Home About us Contact
|
Home About us Contact | ||
|
|
||
Interfacial Adhesion (interfacial + adhesion)
Kinds of Interfacial Adhesion Selected AbstractsInterfacial adhesion between polymer separation layer and ceramic support for composite membraneAICHE JOURNAL, Issue 6 2010Wang Wei Abstract An in situ characterization method for mechanical and adhesive properties of organic/ceramic composite membranes is built on the basis of nanoindentation technique in this work. The polydimethylsiloxane (PDMS) was used as the separation layer with the support of porous ZrO2/Al2O3 ceramic tubes. The effects of roughness of the ceramic support and the viscosity of PDMS solution on the mechanical properties of the PDMS separation layer and the interfacial adhesion at the interface were investigated in detail. It was found that when the roughness of the ceramic support increased and the viscosity of PDMS solution decreased, the interfacial adhesion strength of PDMS/ceramic composite membrane increased, but these two variables had little effect on the mechanical properties of the PDMS separation layer. Our results indicate that the mechanical interlocking dominates the adhesion between the PDMS separation layer and the porous ceramic support. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] A Solvent Free Graft Copolymerization of Maleic Anhydride onto Cellulose Acetate Butyrate Bioplastic by Reactive ExtrusionMACROMOLECULAR MATERIALS & ENGINEERING, Issue 1 2006Arief C. Wibowo Abstract Summary: Interfacial adhesion between fibers and matrix is a crucial factor for effective stress transfer from matrix to fiber; especially in short fiber reinforced composite systems. The use of a chemical compatibilizer is an efficient means to achieve such adhesion. Maleic anhydride-grafted-cellulose acetate butyrate (CAB-g-MA) is one such compatibilizer which can be used in biocomposite fabrication, and this has been synthesized in our laboratory by utilizing a twin-screw reactive extrusion process in the presence of a free radical initiator (2,5-dimethyl-2,5-di(tert -butylperoxy)hexane). The unique feature of this process is its solvent-free approach for grafting of maleic anhydride onto CAB, without hydroxyl group protection. CAB-g-MA was characterized using FTIR as well as by a non-aqueous titration method. The effects of initiator and monomer concentrations and various processing conditions on the graft content were also investigated. The preliminary results show that by adding approximately 10 wt.-% of CAB-g-MA into a plasticized cellulose acetate butyrate (TEB)-industrial hemp fiber biocomposites system, an improvement in tensile strength (20%) and in tensile modulus (45%) were obtained. These results are promising in that they pave the way for future studies involving the use of CAB-g-MA as a suitable compatibilizer for cellulose ester-natural fiber biocomposites. [source] Interfacial adhesion and molecular diffusion in melt lamination of wood sawdust/ebonite NR and EPDMPOLYMER COMPOSITES, Issue 3 2009W. Yamsaengsung Adhesion mechanisms and peel strengths of wood/ebonite NR-EPDM laminates were investigated. Three different chemical coupling agents: namely; N-(, aminoethyl)-,-aminopropyl-triethoxysilane (AAS), 3-methacryloxypropyl trimethoxysilane (ACS), and Bis-(3-triethoxylpropyl) tetrasulfan (Si69) were introduced into the wood/NR composites to enhance an interaction between wood sawdust (SD) particles and NR molecules, and to improve the adhesion strength between the SD/NR and EPDM layers. The quantitative evidences were given to explain the changes in the adhesion or peel strengths of the SD/NR-EPDM laminates through scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDS). The experimental results indicated that the suitable cure time and cure temperature for SD/NR-EPDM melt-laminates were the tc90 of SD/NR composites and 140°C, respectively. The Si69 coupling agent was found to be the most effective coupling agent as compared with AAS and ACS coupling agents. The Si69 of 0.5 wt% was recommended for the optimizations of the tensile modulus of the SD/NR composites and the peel strength of the SD/NR-EPDM laminates. The diffusion level between the SD/NR and EPDM layers could be quantitatively substantiated by determining the sulfur content transfer from the SD/NR layer to the EPDM layer. The diffusion and entanglement of molecular chains from the SD/NR to the EPDM layer initiated the co-crosslinking reaction which played an important role on the changes in the interfacial strength in the SD/NR-EPDM melt-laminates. