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1.
Tensile and impact properties of Neem bark flour (BF) containing high density polyethylene (HDPE) composites were studied at 0–0.26 volume fraction of filler. Tensile modulus and strength and breaking elongation decreased with increase in BF concentration. The decrease in tensile modulus and strength was attributed to the decrease in crystallinity of the polymer compared to the imposed mechanical restraint by the BF. Analysis of tensile strength data indicated formation of stress concentration in the interphase. Because of this stress concentration and the mechanical restraint, the elongation‐at‐break and Izod impact strength decreased. Use of a coupling agent, HDPE‐g‐MAH, brings about enhanced phase adhesion, increasing the tensile modulus and strength. Enhanced adhesion marginally lowers composite ductility at higher filler contents and aids stress transfer increasing the Izod impact strength inappreciably. Scanning electron microscopic studies indicated better dispersion of BF particles and enhanced interphase adhesion in presence of the coupling agent. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007  相似文献   

2.
Tensile behavior and impact strength of poly(butylene terephthlate) (PBT)/styrene‐ethylene‐butylene‐styrene (SEBS) copolymer blends were studied at SEBS volume fraction 0–0.38. Tensile modulus and strength decreased, whereas breaking elongation increased with SEBS content. Predictive models are used to evaluate the tensile properties. Strength properties were dependent on the crystallinity of PBT and phase adhesion. The normalized notched Izod impact strength increased with the SEBS content; at Φd = 0.38, the impact strength enhanced to five times that of PBT. Scanning electron microscopy was used to examine phase morphology. Concentration and interparticle distance of the dispersed phase influenced impact toughening. In the presence of maleic anhydride‐grafted SEBS (SEBS‐g‐MAH), the tensile modulus and strength decreased significantly, while normalized relative notched Izod impact strength enhanced to 7.5 times because of enhanced interphase adhesion. POLYM. ENG. SCI., 53:2242–2253, 2013. © 2013 Society of Plastics Engineers  相似文献   

3.
The nonisothermal crystallization behavior and melting characteristics of high‐density polyethylene (HDPE) in HDPE/teak wood flour (TWF) composites have been studied by differential scanning calorimetry (DSC) and wide angle X‐ray diffraction (WAXD) methods. Composite formulations of HDPE/TWF were prepared by varying the volume fraction (?f) of TWF (filler) from 0 to 0.32. Various crystallization parameters evaluated from the DSC exotherms were used to study the nonisothermal crystallization behavior. The melting temperature (Tm) and crystallization temperature (Tp) of the composites were slightly higher than those of the neat HDPE. The enthalpy of melting and crystallization (%) decrease with increase in the filler content. Because the nonpolar polymer HDPE and polar TWF are incompatible, to enhance the phase interaction maleic anhydride grafted HDPE (HDPE‐g‐MAH) was used as a coupling agent. A shift in the crystallization and melting peak temperatures toward the higher temperature side and broadening of the crystallization peak (increased crystallite size distribution) were observed whereas crystallinity of HDPE declines with increase in ?f in both DSC and WAXD. Linear correlations were obtained between crystallization parameters and tensile and impact strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

4.
The melt rheological studies on HDPE/TWF (teak wood flour) composites were studied at (volume fraction) Φf = 0.00?0.32 and at 180°C, 190°C and 200°C. Viscosity of HDPE/TWF composites increases with Φf while decreases with increase in temperature. Addition of coupling agent, maleic anhydride grafted HDPE (HDPE-g-MAH) enhances viscosity as compared to the corresponding HDPE/TWF. This was attributed to increase in interaction between TWF and HDPE by HDPE-g-MAH which in turn stiffens the system. The power law coefficient, n, decreases with increase in Φf and increase in temperature and lower for HDPE/TWF/HDPE-g-MAH composites as compared to HDPE/TWF composites. The consistency index increases with increase in Φf and were higher for HDPE/TWF/HDPE-g-MAH.  相似文献   

5.
The dynamic mechanical properties of high density polyethylene (HDPE) and teak wood flour (TWF) composites at varying volume fraction (Φ f) of TWF from 0.00 to 0.32 have been studied. In HDPE/TWF composites, storage modulus (E′) decreased at Φ f = 0.05, then increases with Φ f; however, values were lower than HDPE up to Φ f = 0.16, due to a pseudolubricating effect of filler. Loss modulus (E″) values were higher than HDPE in β and α relaxation regions while in γ relaxation region values were marginally equal to HDPE. Tan δ value decreases with Φ f which may be due to enhanced amorphization and decreased crystallinity of HDPE. In presence of maleic anhydride grafted HDPE (HDPE-g-MAH), E′ values were lower than HDPE/TWF composites. In HDPE/TWF/HDPE-g-MAH, E″ were slightly higher than HDPE/TWF due to slippage of HDPE chains facilitated by the extent of degradation of coupling agent. Tan δ were higher for both systems than the rule of mixture.  相似文献   

