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1.
为增强废印刷电路板非金属粉(WPCBP)与聚合物基体之间的界面结合作用,采用溶胶-凝胶法在WPCBP表面原位负载了一层纳米二氧化硅粒子(SiO_2),制备了一种新型的WPCBP-SiO_2杂化填料。SEM、TGA和FTIR证明SiO_2通过化学键成功负载到了杂化填料的表面。采用含双键的界面改性剂对杂化填料进行改性后,应用于不饱和聚酯树脂基体,探讨了未改性杂化填料及表面改性杂化填料对不饱和聚酯复合材料的力学性能、界面结合作用和热稳定性能的影响。结果表明,新型的杂化填料WPCBP-SiO_2能够与不饱和聚酯基体形成强的界面结合作用,显著提高不饱和聚酯复合材料的力学性能和热稳定性能,且表面改性后复合材料的各项性能得到进一步提高。 相似文献
2.
《Materials Science & Technology》2013,29(2):226-230
AbstractComposites of the polymer/filler type, when the filler is a conductive material such as metal particles, exhibit electrical conductivity that increases with concentration of the conductive phase. These complex materials are considered to be chaotic mixtures of conductive particles randomly distributed in an insulating matrix. The conductivity of these materials in dc electric fields is studied in terms of percolation theory, where electrical conductivity σ is rapidly increased at a critical concentration, defined as P c, of the conductive phase, according to σ≈(PP c)α. In this work, various epoxy resin/conductive filler composites were prepared. The filler was metal powder of copper, aluminium, or zinc. The conductive behaviour of these materials was studied at temperatures varied from 20 to 140°C. Data obtained from these measurements are analysed using percolation theory and introducing new parameters β and σc into the above relation. A semiempirical algorithm is introduced for the determination of α, β, σc, and P c. 相似文献
3.
Due to the economical and environmental concern, polymer mortar and polymeric composites were prepared by mixing recycled polystyrene waste and cement dust waste as a filler. Virgin polystyrene and portland cement were used for comparison. Cement dust was treated by the reaction with stearic acid to increase the adhesion between the filler and the polymer matrix. The composites were prepared by mixing different concentration of treated and untreated cement dust (30, 50, 70 and 90 wt.%) with either virgin or recycled polystyrene. The suitability of the prepared polymeric composites as building materials in terms of mechanical properties, water absorption and chemical resistance was studied. After 1 week immersion in water, 10% sodium chloride (NaCl) and 10% sodium sulfate (Na2SO4) solutions, it was found that the chemical resistance and the mechanical properties were enhanced and the water absorption was retarded. The recycled polystyrene composites filled with treated cement dust gave the highest abrasion resistance and the lowest weight loss, also the best compressive and bending strength. 相似文献
4.
The use of particulate filled polymer formulations over wide temperature ranges has resulted in a need to understand their mechanical behaviour better. In this investigation, a crosslinked epoxy-urethane polymer filled with Al2O3 particles was studied. Mechanical and thermal expansion properties were determined at ambient and liquid nitrogen temperatures and compared to theoretical predictions. Other parameters under consideration were volume fraction and adhesion between filler and matrix. The theoretical equations employed for predicting mechanical properties appear fairly reliable at ambient temperature but unreliable at liquid nitrogen temperatures. The degree of bonding between filler and matrix influences mechanical properties at ambient temperature but at liquid nitrogen temperature no difference in properties owing to matrix filler bonding was evident. This result is attributed to compressive stresses on the filler particles resulting from the lower thermal expansion of the filler. 相似文献
5.
The abrasive wear of rubbers is strongly affected by the filler particles dispersed in the elastomer matrix. The fillers are incorporated usually for the purposes of mechanical reinforcement and improving the conductivity of the neat resins. It is found that the wear rates of the filled silicone rubbers increase slowly with filler concentration until a critical volume fraction,v
c, is reached, at which point they increase very rapidly with increasing filler concentration. This behaviour appeared to be universal in all the filled silicones we studied, regardless of the type of filler and silicone rubber used. However the magnitude of the critical filler fraction,v
c, can be changed significantly with the filler shape, resin cross-linking density and filler surface treatments. No reasonable relationship could be found between this wear behaviour and the mechanical properties measured in a macroscopic manner. Experimental evidence suggests that the incipient cracks that lead to wear losses may start within the thin layers of highly stressed material, the damage zones, surrounding the rigid particles. A simple model taking into account the stress concentration induced by the rigid fillers shows excellent correlation between the wear rate and the damage zones volume. With this new model, the observed wear behaviours can be explained satisfactorily. 相似文献
6.
