Tremolite,a kind of inorganic filler,was modified with a silane coupling agentγ-methacryloxypropyl trimethoxy silane (MPS) in ethanol/ammonia solution.The graft of MPS on tremolite was confirmed by X-ray photoelectron spectroscopy (XPS),IR and thermogramitric analysis (TGA) measurements.In addition,contact angle analysis showed that particle surface property was changed from hydrophilicity to hydrophobicity after the modification.Modified tremolite and pure tremolite were blended respectively with PA1010... 相似文献
Graphene oxide nanosheets (GONSs)/cyanate ester (CE) resin composites were prepared via a solution intercalation method. The structures of the GONSs and the composites were studied using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The mechanical and tribological properties of the composites were investigated. In addition, the thermal behavior of the composites was characterized by thermogravimetric analysis (TGA). Results show that the GONSs/CE resin composites were successfully prepared. The addition of GONSs is beneficial to improve the mechanical and tribological properties of the composites. Moreover, the composites exhibit better thermal stability in comparison with the CE resin matrix. 相似文献
In order to enhance the thermal conductivity of MWCNT filled poly(dimethyl siloxane) (PDMS) composites, the MWCNT was coated
with silica layer by three step reactions. The composites filled with raw and silica-coated MWCNTs were prepared and the properties
were investigated in terms of the curing characteristics, mechanical properties, and thermal conductivity. Due to the poor
compatibility between raw MWCNT and PDMS, raw MWCNT showed poor dispersion uniformity and wettability in PDMS. On the other
hand, due to the chemical affinity between silica/MWCNT and PDMS throughout the hydrogen bonding, the silica-coated MWCNT
filled PDMS showed improved mechanical properties in terms of tensile strength and 100% modulus, and good interfacial compatibility
than raw MWCNT incorporated PDMS. Finally, the good wettability of silica/MWCNT in PDMS resulted in higher thermal conductivity
caused from the facile phonon movement at the interface even with the smaller MWCNT contents. 相似文献
Alumina particles were incorporated in poly(dimethyl siloxane) (PDMS) matrix in company with multiwalled carbon nanotube (MWCNT) for improving the thermal and electrical conductivities. The concentration of MWCNT was increased from 0 to 10 wt% to PDMS at fixed amounts of alumina (200 and 300 wt% to PDMS). Thermal conductivity of PDMS composites was increased with the increasing amount of MWCNT and the excellent dispersibility of the incorporated pristine MWCNT was achieved. Thermal and electrical conductivities of the composites were increased with the increasing concentration of the alumina because the alumina particles help disperse MWCNT within the PDMS matrix due to the ball milling effect during compounding. The properties of the alumina and MWCNT incorporated PDMS composites were investigated in terms of the curing characteristics, electrical conductivity, and thermal conductivity. The MWCNT/alumina incorporated composite showed the high electrical conductivity to the level of the semiconductor. 相似文献
In this article, the composites based on long glass fibre reinforced polypropylene/intumescent flame retardant (LGFPP/IFR) were prepared by melt blending. The influence of thermal oxidative ageing on the LGFPP/IFR composites with different thermal oxidative ageing time at 140 °C was studied by means of oven heating. The thermal stability and flammability of the composites were respectively investigated by thermal gravimetric analysis (TG), limiting oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), scanning electronic microscopy (SEM), mechanical properties test and energy-dispersive X-ray analysis (EDAX). A trend of increase first and then decrease in LOI values was shown in 0–50 days ageing, with the same trend as thermal stability obtained from TG in nitrogen condition. The CCT results indicated that the LGFPP/IFR composites after ageing achieved a higher heat release rate, which means a higher fire risk. The mechanical properties showed a global decrease in just 10 days ageing. Morphologies obtained from SEM showed that both the rupture of PP matrix and fibre interface debonding led to the decrease in mechanical properties. The EDAX proved that IFR particles could emerge and gather on the surface of sample in ageing procedure, which had great effects on the thermal stability and flame retardancy of the composites. 相似文献
The Magnesium sulfate whiskers (MOSw) were first modified by Stearic acid or Si69, and Natural rubber (NR)/modified-MOSw composites were prepared by blending the modified-MOSw with natural rubber latex. By adding modified-MOSW into NR, the mechanical properties, the anti-ultraviolet aging property, flammability, and thermal stability of composites were improved obviously. The mechanical properties, crosslink density and thermal stability of composites reach the highest value at 4 wt% Si69-MOSW. The composite with MOSW addtion had a higher retention rate after ultraviolet irradiation and the MOSW could improve the anti-ultraviolet aging property of rubber matrix. The modified MOSW can effectively improve the oxygen index and the flame retardant grade of rubber composites. 相似文献
Biocomposites were fabricated using poly(propylene) carbonate as matrix and cellulosic polysaccharide banana (Musa acuminate) peel powder as filler in varying concentrations (5–25?wt.%) and were characterized for their functional properties. Microscopic analysis indicated the uniform distribution and existence of microfibrils in the filler. The thermal stability of the composites was lower than the matrix till 320?°C, beyond which it increased. The visco-elastic and mechanical behavior of the biocomposites was found to be enhanced with the addition of fillers. Thus, with better thermal, visco-elastic, and mechanical properties, the biocomposite films can be a replacement for the non-biodegradable polymers for packaging applications. 相似文献
The stability of electrical and mechanical properties of two kinds of polymer composites ‐ polyethylene/carbon black and polyethylene/carbon black modified by polypyrrole ‐ was investigated during slow cycle heating and cooling. Conductivity in composites was measured in heating/cooling cycles in the temperature range from 16°C to 125°C. It was found that the thermal treatment resulted in the conductivity changes and the mechanical properties of treated composites have also been influenced. The effect was explained by increased crystallinity in the polymer matrix of thermally treated composites. 相似文献
