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Impact Properties (impact + property)
Selected AbstractsImpact properties and microhardness of double-gated glass-reinforced polypropylene injection moldingsPOLYMER ENGINEERING & SCIENCE, Issue 9 2009Matias Martinez Gamba Injection moldings with weld lines were produced in glass reinforced polypropylene grades differing in filler content using a two-gated hot runner injection mold. The skin-core microstructure developed during injection molding was qualitatively analyzed by means of optical and scanning electronic microscopy techniques. The load bearing capacity of the moldings was assessed by uniaxial tensile-impact and biaxial instrumented falling dart impact tests. Microhardness was also used to ascertain the possibility of using it as a simple nondestructive technique for characterizing glass fiber-reinforced injection moldings. The properties were monitored at various points to evaluate their variation at the bulk and the knit region. The biaxial impact test highlights the 10-fold reduction of the impact strength caused by the weld line. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source] Toughening study of fire-retardant high-impact polystyreneFIRE AND MATERIALS, Issue 2 2009Cui Wenguang Abstract Fire-retardant high-impact polystyrene (HIPS) was modified by melt blending with varying amounts of three types of tougheners. The effects of the tougheners on the properties of the fire-retardant HIPS were studied by mechanical, combustion tests, and thermogravimetric analysis. The morphologies of fracture surfaces and char layers were characterized through scanning electron microscopy. The results show that the impact properties of styrene,butadiene,styrene (SBS)-containing composites were better than those of ethylene,propylene,diene monomer (EPDM)-containing or ethylene,vinyl acetate copolymer (EVA)-containing composites. The tensile strength and flexural modulus of the fire-retardant HIPS decreased evidently with the addition of tougheners. It is found that the compatibility between SBS copolymer and HIPS matrix was best among the three types of tougheners. The addition of SBS had little influence on the thermal property, residue, flammability, and morphology of char layer of the fire-retardant HIPS, but the addition of EPDM rubber or EVA brought adverse influence on the residue, flammability, and morphology of char layer of the fire-retardant HIPS, especially for EPDM. Copyright © 2009 John Wiley & Sons, Ltd. [source] Rotational molding of two-layered polyethylene foamsADVANCES IN POLYMER TECHNOLOGY, Issue 2 2001Shih-Jung Liu Rotational molding of polyethylene foams has increasingly become an important process in industry because of its resultant thicker walls, low sound transfer, high stiffness, and good thermal insulation. This report assesses the rotomoldability of two-layer polyethylene foamed parts. The polymeric material used in this study was linear low-density polyethylene and the foaming material was an endothemic chemical blowing agent. Two different molding methods, by powder and by pellet, were used to mold the multilayer foamed parts. Rotational molding experiments were carried out in a laboratory scale uniaxial machine, capable of measuring internal mold temperature in the cycle. Characterization of molded part properties was performed after molding. Optical microscopy was also employed to determine the bubble distribution in foamed parts. The final goal of this study was to investigate how the blowing agent and processing conditions can influence the process of rotational molding and the final product quality. It was found that the rotational molding of two-layer polyethylene foams produced parts of better impact properties, as well as fine outside surfaces. In addition, rotational molding of foamed parts by pellets saves the cost of powder grinding, but is counteracted by uneven inner surfaces. © 2001 John Wiley & Sons, Inc. Adv Polym Techn 20: 108,115, 2001 [source] Mechanical, flow, and morphological properties of talc- and kaolin-filled polypropylene hybrid compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007M. B. Abu Bakar Abstract Polypropylene (PP) hybrid composites have been produced by compounding two types of mineral fillers, viz., talc and kaolin with PP copolymer using a twin screw extruder. The PP hybrid composite was injection-molded into dumbbell specimen for tensile, flexural, and impact properties characterizations. MFI and SEM studies were used to characterize the flow and morphological properties of the PP hybrid composites. The result shows that most of the hybrid composites showed a significant decrease in flow, tensile, flexural, and impact properties compared with the single filler-filled PP composites. However, a hybridization effect was seen for the PPT20K10 hybrid composites, through the synergistic coalescence of positive characteristics from 20 wt % of talc and 10 wt % of kaolin. This hybrid formulation have given an economically advantageous material with the mechanical properties (tensile, flexural, and impact) comparable