapsulation of phase change materials (PCM) using a poly(methyl methacrylate) network‐silica hybrid as the shell material has been developed. n‐Octadecane melted at 28°C was used as PCM. Based on the suspension polymerization process, the microcapsules were prepared successfully by mixing and by the reaction of ethylene glycol dimethacrylate with precopolymer solution with tetraethoxysilane (TEOS), whose resultant microcapsules had higher latent heat (ΔH = 151 J/g) than those without TEOS (ΔH = 88.3 J/g). The average size of the PCM microcapsules was about 10 μm. The silica content, n‐octadecane content, and latent heat of microcapsules were changed with varying ageing conditions, ageing time, and temperature. The highest amount of latent heat (ΔH = 178.9 J/g) and n‐octadecane content (73.3%) of the microcapsule were obtained when the inorganic/organic ratio of the microcapsule was 5%. It was difficult to increase n‐octadecane content (74% to 55.7–67.9%) and latent heat (180.5 J/g to 135.9–165.7 J/g) of the microcapsules by introducing different functional groups of coupling agents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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To suppress steel corrosion at elevated temperature and in humid condition, silane coupling agents N‐β‐aminoethyl aminopropyltrimethoxysilane (AAPS), γ‐glycidoxypropyltrimethoxysilane (GPS), and bis[3‐(trimethoxysilyl)‐1‐phenylpropyl]tetrasulfide (RC‐2) were introduced as primers into an epoxy/steel system. Silane coupling agents and epoxy were coated onto the steel surface using the solution casting method. The polymer degradation and steel corrosion formation after heat and humid treatment were investigated by Fourier transform infrared reflection and absorption spectroscopy (FTIR–RAS) and scanning electron microscopy (SEM). Compared to various silane treated epoxy/steel systems, the AAPS‐treated epoxy/steel (AAPS/epoxy = 6 : 4) system suppressed steel corrosion at 400°C for 10 min in air and for 5 days at 60°C in 100% relative humidity. This is due to the formation of Si O Si linkage and Fe O Si bond on steel surface, which are resistant to water diffusion and thermally stable at elevated temperature. The relationship between chemical bonding at the steel–epoxy interface and corrosion protection on the steel surface was also investigated. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 585–593, 1999 相似文献
6.
Aniline/p‐phenylenediamine copolymer [poly(ANI‐co‐p‐PDA)] was prepared by chemical oxidative polymerization. FTIR and 1H‐NMR analysis indicate that the poly(ANI‐co‐p‐PDA) is oligomer with end‐capped amino groups, which can cure epoxy resin. The anticorrosion performance of carbon steel (CS) samples coated by epoxy resin coating cured with poly(ANI‐co‐p‐PDA) and epoxy resin coating cured with triethylenetetramine exposed to 5 wt % NaCl and 0.1 mol/L HCl aqueous solution is studied by the potentiodynamic polarization and electrochemical impedance spectroscopy. The results show that the CS coated by epoxy resin coating cured with poly (ANI‐co‐p‐PDA) has more excellent corrosion protection than that of epoxy resin coating cured with triethylenetetramine. Raman spectroscopy analysis indicates that the surface of CS coated by epoxy resin coating cured with poly(ANI‐co‐p‐PDA) forms passive layer, which is composed of α‐Fe2O3. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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UV‐curable, transparent hybrid material of urethane‐acrylate resin was prepared by the sol‐gel process using 3‐(trimethoxysilyl)propylmethacrylate (TMSPM) as a coupling agent between the organic and inorganic phases. The effects of the content of acid and silica on the morphology and mechanical properties of UV‐curable polyurethane‐acrylate/silica hybrid (UA‐TMSPM)/SiO2 materials have been studied. The results of thermogravimetric analysis for the (UA‐TMSPM)/SiO2 hybrid materials indicated that the thermal stability of the hybrids is greatly improved. It was found that with the increase of HCl content, the interfacial interaction between organic and inorganic phases had been strengthened, as demonstrated by field emission scanning electron microscopy. Without sacrificing flexibility, the hybrid materials showed improved hardness with increasing content of acid and silica. Compared with the pure organic counterpart UA/hexanediol diacrylate (UA/HDDA) system, abrasion resistance of the hybrids improved with increasing acid content, at low silica content. Copyright © 2004 Society of Chemical Industry 相似文献
9.