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Thermotropic liquid crystal polymer fabric reinforced polyimide composite materialsPOLYMER COMPOSITES, Issue 5 2000Asst. Prof. Seong Hun Kim Ph.D An aromatic copolyeste thermotropic liquid crystal polymer (LCP) fabric was used to reinforce a polyimide (PI) matrix to produce composites. The LCP/PI composite was made to eliminate directional difference in the mechanical properties of LCP by controlling the individual reinforcement fabric alignment in different directions without losing any mechanical properties. As a result, a transversely isotropic LCP composite material could be obtained from the highly anisotropic LCP fiber. Interfacial adhesion between the LCP and polyimide was greatly improved by a NH3/H2 plasma treatment on the LCP fabric, thereby the significantly improving mechanical properties of the composite. Moreover, inter-laminar shear strength of the LCP/PI composite was further increased after heat treatment at 220°C for 1 hour. The LCP/polyimide composite retains stable mechanical properties up to 250°C. [source] Specific Functionalization of Carbon Nanotubes for Advanced Polymer NanocompositesADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Nanda Gopal Sahoo Abstract A novel approach to chemically functionalize multiwalled carbon nanotubes (MWCNTs) for making advanced polymeric nanocomposites with liquid crystalline polymers (LCPs) is presented. In this approach, two types of chemical moieties (i.e., carboxylic and hydroxyl benzoic acid groups) are selectively introduced onto the sidewalls of the MWCNTs. Fourier transform IR and Raman spectroscopy are used to examine the interaction between the functionalized MWCNTs and the LCP. The strong interaction between the functionalized MWCNTs and the LCP greatly improved the dispersion of MWCNTs in the polymer matrix as well as the interfacial adhesion. The dispersion of the MWCNTs in the LCP matrix is observed by optical microscopy and field-emission scanning electron microscopy. As a result, the addition of 1,wt% MWCNTs in the LCP resulted in the significant improvement (41 and 55%) in the tensile strength and modulus of the LCP. [source] Efficient utilization of plastic waste through product design and process adaptation: A case study on stiffness enhancement of beams produced from plastic lumberADVANCES IN POLYMER TECHNOLOGY, Issue 3 2008Cristian Pio Abstract The aim of the present work is the development of a method for structural reinforcement of beams obtained by in-mold extrusion of plastics from solid urban waste. The beams obtained by in-mold extrusion are commonly used for outdoor furniture and structures. The material used for such applications is mainly composed of low-density polyethylene derived from bags and films, with small amounts of high density polyethylene and polypropylene, as well as traces of polyethylene terephthalate. This material is usually referred to as "plastic lumber." Plastic lumber products have a low stiffness, which results in high deflections under flexural loads, particularly under creep loading. In this study, reinforcing rods of high aspect ratio were incorporated into plastic lumber beams in specific positions with respect to the cross section of the beam. The reinforcement of the plastic lumber beams with fine rods is introduced in the typical intrusion process used for the production of unreinforced beams. Glass fiber reinforced pultruded rods were chosen for this purpose from a preliminary evaluation of different materials. Different diameter glass fiber reinforced pultruded rods, including surface-abraded systems to increase the roughness, were used for the reinforcement of plastic lumber beams. The reinforced beams were tested in terms of flexural stiffness, creep resistance, and pullout resistance of the embedded rods. The results obtained from the mechanical tests showed a significant enhancement of flexural stiffness and creep resistance behavior. The performance at higher stress levels was shown to be significantly dependent on the interfacial adhesion between rods and polymer matrix. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:133,142, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20131 [source] Flammability and mechanical properties of Al(OH)3 and BaSO4 filled polypropyleneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010S. Tan Abstract The flammability and mechanical properties of Al(OH)3/BaSO4/polypropylene (PP) composites were investigated. The flow, morphological, and thermal properties were also analyzed by melt flow index (MFI), Scanning electron microscopy (SEM), and Differential scanning calorimeter (DSC) studies, respectively. Total filler amount was fixed at 30 wt % to optimize physical characteristics of the composites. In addition to the flame retardant filler Al(OH)3, BaSO4 was used to balance the reduction in impact strength at high filler loadings. Substantial improvement in mechanical properties was achieved for 20 wt % Al(OH)3 (i.e., 10 wt % BaSO4) composition while maximum flammability resistance was obtained for 30 wt % Al(OH)3 composite. SEM studies showed that the presence of aggregated Al(OH)3 particles led to low interfacial adhesion between them and PP matrix ending up with decreased mechanical strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Effect of solid state grinding on properties of PP/PET blends and their composites with carbon nanotubesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Ozcan Koysuren Abstract In this study, it was aimed to improve electrical conductivity and mechanical properties of conductive polymer composites, composed of polypropylene (PP), poly(ethylene terephthalate) (PET), and carbon nanotubes (CNT). Grinding, a type of solid state processing technique, was applied to PP/PET and PP/PET/CNT systems to reduce average domain size of blend phases and to improve interfacial adhesion between these phases. Surface energy measurements showed that carbon nanotubes might be selectively localized at PET phase of immiscible blend systems. Grinding technique exhibited improvement in electrical conductivity and mechanical properties of PP/PET/CNT systems at low PET compositions. Ground composites molded below the melting temperature of PET exhibited higher tensile strength and modulus values than those prepared above the melting temperature of PET. According to SEM micrographs, micron-sized domain structures were obtained with ground composite systems in which PET was the minor phase. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Structure and properties of phase change materials based on HDPE, soft Fischer-Tropsch paraffin wax, and wood flourJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2010M. E. Mngomezulu Abstract Phase-change materials based on high density polyethylene (HDPE), soft Fischer-Tropsch paraffin wax (M3), and alkali-treated wood flour (WF) were investigated. The blend and composite samples were prepared by melt mixing using a Brabender Plastograph, followed by melt pressing. They were characterized in terms of their morphology, as well as thermal, mechanical, thermo-mechanical, and water absorption properties. Although SEM micrographs showed some evidence of intimate contact between the WF particles and the HDPE matrix as a result of alkali treatment, poor filler dispersion, and interfacial adhesion were also observed. Partial immiscibility of the HDPE and the M3 wax was noticed, with the WF particles covered by wax. There was plasticization of the HDPE matrix by the wax, as well as partial cocrystallization, inhomogeneity and uneven wax dispersion in the polymer matrix. The HDPE/WF/M3 wax composites were more homogeneous than the blends. The presence of wax reduced the thermal stability of the blends and composites. Both the presence of M3 wax and WF influenced the viscoelastic behavior of HDPE. The HDPE/M3 wax blends showed an increase in the interfacial amorphous content as the wax content increases, which resulted in the appearance of a ,-relaxation peak. The presence of M3 wax in HDPE reduced the mechanical properties of the blends. For the composites these properties varied with WF content. An increase in wax content resulted to a decrease in water uptake by the composites, probably because the wax covered the WF particles and penetrated the pores in these particles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Effect of interfacial strengthening in blends of reclaimed rubber and polypropyleneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2010S.-H. Zhu Abstract Thermoplastic vulcanizates (TPVs) were prepared from polypropylene (PP) and reclaimed ground tire rubber crumbs. Three types of interfacial strengthening agents,degraded PP, hydrosilylated PP, and hydrosilylated PP grafted onto styrene,butadiene rubber,were prepared in melt via a stepwise series of reactions and employed to generate various degrees of interfacial adhesion in the aforementioned blends. The incorporation of the interfacial agents resulted in improvements in the mechanical properties of these TPVs, and the rubber particle size remained constant. The PP chain length and the functional groups present in the interfacial agents affected the magnitude of the improvement in the mechanical properties. The interfacial agents were primarily present on the surface of the rubber particles in the blends, as shown by energy-dispersive X-ray spectra. These interfacial agents in the PP/rubber crumb blends led to a unique preyield kink in their stress,strain curves, a plateau, or a sharp turning point in the region of approximately 3% elongation and approximately 4-MPa stress. These kinks were interpreted similarly to the cold flow of semicrystalline polymers in tension. The addition of the interfacial modifiers decreased the shear viscosity and increased the entrance pressure drop in flow through capillary dies, and this was attributed to changes in the elongational viscosity of the blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Influence of high temperature and pressure ammonia solution treatment on interfacial behavior of carbon fiber/epoxy resin compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2009L. H. Meng Abstract The method of high temperature and pressure ammonia solution treatment to improve the interfacial performances of carbon fiber/epoxy composites is discussed in this study. Besides, the influence of high temperature and pressure ammonia solution treatment on carbon fiber and its reinforced epoxy composite interface performance were studied. The untreated and treated carbon fibers were characterized by monofilament tensile test, X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM). The interfacial adhesion of the untreated and treated carbon fibers reinforced epoxy resin composites were also evaluated by interface shear strength (IFSS) test, interlaminar shear strength (ILSS) test, and fracture morphology analysis. It was found that the interfacial adhesion of composites increased greatly after high temperature and pressure ammonia solution treatment. The improvement of interfacial adhesion was attributed to the increase of polar functional groups and surface roughness of carbon fibers surface after