to those of the talc-filled PP composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 434,441, 2007 [source] Effects of addition of functionalized SEBS on rheological, mechanical, and tribological properties of polyamide 6 nanocompositesPOLYMER ENGINEERING & SCIENCE, Issue 1 2010Yosuke Nishitani The effects of the addition of styrene-ethylene/butylene-styrene copolymer (SEBS) with various functionalized groups on the rheological, mechanical, and tribological properties on polyamide 6 nanocomposite filled with layered silicate (PA6/Clay) were investigated. Four types of SEBS: unmodified SEBS (SEBS), maleic anhydride grafted SEBS (SEBS- g -MA), amine group grafted SEBS (SEBS- g -NH2), and carboxyl group grafted SEBS (SEBS- g -COOH) were added with PA6/Clay nanocomposite to prepare various polymer blends. These polymer blends were extruded by a twin screw extruder and injection molded. Dynamic viscoelastic properties of these blends in the molten state and their tensile, impact, and tribological properties were evaluated. The viscoelastic properties were found to increase with the addition of SEBS and were highly influenced by the types of functionalized groups contained. Influence of the addition of SEBS on the mechanical properties of these systems differed for each mechanical property. Although the tensile properties decreased with SEBS, Izod impact properties improved with the addition of various functionalized SEBS. These mechanical properties and viscoelastic properties correlated closely with the size of dispersed SEBS particles and interparticle distance. The tribological properties also improved with the addition of SEBS, and the influence of the amount added was higher than the type of SEBS used. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source] Effects of organoclay on morphology and properties of nanocomposites based on LDPE/PA-6 blends without and with SEBS- g -MA compatibilizerPOLYMER ENGINEERING & SCIENCE, Issue 6 2009Sara Filippi LDPE/PA-6 blends (75/25 wt/wt) were added with SEBS- g -MA (S) and/or an organoclay (20A) using different compounding sequences and the morphology and the properties of the blends or composites were investigated. An XRD study of the nanocomposites with pure polymers showed that 20A is intercalated by LDPE or PA-6 chains, whereas it is exfoliated by S if the clay concentration does not exceed 10 wt%. The SEM investigation showed that both S and 20A behave as efficient emulsifying agents for the LDPE/PA-6 blends. However, their effect on the mechanical properties was found to be opposite: S enhanced toughness but lowered the stiffness, whereas 20A improved the elastic modulus but impaired the impact properties. When used together, these additives failed to have synergistic effects and the blends mechanical properties could not be improved strongly. A possible interpretation for this behavior was suggested, considering that the anhydride groups of S can competitively interact with the amine end groups of PA-6 and with the surface of the silicate layer of 20A. Nevertheless, an optimization of the compounding procedure and the use of appropriate proportions of S and 20A allow the preparation of composites with excellent morphology and a satisfactory balance of stiffness and toughness. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source] Reactive acrylic liquid rubber with terminal and pendant carboxyl groups as a modifier for epoxy resinPOLYMER ENGINEERING & SCIENCE, Issue 1 2007D. Ratna Reactive acrylate rubbers with the terminal and pendent carboxyl groups have been investigated as a modifier for a room temperature curing epoxy resin. The liquid rubbers with varying molecular weights and carboxyl-functionality were synthesized by bulk polymerization of 2-ethyl hexyl acrylate using acrylic acid as a comonomer. The liquid rubbers were characterized by FTIR, 13C NMR spectroscopic analysis, nonaqueous titration, vapor pressure osmometry, and solubility characteristics. The liquid rubbers were incorporated into the epoxy resin by the prereact method and the effect of functionality on impact properties of the modified networks were investigated. The results were explained in terms of dynamic mechanical properties and morphology analyzed by scanning electron microscope (SEM). Polym. Eng. Sci. 47:26,33, 2007. © 2006 Society of Plastics Engineers. [source] A comparative study of multimodal vs. bimodal polyethylene pipe resins for PE-100 applications,POLYMER ENGINEERING & SCIENCE, Issue 9 2005Paul J. DesLauriers In this paper several high density polyethylene pipe resins are compared to polyethylene resins made in the Phillips Loop-Slurry Process (single-reactor), using a catalyst of chromium on modified aluminophosphate (Cr/AlPO4). A brief description of the Cr/AlPO4 system is presented along with polymer chain architecture (i.e., topology) and other structural aspects of polymers made from these catalysts. The physical properties of these resins and their fabricated pipe processing/performance properties were compared to both PE80 and conventional bimodal type PE-100 resins. Results from