6.
Tensile properties and Izod impact strength of mica‐filled composites of poly(butylene terephthlate) (PBT)/polyacrylonitrile‐butyl acrylate‐styrene (ABAS) were studied at mica concentration range 0 to 0.14 volume fraction, (?f). Tensile properties such as tensile modulus, strength, and breaking strain were normalized by dividing the data with the crystallinity (%) of the major component PBT in the composites and the matrix blends. The normalized relative tensile properties were compared with simple models to evaluate the interphase interactions between the matrix (i.e. PBT/ABAS blend) and the dispersed phase mica. Mica reinforced the blend increasing the tensile modulus and strength with mica concentration while the strain‐at‐break was increased marginally up to ?f = 0.04 and decreased beyond this ?f. The impact strength, however, decreased with increase in ?f due to enhanced matrix stiffening and lack of plastic deformation of the matrix. Scanning electron microscopic studies revealed good dispersion of mica in the composites. The effect of surface treatment with a zirconate coupling agent, NZ‐97, on the above properties has also been examined. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

7.
In this article, high density polyethylene/styrene‐ethylene‐butylene‐styrene block copolymer blends (HDPE/SEBS) grafted by maleic anhydride (HDPE/SEBS‐g‐MAH), which is an effective compatibilizer for HDPE/wood flour composites was prepared by means of torque rheometer with different contents of maleic anhydride (MAH). The experimental results indicated that MAH indeed grafted on HDPE/SEBS by FTIR analysis and the torque increased with increasing the content of maleic anhydride and dicumyl peroxide (DCP). Styrene may increase the graft reaction rate of MAH and HDPE/SEBS. When HDPE/SEBS MAH was added to HDPE/wood flour composites, tensile strength and flexural strength of composites can reach 25.9 and 34.8 MPa in comparison of 16.5 and 23.8 MPa (without HDPE/SEBS‐g‐MAH), increasing by 157 and 146%, respectively. Due to incorporation of thermoplastic elastomer in HDPE/SEBS‐g‐MAH, the Notched Izod impact strength reached 5.08 kJ m?2, increasing by 145% in comparison of system without compatibilizer. That HDPE/SEBS‐g‐MAH improved the compatibility was also conformed by dynamic mechanical measurement. Scanning electron micrographs provided evidence for strong adhesion between wood flour and HDPE matrix with addition of HDPE/SEBS‐g‐MAH. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

8.
In this study, the effect of Fe powder on the physical and mechanical properties of high density polyethylene (HDPE) was investigated experimentally. HDPE and HDPE containing 5, 10, and 15 vol % Fe metal–polymer composites were prepared with a twin screw extruder and injection molding. After this, fracture surface, the modulus of elasticity, yield and tensile strength, % elongation, Izod impact strength (notched), hardness (Shore D), Vicat softening point, heat deflection temperature (HDT), melt flow index (MFI), and melting temperature (Tm) were determined, for each sample. When the physical and mechanical properties of the composites were compared with the results of unfilled HDPE, it was found that the yield and tensile strength, % elongation, and Izod impact strength of HDPE decreased with the vol % of Fe. As compared with the tensile strength and % elongation of unfilled HDPE, tensile strength and % elongation of 15 vol % Fe filled HDPE were lower, about 17.40% and 94.75% respectively. On the other hand, addition of Fe into HDPE increased the modulus of elasticity, hardness, Vicat softening, MFI, and HDT values, such that 15 vol % Fe increased the modulus of elasticity to about 48%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006  相似文献   

9.
Poly(butylene terephthalate)/high density polyethylene (PBT/HDPE) blends and PBT/HDPE‐grafted maleic anhydride (PBT/HDPE‐g‐MAH) blends were prepared by the reactive extrusion approach, and the effect of blend compositions on the morphologies and properties of PBT/HDPE blends and PBT/HDPE‐g‐MAH blends was studied in detail. The results showed that flexural strength, tensile strength, and notched impact strength of PBT/HDPE blends decreased with the addition of HDPE, and flexural strength and tensile strength of PBT/HDPE‐g‐MAH blends decreased, while the notched impact strength of PBT/HDPE‐g‐MAH increased with the addition of HDPE‐g‐MAH. Compared with PBT/HDPE blends, the dimension of the dispersed phase particles in PBT/HDPE‐g‐MAH blends was decreased and the interfacial adhesion was increased. On the other hand, the effects of HDPE and HDPE‐g‐MAH contents on the crystalline and the rheological properties of the blends were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 6081–6087, 2006  相似文献   

