Biocomposites compounded using acrylonitrile butadiene styrene with sunflower hull and distillers’ dried grains with soluble fibers were analyzed for their effectiveness in hybrid form to understand the combined effect of two fillers. The thermal and mechanical properties of the 20 wt.% fiber hybrid biocomposites were compared against the neat polymer. The biocomposites were processed using twin screw extrusion and injection molded as ASTM test specimens. The hybrid biocomposites showed marginal variations in thermal and physical properties, and showed near equivalent mechanical properties. The thermal and structural properties were attributed to the nonstructural and structural constituents of the fibers, respectively. 相似文献
Preparation and properties of poly(propylene)‐poly(propylene) composites have been investigated. Poly(propylene) fibres of varying diameter have been incorporated in a random ethylene co‐poly(propylene). The composites prepared from the same semi‐crystalline polymer in the matrix and reinforcement have lead to inherently strong interfacial bonding between the two phases of the same polymer. The composites demonstrated enhanced stiffness, which increased with fibre diameter. The structure, thermal, static and mechanical properties of poly(propylene) long fibre reinforced random co‐poly(propylene) composites have been studied with reference to the fibre diameter. The matrix and fibre components retained their separate melting temperatures. After melting, the two phases remained separate and showed their individual crystallization temperatures on cooling, and melting temperatures on a second heating. The melting temperature of the poly(propylene) fibres increased after formation of the composites. The compression molding of the composites at a temperature below the melting temperature of the fibres caused annealing of the fibre crystals. By incorporation of long poly(propylene) fibre into random co‐poly(propylene), the glass transition, storage and static modulus have been found to be increasing and composite with the largest fibre diameter shows better properties. Transcrystallization of the matrix poly(propylene) was observed.
Optical microscopy of composites with fibre diameter 68 μm. 相似文献
The influence of type and content of modified montmorillonite (MMT) clay and amount of compatibilizing agent on physical-mechanical properties of polypropylene (PP)/organoclay films were studied. An unexpected decrease in tensile elastic modulus and yield stress was observed, and a striking drop in film density. SEM micrographs showed film microcavitation at polymer/clay interfaces. Experimental design analysis indicated that the most important parameter was the organoclay content: the higher the proportion of MMT, the lower the values of film properties. The addition of compatibilizer promoted an improvement in these film properties, probably due to the formation of less porous film. 相似文献
In order to improve the mechanical and ablation properties of 2D-carbon/carbon composites, a SiC filler was added to a 2D-preform before isothermal chemical vapor infiltration densification by using a powder infiltration technique. Backscattered electron images showed that the SiC filler was mainly concentrated between the fiber bundles and between the layers. The tensile and flexural strengths of the composites were improved by the addition of the SiC filler because of the increase of interfacial surface areas between the bundles and between the layers, the less residual open porosity, and also the strong bonding between the SiC particles and the pyrocarbon matrix. The composites with filler experienced a 15.2% lower thickness erosion rate and a 51.7% lower mass erosion rate, compared to those C/C without filler. This was attributed to the low oxygen permeability of the SiO2 shielding the exterior inter-bundle pores as well as to a thermal barrier effect. 相似文献
Isotactic polypropylene (PP) has been blended with poly(ethylene-co-methyl acrylate) (EMA) (75/25 wt/wt%) in a single-screw extruder. The compatibilizing effect of polypropylene grafted with maleic anhydride (PP-g-MAH) has been examined. The nonisothermal crystallization of the developed blends has been investigated using differential scanning calorimetry (DSC) and analyzed using Avrami, Tobin and Liu models. The thermal stability of the blends was assessed through thermogravimetric analysis (TGA). The tensile and impact properties, as well as the melt viscosity, have also been determined. The presence of rubber accelerates the crystallization of PP. The thermal stabilities of the blends are intermediate between those of their constituents. Tensile strength and modulus are reduced upon incorporation of EMA into PP, but ultimate elongation and impact strength are improved. The melt viscosity variation with shear rate for all the systems was typical of shear-thinning behavior. The compatibilizing agent has a pronounced effect on enhancing the thermal and mechanical properties of the blend. 相似文献