this study show that high-density polyethylene resins made from Cr/AlPO4 catalysts possess primary structural attributes that are truly unique for chromium-catalyzed resins. These multimodal resins have very high molecular weights (MW; Mw > 400 kg/mol) and exceptionally broad MW distributions (MWD; Mw/Mn > 50). Topologically, these resins were found to have uniform short chain branching distributions across the MWD; as in polymers made from single site metallocene catalysts) and significantly reduced levels (10 times less) of long chain branching when compared to resins made using chromium catalysts on conventional supports. Furthermore, results from rheological, fabricated pipe processing, and performance studies suggest that these resins should be especially well suited for high performance pipe applications. Pipe samples made from these resins were found to meet PE-100 requirements including low temperature impact properties. POLYM. ENG. SCI., 45:1203,1213, 2005. © 2005 Society of Plastics Engineers [source] Reactive extrusion of recycled bottle waste materialPOLYMER ENGINEERING & SCIENCE, Issue 4 2002R. Hettema The objective of this study is to investigate the effect of reactive processing of commingled bottle waste polymer in an extruder. A variety of peroxides and monomers were tested to assess their influence on the final mechanical properties of the product. The reactive extruded polymer blends were prepared in two types of extruders: a co-rotating twin-screw extruder and a Buss co-Kneader single-screw extruder. Blends were analyzed for mechanical and thermal properties. The effectiveness of the different monomers and peroxides was evaluated in terms of improvement in impact properties. It has been found that the toughness of the polymer blend is improved by reactive processing. Depending on the amount and type of reactants, the impact strength can be improved by 220%, with a slight reduction in the modulus compared to an unmodified physical blend. The most suitable monomers were n-butylmethacrylate (BMA), t-butylamino ethylmethacrylate (TBAEMA) and a combination of styrene/maleic anhydride (ST/MAH). The peroxide should have a short half-lifetime compared to the average residence time in the extruder. The most effective monomers have a high initial reactivity and low rate of evaporation at the processing conditions used. Changes in processing conditions in the extruder influence the reaction conditions and therefore the final properties of the blend. Results were interpreted in terms of residence time, melting profile and peroxide concentration. [source] Impact fracture behavior of PP/EPDM/glass bead ternary compositesPOLYMER ENGINEERING & SCIENCE, Issue 9 2000J. Z. Liang The effects of glass bead filler content and surface treatment of the glass with a silane coupling agent on the room temperature impact fracture behavior of polypropylene (PP)/ethylene-propylene-diene monomer copolymer (EPDM)/glass bead(GB) ternary composites were determined. The volume fraction of EPDM was kept constant at 10%. The impact fracture energy and impact strength of the composites increased with increasing volume fraction of glass beads (,g). Surface pretreatment of the glass beads had an insignificant effect on the impact behavior. For a fixed filler content, the best impact strength was achieved when untreated glass beads and a maleic anhydride modified EPDM were used. The impact strength exhibited a maximum value at ,g=15%. Morphology/impact property relationships and an explanation of the toughening mechanisms were developed by comparing the impact properties with scanning electron micrographs of fracture surfaces. [source] Thermal, mechanical, and diffusional properties of nylon 6/ABS polymer blends: Compatibilizer effectPOLYMER ENGINEERING & SCIENCE, Issue 7 2000Seung Phil Jang The thermal, mechanical, and water absorption properties of blends of nylon 6 (PA6) and acrylonitrile-butadiene-styrene copolymer (ABS) with and without the compatibilizer maleic anhydride (MAH) were studied. Polymers were melt-blended using a twin screw extruder, and injection molded into sheets. Tensile and impact properties, hardness, heat deflection resistance, and dimensional stability were enhanced by the incorporation of MAH. Synergistic effects were observed for tensile elongation and flexural properties. The melting temperature and the thermal stability were not significantly affected by the incorporation of MAH. The mechanical property enhancement by the introduction of compatibilizer was explained by the formation of a micro-domain structure in the blends. The equilibrium water uptake increased with increasing concentration of PA6, and the diffusion coefficient was determined from the water transport kinetics at different temperatures. Activation energy was extracted from the temperature dependence of the diffusion coefficient. No compatibilizer effect was observed in the swelling behavior. [source] Intraply and interply hybrid composites based on E-glass and poly(vinyl alcohol) woven fabrics: tensile and impact propertiesPOLYMER INTERNATIONAL, Issue 9 2004Prof