10.
The reactive extrusion of maleic anhydride grafted polypropylene (PP‐g‐MAH) with ethylenediamine (EDA) as coupling agent is carried out in a corotating twin‐screw extruder to produce long chain branched polypropylene (LCBPP). Part of PP‐g‐MAH is replaced by maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MAH) or linear low‐density polyethylene (LLDPE‐g‐MAH) to obtain hybrid long chain branched (LCB) polyolefins. Compared with the PP‐g‐MAH, PE‐g‐MAH, and their blends, the LCB polyolefins exhibit excellent dynamic shear and transient extensional rheological characteristics such as increased dynamic modulus, higher low‐frequency complex viscosity, broader relaxation spectra, significantly enhanced melt strength and strain‐hardening behaviors. The LCB polyolefins also have higher tensile strength, tensile modulus, impact strength and lower elongation at break than their blends. Furthermore, supercritical carbon dioxide (scCO2) is constructively introduced in the reactive extrusion process. In the presence of scCO2, the motor current of the twin extruder is decreased and LCB polyolefins with lower melt flow rate (MFR), higher complex viscosity and increased tensile strength and modulus can be obtained. This indicates that the application of scCO2 can reduce the viscosity of melt in extruder, enhance the diffusion of reactive species, and then facilitate the long chain branching reaction between anhydride group and primary amine group. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

11.
Miscanthus fibers reinforced biodegradable poly(butylene adipate‐co‐terephthalate) (PBAT) matrix‐based biocomposites were produced by melt processing. The performances of the produced PBAT/miscanthus composites were evaluated by means of mechanical, thermal, and morphological analysis. Compared to neat PBAT, the flexural strength, flexural modulus, storage modulus, and tensile modulus were increased after the addition of miscanthus fibers into the PBAT matrix. These improvements were attributed to the strong reinforcing effect of miscanthus fibers. The polarity difference between the PBAT matrix and the miscanthus fibers leads to weak interaction between the phases in the resulting composites. This weak interaction was evidenced in the impact strength and tensile strength of the uncompatibilized PBAT composites. Therefore, maleic anhydride (MAH)‐grafted PBAT was prepared as compatibilizer by melt free radical grafting reaction. The MAH grafting on the PBAT was confirmed by Fourier transform infrared spectroscopy. The interfacial bonding between the miscanthus fibers and PBAT was improved with the addition of 5 wt % of MAH‐grafted PBAT (MAH‐g‐PBAT) compatibilizer. The improved interaction between the PBAT and the miscanthus fiber was corroborated with mechanical and morphological properties. The compatibilized PBAT composite with 40 wt % miscanthus fibers exhibited an average heat deflection temperature of 81 °C, notched Izod impact strength of 184 J/m, tensile strength of 19.4 MPa, and flexural strength of 22 MPa. From the scanning electron microscopy analysis, better interaction between the components can be observed in the compatibilized composites, which contribute to enhanced mechanical properties. Overall, the addition of miscanthus fibers into a PBAT matrix showed a significant benefit in terms of economic competitiveness and functional performances. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45448.  相似文献   

12.
A functionalized high‐density polyethylene (HDPE) with maleic anhydride (MAH) was prepared using a reactive extruding method. This copolymer was used as a compatibilizer of blends of polyamide 6 (PA6) and ultrahigh molecular weight polyethylene (UHMWPE). Morphologies were examined by a scanning electron microscope. It was found that the dimension of UHMWPE and HDPE domains in the PA6 matrix decreased dramatically, compared with that of the uncompatibilized blending system. The size of the UHMWPE domains was reduced from 35 μm (PA6/UHMWPE, 80/20) to less than 4 μm (PA6/UHMWPE/HDPE‐g‐MAH, 80/20/20). The tensile strength and Izod impact strength of PA6/UHMWPE/HDPE‐g‐MAH (80/20/20) were 1.5 and 1.6 times as high as those of PA6/UHMWPE (80/20), respectively. This behavior could be attributed to chemical reactions between the anhydride groups of HDPE‐g‐MAH and the terminal amino groups of PA6 in PA6/UHMWPE/HDPE‐g‐MAH blends. Thermal analysis was performed to confirm that the above chemical reactions took place during the blending process. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 232–238, 2000  相似文献   