Brominated epoxy resin (BER) composites containing various amounts of SBA-15 and SBA-16 types mesoporous silicas were prepared through the thermal curing with 3-methyl-tetrahydrophthalic anhydride, and their morphologies, dielectric constants (κ), thermal properties and mechanical properties were studied. The investigation suggested that the dielectric constant could be reduced from 4.09 of the pure thermosetting BER to 3.74 and 3.7 by incorporating 3 wt.% SBA-15 and SBA-16, respectively. The reduction of the dielectric constant is attributed to the incorporation of the air voids (κ = 1) stored within the mesoporous silica materials, the air volume existing in the gaps on the interfaces between the mesoporous silica and the BER matrix, and the free volume created by introducing large-sized domains. The BER/mesoporous silica composites also present stable dielectric constants across the wide frequency range. An improvement of thermal stability of the BER is achieved by incorporation of the mesoporous silica materials. The enhanced interfacial interaction between the surface-modified mesoporous silica and the BER matrix has also led to an improvement of the toughness. 相似文献
Modified graphite oxide (MGO)/Poly (propylene carbonate) (PPC) composites with excellent thermal and mechanical properties have been prepared via a facile solution intercalation method. An intercalated structure of MGO/PPC composites was confirmed by X-ray diffraction and scanning electron microscope. The thermal and mechanical properties of MGO/PPC composites were investigated by thermal gravimetric analysis, differential scanning calorimetric, dynamic mechanical analysis, and electronic tensile tester. Due to the nanometer-sized dispersion of layered graphite in PPC matrix and the strong interfacial interaction between MGO and PPC, the prepared MGO/PPC composites exhibit improved thermal and mechanical properties in comparison with pure PPC. Compared with pure PPC, the MGO/PPC composites show the highest thermal stability and the Tg is 13.8 °C higher than that of pure PPC, while the tensile strength (29.51 MPa) shows about 2 times higher than that of pure PPC when only 3.0 wt.% MGO is incorporated. These results indicate that this approach is an efficient method to improve the properties of PPC. 相似文献
The aim of this paper was to prepare composites of bacterial cellulose (BC) and collagen to evaluate both the effect of collagen on the morphological, mechanical and thermal properties of BC and the effect of BC on the thermal stability of collagen for designing composites with increased potential biomedical applications. Two series of composites were prepared, the first series by immersing BC pellicle in solutions of collagen obtained in three forms, collagen gel (CG), collagen solution (CS) and hydrolysed collagen (HC), followed by freeze drying; and the second series of composites by mixing BC powder in solutions of collagen (CG, CS and HC), also followed by freeze drying. The properties of obtained composites were evaluated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), mechanical tests, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results revealed that BC acts as a thermal stabilizer for CS matrix, while with CG matrix it interacts synergistically leading to composites with improved properties. On the other hand, the BC sheet impregnated with collagen has a significantly improved thermal stability. Collagen (as HC, CS or CG) has also a positive influence on the mechanical properties of lyophilized BC sheet. A four times increase of modulus was observed in BC/HC and BC/CG composites. and an increase of 60 times for BC/CS. The spectacular increase of elastic modulus and tensile strength in the case of BC/CS composite was explained by the easier penetration of collagen solution in the BC network and impregnation of BC fibrils as revealed by SEM and AFM analyzes.
We demonstrate the preparation of extremely cross-linked poly(dimethylsiloxane) (PDMS)-based materials and report optical, mechanical, and surface properties. Transparent monolithic molded objects are prepared catalytically with no byproducts; parts per million levels of platinum (catalyst) remain in the articles. Essentially the same material was prepared in 1993 and described as a "hard transparent glass." We confirm the thermal stability and chemical structure described in this report. We show that the catalytic reaction used, which was reported in 1999 always to exhibit a "violent exotherm", can be controlled conveniently using a low (parts per million) catalyst concentration. The combination of low surface energy, transparency, hardness, elasticity, and thermal stability makes this an unusual and interesting material. That it can be prepared from commercially available low-viscosity monomers adds to its interest. We comment that the class of materials known as siloxanes or silicones and PDMS in particular is not currently generally well understood (or taught) and review aspects of the structure, properties, and cross-linking chemistry of PDMS. 相似文献
Polyamide-6 (PA6)/carbon fiber (CF) composites were prepared by melt-extrusion via continuous fiber fed during extruding. The mechanical, thermal properties, and crystallization behavior of PA6/CF composites were investigated. It was found that the tensile modulus and strength of the composites were increased with the addition of CF, while their elongations at break were decreased. Scanning electron microscopy observation on the fracture surfaces showed the fine dispersion of CF and strong interfacial adhesion between fibers and matrix. Dynamic mechanical analysis results showed that the storage modulus of PA6/CF composites was improved with the addition of CF. Non-isothermal crystallization analysis showed that the CF plays a role as nucleating agent in PA6 matrix, and the α-form crystalline structure was favorable in the PA6/CF composites, as confirmed from the X-ray diffraction analysis. A trans-crystallization layer around CF could be observed by polarizing optical microscopy, which proved the nucleation effect of carbon fiber surface on the crystallization of PA6. The thermal stability of PA6/CF composites was also enhanced. 相似文献