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1.
The organic–inorganic hybrid boron‐containing phenol–formaldehyde (BPFR) resin/SiO2 nanocomposites was synthesized in‐situ from boric acid, phenol, and tetramethoxysilane. The structure of BPFR modified and the distributions of silicon element were studied by Fourier‐transform infrared spectroscopy, energy dispersive X‐ray spectrometry, and transmission electron microscope, respectively. The glass transition temperature (Tg) was determined by torsional braid analysis. The results show that silicon element distribution is homogeneous, and the size of nanosilica is about 40–60 nm. The thermal stability and kinetics parameters of thermal degradation were determined by thermogravimetry analysis (TGA). TGA results show that the resin modified has higher heat resistance property when the additive quantity of SiO2 was 3 wt%. The temperature of 5% weight loss is 487.7°C, which is 12.4°C higher than that of common BPFR. The residual ratio of 3 wt% SiO2/BPFR was 62.3% at the temperature of 900°C, which is 11.2% higher than that of common BPFR. The mechanics loss peak Tp of 3% SiO2/BPFR is 33°C higher than common BPFR. Fiberglass‐reinforced BPFR modified by 3 wt% SiO2 has better mechanical and dielectric properties than that of common BPFR. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers  相似文献   

2.
In order to prepare the bio‐based polymeric materials, a gallic acid epoxy resin (GA‐ER) is synthesized by using biodegradable gallic acid, and the nanocomposites of GA‐ER/glycidyl methacrylate (GMA)/multiwalled carbon nanotubes (MWCNTs) were prepared by dual hybrid cationic ring‐opening reaction. Differential scanning calorimetry (DSC) results show that the curing reaction temperature of the nanocomposites is between 150 and 225°C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results suggest that MWCNTs are homodispersing in the GA‐ER/GMA matrix when the MWCNTs content is not more than 1.0 wt%. The glass transition temperature of the nanocomposite with 0.5 wt% MWCNTs is 9.3°C higher than that of pure resin system. The initial thermal degradation temperature and degradation activation energies Ea of the nanocomposite with 1.0 wt% MWCNTs is 10°C and 68.6 kJ/mol higher than that the pure resin system, respectively. POLYM. COMPOS., 37:3093–3102, 2016. © 2015 Society of Plastics Engineers  相似文献   

3.
A series of cyanate ester resin (CE) based organic–inorganic hybrids containing different contents (0, 5, 10, 15 and 20 wt%) of epoxy‐functionalized polyhedral oligomeric silsesquioxane (POSS‐Ep) were prepared by casting and curing. The hybrid resin systems were studied by the gel time test to evaluate the effect of POSS‐Ep on the curing reactivity of CE. The impact and flexural strengths of the hybrids were investigated. The micromorphological, dynamic mechanical and thermal properties of the hybrids were studied by SEM, dynamic mechanical analysis (DMA) and TGA, respectively. Results showed that POSS‐Ep prolonged the gel time of CE. CE10 containing 10 wt% POSS‐Ep displayed not only the optimum impact strength but the optimum flexural strength. SEM results revealed that the improvement of mechanical properties was attributed to the large amount of tough whirls and fiber‐like pull‐outs observed on the fracture surfaces of CE10. DMA results indicated that POSS‐CE tended to decrease E′ of the hybrids in the glassy state but to increase E′ of the hybrids in the rubbery state. TGA results showed that CE10 also possesses the best thermal stability. The initial temperature of decomposition (Ti) of CE10 is 426 °C, 44 °C higher than that of pristine CE. © 2013 Society of Chemical Industry  相似文献   

4.
Towards the development of copolymeric nanocomposites, N‐3(trifluoromethyl)phenyl‐7‐oxanorbornene‐5,6‐dicarboximide (TFI) monomer and a macromonomer of polyhedral oligomeric silsesquioxane (POSS) were synthesized. Ring‐opening metathesis polymerization to copolymerization of specified proportions of the two co‐monomers was carried out. All the monomers and polymers were characterized using Fourier transform IR analysis and 1H and 29Si NMR. Gel permeation chromatography shows that copolymeric nanocomposites have a lower average molar mass than a homopolymer of TFI (HTFI). TGA shows that the thermal stability of the copolymer is inversely proportional to the proportion of POSS units. DSC studies have demonstrated that the glass transition temperature (Tg) of a nanocomposite possessing 25 wt% POSS is at a higher temperature (180 °C) than that of HTFI (175 °C). Transmission electron microscopy and AFM images of copolymers are consistent with the self‐assembled spherical aggregation of POSS units, while X‐ray diffraction studies have confirmed the homogeneous dispersion of the same units within the nanocomposites. © 2012 Society of Chemical Industry  相似文献   