13.
The mechanical properties including tensile, flexural, and impact of the nanometer on calcium carbonate (nano‐CaCO3) filled polypropylene (PP)/poly (ethylene‐co‐octene) (POE) composites were measured at room temperature to identify the effects of the POE content on the mechanical properties. It was found that the Young's modulus, tensile strength, and tensile elongation at break decreased nonlinearly while the tensile fracture strength varied slightly with increasing the POE weight fraction; the V‐notched and unnotched Izod impact fracture strength increased nonlinearly with an increase of the POE weight fraction; the flexural modulus and strength decreased roughly linearly with increasing the POE weight fraction. Furthermore, the impact fracture surface of the specimens was observed by means of a scanning electronic microscope to discuss the toughening mechanisms. POLYM. COMPOS., 37:539–546, 2016. © 2014 Society of Plastics Engineers  相似文献   

14.
ABSTRACT

Tensile and impact properties of talc-filled i-PP/CSM rubber (20 phr, 0.13 vol fraction) blends were studied in the talc concentration range 0–0.149 vol fraction (0–50 phr). The tensile modulus increased whereas the tensile breaking strength and the strain-at-break decreased with increase in the talc concentration. The modulus increase and the strain decrease were due to enhanced mechanical restraint imposed by the talc particles on the polymer blend decreasing its deformability. Formation of stress concentration points explained the decrease in the tensile strength. The Izod impact strength showed a significant decrease with increase in the filler content. Surface treatment of the talc particles with a titanate coupling agent LICA 12 increased the wetting of the talc by the polymer blend, further modifying the strength properties. Scanning electron microscopic studies showed enhanced dispersion of the filler particles sequential to the surface treatment, effecting modifications of the composite strength properties.  相似文献   

15.
Poly(lactic acid) (PLA) was melt blended with thermoplastic elastomer (TPE) styrene–ethylene–butylene–styrene‐g‐maleic anhydride (SEBS‐g‐MA) copolymer using a micro compounder which used melt recirculation approach for efficient dispersion of SEBS‐g‐MA in PLA. The SEBS‐g‐MA volume fraction (Φd) was varied between 0.07 and 0.48. Dynamic mechanical analysis showed 10.4 °C decrease in glass transition temperature at Φd = 0.48. Differential scanning calorimetry results exhibited shift in cold crystallization temperature to a higher temperature in the presence of SEBS‐g‐MA. Thermogravimetric analysis presented enhanced thermal stability of PLA/SEBS‐g‐MA blends. Tensile strength and modulus decreased while elongation‐at‐break and Izod impact strength increased in the blends. Theoretical models were employed to analyze the tensile properties of the blends in order to evaluate the blend structure. The microstructural attributes were characterized by wide‐angle X‐ray diffraction, Fourier‐transform infrared spectroscopy, and scanning electron microscopy of cryofractured, impact fractured, and tensile fractured surfaces. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45644.  相似文献   

16.
The morphologies, crystallization and melting behaviors, and mechanical, thermal and processing properties of polypropylene (PP)/CaCO3 toughening masterbatch (CTM) composites were investigated. The good dispersion of CaCO3 particles via appropriate surface encapsulation in the composites is proven by density measurements and scanning electron microscopy images. The crystallinity and tensile strength of PP decrease with the addition of CTM. The flexural modulus and storage modulus (E′) at 23 °C increase with CTM content, implying improved stiffness. A sharp increase in the Izod notched impact strength can be observed for the composites, and the critical ligament thickness (τc) is calculated to be 1.31 and 2.46 μm for PP (S1003) and PP (001 G) composites, respectively. The morphologies of the impact‐fractured surfaces of the specimens were observed, and the shear deformation is enhanced by the addition of CTM. The presence of CTM also increases the melt flowability and decreases the shrinkage of the composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45515.  相似文献   

17.
Ethylenediamine (EDA) covalently functionalized graphene sheets (GS‐EDA) and acidized carbon nanotubes (MWNTs‐COOH) were first prepared, followed by synthesizing l ‐aspartic acid functionalized GS‐EDA/MWNTs‐COOH (LGC) hybrid nanomaterials by using l ‐aspartic acid as a bridging agent. Then nanocomposites of high density polyethylene‐g ‐maleic anhydride (HDPE‐g ‐MAH) synergistic strengthening–toughening using LGC hybrids were prepared via melt compounding method. The surface structure of filler was characterized by using infrared (FTIR) and Raman spectrum. The synergistic strengthening–toughening effects of LGC hybrids on the HDPE‐g ‐MAH were investigated by scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), tensile, and impact tests. FTIR showed that EDA has been grafted on the graphene sheets, and ? COOH group has been introduced into MWNTs. The l ‐aspartic acid connected GS‐EDA and MWNTs‐COOH through chemical bonds. SEM observations showed that LGC hybrids were homogeneously dispersed in HDPE‐g ‐MAH nanocomposites. Tensile and impact tests indicated that the mechanical properties of nanocomposites were improved obviously when LGC hybrid nanomaterials were incorporated simultaneously. DMA analysis indicated that the storage modulus of composites was higher than that of pure HDPE‐g ‐MAH matrix. TGA results revealed that the maximum decomposition temperature of HDPE‐g ‐MAH composites containing 0.75 wt % of LGC showed 11.5 °C higher than that of HDPE‐g ‐MAH matrix. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45055.  相似文献   

