Maleic Anhydride Polypropylene Copolymer Research Articles

Banana fiber-reinforced polypropylene nanocomposites: Effect of fiber treatment on mechanical, thermal, and dynamic-mechanical properties

Banana fiber-reinforced nanocomposites were fabricated by melt mixing in a twin-screw extruder followed by compression molding in this study. Maleic anhydride polypropylene copolymer (MA-g-PP) was used as a compatibilizer to increase the compatibility between the PP matrix, clay, and banana fiber to enhance exfoliation of organoclay and dispersion of fibers into the polymer matrix. Variation in mechanical, thermal, and physico-mechanical properties with the addition of banana fiber into the PP nanocomposites was investigated. It was observed that presence 3 wt% of nanoclay and 5 wt% MA-g-PP within PP matrix results in an increase in tensile and flexural strengths by 41.3%, and 45.6%, respectively, compared with virgin PP due to the high aspect ratio of clay stacks in the fully exfoliated nanocomposites. Further, incorporation of 30 wt% banana fiber in PP nanocomposites system increases the tensile and flexural strengths to the tune of 27.1%, and 15.8%, respectively. The morphology of fiber-reinforced PP nanocomposites has been examined using scanning and transmission electron microscopies. Significant enhancement in thermal stability of nanocomposites was also observed due to the presence of nanoclay under thermogravimetric analysis. Dynamic mechanical analysis tests revealed an increase in storage modulus ( E′) and damping factor (tan δ), conforming the strong interaction between nanoclay/banana fiber and MA-g-PP in the fiber-reinforced nanocomposites systems.

Mechanical, thermal and dynamic‐mechanical behavior of banana fiber reinforced polypropylene nanocomposites

AbstractNatural fiber‐reinforced nanocomposites based on polypropylene/nanoclay/banana fibers were fabricated by melt mixing in a twin‐screw extruder followed by compression molding in this current study. Maleic anhydride polypropylene copolymer (MA‐g‐PP) was used as a compatibilizer to increase the compatibility between the PP matrix, clay, and banana fiber to enhance exfoliation of organoclay and dispersion of fibers into the polymer matrix. Variation in mechanical, thermal, and physico‐mechanical properties with the addition of banana fiber into the PP nanocomposites was investigated. It was observed that 3 wt% of nanoclay and 5 wt% of MA‐g‐PP within PP matrix resulted in an increase in tensile and flexural strength by 41.3% and 45.6% as compared with virgin PP. Further, incorporation of 30 wt% banana fiber in PP nanocomposites system increases the tensile and flexural strength to the tune of 27.1% and 15.8%, respectively. The morphology of fiber reinforced PP nanocomposites has been examined by using scanning electron microscopy and transmission electron microscopy. Significant enhancement in the thermal stability of nanocomposites was also observed due to the presence of nanoclay under thermogravimetric analysis. Dynamic mechanical analysis tests revealed an increase in storage modulus (E′) and damping factor (tan δ), conforming the strong interaction between nanoclay/banana fiberand MA‐g‐PP in the fiber‐reinforced nanocomposites systems. POLYM. COMPOS., © 2011 Society of Plastics Engineers.

Effect of Maleic Anhydride Polypropylene Copolymer Addition on the Physical and Mechanical Properties of Polymeric Diphenylmethane Diisocyanate–Bonded Oriented Strand Board Panels

The effect of varying proportions of maleic anhydride polypropylene (MAPP) on the physical and mechanical properties of polymeric diphenylmethane diisocyanate (pMDI)-bonded oriented strand board panels was investigated. Additionally, two forms of MAPP (powder and emulsion) were used to determine the effect of MAPP type on panel properties. Panels were produced by combining southern yellow pine (Pinus spp.) flakes with 4 percent pMDI binder and 0, 1.5, 3, 4.5, or 6 percent powdered or emulsified MAPP. Addition of emulsified MAPP decreased panel mechanical properties regardless of addition level. Powdered MAPP had a negligible effect on panel modulus of elasticity and only produced significant decreases in panel modulus of rupture and internal bond strength at the highest addition level (6%). Emulsified MAPP effected greater reductions in panel mechanical properties relative to powdered MAPP. Increasing levels of emulsified MAPP caused undesirable increases in both 24-hour water absorption and thickness swelling. Powdered MAPP did not provide a significant improvement over control panels in water absorption and thickness swell tests. Addition of either powdered or emulsified MAPP appeared to have a negligible effect on panel permeance.