5.
The organic–inorganic hybrid nanocomposites from high‐impact polystyrene/octavinyl polyhedral oligomeric silsesquioxane (HIPS/POSS) containing various percentages of POSS were prepared by free radical polymerization and characterized by Fourier transform infrared spectroscopy (FTIR), 1H‐NMR, thermal gravity analysis (TGA), X‐ray diffraction (XRD), and transmission electron microscopy (TEM). The octavinyl POSS has formed covalent bond connected PS‐POSS hybrid with polystyrene. POSS can well disperse in the composites at the composition of 0.5 and 1 wt%. The mechanical properties and thermostability of HIPS/POSS nanocomposites were significantly improved. The tensile strength, the izod impact strength, and the elongation at break of the nanocomposite containing 1 wt% of POSS was increased, respectively, by 15.73%, 75.62%, and 72.71% in comparison with pristine HIPS. The thermal decomposition temperature of HIPS/POSS (1 wt% of POSS) was 33°C higher than that of pristine HIPS. The HIPS/POSS nanocomposites showed great potential for applications in many fields, such as electric appliance and automotive trim. POLYM. COMPOS. 37:1049–1055, 2016. © 2014 Society of Plastics Engineers  相似文献   

6.
A comparative study concerning the thermal stability of polystyrene (PS) and three polyhedral oligomeric silsesquioxane/polystyrene (POSS/PS) nanocomposites of formula R7R′(SiO1.5)8/PS (where R = isobutyl and R′ = phenyl), at various (3, 5, and 10%) POSS concentration was carried out in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Nanocomposites were synthesized by in situ polymerization of styrene in the presence of POSS and the experimental filler concentration in the obtained compounds, determined by 1H NMR spectroscopy, was in all cases slightly higher than that in the reactant mixtures. Inherent viscosity (ηinh) determinations indicated that the average molar mass of polymer in the nanocomposites was practically the same than neat PS and were in agreement with calorimetric glass transition temperature (Tg) measurements. The temperature at 5% mass loss (T5%) and the activation energy (Ea) of degradation process of synthesized nanocomposites were determined and compared with each other and with those of unfilled PS. On the basis of the results from thermal and IR spectroscopy characterizations, nanocomposite with 5% of molecular filler appears the most thermally stable. The results were also compared with literature data on similar PS‐based nanocomposites. POLYM. COMPOS., 2013 © 2013 Society of Plastics Engineers  相似文献   

7.
The objective of this research was to investigate thermal stability and dynamic mechanical behavior of Exfoliated graphite nanoplatelets (xGnP™)‐Linear Low‐Density Poly Ethylene (LLDPE) nanocomposites with different xGnP loading content. The xGnP‐LLDPE nanocomposites were fabricated by solution and melt mixing in various screw rotating systems such as co‐, counter‐, and modified‐corotating. The storage modulus (E′) of the composites at the starting point of −50°C increased as xGnP contents increased. E′ of the nanocomposite with only 7 wt% of xGnP was 2.5 times higher than that of the control LLDPE. Thermal expansion and the coefficient of thermal expansion of xGnP‐loaded composites were much lower than those of the control LLDPE in the range of 45–80°C (299.8 × 10−6/°C) and 85–100°C (365.3 × 10−6/°C). Thermal stability of the composites was also affected by xGnP dispersion in LLDPE matrix. The xGnP‐LLDPE nanocomposites by counter‐rotating screw system showed higher thermal stability than ones by co‐rotating and modified‐co‐rotating system at 5 wt% and 12 wt% of xGnP. xGnP had a great effect on high thermal stability of xGnP‐LLDPE composites to be applied as tube and film for electrical materials. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers  相似文献   

8.
《Polymer Composites》2017,38(4):691-698
Liquid‐like trisilanol isobutyl polyhedral oligomeric silsesquioxanes derivative (L‐POSS‐D) was synthesized with γ‐(2,3‐epoxypropoxy)propytrimethoxysilane (KH560) as corona and polyetheramine M1000 as canopy. Its structure and properties were characterized by FTIR, XPS, TGA and Rheology data. Epoxy nanocomposites with 0.0, 0.5, 1.0 and 2.0 wt% content of L‐POSS‐D were prepared. T g of the nanocomposites improved 47.6°C higher than pure epoxy resin. Mechanical properties, including flexural strength and impact toughness, were improved markedly with L‐POSS‐D. The morphologies of impact fracture were studied by SEM. POLYM. COMPOS., 38:691–698, 2017. © 2015 Society of Plastics Engineers  相似文献   