Tsao‐Cheng Huang Chi‐Fa Hsieh Tzu‐Chun Yeh Cheug‐Ling Lai Mei‐Hui Tsai Jui‐Ming Yeh 《应用聚合物科学杂志》2011,119(1):548-557
Comparative studies on corrosion protection properties of polyimide‐silica‐clay composites were studied in this article. A series of polyimide‐silica (PIS), polyimide‐clay (PIC), and polyimide‐silica‐clay composites (PISC) materials, consisting of an organo‐soluble polyimide (ODA‐BSAA) matrix, inorganic silica particles prepared through the sol–gel reaction of tetraethyl orthosilicate (TEOS) and dispersed nanolayers of inorganic montmorillonite clay, were successfully prepared by solution dispersion technique. Then, all samples were characterized by FTIR, powder X‐ray diffraction patterns, transmission electron microscopy, and 29Si solid‐state NMR. The main focus of this article is the comparison of the corrosion protection properties of PIS, PIC, and PISC composite materials. Normally, the aspect ratio of clay is higher than silica. Superior dispersion of clay platelets into a polymer matrix may effectively increase the length of diffusion pathways for oxygen and water. The effects of the materials composition on the corrosion protection performance, gas barrier, and optical properties, in the form of both coating and film, were also studied by electrochemical corrosion measurements (e.g., corrosion potential, polarization resistance, corrosion current, and impedance spectroscopy), gas permeability analysis, and UV‐visible transmission spectroscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
10.
Polyurethane dispersions (PUDs) have been an active area of research since the early 1940s because of legislative restrictions on the use of organic solvents in conventional solvent‐based products and also because PUDs exhibit almost the same high performance levels as solvent‐borne polyurethanes. In the present study, properties of conventional waterborne PUDs are modified with epoxy‐acrylic graft copolymer blocks. The epoxy‐acrylic graft copolymers were first modified with ethylene diamine to give amine‐terminated blocks which in turn reacted with isocyanate‐terminated prepolymer (prepolymer mixing process) to give modified PUDs. Several experimental sets were prepared with varying compositions. The experimental sets were also prepared using conventional poly(ethylene glycol) blocks and ethylene diamine chain‐extenders. The physico‐chemical properties and film characteristics of the experimental sets show the dramatic improvement in important mechanical properties of PUDs due to grafting with epoxy‐acrylic copolymer blocks. Copyright © 2004 Society of Chemical Industry 相似文献
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Silica–polyaniline hybrid materials prepared by inverse emulsion polymerization for epoxy‐based anticorrosive coating
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Polyaniline doped with dodecylbenzene sulfonic acid (PAni.DBSA) was prepared by inverse emulsion polymerization of aniline in toluene medium in the presence of silica (SiO2) nanoparticles. The presence of cetyltrimethylammonium bromide (CTAB) during the aniline polymerization results in hybrid material with smaller particle size, as indicated by dynamic light scattering analysis and scanning electron microscopy. Also the electrical conductivity of such hybrid is one order higher, as compared with that prepared without CTAB. Moreover, more ordered PAni chain is obtained as indicated by the red shift of the π–polaron transition band observed by UV–vis spectroscopy and higher crystallinity observed by X‐ray diffraction analysis. Anti‐corrosive properties of carbon steel substrate coated with epoxy resin containing 5 wt % of PAni.DBSA and the corresponding SiO2‐based hybrid materials were evaluated in 3.5% NaCl solution by electrochemical impedance spectroscopy. The coating resistance increases by one order for the epoxy system containing PAni.DBSA/SiO2 hybrid prepared in the presence of CTAB, thus confirming the anticorrosion efficiency of this hybrid. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45505. 相似文献
13.