treatment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Effects of bivalve shell particles of hyriopsis cumingii on the performances of epoxy resin studied by positron annihilationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Xudong Sun Abstract Mussel shell particles sized in micrometer level have been prepared with a ball mill. The X-ray powder diffractrometer (XRD) and Fourier transform infrared (FTIR) results proved that the shell particles contained mainly CaCO3 in the form of aragonite, together with small amount of organic phase. EP modified with shell particles showed a much rougher fracture surface than unfilled EP. The mechanical properties have been improved obviously by adding the shell particles in EP from 1% to 5%. The particle would occupy a number of free volume holes of the EP matrix. This would lead to a decrease in the total free volume concentration of the composites. The particles acted as a bridge to make more molecules interconnected for the good interfacial adhesion, resulting in a reduction of the free volume hole size in the interfacial layers. I2 reached its highest value when 3% shell particles were added and then decreased as the shellparticles content increased. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Poly(lactic acid)-based biocomposites reinforced with kenaf fibersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Maurizio Avella Abstract Biodegradable thermoplastic-based composites reinforced with kenaf fibers were prepared and characterized. Poly(lactic acid) (PLA) was selected as polymeric matrix. To improve PLA/fibers adhesion, low amount of a proper reactive coupling agent, obtained by grafting maleic anhydride onto PLA, was added during matrix/fibers melt mixing. Compared with uncompatibilized composites, this compatibilization strategy induces a strong interfacial adhesion and a pronounced improvement of the mechanical properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Recycled carbon fiber filled polyethylene compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Tony McNally Abstract Composites of recycled carbon fiber (CF) with up to 30 wt % loading with polyethylene (PE) were prepared via melt compounding. The morphology of the composites and the degree of dispersion of the CF in the PE matrix was examined using scanning electron microscopy, and revealed the CF to be highly dispersed at all loadings and strong interfacial adhesion to exist between the CF and PE. Raman and FTIR spectroscopy were used to characterize the surface chemistry and potential bonding sites of recycled CF. Both the Young's modulus and ultimate tensile stress increased with increasing CF loading, but the percentage stress at break was unchanged up to 5 wt % loading, then decreased with further successive addition of CF. The effect of CF on the elastic modulus of PE was examined using the Halpin-Tsai and modified Cox models, the former giving a better fit with the values determined experimentally. The electrical conductivity of the PE matrix was enhanced by about 11 orders of magnitude on addition of recycled CF with a percolation threshold of 7 and 15 wt % for 500-,m and 3-mm thick samples. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Effect of silane KH-550 to polypropylene/brucite compositeJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008Zhiling Ma Abstract The effect of the KH-550 type silane coupling agent on the properties of polypropylene (PP)/brucite (BC) composite was studied. X-ray diffraction, scanning electron microscope, and polarization optical microscope indicated that morphology structure of PP changed with the addition of KH-550, which activated the heterogeneous nucleation centers on BC surface, which made the distribution of the spherulite diameter become narrow and uniform, and improved the dispersibility of BC in the matrix. Therefore, KH-550 enhanced the interfacial adhesion of matrix-filler and improved the compatibility of the PP/BC composite, when KH-550's content was 2.9% the tensile strength and impact strength increased approximately by 90% and by 30%, respectively than PP/BC. Flow tests and IR proved that some reactions took place between BC and KH-550. All the investigations showed KH-550 was a proper coupling agent in the PP/BC composite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Interfacial adhesion between polymer separation layer and ceramic support for composite membraneAICHE JOURNAL, Issue 6 2010Wang Wei Abstract An in situ characterization method for mechanical and adhesive properties of organic/ceramic composite membranes is built on the basis of nanoindentation technique in this work. The polydimethylsiloxane (PDMS) was used as the separation layer with the support of porous ZrO2/Al2O3 ceramic tubes. The effects of roughness of the ceramic support and the viscosity of PDMS solution on the mechanical properties of the PDMS separation layer and the interfacial adhesion at the interface were investigated in detail. It was found that when the roughness of the ceramic support increased and the viscosity of PDMS solution decreased, the interfacial adhesion strength of PDMS/ceramic composite membrane increased, but these two variables had little effect on the mechanical properties of the PDMS separation layer. Our results indicate that the mechanical interlocking dominates the adhesion between the PDMS separation layer and the porous ceramic support. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Preparation of Crystalline-Oriented Titania Photoelectrodes on ITO Glasses from a 2-Propanol,2,4-Pentanedione Solvent by Electrophoretic Deposition in a Strong Magnetic FieldJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2009Mamiko Kawakita Crystal-oriented and crack-free thin TiO2 films with a good interfacial adhesion on indium,tin oxide glass substrates for photoelectrodes of dye-sensitized solar cells were fabricated by the constant voltage electrophoretic deposition (EPD) method in a strong magnetic field of 12 T generated by a superconducting magnet. A binder-free suspension for the EPD was prepared by dispersing TiO2 in a mixture of 2-propanol and 2,4-pentanedione (acetylacetone). The electrical conductivity, sedimentation rate, and the electrophoretic mobility were measured at varying ratios of the mixed solution. The optimized state of the suspension exhibiting the highest surface charge potential and producing deposits with the highest green density was obtained at the 50:50 mixing ratio. The TiO2 films were characterized by X-ray diffraction and scanning electron microscopic analyses. [source] Effects of alkali and silane treatment on the mechanical properties of jute-fiber-reinforced recycled polypropylene compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2010Xinxin Wang Jute-fibers-reinforced thermoplastic composites are widely used in the automobile, packaging, and electronic industries because of their various advantages such as low cost, ease of recycling, and biodegradability. However, the applications of these kinds of composites are limited because of their unsatisfactory mechanical properties, which are caused by the poor interfacial compatibility between jute fibers and the thermoplastic matrix. In this work, four methods, including (i) alkali treatment, (ii) alkali and silane treatment, (iii) alkali and (maleic anhydride)-polypropylene (MAPP) treatment, and (iv) alkali, silane, and MAPP treatment (ASMT) were used to treat jute fibers and improve the interfacial adhesion of jute-fiber-reinforced recycled polypropylene composites (JRPCS). The mechanical properties and impact fracture surfaces of the composites were observed, and their fracture mechanism was analyzed. The results showed that ASMT composites possessed the optimum comprehensive mechanical properties. When the weight fraction of jute fibers was 15%, the tensile strength and impact toughness were increased by 46 and 36%, respectively, compared to those of untreated composites. The strongest interfacial adhesion between jute fibers and recycled polypropylene was obtained for ASMT composites. The fracture styles of this kind of composite included fiber breakage, fiber pull-out, and interfacial debonding. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers. [source] Morphological, mechanical, and rheological studies of PVC/ABS blends in the presence of maleic anhydrideJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2010Pegah Mohammad Hosseinpour A novel method of enhancing compatibility in PVC/ABS blends is the use of ABS-grafted-(maleic anhydride) (ABS- g -MAH) as a compatibilizer. In this study, maleic anhydride was grafted onto ABS (initiated by peroxide) in an internal mixer. Grafting degree was determined by a back-titration method, and certain amounts of the resultant ABS- g -MAH were added to PVC/ABS blends during their melt blending in the mixer. The weight ratio of PVC to ABS was kept at 70:30. Evaluation of compatibilization was accomplished via tensile and notched Izod impact tests, scanning electron microscopy (SEM), and rheological studies. According to the SEM micrographs, better dispersion of the rubber phase and its finer size in properly compatibilized blends were indications of better compatibility. Besides, in the presence of a proper amount [5 parts per hundred parts of PVC (php)] of ABS- g -MAH, PVC/ABS blends showed significantly higher impact strengths than uncompatibilized blends. This result, in turn, would be an indication of better compatibility. In the presence of 5 php of compatibilizer, the higher complex viscosity and storage modulus, as well as a lower loss modulus and loss factor in the range of frequency studied, indicated stronger interfacial adhesion as a result of interaction between maleic anhydride and the PVC-SAN matrix. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Mechanochemical copolymerization of poly(vinyl chloride) with methyl methylacrylate in an open mill machineJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2006Peixin He Mechanical degradation of poly(vinyl chloride) (PVC) and mechanochemical copolymerization in poly(vinyl chloride)/methyl methylacrylate (PVC/MMA) systems were studied in an open mill machine. The effects of the mastication temperature, mastication time, and additives (oxygen, THF, or hydroquinone) on the mechanical degradation of PVC were investigated. The molecular weight of PVC decreased with increasing mastication time, and the efficiency of the mechanodegradation of PVC was lowered with increasing mastication temperature. The effects of the ratio of PVC to MMA, thin-passage time, and initiator on mechanochemical copolymerization also were studied. The experimental results indicated that the degree of copolymerization increased with increasing thin-passage times up to 45 times and then remained constant. There was a maximum degree of copolymerization at a ratio of 0.22 g/mL (PVC/MMA), and the efficiency of copolymerization always decreased with increasing time. The maximum degree and efficiency of copolymerization were 5.8 and 89%, respectively. The poly(vinyl chloride- co -methyl methylacrylate) copolymer can further improve the interfacial adhesion of PVC and PMMA. Thus it improves the mechanical properties of the PVC/CPE blend more effectively than pure PMMA. J. VINYL. ADDIT. TECHNOL. 12:42,48, 2006. © 2006 Society of Plastics Engineers. [source] Effects of copper amine treatment on mechanical properties of PVC/wood-flour compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2004Haihong Jiang Copper amine,treated wood flour was added to PVC [poly(vinyl chloride)] matrix in order to manufacture PVC/wood-flour composites. Effects of copper treatments on the mechanical properties of PVC-wood composites were evaluated. Unnotched impact strength, flexural strength, and flexural toughness of the composites were significantly improved by the wood-flour copper treatment. The optimum copper concentration range was 0.2 to 0.6 wt% of wood flour. Fractured surfaces were examined by using scanning electron microscopy (SEM) combined with energy-dispersive spectroscopy (EDS). PVC/wood interfacial debonding was the main fracture mode of untreated wood-flour composites, whereas wood-particle pullout and breakage dominating the fractured surfaces of copper-treated wood-flour composites. On the fractured surfaces, more PVC could be found on the exposed copper-treated wood particles than on untreated wood, a result suggesting improved PVC-wood interfacial adhesion after copper treatments. J. Vinyl Addit. Technol. 10:70,78, 2004. © 2004 Society of Plastics Engineers. [source] Preparation and Characterization of Hybrid Nanocomposites Coated on LDPEMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 22 2006Laura Mazzocchetti Abstract Summary: Hybrid organic-inorganic nanocomposites containing hyperbranched structures were prepared through a dual-curing process, which involves photopolymerization and condensation alkoxysilane groups. In particular, an oligomer containing PEO units and ,,, -methacrylate groups was used together with a HBP bearing acrylic groups as the organic phase precursors. MEMO, as the organic-inorganic linker, and TEOS, as inorganic phase precursor, were also employed. The kinetics of both photopolymerization and condensation reactions were investigated by double bond conversion analysis (via FT-IR) and weight loss determination, respectively. The mobility of the organic phase was studied by means of DSC and DMTA and correlated with hybrid composition. TEM analyses performed on microtomed film slices indicated the formation of nanoscale silica domains. Hybrids were coated onto an LDPE film previously subjected to a plasma treatment, and substrate-coating interfacial adhesion was investigated through stress-strain and DMTA experiments. Reaction scheme showing the insertion of furanic units in copolyester chains by ester interchange reaction. [source] Functionalization of LDPE by Melt Grafting with Glycidyl Methacrylate and Reactive Blending with Polyamide-6MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 8 2003Qian Wei Abstract Low-density polyethylene (LDPE) was functionalized by melt radical grafting with glycidyl methacrylate (GMA) and employed for reactive blending with polyamide-6 (PA6). The effect of the reaction procedure on the grafting degree of LDPE- g -GMA samples (0.5,12.5 wt.-% GMA) was analyzed as a function of the concentration of GMA monomer, radical initiator (BTP), and addition of styrene as co-monomer. Optimized grafting conditions were obtained when the amount of the monomer is below 10 wt.-% and that of peroxide in the range 0.2,0.4 wt.-%. Binary blends of PA6 with LDPE- g -GMA (3.5 wt.-% GMA) and with LDPE at various compositions (80/20, 67/33, 50/50 wt.-%) were prepared in an internal mixer and their properties were evaluated by torque, SEM and DSC analyses. Morphological examination by SEM showed a large improvement of phase dispersion and interfacial adhesion in PA6/LDPE- g -GMA blends as compared with PA6/LDPE blends. The average diameter of dispersed polyolefin particles was about 0.4 ,m for LDPE- g -GMA contents <,50 wt.