9.
The elastomeric nanocomposites based on organomontmorillonite (OMMT) and styrene‐(ethylene‐butylene)‐styrene (SEBS) thermoplastic elastomer were prepared by melt processing using maleic anhydride grafted SEBS (SEBS‐g‐MA) as compatibilizer. Thermo‐oxidative decomposition behavior of the neat components and the nanocomposites were investigated using thermogravimertic analysis (TGA) in air atmosphere. The isoconversional method is employed to study the kinetics of thermo‐oxidative degradation. The heating modes and the composition of nanocomposites were found to affect the kinetic parameters (Ea, lnA and n). The Ea and lnA values of SEBS, OMMT, and their composites are much higher under dynamic heating than under isothermal heating. The reaction order (n) of OMMT was lower than those of SEBS and their composites. The obtained TG profiles and calculated kinetic parameters indicated that the incorporation of OMMT into SEBS significantly improved the thermal stability both under dynamic heating and under isothermal heating. The simultaneously obtained DSC data showed that the enthalpy of thermal decomposition decreased with OMMT loading. No significant change in the nonisothermal and isothermal stability of the nanocomposites with addition of SEBS‐g‐MA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

10.
Amine modified polyhedral oligomeric silsesquioxane (POSS‐NH2) was used to modify sodium montmorillonite (MMT) nanoclays for improved dispersion in epoxy resin. The dispersion of the clay particles was inspected using scanning electron microscopy, energy dispersive spectroscopy (EDS) and X‐Ray diffraction and the thermal properties compared using differential scanning calorimetry (DSC) and thermogravametric analysis. The introduction of the amine‐POSS was found to have a positive effect on the dispersion of the MMT clays and prevented agglomeration. The absence of clay agglomerates lead to an increase in glass transition temperature (Tg) from 44°C in the samples with the untreated clay up to 54°C in the samples with 10% additional POSS‐NH2. The addition of POSS‐NH2 initial increase of the weight loss (Td 5%) but slowed down the rate of degradation due to the formation of an inert silica layer and eventually leading to an increased charyield. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

11.
To improve the thermal properties of linear low‐density polyethylene (LLDPE), the CaCO3/LLDPE nanocomposites were prepared from nanometer calcium carbonate (nano‐CaCO3) and LLDPE by melt‐blending method. A series of testing methods such as thermogravimetry analysis (TGA), differential thermogravimetry analysis, Kim‐Park method, and Flynn‐Wall‐Ozawa method were used to characterize the thermal property of CaCO3/LLDPE nanocomposites. The results showed that the CaCO3/LLDPE nanocomposites have only one‐stage thermal degradation process. The initial thermal degradation temperature T0 increasing with nano‐CaDO3 content, and stability of LLDPE change better. The thermal degradation activation energy (Ea) is different for different nano‐CaCO3 content. When the mass fraction of nano‐CaCO3 in nanocomposites is up to 10 wt %, the nanocomposite has the highest thermal degradation Ea, which is higher (28 kJ/mol) than pure LLDPE. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

12.
The thermal degradation of two polyhedral oligomeric silsesquioxane/polystyrene (POSS/PS) nanocomposites of formula R8(SiO1.5)8 POSS/PS and R′1R7(SiO1.5)8 POSS/PS (where R′ = Phenyl and R = Cyclopentyl), at 5% of POSS concentration, was studied in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Compounds were prepared by the polymerization of styrene in the presence of POSS. Degradations were carried out into a thermobalance, in the scanning mode, at various heating rates, and the obtained thermogravimetric (TG) curves were discussed and interpreted. The initial decomposition temperature (Ti), the temperature at 5% mass loss (T5%), the glass transition temperature (Tg), and the activation energy (Ea) of degradation of nanocomposites were determined and compared with each other and with those of unfilled PS. The Ti, T5%, and degradation Ea values of nanocomposites were higher than those of neat PS, thus indicating a better heat resistance and lower degradation rate, and then a better overall thermal stability. The use of POSS with a symmetric structure, in the synthesis of PS based nanocomposite, showed a decrease of Tg value not only in respect to asymmetric POSS/PS nanocomposite but also in respect to neat polymer, thus suggesting an influence of filler structure in the thermal properties of the materials. POLYM. COMPOS., 33:1903–1910, 2012. © 2012 Society of Plastics Engineers  相似文献   

