共查询到20条相似文献,搜索用时 15 毫秒
1.
Nabil Hayeemasae Lim Wey Song Hanafi Ismail 《International Journal of Polymer Analysis and Characterization》2019,24(3):266-275
One of the ideas to recycle plastic waste is to mix it with virgin plastic in order to produce sustainable material. In this study, recycled polystyrene (R-PS) is used as a mixing component with virgin polystyrene (PS). Besides, eggshell powder (ESP) was also incorporated to reduce the compounding cost of the composite. Effects of R-PS/PS weight percentage on properties of composites were studied. Increasing PS content has increased tensile properties and impact strength of composites. Results obtained from these properties are in good relation to SEM micrographs. More surprisingly, R-PS plays a crucial role in enhancing the thermal stability of composites. This is simply due to the impurities contained in R-PS. 相似文献
2.
Novel zinc oxide thin films with nano-screw superstructure were prepared via a soft solution route without any polymer additives. A ZnO thin film could be produced directly on the substrates. The ZnO
thin film with nano-screw superstructure was prepared using visible-light-induced nitrogen-doped titania nano-particles. The
ZnO nano-screw/TiO2−x
N
y
composite film showed excellent photocatalytic deNO
x
ability and quantum efficient. 相似文献
3.
V. A. Petrova L. A. Nud’ga A. M. Bochek V. E. Yudin I. V. Gofman V. Yu. Elokhovskii I. P. Dobrovol’skaya 《Polymer Science Series A》2012,54(3):224-230
The rheological properties of chitosan solutions in a 2% aqueous solution of acetic acid with added montmorillonite nanoparticles
and the mechanical properties and structural organization of chitosan-based composite films are studied. The interaction between
the polymer functional groups and surface charges of nanoplatelets is confirmed by conductometric and potentiometric measurements.
With the use of a X-ray diffraction analysis, it is shown that the nanoparticles in films are in the exfoliated and intercalated
states. The incorporation of up to 10 wt % modified montmorillonite nanoparticles into the chitosan matrix results in a successive
increase in rigidity and a decrease in the elongation at break. 相似文献
4.
We used poly(aspartic acid) (PAsp) synthesized by ion exchange with sodium polyaspartate (PAspNa) as a dispersion stabilizer. PAsp improved the dispersion stability and the solubility in the medium for dispersion polymerization. The effects of the stabilizer hydrophobicity on particle formation, conversion, particle diameter, and its distribution of polystyrene microspheres were investigated by using both biodegradable polymers as a dispersion stabilizer. According to these results, we concluded that the polymerization rate of the styrene with PAsp was higher than that of styrene with PAspNa. That is why, smaller and more monodisperse microspheres were prepared with PAsp, compared to those with PAspNa. 相似文献
5.
N. V. Afanas’eva V. A. Petrova E. N. Vlasova S. V. Gladchenko A. R. Khayrullin B. Z. Volchek A. M. Bochek 《Polymer Science Series A》2013,55(12):738-748
The interaction of chitosan in the basic form with montmorillonite at different concentrations in composite films is studied with the use of dielectric spectroscopy and FTIR measurements. It is shown that the interaction of amino groups and primary hydroxyl groups of chitosan with local charges on the surfaces of montmorillonite nanoparticles is responsible for a change in the system of intramolecular and intermolecular hydrogen bonds that is typical for polysaccharides. The glass-transition temperature of chitosan in the composite systems is measured. 相似文献
6.
Mouffouk F Higgins SJ Brown SJ Sedghi N Eccleston B Reeman S 《Chemical communications (Cambridge, England)》2004,(20):2314-2315
A regioregular copolymer of 3-hexylthiophene and 3-(6-hydroxyhex-1-yl)thiophene has been functionalised with biotin hydrazide; binding of avidin to the biotin moieties causes drastic changes to the absorption spectrum of the polymer in solution, and to the electrochemistry and conductivity of the polymer in thin films. 相似文献
7.
Morphology and electro-optic properties of composite films composed of polystyrene (PS) and nematic liquid crystal (LC) have been studied for a wide range (30-70 wt% of liquid crystal) of film composition. At two specific levels of LC loadings (50 and 60 wt%), effects of temperature, frequency and voltage of applied ac electric field on the transmittance of the films were intensively measured, and the results were interpreted in terms of aggregation structure of the film, the geometry of LC domains, LC loading, dielectric constant, conductivity, birefringence, and the solubility of LC in polymer. © 1994 John Wiley & Sons, Inc. 相似文献
8.
Radical copolymerization of styrene with benzalacetophenone or benzalacetone in bulk or in suspension yielded copolymers with as much as 10 wt% of carbonyl monomer. They were characterized by GPC, viscometry and spectroscopy. Photolysis of copolymers was investigated in benzene at 313 nm. Quantum yields for main chain scissions were about 0.005 and the life-time of the triplet state was 5 nsec. Photo-oxidation in films was followed by monitoring the decrease in molecular weight and by i.r. and emission spectra. Quantum yield for main chain scission in films was about 0.0002. During photooxidation in film, the molecular weight distribution widened. A new i.r.-band appeared at 3580 cm?1 and the carbonyl band was spread between 1700 and 1800 cm?1. In the emission spectra, the vibrational resolved emission (typical of the carbonyl chromophore) disappeared. 相似文献
9.