LLDPE/modified nano-ZnO composite films were prepared using LLDPE and KH550-modified nano-ZnO by melt blending and blowing. The research results indicated that the introduction of the modified nano-ZnO improved the mechanical properties of the LLDPE films, the maximum tensile strength and elongation at break were obtained at modified nano-ZnO content of 0.3 wt%. The composite films exhibited favorable antibacterial activity against Escherichia coli and Staphylococcus aureus. The low doped content of modified nano-ZnO in LLDPE matrix made the melt viscosity of the composites increase slightly, it was coincident with variation of the balance torque with the nano-ZnO content. 相似文献
Halogen-free flame-retarded linear low density polyethylene (LLDPE) composites were prepared in a melt process using magnesium hydroxide (MH) as a flame retardant. The effects of surface modifiers on mechanical properties and rheological behavior of the filled LLDPE have been studied. The results show that the use of surface modifiers with low molecular weight (MW) such as stearic acid or its salts, and silane coupling agents can improve greatly the elongation at break of the composites, and decrease the tensile strength in most cases. However, PE-g-DBM (LLDPE grafted with dibutyl maleate) as a polymeric compatibilizer can make the strength and elongation at break of the composites increase simultaneously. It was found from the rheological measurements that the composites containing low MW surface modifiers exhibited a lower viscosity compared with that of the composites without them, whereas the use of PE-g-DBM compatibilizer increased the viscosity of the composites. In addition, their effects on the morphological structure of the flame-retarded LLDPE composites containing surface modifiers have been investigated using scanning electron microscope (SEM). 相似文献
Two types of carbon nanotubes (CNTs), the network multi-walled nanotubes (MWNTs) and the dispersed MWNTs, were used for fabricating MWNTs/phenolic composites. The MWNTs were synthesized using the floating catalyst method through the chemical vapor deposition process. The effects of the MWNT content on the mechanical properties of the composites were investigated. Modified Halpin-Tsai equation was proposed to evaluate the Young’s modulus and tensile strength of the MWNTs/phenolic composites by adopting an orientation factor and an exponential shape factor in the equation. It is found that the results obtained from the modified Halpin-Tsai equation on tensile strengths and Young’s moduli fit successfully the experimental ones. The tensile fracture surfaces of MWNTs/phenolic composites were examined using field emission scanning electron microscope to study the failure morphologies of the MWNTs/phenolic composites. 相似文献
Aromatic silicon-containing poly(amide-imide)s have been prepared by low temperature solution polycondensation reaction of various aromatic diamines having ether bridges between phenylene rings with a diacid chloride, namely bis[N-(4-chlorocarbonylphenyl) phthalimidyl]dimethylsilane. These polymers were easily soluble in polar amidic solvents such as N-methylpyrrolidone,N,N-dimethylacetamide, and N,N-dimethylformamide and can be cast from solutions into thin, flexible films. They showed good thermal stability, with initial decomposition temperature being above 410°C and glass transition temperature in the range of 263–285°C. The polymer films exhibited good mechanical properties with tensile strengths in the range of 78–109 MPa, tensile modulus in the range of 1.44–1.76 GPa, and elongation at break values ranging from 11% to 24%. Electrical insulating properties of two polymer films were evaluated on the basis of dielectric constant and dielectric loss and their variation with frequency and temperature. 相似文献
In the present work, effects of oxidation and fiber content (from 20 to 35 wt. %) on the physicomechanical properties of jute-polypropylene (PP) composites were studied. Mechanical properties (tensile strength, tensile modulus, elongation at break, flexural strength, flexural modulus, and charpy impact strength) were measured for all raw and oxidized jute-PP composites. Improved mechanical properties were obtained for oxidized jute-PP composites. Interfacial adhesion and bonding between the fiber and PP matrix were investigated by scanning electron micrograph analysis. Improved interfacial interactions and reduced water absorption were found for oxidized jute-PP composites. Water absorption tests of all composites were also performed. 相似文献