13.
The thermal stability of nylon 1010/polyhedral oligomeric silsesquioxane (POSS) composites prepared by melt blending was investigated with thermogravimetric analysis. The octavinyl POSS (vPOSS) and epoxycyclohexyl POSS (ePOSS) were used, and it was found that nylon/vPOSS composites have higher integral procedure decomposition temperature and char yield at 800°C than nylon/ePOSS composites. The Doyle–Ozawa (model‐free) and Friedman (model‐fitting) methods were used to characterize the nonisothermal decomposition kinetics of nylon 1010 and its composites. The activation energy (Ea), reaction order (n), and the natural logarithm of frequency factor of nylon 1010 were 267 kJ/mol, 1.0, and 47 min?1, respectively, in nitrogen. After the addition of POSS, the Ea of nylon 1010 considerably increased, whereas n had less change. The Ea steadily increased with increasing conversion and with increasing heating rate. The lifetime of nylon 1010 and its composites decreased with increasing temperature. At a given temperature, POSS significantly prolonged the lifetime of nylon 1010. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

14.
Two types of silsesquioxanes were synthesized by hydrolytic condensation reaction, and then were incorporated into polycarbonate (PC) matrix by melt blending to prepare PC/POSS hybrid composites. The study of morphology of the composites showed that octaphenylsilsesquioxane (PH‐POSS) exhibited partial compatibility with PC matrix, while 3‐glycidyloxypropylsilsesquioxane (EP‐POSS) could react with phenolic hydroxyl groups of matrix. Thermal and mechanical properties were studied by DSC, TGA, and DMA. The result showed that the incorporation of POSS not only improved thermal stabilities of PC composites, but also retarded their thermal degradation. Si O fractions left during POSS degradations were the key factor governing the formation of a gel network layer on the exterior surface. This layer possessed more compact structures, higher thermal stabilities, and some thermal insulation. In addition, percentage residues at 700°C (C700) significantly increased from 10.8 to 15.5–22.8% in air. The storage modulus of two series of composites was slightly improved up to 90°C; furthermore, the temperature range of the rubbery state of them shifted to high temperature. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers  相似文献   

15.
BACKGROUND: Organic–inorganic nanocomposites were prepared by copolymerization of various monomers and polyhedral oligomeric silsesquioxane (POSS) derivatives. Preliminary results showed that styrene/styryl–POSS copolymers could be obtained using CpTiCl3 catalyst. In the work reported here, the copolymerization of styrene and styryl‐substituted POSS was studied in detail for a more effective catalyst, Cp*TiCl3. RESULTS: The glass transition temperature (Tg) of the copolymers prepared increased with increasing POSS content. The degradation temperature (Td) of the copolymers was 60 °C higher than that of syndiotactic polystyrene under nitrogen. Although the thermal properties were improved by incorporation of POSS, the catalytic activity decreased with POSS content. The racemic triad and syndiotactic index of the copolymers decreased with increasing POSS content. Gel permeation chromatograms of the copolymers exhibited multimodal distribution due to the presence of multi‐active centres, which were formed by interaction of Ti with the POSS siloxane linkage. CONCLUSION: With the incorporation of POSS, the thermal properties of polystyrene were improved. The styrene/styryl–POSS copolymers are formed through the various active sites arising from the interactions of Ti with POSS. Copyright © 2008 Society of Chemical Industry  相似文献   

16.
Nanozirconia (nano‐ZrO2) was prepared by the sol–gel method and incorporated into poly(methyl methacrylate) (PMMA) by the in situ bulk polymerization of methyl methacrylate. The structure of the nano‐ZrO2 was confirmed by X‐ray diffraction (XRD), transmission electron microscopy, and Fourier transform infrared (FTIR) spectroscopy. The structure of the nano‐ZrO2 nanocomposites were studied by differential scanning calorimetry, FTIR spectroscopy, XRD, and scanning electron microscopy, and the results show that there were interactions between the nanoparticles and the polymer. The influence of the nano‐ZrO2 on the thermal stability of PMMA was investigated by thermogravimetric analysis (TGA). The results indicate that nano‐ZrO2 enhanced the thermal stability of the PMMA/nano‐ZrO2 nanocomposites. The effects of the heating rate in dynamic measurements (5–30°C/min) on kinetic parameters such as apparent activation energy (Ea) in TGA both in nitrogen and air were investigated. The Kissinger method was used to determine Ea for the degradation of pure PMMA and the PMMA/nano‐ZrO2 nanocomposites. The kinetic results show that the values of Ea for the degradation of the nanocomposites were higher than that of pure PMMA in air. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