Alessandro Pegoretti Abstract E-glass and poly(vinyl alcohol) (PVA) fibres were used to produce both homogeneous and hybrid composites with an orthophthalic unsatured polyester resin. Results are presented regarding the tensile and impact behaviour of both intraply and interply hybrid composites, with particular regard to the effects of the plies stacking sequence and the loading direction. With a proper choice of composition and stacking sequence, E-glass/PVA hybrid composites were proved to achieve a property profile superior to those of homogeneous E-glass laminates in terms of specific properties. In particular, hybridization with PVA fibres resulted in improving the specific impact energy of E-glass laminates. Resistance to impact crack propagation was higher for intraply with respect to interply hybrid composites, as evidenced by their ductility index values. Copyright © 2004 Society of Chemical Industry [source] Influence of compatibilizer on notched impact strength and fractography of HDPE,organoclay compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2009Waraporn Rattanawijan Abstract The focus of this study was the notched impact property of high-density polyethylene (HDPE),organoclay composites and the resultant morphology of impact-fractured surfaces. Composites with a different organoclay content and degree of organoclay dispersion were compared with neat HDPE under identical conditions. The degree of organoclay dispersion was controlled through the use of a compatibilizer, maleic anhydride grafted polyethylene. It was found that the addition of organoclay can slightly increase the elastic modulus and notched impact strength of the composite. When the level of organoclay dispersion was improved by using compatibilizer, elastic modulus and toughness further increased. A significant increase in yield strength was also notable. The presence of organoclay was found to suppress strain hardening of the matrix during tensile testing. The impact-fractured surfaces of failed specimens were studied with scanning electron microscopy. The micromechanism for the increased toughness of HDPE,organoclay composites was discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Toughening and compatibilization of polyphenylene sulfide/nylon 66 blends with SEBS and maleic anhydride grafted SEBS triblock copolymersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007Weihua Tang Abstract In this study, styrene- b -ethylene/butylene- b -styrene triblock copolymer (SEBS) and maleic anhydride grafted SEBS (SEBS- g -MA) were used as compatibilizers for the blends of polyphenylene sulfide/nylon 66 (PPS/PA66). The mechanical properties, including impact and tensile properties and morphology of the blends, were investigated by mechanical properties measurements and scanning electron microscopy. Impact measurements indicated that the impact strength of the blends increases slowly with elastomer (SEBS and SEBS- g -MA) content upto 20 wt %; thereafter, it increases sharply with increasing elastomer content. The impact energy of the elastomer-compatibilized PPS/PA66 blends exceeded that of pure nylon 66, implying that the nylon 66 can be further toughened by the incorporation of brittle PPS minor phase in the presence of SEBS or SEBS- g -MA. The compatibilization efficiency of SEBS- g -MA for nylon-rich PPS/PA66 was found to be higher than SEBS due to the in situ forming SEBS interphase between PPS and nylon 66. The correlation between the impact property and morphology of the SEBS- g -MA compatibilized PPS/PA66 blends is discussed. The excellent impact strength of the nylon-rich blends resulted from shield yielding of the matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source] Flame retardancy and toughening of high impact polystyrenePOLYMER COMPOSITES, Issue 4 2007Wenguang Cui Flame retardant high impact polystyrene (HIPS) was prepared by melt blending HIPS, nano-modified aluminum trihydrate (nano-CG-ATH), red phosphorus masterbatch (RPM), and modified polyphenylene oxide (MPPO). Styrene-butadiene-styrene (SBS) was used as a toughener in this research. The effects of nano-CG-ATH, RPM, MPPO, and SBS on properties of HIPS composites were studied by combustion test, mechanical tests, and thermogravimetric analysis. The morphologies of fracture surfaces and char layers were characterized through scanning electron microscopy (SEM). The HIPS/nano-CG-ATH/RPM/MPPO (60/6/9/25) composite and its combustion residues at various temperatures were characterized by Fourier transform infrared (FTIR) spectra analysis. The results showed that the UL-94 rating of the HIPS/nano-CG-ATH/RPM/MPPO (60/6/9/25) composite reached V-0 and its char layer after flame test was integrated, but its impact strength was low. Addition of SBS improved its impact property and did not influence its thermal and flame retardant properties but lowered its tensile strength and flexural modulus to some extent. The FTIR spectra confirmed that the POC group was present in the charred substance. POLYM. COMPOS., 28:551,559, 2007. © 2007 Society of Plastics Engineers [source] | ||||||||||