Yeliz PEK 《Turkish Journal of Chemistry》2020,44(1):214
Zinc borate is a boron-containing chemical material that is used to increase the flame retardancy of polymeric materials, dyes, cables, fabrics, carpets, and the internal parts of automobiles and planes. Commercially used zinc borate, which has the formula of 2ZnO·3B 2 O 3 ·7H 2 O, has a particle size between 10 and 20 μm. However, recent studies have shown that nanosized flame retardants have more superior flame retardancy and less negative effects on mechanical properties than microsized flame retardants. Nanosized flame retardants disperse more homogeneously and even low quantities are sufficient to provide high flame resistance. In this study, nano zinc borate powder was synthesized by a wet chemical method and the effects of nonionic, anionic, and cationic surfactants on the particle size and morphology of the zinc borate particles were investigated. Chemical purity and physical structures of the synthesized zinc borate powder were analyzed by XRD, FTIR, TG-DTA, TEM, and Zetasizer. The analysis results showed that the zinc borate powder had a chemical formula of 2ZnO·3B 2 O 3 ·7H 2 O. TEM and Zetasizer results indicated that the nano zinc borate powder, which had nanoscale particle size distribution with needle- and flake-like structures, was synthesized using nonionic, anionic, and cationic surfactants. 相似文献
10.
Kyung Min Do Haldorai Yuvaraj Min Hee Woo Hyun Gyu Kim Euh Duck Jeong Keith P. Johnston Kwon Taek Lim 《Colloid and polymer science》2008,286(11):1343-1348
A novel synthetic route to prepare polystyrene/SiO2 composite microparticles in supercritical carbon dioxide (scCO2) is presented. Silica particles with the size of 130 nm which were surface-modified with 3-(trimethoxysilyl) propyl methacrylate
were used as seeds in the dispersion polymerization of styrene in the presence of a polymeric stabilizer, poly(1,1-dihydroheptafluorobutyl
methacrylate-co-diisopropylaminoethyl methacrylate) to produce dry composite particles. The transmission electron microscopy analysis revealed
that the composite microspheres contained several silica particles. 相似文献
11.
The effects of methyl methacrylate (MMA) grafting and in situ formation of silica particles on the morphology and mechanical properties of natural rubber latex (NRL) were investigated. MMA grafting on NRL was carried out using cumyl hydroxy peroxide/tetraethylene pentamine (CHPO/TEPA) as a redox initiator couple. The grafting efficiency of the grafted NR was determined by solvent extractions and the grafted NRL was then mixed with tetraethoxysilane (TEOS), a precursor of silica, coated by adherence to a glass surface to form a film and cured at 80°C. The resultant products were characterized by FT‐IR and transmission electron microscopy. The influence of varying the MMA monomer weight ratio on the surface morphology of the composites was investigated by scanning electron and atomic force microscopy. The PMMA (poly MMA) grafted NRL particles were obtained as a core/shell structure from which the NR particles were the core seed and PMMA was a shell layer. The silane was converted into silica particles by a sol–gel process which was induced during film drying at 80°C. The silica particles were fairly evenly distributed in the ungrafted NR matrix but were agglomerated in the grafted NR matrix. The root‐mean‐square roughness increased with an increasing weight ratio of MMA in the rubber. The in situ silica particles in the grafted NR matrix slightly increased both the modulus and the tear strength of the composite film. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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14.
《印度化学会志》2021,98(12):100243
This study introduces varying concentrations of graphene oxide (GO) as a filler into zinc chromate in forming composite coatings to improve the corrosion protection of mild steel. The purity of synthesized GO was inferred through the application of complementary characterization techniques, including FT-IR, XRD, Raman, SEM-EDX, and TEM analyses. GO doped zinc chromate coatings were deposited on the surface of mild steel through the brushing method. Electrochemical studies, i.e., electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) were conducted to elucidate the anticorrosion properties of the coated mild steel exposed to 0.5 M HCl solution. It was revealed that the highest anticorrosion protection was attained at low doping amount of 0.5% of GO with a corrosion rate of 0.036 mpy. Surface analyses revealed that incorporating GO into zinc chromate coating can effectively improve the anticorrosion properties and adhesion strength. 相似文献
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16.
Eugene Kim Edward J. Kramer John O. Osby David J. Walsh 《Journal of Polymer Science.Polymer Physics》1995,33(3):467-478
A study was made of miscible polymer blends of deuterated polystyrene (d-PS) and tetramethylbisphenol-A polycarbonate (TMPC). The Flory interaction parameter χ was obtained from the relation between mutual and tracer diffusion coefficients, D? and D*, which were measured by forward recoil spectrometry. The temperature dependence of diffusion at PS weight fractions ω of 0.25 and 0.5, and the composition dependence at temperatures 45°C above the glass transition temperature, Tg, were investigated. A stronger dependence of χ on both temperature (at ω = 0.5) and composition was observed in comparison with other miscible binary polymer blends involving PS. Analysis using the generalized lattice-fluid model of Sanchez and Balazs1 showed that the incorporation of a significant specific interaction is needed to explain the temperature dependence of χ. The diffusion coefficients obtained in the one-phase region were extrapolated to the two-phase region, and these were compared with the effective diffusion coefficient extracted from phase separation dynamics measured by light scattering.2 A significant discrepancy between the extrapolated and effective diffusion coefficients was observed. © 1995 John Wiley & Sons, Inc. 相似文献
17.