A series of nanocomposites from poly(vinyl chloride) loaded with different concentrations of Al2O3 nanopowder was prepared. The tensile mechanical properties of these composites were studied at different temperatures namely; stress–strain curves. The elastic modulus was calculated and found to decrease with increasing both filler loading and temperature. The strain at a certain stress at different temperatures was studied and the thermal activation energy for polymer chains was calculated. The complex viscosity as well as the storage modulus was found to decrease with increasing the filler loadings at different frequencies. The relaxation time of the polymer matrix was calculated and found to independent on the concentration of the filler but it decreased linearly with increasing frequency. The glass transition temperature was found to increase with increasing both filler loading and frequency. 相似文献
7.
K. M. Blackwood R. A. Pethrick F. I. Simpson R. E. Day C. L. Watson 《Journal of Materials Science》1995,30(17):4435-4445
Incorporation of low levels of fillers into thermoplastics can often lead to an increase in the modulus and a general improvement
in the mechanical properties. However, increasing the level of filler loading can lead to a dramatic loss of impact strength
and related mechanical properties. In this study the pigmentation of polycarbonate (PC) with titanium dioxide (TiO2) is shown to lead to a reduction in the fracture energy and changes in the failure mechanism of injection moulded test samples.
Electron microscopic examination of the fracture surfaces indicates that changes in the failure mechanism are a result of
the occurrence of large areas of densified polymer around pigment particles. Densification reduces the extent of segmental
motion within the polymer matrix, as indicated by dielectric and thermally stimulated discharge current measurements. The
influence on the molecular motion and mechanical properties of the degree of drying, molecular weight of the polymer and concentration
of TiO2 are reported. Complementary positron annihilation measurements allow a tentative mechanism to be proposed to explain the
loss of impact strength in these materials. Data is also presented on polybutylene terephthalate (PBT) pigmented materials
and a PC system in which the TiO2 has been mixed with polyethylene prior to dispersion in the PC matrix. These observations confirm the importance of polymer-pigment
interactions in determining the fracture properties of samples. 相似文献
8.
Polypropylene(PP)/Polystyrene(PS) (PP/PS = 80/20) blend with different types of fillers were prepared by using melt method. Four different types of fillers, namely mesoporous MCM-41 (without template), nano-SiO2, Polymethylmethacrylate (PMMA)/MCM-41 and PMMA/SiO2 were considered. For PMMA/MCM-41 filler, the synthesis of the filler consisting of entrapped strand of PMMA within the pores of mesoporous MCM-41 (without template) was described. The mechanical properties of the blend determined as the nano-fillers contents and the different types of blend were found to vary with the different interface between fillers and the matrix. SEM revealed a good interaction between the matrix phases and PMMA/MCM-41 or MCM-41 (without template). The decreased Tg of PS implied that the good adhesion between PP and PS blend was obtained by adding PMMA/MCM-41 nano-filler. 相似文献
9.
S. F. Mendes C. M. Costa C. Caparros V. Sencadas S. Lanceros-Méndez 《Journal of Materials Science》2012,47(3):1378-1388
The effect of filler size and content in the thermal, mechanical, and electrical response of poly(vinylidene fluoride) (PVDF)/BaTiO3 nanocomposites has been investigated. Dielectric constant increases significantly with increasing filler content and decreasing
filler size. Space charge effects at the interface between BaTiO3 and PVDF strongly influence the dielectric response. The electroactive β-phase of PVDF is nucleated by the presence of the
ceramic filler, the effect being strongly dependent on filler size and independent on filler content. This filler/matrix interaction
is also responsible for the variations observed in the activation energy of the thermal degradation of the polymer. Smaller
particles lead to larger relative contact areas and are responsible for the main variations observed in the thermal, mechanical,
and electrical properties of the composites. 相似文献
10.