Tao Fu Zafer Alajmi Yaogen Shen Lijun Wang Shuiyun Yang Man Zhang 《International Journal of Applied Ceramic Technology》2017,14(6):1117-1124
Ag‐containing bioactive glass films (Ag/Ca atomic ratios of 0, 5% and 10%) were sol‐gel prepared for bioactive and antibacterial modification of titanium. The gel powders calcined at 610°C are mainly amorphous confirmed by x‐ray diffraction, but small diffraction peaks of Ca3SiO5 and silver are detected. The film surface is porous with the pore size of ~200 nm. Silver‐rich sub‐micro particles with sizes of 100‐480 nm are present at the surface of Ag‐glass films. CaP phase, metallic silver and silica are detected by x‐ray photoelectron spectroscopy. The mean apparent bonding strength of the films is as high as 21±1 MPa measured by the pull‐off test. The potentiodynamic polarization test shows that the coated samples have better corrosion resistance than the polished sample. The Ag‐glass coatings and their wafer samples exhibit antibacterial activity against S. aureus. The coated samples are covered by apatite layer after soaked in the simulated body fluid for 2 weeks, demonstrating their bioactivity. 相似文献
14.
Manawwer Alam Naser M. Alandis Fahmina Zafar Anujit Ghosal Mukhtar Ahmed 《Polymer Engineering and Science》2021,61(9):2243-2256
Formulation of sustainable resource-based organic–inorganic hybrid protective coatings have been achieved using Linseed oil-based silica hybrid with terpolymer (TP) as basic skeletal matrix. The fabrication of TP system was performed by using systematic one pot multi-facile steps (diol fatty amide–linseed oil-based polyester amide TP) synthesis route. The conversion of ester amide functional ends of TP to urethane was initiated to enhance adhesiveness, impermeability, and corrosion resistivity of the processed hybrid material. FT-IR and NMR (1H, 13C, and 29Si) studies help in verifying the chemical structure and progress of the reaction. The formulation of smooth corrosion resistive coating was further analyzed by transmission electron microscopy, scanning electron microscope, and electrochemical corrosion studies. The in-situ tethering and homogeneous dispersion of inorganic moiety in nanoregime throughout the TP system further enhances the stability, wettability, and corrosion protection ability of the nanohybrid vegetable oil-based coating under corrosive environment. High phase angle value at higher frequency end indicates the stability of the coating system. Such coating systems composed of sustainable resource with improved mechanical, thermal, and corrosion protective properties have great potential in future applications. 相似文献
15.
Tsao-Cheng Huang Yu-An Su Tzu-Chun Yeh Hsiu-Ying Huang Chi-Phi Wu Kuan-Yeh Huang Yi-Chen Chou Jui-Ming Yeh Yen Wei 《Electrochimica acta》2011,(17):10151
A series of electroactive epoxy/amino-SiO2 nanocomposite materials containing conjugated segments of electroactive amino-capped aniline trimer (ACAT) unit were successfully prepared. First of all, the amino-modified silica (AMS) particles of ∼50 nm in diameter were synthesized by performing the conventional base-catalyzed sol–gel reactions of tetraethyl orthosilicate (TEOS) in the presence of (3-aminopropyl)-trimethoxysilane (APTES) molecules. Subsequently, the AMS nanoparticles were blended into the epoxy ring-opening polymerization reactions between amino-terminated aniline trimer (ACAT)/T-403 and DGEBA, leading to the formation of electroactive epoxy resin–silica hybrid nanocomposites (EES). Furthermore, the redox behavior of as-prepared EES materials was identified by the electrochemical cyclic voltammetry studies. It should be noted that the as-prepared electroactive hybrid materials in the form of coating on cold-rolled steel (CRS) electrode were found to be much superior in corrosion protection over those of non-electroactive epoxy (NEE) and electroactive epoxy (EE) materials based on a series of electrochemical corrosion measurements in saline. The possible mechanism for the advanced enhancement of corrosion protection of EES coatings on CRS electrode could be interpreted as follows: (1) electroactive epoxy coatings may act as physical barrier coating; (2) redox catalytic capabilities of ACAT units existed in electroactive epoxy may induce the formation of passive metal oxide layers on CRS electrode, as further evidenced by SEM and ESCA studies; (3) well-dispersed AMS nanoparticles in EES matrix could act as effective hinder to enhance the oxygen barrier property of electroactive epoxy matrix, the result could be demonstrated by gas permeability analysis (GPA). Electroactive epoxy/SiO2 nanocomposites were identified by a series of electrochemical measurements such as corrosion potential (Ecorr), polarization resistance (Rp), corrosion current (Icorr) and electrochemical impedance spectroscopy (EIS) studied in 5 wt% NaCl electrolyte. 相似文献