采用荧光光谱法和紫外光谱法研究了Zn2+离子对槲皮素(Qct)和牛血清白蛋白(BSA)在pH=7.4的Tris-HCl缓冲溶液中相互作用的影响;根据荧光猝灭双倒数图计算了Qct和BSA之间的结合常数和结合位点数.结果表明,Qct和Zn2+离子都可以使BSA的荧光强度发生猝灭;Qct和BSA之间的结合常数为3.17×107L.mol-1.s-1,结合位点数为1.32.定量计算表明,加入Zn2+离子后,Qct与BSA间的结合常数显著降低、结合位点数减小,表明Zn2+离子参与了Qct与BSA的结合过程. 相似文献
18.
Olga V. Alekseeva Vladimir P. Barannikov Nadezhda A. Bagrovskaya Andrew V. Noskov 《Journal of Thermal Analysis and Calorimetry》2012,109(2):1033-1038
Polystyrene composite films with different content of C60?+?C70 fullerene mix have been obtained from o-xylene solutions. The mass fraction of fullerene was varied from 0.01 to 0.1 mass%. The glass transition temperatures and specific heat capacities in range of 293?C423?K have been determined for the films by DSC method. The plasticization of the polymer is observed in thermal properties of the films under influence of small fullerene additions. The values of T g and C P decrease and thermal coefficient of heat capacity b increase as fullerene content increases up to 0.02 mass%. The effect of interaction between polymer and fullerene molecules on thermal properties becomes evident at higher fullerene content in range from 0.02 to 0.1 mass%. At this the values of T g and C P increase and b coefficient decrease with increasing content of fullerene. Concentration dependence of C P and b values is less steep for polymer composite films in elastic state at temperatures above T g. Molecular interactions in the composites are discussed in view of our-self and literature data. 相似文献
19.
A. Bardaine P. Boy P. Belleville O. Acher F. Levassort 《Journal of Sol-Gel Science and Technology》2008,48(1-2):135-142
In this work, piezoelectric PbZr0.52Ti0.48O3 (PZT) thick films were deposited onto silicon and alumina substrates using sol-gel composite slurry. Thick films prepared with rough and attrited powders are compared. A time stable polymeric PZT sol was first synthesised as the binder. It was then used as a precursor for PZT powder fabrication. Powder attrition ball milling was optimised to reduce the particles size to 200 nm. Composite slurries were obtained by mixing PZT sol with attrited or rough powders and thick films were deposited by dip-coating. The film thickness, roughness and microstructure were studied as a function of powder content, particle size, sol concentration and slurry ageing. Electromechanical measurements were performed. By strictly controlling each step of the thick film fabrication, high coupling factor (thickness mode, kt) can be obtained using both types of powder. Nevertheless, with attrited powder, better and more reproducible effective coupling coefficients in thickness mode (kt up to 46%) were reported on silicon and alumina substrates. 相似文献
20.
O. C. Tsang Fengchao Xie O. K. C. Tsui Z. Yang Jianmin Zhang Deyan Shen Xiaozhen Yang 《Journal of Polymer Science.Polymer Physics》2001,39(22):2906-2914
Rubbing‐induced molecular alignment and its relaxation in polystyrene (PS) thin films are studied with optical birefringence. A novel relaxation of the alignment is observed that is distinctly different from the known relaxation processes of PS. First, it is not the Kohlrausch–Williams–Watts type but instead is characterized by two single exponentials plus a temperature‐dependent constant. At temperatures several degrees or more below the glass‐transition temperature (Tg), the relaxation time falls between that of the α and β relaxations. Second, the decay time constants are the same within 40% for PS with weight‐average molecular weights (Mw's) of 13,700–550,000 Da at temperatures well below the sample Tg's, indicating that the molecular relaxations involved are mostly local within the entanglement distance. Nonetheless, the temperature at which the rubbing‐induced molecular alignment disappears (T0) exhibits a strong Mw dependence and closely approximates the Tg of the sample. Furthermore, T0 depends notably on the thickness of the polymer in much the same way as previously found for the Tg of supported PS films. This suggests that the α process becomes dominant near Tg. Preliminary spectroscopic studies in the mid‐infrared range show a significant degree of bending of the phenyl ring toward the sample surface, with the C? C bond connecting the phenyl ring and the main chain tends to lie along the rubbing direction, which indicates that the relaxation is connected with the reorientation of this C? C bond. We exclude the observed relaxation, as predominantly a near‐surface one, because detailed studies on the effects of rubbing conditions on the degree of molecular alignment indicate that the alignment is not local to the polymer–air surface. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2906–2914, 2001 相似文献