Annalisa Cataldi Andrea Dorigato Flavio Deflorian Alessandro Pegoretti 《Journal of Materials Science》2014,49(5):2035-2044
Microcrystalline cellulose (MCC) powder was selected as a natural reinforcement for a commercial acrylic adhesive widely used in the field of art protection and restoration (Paraloid B72). In particular, various amounts (from 5 to 30 wt%) of MCC were melt compounded with Paraloid B72 to prepare new thermoplastic polymer composites for the cultural heritage conservation field. Scanning electron microscopy showed that MCC flakes are uniformly dispersed within the matrix at all the tested compositions, without preferential orientation. Thermogravimetric analysis evidenced an increase of thermal stability due to the MCC introduction, even at low filler amounts, while DSC measurements demonstrated that the glass transition temperature progressively increases with the MCC content. Interestingly, DMTA analysis revealed a stabilizing effect on the material produced by microcellulose addition, with an increase of the storage modulus and a decrease of the thermal expansion coefficient, in proportion to the filler loading. Moreover, MCC addition determined an increase of the elastic modulus and creep stability with respect to the neat resin, and an enhancement of fracture toughness (K IC). 相似文献
11.
P. Martins C. M. Costa M. Benelmekki G. Botelho S. Lanceros-Méndez 《Journal of Materials Science》2013,48(6):2681-2689
Flexible multiferroic 0–3 composite films, with CoFe2O4, Ni0.5Zn0.5Fe2O4 or NiFe2O4 ferrite nanoparticles as filler and polyvinylidene fluoride (PVDF) as the polymer matrix, have been prepared by solvent casting and melt crystallization. The inclusion of ferrite nanoparticles in the polymer allows to obtain magnetoelectric nanocomposites through the nucleation of the piezoelectric β-phase of the polymer by the ferrite fillers. Since the interface between PVDF and the nanoparticles has an important role in the nucleation of the polymer phase, thermogravimetric analysis was used in order to identify and quantify the interface region and to correlate it with the β-phase content. It is found that an intimate relation exists between the size of the interface region and the piezoelectric β-phase formation that depends on the content and type of ferrite nanoparticles. The interface value and the β-phase content increase with increasing ferrite loading and they are higher for CoFe2O4 and Ni0.5Zn0.5Fe2O4 ferrite nanoparticles. The composites shows lower thermal stability than the pure polymer due to the existence of mass loss processes at lower temperature than the main degradation of the polymer. The main degradation of the polymer matrix, nevertheless, shows increased degradation temperature with increasing ferrite content. 相似文献
12.
C. B. Patil U. R. Kapadi D. G. Hundiwale P. P. Mahulikar 《Journal of Materials Science》2009,44(12):3118-3124
Calcium carbonate was synthesized by in situ deposition technique and its nano size (35–60 nm) was confirmed by transmission
electron microscopy (TEM). Composites of the filler CaCO3 (micro and nano) and the matrix poly(vinyl chloride) (PVC) were prepared with different filler loadings (0–5 wt%) by melt
intercalation. Brabender torque rheometer equipped with an internal mixer has been used for preparation of formulations for
composites. The effect of filler content both nano- and micro level on the nanostructure and properties is reported here.
The nanostructures were studied by wide angle X-ray diffraction and scanning electron microscopy. The mechanical, thermal,
and dynamic mechanical properties of PVC/micro- and nano-CaCO3 composites were characterized using universal testing machine, thermogravimetric analyzer, and dynamic mechanical analyzer.
The results of thermal analysis indicated that the thermal stability of PVC/nano-CaCO3 composites was improved as compared with corresponding microcomposites, and that of pristine PVC and maximum improvement
was obtained at 1 and 3 phr loadings. However, the tensile strength decreased significantly with increase loading of both
nano- and micro-CaCO3, whereas storage modulus and glass transition temperature increased significantly. 相似文献
13.