-%. A marked increase of melt viscosity was observed for the compatibilized blends depending on the concentration of grafted polyolefin, and it was accounted for by the reaction between the epoxy groups of GMA and the carboxyl/amine end-groups of PA6. The variation of torque was thus related to the molar ratio of reactive group concentration. The analysis of crystallization and melting behavior pointed out marked differences in the phase structure of the blends due to the presence of the functionalized polyolefin. Finally, the in situ formation of a graft copolymer between LDPE- g -GMA and PA6 was investigated by means of a selective dissolution method (Molau test) and by FT-IR and DSC analyses. SEM micrograph of fracture surface of PA6/LDPE- g -GMA 50/50 blend. [source] Evaluation of the Effectiveness of New Compatibilizers Based on EBAGMA-LDPE and EBAGMA-PET Masterbatches for LDPE/PET BlendsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 3 2010Aida Benhamida Abstract The present paper is aimed to evaluate the efficiency of two masterbatches, i.e., EBAGMA/LDPE (MB1) and EBAGMA/PET (MB2) with 50/50 w/w composition, prepared by melt mixing and used as new compatibilizers for blends of LDPE/PET. The morphology, the mechanical and the thermal properties of LDPE/PET/MB1 and LDPE/PET/MB2 ternary blends have been investigated. Morphological investigation by SEM of LDPE/PET/MB1 ternary blends showed a finer dispersion of PET in LDPE matrix with a better interfacial adhesion compared to those of both LDPE/PET/MB2 and binary LDPE/PET blends. The results also indicated a substantial improvement in both elongation at break and impact strength, while the Young's modulus decreased. Moreover, the thermal properties showed a decrease of the crystallization phenomena of PET in LDPE/PET/MB1 blend, thus confirming the good dispersion of PET particles into the continuous phase of LDPE matrix, leading to the conclusion that MB1 could be an efficient compatibilizer for LDPE/PET system. [source] Novel High-Performance Talc/Poly[(butylene adipate)- co -terephthalate] Hybrid MaterialsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 4 2008Jean Marie Raquez Abstract New talc/PBAT hybrid materials were prepared through reactive extrusion. First, PBAT was free-radically grafted with MA to improve the interfacial adhesion between PBAT and talc. Then, the resulting MA- g -PBAT was reactively melt-blended with talc through esterification reactions of MA moieties with the silanol functions from talc. Sn(Oct)2 and DMAP were used as catalysts. Interestingly, the tensile properties for these compatibilized composites were improved due to a better interfacial adhesion between both partners. XPS showed the formation of covalent ester bonds between the silanol functions from talc particles, and the MA moieties grafted onto the polyester backbones. [source] Effect of EPDM on Morphology, Mechanical Properties, Crystallization Behavior and Viscoelastic Properties of iPP+HDPE BlendsMACROMOLECULAR SYMPOSIA, Issue 1 2007Nina Vranjes Abstract Summary: Blends of isotactic polypropylene (iPP) and high density polyethylene (HDPE) with and without ethylene-propylene-diene (EPDM) terpolymer as compatibilizer were systematically investigated to determine the influence of the EPDM on blends properties. The morphology was studied by Scanning Electron Microscopy (SEM). Mechanical properties of investigated systems: tensile strength at break, elongation at break, yield stress and Izod impact strength were determined. Crystallization behavior was determined by Differential Scanning Calorimetry (DSC). Dynamic Mechanical Analysis (DMA) was used to determined the storage modulus (E,), loss modulus (E,), and loss tangent (tan ,). The PP+HDPE blend revealed poor adhesion between PP and HDPE phases. Finer morphology was obtained by EPDM addition in PP+HDPE blends and better interfacial adhesion. Addition of HDPE to PP decreased tensile strength at break, elongation and yield stress. Decrease of tensile strength and yield stress is faster with EPDM addition in PP+HDPE blends. Elongation at break and impact strength was significantly increased with EPDM addition. The addition of EPDM in PP+HDPE blends did not significantly change melting points of PP phase, while melting points of HDPE phase was slightly decreased in PP+HDPE+EPDM blends. The EPDM addition increased the percentage of crystallization (Xc) of PP in PP+HDPE blends. The increase of Xc of HDPE was found in the blend with HDPE as matrix. Dynamical mechanical analysis showed glass transitions of PP and HDPE phase, as well as the relaxation transitions of their crystalline phase. By addition of EPDM glass transitions (Tg) of HDPE and PP phases in PP+HDPE blends decreased. Storage modulus (E,) vs. temperatures (T) curves are in the region between E,/T curves of neat PP and HDPE. The decrease of E, values at 25,°C with EPDM addition in PP+HDPE blends is more pronounced. [source] Morphology and mechanical properties of extruded ribbons of LDPE/PA6 blends compatibilized with an ethylene-acrylic acid copolymerMACROMOLECULAR SYMPOSIA, Issue 1 2003Francesco Paolo La Mantia Abstract Two grades of low density polyethylene (LDPE) were blended with polyamide-6 (PA) in the 75/25 and 25/75 wt/wt ratios and shaped into ribbons with a Brabender single screw extruder. An ethylene-acrylic acid copolymer (EAA) was used in the 2 phr concentration as a compatibilizer precursor (CP). The morphology of the ribbons and its evolution during high temperature annealing were investigated by scanning electron microscopy (SEM). The results confirmed that EAA does actually behave as a reactive compatibilizer for the LDPE/PA blends. In fact, in the presence of EAA, the interfacial adhesion is improved, the dispersion of the minor phase particles is enhanced and their tendency toward fibrillation is increased, especially for the blends with the higher molar mass LDPE grade. The