18.
Glass beads were used to improve the mechanical and thermal properties of high‐density polyethylene (HDPE). HDPE/glass‐bead blends were prepared in a Brabender‐like apparatus, and this was followed by press molding. Static tensile measurements showed that the modulus of the HDPE/glass‐bead blends increased considerably with increasing glass‐bead content, whereas the yield stress remained roughly unchanged at first and then decreased slowly with increasing glass‐bead content. Izod impact tests at room temperature revealed that the impact strength changed very slowly with increasing glass‐bead content up to a critical value; thereafter, it increased sharply with increasing glass‐bead content. That is, the Izod impact strength of the blends underwent a sharp transition with increasing glass‐bead content. It was calculated that the critical interparticle distance for the HDPE/glass‐bead blends at room temperature (25°C) was 2.5 μm. Scanning electron microscopy observations indicated that the high impact strength of the HDPE/glass‐bead blends resulted from the deformation of the HDPE matrix. Dynamic mechanical analyses and thermogravimetric measurements implied that the heat resistance and heat stability of the blends tended to increase considerably with increasing glass‐bead content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2102–2107, 2003  相似文献   

19.
The effects of the fiber reinforcement of a novel bioabsorbable chitin‐fiber‐reinforced poly(?‐caprolactone) (PCL) composite were improved by irradiation treatment. The tensile strength and tensile modulus of the treated specimens were enhanced with respect to those of the untreated specimens. An increase in the fiber content (Cf) resulted in an increase in this enhancement tendency until Cf was 45%. A further increase in Cf increased the tensile modulus but decreased the strength. The flexural strength and flexural modulus were increased for the irradiation‐treated specimens in the same way as the tensile test. The microstructure of the tensile fracture showed an improvement in interfacial bonding for the irradiated specimens. The glass‐transition temperature (Tg) of the composite increased with an increase in Cf for the irradiation‐treated specimens, but there was no change in Tg for the untreated specimens with various values of Cf. This indicated that, for the composites with irradiation treatment, the fiber intensively affected the molecular segmental motion of PCL and thereby enhanced the interfacial interaction between the matrices and fibers. The same slope of the storage modulus (G′) versus the loss modulus (G″) for the irradiated specimens suggested an increase in the compatibility of the composite in comparison with the decrease in the slope with increasing Cf for the untreated specimens. All this demonstrated that there was some interfacial reaction between the fiber and matrix that resulted in the presence of an interfacial phase and improved the mechanical properties of the materials. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 486–492, 2002; DOI 10.1002/app.10149  相似文献   

20.
Mechanical properties and morphological studies of compatibilized blends of polyamide‐6 (PA‐6)/K resin grafted with maleic anhydride (K‐g‐MAH) and PA‐6/K resin/K‐g‐MAH were investigated as functions of K resin/K‐g‐MAH and dispersed phase K resin concentrations, and all the blends were prepared using twin screw extruder followed by injection molding. Scanning electron microscopy (SEM) were used to assess the fracture surface morphology and the dispersion of the K resin in PA‐6 continuous phase, the results showing extensive deformation in presence of K‐g‐MAH, whereas, uncompatibilized PA‐6/K resin blends show dislodging of K resin domains from the PA‐6 matrix. Dynamic mechanical thermal analysis (DMTA) test reveals the partially miscibility of PA‐6 with K‐g‐MAH, and differential scanning calorimetry (DSC) results further identified that the introduction of K‐g‐MAH greatly improved the miscibility between PA‐6 and K resin. The mechanical properties of PA‐6/K resin blends and K‐g‐MAH were studied through bending, tensile, and impact properties. The Izod notch impact strength of PA‐6/K‐g‐MAH blends increase with the addition of K‐g‐MAH, when the K‐g‐MAH content adds up to 20 wt %, the impact strength is as more than 6.2 times as pure PA‐6, and accompanied with small decrease in the tensile and bending strength less than 12.9% and 17.5%, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

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