17.
In this study, the gallic acid‐based epoxy resin (GA‐ER) and alkali‐catalysed biphenyl‐4,4′‐diol formaldehyde resin (BPFR) are synthesized. Glass fibre‐reinforced GA‐ER/BPFR composites are prepared. Graphene oxide (GO) is used to improve the mechanical and thermal properties of GA‐ER/BPFR composites. Dynamic mechanical properties and thermal, mechanical, and electrical properties of the composites with different GO content are characterized. The results demonstrate that GO can enhance the mechanical and thermal properties of the composites. The glass transition temperature, Tg, of the BPFR/GA‐ER/GO composites is 20.7°C higher than the pure resin system, and the 5% weight loss temperature, Td5, is enhanced approximately 56.6°C. When the BPFR: GA‐ER mass ratio is at 4 : 6 and GO content is 1.0–1.2 wt %, the tensile and impact strengths of composites are 60.97 MPa and 32.08 kJ/m2 higher than the pure resin composites, respectively. BPFR/GA‐ER composites have better mechanical properties, and can replace common BPA epoxy resins in the fabrication of composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42637.  相似文献   

18.
Polymer nanocomposites consisted of biodegradable poly(3‐hydroxybutyrate) (PHB) and organically modified montmorillonite Cloisite25A (OMMT), prepared by the solution‐casting method, were isothermally degraded for 120 min at 230, 235, 240, and 245°C in the nitrogen atmosphere. The addition of OMMT increases the thermal stability of PHB, and the most pronounced effect has the addition of 7 wt% of OMMT. Kinetic analysis was performed using reduced time plots and model‐free isoconversional methods. The empirical kinetic triplets (E, A, and g(α)) for the isothermal degradation of pure PHB and PHB/OMMT nanocomposites were determined. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers  相似文献   

19.
The hybrid material of EP‐POSS mixture was synthesized by the hydrolysis and condensation of (γ‐glycidoxypropyl) trimethoxysilane. A series of binary systems of EP‐POSS/epoxy blends, epoxy resin modified by silica nanoparticles (SiO2/epoxy), and ternary system of SiO2/EP‐POSS/epoxy nanocomposite were prepared. The dispersion of SiO2 in the matrices was evidenced by transmission electron micrograph, and the mechanical properties, that is, flexural strength, flexural modulus, and impact strength were examined for EP‐POSS/epoxy blends, SiO2/epoxy, and SiO2/EP‐POSS/epoxy, respectively. The fractured surface of the impact samples was observed by scanning electron micrograph. Thermogravimetry analysis were applied to investigate the different thermal stabilities of the binary system and ternary system by introducing EP‐POSS and SiO2 to epoxy resin. The results showed that the impact strength, flexural strength, and modulus of the SiO2/EP‐POSS/epoxy system increased around by 57.9, 14.1, and 44.0% compared with the pure epoxy resin, Ti, Tmax and the residues of the ternary system were 387°C, 426°C, and 25.2%, increased remarkably by 20°C, 11°C and 101.6% in contrast to the pure epoxy resin, which was also higher than the binary systems. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 810‐819, 2013  相似文献   

20.
In this study, epoxy nanocomposites containing 0.5, 1, 2, and 5% (m/m) of epoxycyclohexyl—POSS were prepared by mechanical mixture. The samples were characterized by gel content, thermogravimetric analysis (TGA), transmission electron microscopy, and scanning electron microscopy (SEM). TGA analysis was carried out at different heating rates (5, 10, 20, and 40°C min−1) aiming to evaluate the decomposition by Avrami, Flynn‐Wall‐Ozawa and Criado kinetic models. It was constated an increase in the gel fraction and dispersion of the nanocages only for the sample containing 5% POSS. The degradation study showed two distinct stages of weight loss and only for the first stage a shift in the temperature up POSS incorporation was observed. The Avrami kinetic parameters showed that the incorporation of POSS does not affect the degradation rate constant; however, there is an increase in the time required for the degradation reaction occurs. Also, it was observed an increase in the activation energy values for the sample containing 5% (m/m) of POSS. The degradation kinetic mechanisms in presence of POSS was changed from deceleratory mode (F1) for diffusion (Dn) in the range corresponded to the second stage of weight loss. SEM analysis showed that the morphology of the epoxy resin was modified by the POSS presence, and for 5% (m/m) of POSS was constated a more homogeneous morphology in relation to other samples. © 2012 Society of Plastics Engineers  相似文献   

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