G. S. Deshmukh S. U. Pathak D. R. Peshwe J. D. Ekhe 《Bulletin of Materials Science》2010,33(3):277-284
PBT/CaCO3 composites were prepared in a single screw extruder with particle content varying from 0–30% by weight. The influence of
surface treatment of the particles, with and without stearic acid (SA), on the mechanical, thermal and structural properties
was studied. The experiments included tensile tests, impact tests, differential scanning calorimetry (DSC), scanning electron
microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy. The composite systems containing SA
coated CaCO3 were found to exhibit better mechanical properties as compared to composite systems containing uncoated CaCO3, with the S3 system (20% of SA coated CaCO3) exhibiting best combination of mechanical properties. Thermal study revealed that particle type and content had no influence
on the melting temperature but the crystallization temperature, % crystallinity and thermal stability increased on increasing
the CaCO3 content in PBT matrix. Morphological observation indicated that in PBT composites containing SA coated CaCO3, the coupling agent favours a better polymer filler interaction rendering inorganic polymer interface compatible, which is
also evident from better mechanical and thermal properties. 相似文献
14.
In present research work, pultrusion process is used to develop jute fibre-reinforced polyester (GFRP) composite and experiments have been performed on an indigenously developed pultrusion experimental setup. The developed composite consists of natural jute fibre as reinforcement and unsaturated polyester resin as matrix with hybrid filler containing bagasse fibre, carbon black and calcium carbonate (CaCO3). The effect of weight content of bagasse fibre, carbon black and calcium carbonate on tensile strength of pultruded GFRP composite is evaluated and the optimum hybrid filler composition for maximizing the tensile strength is determined. Different compositions of hybrid filler are prepared by mixing three fillers using Taguchi L9 orthogonal array. Fifteen percent of hybrid filler of different composition by weight was mixed in the unsaturated polyester resin matrix. Taguchi L 9 orthogonal array (OA) has been used to plan the experiments and ANOVA is used for analysing tensile strength. A regression model has also been proposed to evaluate the tensile strength of the composite within 7% error by varying the above fillers weight. A confirmation experiment was performed which gives 73.14 MPa tensile strength of pultruded jute fibre polymer composite at the optimum composition of hybrid filler. 相似文献
15.
High strength and high toughness metallic filament was produced by glass-coated melt spinning. The mechanical properties of the composite consisting of the filaments uniaxially aligned in brittle epoxy resin, ductile epoxy resin with plasticizer and poly(ether ether ketone) matrices were investigated. It was found that the Young's modulus (E
c) and tensile strength (,cu) of the composite consisting of uncoated filaments in brittle epoxy matrix were higher than those predicted by a linear function of the filament content (Vf), and the filaments fractured tightly in contact with the matrix. On the other hand, no improvement of the mechanical properties of the composite consisting of glass-coated filaments in brittle epoxy matrix was detected, due to the weak interfacial force between metallic filaments and the coating glass. The composite consisting of filaments in a ductile matrix was a high toughness material with a long range of plasticity deformation, and the experimental values ofE
c and cu against Vf agreed with the simple law of mixtures. 相似文献
16.
为增强废印刷电路板非金属粉(WPCBP)与聚合物基体之间的界面结合作用,采用溶胶-凝胶法在WPCBP表面原位负载了一层纳米二氧化硅粒子(SiO2),制备了一种新型的WPCBP-SiO2杂化填料.SEM、TGA和FTIR证明SiO2通过化学键成功负载到了杂化填料的表面.采用含双键的界面改性剂对杂化填料进行改性后,应用于不饱和聚酯树脂基体,探讨了未改性杂化填料及表面改性杂化填料对不饱和聚酯复合材料的力学性能、界面结合作用和热稳定性能的影响.结果表明,新型的杂化填料WPCBP-SiO2能够与不饱和聚酯基体形成强的界面结合作用,显著提高不饱和聚酯复合材料的力学性能和热稳定性能,且表面改性后复合材料的各项性能得到进一步提高. 相似文献
17.