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Mechanical and anticorrosion properties of furan/epoxy‐based basalt fiber‐reinforced composites
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A furan/epoxy blend applicable to composite manufacture was studied and corresponding basalt fiber‐reinforced composites were prepared. The processability, mechanical properties, and reasons for the improved mechanical properties of this blend were investigated by rheology machine, mechanical testing machine, and scanning electron microscopy. With excellent processability, furan/epoxy was suitable for manufacturing composites. Furan/epoxy with the ratio of 5/5 showed the best properties, and the impact strength, flexural strength and flexural modulus were 15.43 kJ/m2, 102.81 MPa, and 3209.40 MPa, respectively. The river‐like fracture surface of the furan/epoxy system was well consistent with the mechanical properties. The mechanical and anti‐corrosive properties of basalt fiber‐reinforced furan/epoxy composites were also studied. The mechanical properties of composites changed the same as those of furan/epoxy matrix did. Furan resin effectively improved the anti‐acid but not anti‐alkali property of composites, probably because furan could be cured in acidic condition and basalt fiber was resistant to acid and alkali. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44799. 相似文献
18.
本文在环氧涂料中添加玄武岩鳞片,提高其防腐蚀性能。针对玄武岩鳞片的团聚问题,通过机械力化学改性工艺,采用正硅酸四乙酯、HY-311型钛酸酯偶联剂、E-44型环氧树脂对玄武岩鳞片进行杂化包覆,结果表明,杂化包覆后玄武岩鳞片的沉降时间从2h提高至96 h。杂化包覆玄武岩鳞片添加量为20%涂层的性能最优,附着力为13.40 MPa,耐盐雾时间为2000 h,在3.5%NaCl溶液中浸泡2000 h后,0.01 Hz的阻抗模值仍然有5.15×109 Ω·cm2。 相似文献
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Polyimide (PI) materials with a low coefficient of thermal expansion (CTE) while still retaining high strength and toughness are desirable in various applications. In this study a sol–gel process was used to incorporate silica into homopolyimides and copolyimides with highly rigid structures in an attempt to pursue this aim. A number of highly rigid monomers were used, including pyromellitic dianhydride (PMDA), p‐phenylene diamine (PPA), m‐phenylene diamine (MPA), benzidine, 2,4‐diaminotoluene, and o‐toluidine. No homopolyimide flexible films were obtained. However, it was possible to obtain flexible films from the copolyimides. Therefore, a copolyimide based on PPA, MPA, and PMDA (PPA/MPA = 2/1 mol) was then chosen as the matrix to prepare the PI/silica hybrids. Flexible films were obtained when the silica content was below 40 wt %. The hybrid films possessed low in‐plane CTEs ranging from 14.9 to 31.1 ppm with the decrease of the silica content. The copolyimide film was strengthened and toughened with the introduction of an appropriate amount of silica. The thermal stability and the Young's modulus of the hybrid films increased with the increase of the silica content. The silica particle size was assessed by scanning electron microscopy and was about 100 nm for the hybrids containing 10 and 20 wt % silica and 200–500 nm for the hybrids containing 30 and 40 wt % silica. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 794–800, 2001 相似文献
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A novel phase‐separating liquid rubber based on oligo(alkylmethacrylate) in combination with microglass beads was used to toughen an anhydride‐cured epoxy resin. The resulting hybrid composites, containing 5 or 10 wt % of oligomeric liquid rubber and between 10 and 60 wt % glass beads as well as composites containing corresponding amounts of glass beads but no liquid rubber, were characterized mechanically. The experimental data show that modification with glass beads results in increased stiffness and toughness compared to the neat resin but reduces tensile strength. Compared to the glass bead–filled composites, additional modification with methacrylic rubber leads to a further increase in toughness and also to an increase in strength but does not alter stiffness and glass‐transition temperature. This synergistic behavior is explained by the fact that the rubber separates preferably on the surface of the glass bead, forming a core–shell morphology during curing. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1040–1048, 2003 相似文献