mechanical properties of the latter blends were found to be considerably enhanced by the addition of EAA, whereas the improvement was relatively modest for the blends with the lower molar mass LDPE. The fracture properties of double end notched samples of the ribbons prepared with the blends containing the lower molar mass LDPE grade were also studied. It was shown that, despite of the increased interfacial adhesion caused by the presence of EAA, the latter plays a measurable positive effect on the fracture properties only for the blends with LDPE as the matrix. [source] Interaction of Plasma Deposited HMDSO-Based Coatings with Fibrinogen and Human Blood Plasma: The Correlation between Bulk Plasma, Surface Characteristics and Biomolecule InteractionPLASMA PROCESSES AND POLYMERS, Issue 5 2010Ram P. Gandhiraman Abstract The success of a biomaterial depends on the nature of interaction and the progressive reaction between the biological components and the surface of the biomaterial. In order to control the interaction between the biomaterial and biological component, it is necessary to understand the factors that influence the protein adsorption and cell proliferation. Surface chemistry plays a crucial role in the success of any blood contacting biomaterial. Plasma enhanced chemical vapour deposition (PECVD) is an interesting commonly used technique for tailoring surface characteristics while retaining bulk material properties. Two different films, namely polymer-like and silica-like coatings, with varying surface characteristics have been deposited from hexamethyldisiloxane, by PECVD, on 316L stainless steel. A correlation between the bulk plasma, interfacial adhesion of the coating to 316L steel, surface characteristics and biomolecule interaction is presented in this work. The interfacial adhesion strength analysis demonstrated that silica-like coatings have higher adhesion strength to 316L stainless steel than polymer-like coatings, caused due to the formation of a strong FeOSi and CrOSi bonds. It was observed that the effect of nanoscale surface roughness (close to 6,nm) was less significant, and that the surface chemistry played a significant role in governing the fibrinogen adsorption. Highest fibrinogen adsorption on plain steel was due to the electrostatic interaction of the metal oxide layer with the protein. Hydrophobicity of the polymer-like film resulted in a higher fibrinogen binding than the silica-like films. [source] The research on the mechanical and tribological properties of carbon fiber and carbon nanotube-filled PEEK compositePOLYMER COMPOSITES, Issue 8 2010Jian Li The main objective of this article is to develop high wear resistance carbon fiber reinforced polyether ether ketone composite with addition of multiwall carbon nanotube (MWCNT). These compounds were well mixed in a Haake batch mixer, and compounded polymers were fabricated into sheets of known thickness by compression molding. Samples were tested for wear resistance with respect to different concentration of fillers. The wear resistance properties of these samples depend on filler aspect ratio. Wear resistance of composite with 20 wt% of CF increases when MWCNT was introduced. The worn surface features have been examined using scanning electron microscope. Photomicrographs of the worn surfaces revealed higher wear resistance with the addition of carbon nanotube. Also, better interfacial adhesion between carbon and vinyl ester in carbon-reinforced vinyl ester composite was observed. POLYM. COMPOS., 31:1315,1320, 2010. © 2009 Society of Plastics Engineers [source] Influence of interfacial adhesion on the structural and mechanical behavior of PP-banana/glass hybrid compositesPOLYMER COMPOSITES, Issue 7 2010Sanjay K. Nayak Hybrid composites of polypropylene (PP), reinforced with short banana and glass fibers were fabricated using Haake torque rheocord followed by compression molding with and without the presence maleic anhydride grafted polypropylene (MAPP) as a coupling agent. Incorporation of both fibers into PP matrix resulted in increase of tensile strength, flexural strength, and impact strength upto 30 wt% with an optimum strength observed at 2 wt% MAPP treated 15 wt% banana and 15 wt% glass fiber. The rate of water absorption for the hybrid composites was decreased due to the presence of glass fiber and coupling agent. The effect of fiber loading in presence of coupling agent on the dynamic mechanical properties has been analyzed to investigate the interfacial properties. An increase in storage modulus (E,) of the treated-composite indicates higher stiffness. The loss tangent (tan ,) spectra confirms a strong influence of fiber loading and coupling agent concentration on the , and , relaxation process of PP. The nature of fiber matrix adhesion was examined through scanning electron microscopy (SEM) of the tensile fractured specimen. Thermal measurements were carried out through differential scanning calorimetry (DSC) and the thermogravimetric analysis (TGA), indicated an increase in the crystallization temperature and thermal stability of PP with the incorporation of MAPP-treated banana and glass fiber. POLYM. COMPOS., 31:1247,1257, 2010. © 2009 Society of Plastics Engineers [source] | |||||||||||||||||||||||||