Three metal hydroxide nanorods (MHR) with uniform diameters were synthesized, and then combined with graphene nanosheets (GNS) to prepare acrylonitrile–butadiene–styrene (ABS) copolymer composites. An excellent dispersion of exfoliated two-dimensional (2-D) GNS and 1-D MHR in the ABS matrix was achieved. The effects of combined GNS and MHR on the mechanical, thermal and flame retardant properties of the ABS composites were investigated. With the addition of 2 wt% GNS and 4 wt% Co(OH)2, the tensile strength, bending strength and storage modulus of the ABS composites were increased by 45.1%, 40.5% and 42.3% respectively. The ABS/GNS/Co(OH)2 ternary composite shows the lowest maximum weight loss rate and highest residue yield. Noticeable reduction in the flammability was achieved with the addition of GNS and Co(OH)2, due to the formation of more continuous and compact charred layers that retarded the mass and heat transfer between the flame and the polymer matrix. 相似文献
18.
Izzuddin Zaman Bukhari Manshoor Amir Khalid Qingshi Meng Sherif Araby 《Journal of Materials Science》2014,49(17):5856-5865
The interface between the matrix phase and dispersed phase of a composite plays a critical role in influencing its properties. However, the intricate mechanisms of interface are not fully understood, and polymer nanocomposites are no exception. This study compares the fabrication, morphology, and mechanical and thermal properties of epoxy nanocomposites tuned by clay layers (denoted as m-clay) and graphene platelets (denoted as m-GP). It was found that a chemical modification, layer expansion and dispersion of filler within the epoxy matrix resulted in an improved interface between the filler material and epoxy matrix. This was confirmed by Fourier transform infrared spectroscopy and transmission electron microscope. The enhanced interface led to improved mechanical properties (i.e. stiffness modulus, fracture toughness) and higher glass transition temperatures (T g) compared with neat epoxy. At 4 wt% m-GP, the critical strain energy release rate G 1c of neat epoxy improved by 240 % from 179.1 to 608.6 J/m2 and T g increased from 93.7 to 106.4 °C. In contrast to m-clay, which at 4 wt%, only improved the G 1c by 45 % and T g by 7.1 %. The higher level of improvement offered by m-GP is attributed to the strong interaction of graphene sheets with epoxy because the covalent bonds between the carbon atoms of graphene sheets are much stronger than silicon-based clay. 相似文献
19.
The flow properties of polypropylene(PP)/ethylene-propylene-diene monomer copolymer(EPDM)/glass bead (GB) ternary composites were measured in a wide scope of shear rates by using a Rosand capillary rheometer. The apparent shear rates varied from 10 to 105 s–1, and the test temperature was from 210 to 240°C. The results showed that the flow behavior of the composite melts may be considered to approximate that of a power law fluid although the slope of the melt flow curves somewhat varied around shear rate of 700 s– 1. The dependence of the melt shear viscosity on the test temperature was roughtly consistent with the Arrhenius expression. The melt shear viscosity increased dramatically with increasing the volume fraction (g) of GB under lower shear rate level, white it increased gently with an addition of g under higher shear rate level. Furthermore, there were certain effects of the filler surface treatment on the melt shear viscosity and its sentivity to the filler content at higher concentration of the beads at lower shear rates. 相似文献
20.
Costantini A Luciani G Annunziata G Silvestri B Branda F 《Journal of materials science. Materials in medicine》2006,17(4):319-325
A novel hydrogel based on 2-hydroxyethyl- methacrilate and SiO2 nanoparticles was prepared. The filler was added at a concentration of 30% w/w of silica nanoparticles to the mass of polymer.
The composite material was characterised as far as concerns swelling behaviour in comparison to pHEMA. Swelling ratio of modified
pHEMA was higher. Bioactivity of both SiO2 nanoparticles and the modified hydrogel was evaluated by soaking samples into a simulated body fluid (SBF). FT-IR spectroscopy,
scanning electron microscopy (SEM) and energy dispersive system (EDS) results suggest silica nanoparticles keep bioactive
in the polymer. SiO2 filler in a p(HEMA) matrix makes the composite bioactive. Therefore, these composites can be used to make bioactive scaffold
for bone engineering. 相似文献