The trial-and-error method used in ceramics research has certain limitations such as the high blindness of material component design. Moreover, calculations of the toughness of ceramics using the extended finite element method, which is the most broadly applied technique, are complicated. To overcome these issues, in this study, multilayer graphene (MLG)/Si3N4 whisker (Si3N4w)-reinforced Si3N4 ceramics (MWSCs) were used as the model material, and the modeling of MWSCs was conducted using Voronoi tessellation. Additionally, a more concise novel approach was applied for the prediction of the fracture toughness of MWSCs. Furthermore, the optimal MLG and Si3N4w contents were predicted, and then they were verified by fabricating MWSCs using spark plasma sintering (SPS). Simulation results indicated that the optimum MLG and Si3N4w contents to enable the toughness and hardness to reach the maximum values (9.87 MPa·m1/2 and 23.19 GPa) were 1 wt% and 3 wt%, which were consistent with the experimental results. Consequently, the effectiveness of the proposed method was verified. Moreover, the experimental values of the maximum fracture toughness and hardness were 11.04 MPa·m1/2 and 20.29 GPa, which were 47.20% and 12.10% higher than those of Si3N4 ceramics reinforced with 1 wt% MLG, respectively. The synergistic toughening effects of MLG and Si3N4w were significantly reflected. The load-bearing effect, bridging, and crack deflection induced by MLG and Si3N4w were the key reasons for the improvement in the mechanical properties of MWSCs. 相似文献
The effects of different silica grades and elastomer content on interfacial properties, morphology and mechanical properties of polypropylene/silica 96/4 composites modified with added 5, 10, 15, and 20% of poly(styrene-b-ethylene-co-butylene-b-styrene) grafted with maleic anhydride (SEBS-g-MA) were investigated. The iPP/silica/SEBS-g-MA composites were designed by adding four silica fillers differing in size (nano- vs. micro-) and in surface properties (hydrophilic vs. hydrophobic) and SEBS-g-MA that was used as a proven effective impact modifier and compatibilizer simultaneously. The morphology of every composite was a spectrum of several morphologies rather than one exclusive morphology. Good concordance between observed and predicted morphology indicated that the morphology of a particular composite was controlled primarily by interfacial properties. Tensile and impact properties were influenced primarily by competitive effects of a stiff filler and tough SEBS-g-MA elastomer. Increased impact strength and strain at break caused by adding SEBS-g-MA indicated a significant overcoming of the elastomeric toughening effect in relation to the filler’s stiffening effect. 相似文献
Acrylonitrile-butadiene-styrene (ABS) high-rubber powder (HRP) toughened acrylonitrile-butadiene-styrene (ABS)/polymethyl methacrylate (PMMA) blends were prepared in a co-rotating twin screw extruder. The effect of ABS HRP on mechanical and morphology properties of ABS/PMMA blends was studied. It is shown that the toughness of ABS/PMMA blends was improved effectively with the incorporation of ABS HRP, while the elastic modulus and tensile strength decrease slightly. Tensile tests at different strain rates were carried out in order to investigate the influence of strain rate on mechanical properties of various blends. Finally, the strain rate sensitive behavior of different blends was explored by using the Eyring model. 相似文献
The effect of electron beam (EB) irradiation on the cure characteristics and mechanical properties of unirradiated and irradiated SBR/NBRr blends were investigated. The SBR/NBRr blends were prepared at 95/5, 85/15, 75/25, 65/35, and 50/50 blend ratio with and without the presence of a polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). Results indicated that the scorch time t2, cure time t90 and minimum torque (ML) of irradiated SBR/NBRr blend decreased, but the maximum torque (MH) particularly at 35 and 50 phr of NBRr (recycled NBR) increased with the presence of TMPTA. The stress at 100% elongation (M100), hardness, cross-linking density and tensile strength (particularly after 15 phr of NBRr content) of irradiated SBR/NBRr blends increased after irradiation but the elongation at break (EB) and resilience decreased. The irradiated SBR/NBRr blends showed lower thermal stability than non-irradiated blends. Scanning electron microscopy proved the enhancement in tensile strength when more NBRr were added in SBR matrix where the irradiated surfaces demonstrate more irregularity with increasing crack branching (fracture planes are located at different heights) due to the increased of cross-linked density. 相似文献
The mechanical and thermal properties of poly(phthalazinone ether sulfone) (PPES)/poly(aryl ether sulfone) (PES) blends prepared by melt-mixing were investigated by dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The dynamic mechanical thermal analysis results show that the incorporated PES has a large influence on the heat stability of PPES. The DMTA results display that the blends with a single glass transition temperature, which increases with increasing PPES content, indicates that PPES and PES are completely miscible over the studied composition range. The thermodegradative behavior of PPES/PES blends was used to analyze their thermal stability. The Friedman technique was used to determine the kinetic parameters (i.e., the apparent activation energy and order of reaction of the degradation process). The results indicate that the presence of the PES component influences the thermal stability of the PPES. On the basis of the kinetic data derived from Friedman' approach, the lifetime estimates for pure PPES, pure PES, and the blends generated from the weight loss of 5% were constructed. 相似文献