Preparation and physical properties of wood/polypropylene/clay nanocomposites

AbstractWood plastic composites (WPCs) are attracting a lot of interests because they are economic, environmentally friendly, and show fairly good performance. To improve the performance of a wood/polypropylene (PP) composite, an organoclay was incorporated as a nanosize filler in this work. WPCs were prepared by melt blending followed by compression molding, and their performance was investigated by universal testing machine, izod impact tester, dynamic mechanical analyzer, thermal mechanical analyzer, differential scanning calorimetry, and TGA. Maleic anhydride polypropylene copolymer (MAPP) was used to increase compatibility between the PP matrix and wood particles and also improve the dispersion and exfoliation of the organoclay in the PP matrix. XRD analysis showed that the matrix of the WPCs with organoclay had intercalated structure. The SEM images of the WPCs with MAPP showed improved interfacial adhesion between the matrix and wood particles. The degree of water absorption increased with immersion time, but it could be restrained by incorporating MAPP. The performance of the WPCs was improved by the incorporation of the organoclay. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Injection Molding of Postconsumer Wood–Plastic Composites I: Morphology

In this study, fiber-reinforced microcellular foams are produced via injection molding and studied as a function of mold temperature as well as wood, blowing agent, and coupling agent concentrations. Birch wood fibers are added to a post-consumer recycled HDPE/PP matrix (85: 15 ratio) in proportions ranging from 0 to 40 wt% and then foamed. Maleic-anhydride-polypropylene copolymer (MAPP) is also used as a coupling agent in proportions ranging from 0 to 10 wt% of wood content. In this first part, the morphological analysis of composite foams is presented including cell roundness, cell size, skin thickness, void fraction, and fiber aspect ratio.

Injection Molding of Postconsumer Wood–Plastic Composites II: Mechanical Properties

ABSTRACT: In the first part of this study, fiber-reinforced microcellular foams were produced via injection molding to study their morphological properties as a function of mold temperature as well as wood, blowing agent, and coupling agent concentrations. Yellow birch wood fibers are added to a recycled postconsumer HDPE/PP matrix (85: 15 ratio) in proportions ranging from 0 to 40 wt% and then foamed with a chemical blowing agent. Maleic-anhydride-polypropylene copolymer (MAPP) is also used as a coupling agent in proportions ranging from 0 to 10 wt% of wood content. In this second part, the mechanical properties in flexion, torsion, and traction are presented.

Effects of hygrothermal ageing on mechanical properties of flax pulps and their polypropylene matrix composites

AbstractThe aim of this work was to study the kinetics of water uptake and its influence on mechanical behavior of both flax pulps and their composites with a maleic anhydride polypropylene copolymer (MAPP) modified polypropylene (PP) matrix by immersion in distilled water at 30, 50, 70, and 100°C. Both the influence of two different MAPP compatibilizers and the optimum doses of each ones were analyzed. The kinetics of water uptake was studied from weight measurements at regular interval times. The diffusion coefficient was dependent on the immersion temperature and MAPP content. Tensile modulus and strength of single flax fiber decreased by water immersion. Both flexural strength and modulus of composites decreased as a result of the combined effect of thermal ageing and moisture absorption. MAPP coupling agent increases moisture resistance and mechanical properties for MAPP‐modified systems with respect to the unmodified ones. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3438–3445, 2006

Thermal and crystallization studies of short flax fibre reinforced polypropylene matrix composites: Effect of treatments

The effect of fibre treatments on thermal stability of flax fibre and crystallization of flax fibre/polypropylene composites was investigated. For thermal stability study, flax fibres have been treated using maleic anhydride, maleic anhydride polypropylene copolymer, vinyltrimethoxy silane and alkalization. In order to compare thermal stability of flax fibres thermogravimetry (TG) analysis has been used. Kinetic parameters have been determined by Kissinger method. Results showed that all treatments improved thermal stability of flax fibres. For crystallinity analysis, three different techniques have been used, differential scanning calorimetry analysis (DSC), pressure–volume–temperature (PVT) measurements for analysis of volume shrinkage and polarized optical microscopy (POM). All techniques results showed that addition of flax fibre increased crystallization rate. Besides, depending on fibre surface treatment and crystallization temperature, flax fibre/PP composites can show transcrystallinity.

Injection moulded microcellular wood fibre–polypropylene composites

Abstract The polymer–wood fibre composites utilize wood fibres as a reinforcing filler in the polymer matrix and are known to be advantageous over the neat polymers in terms of the materials cost and some mechanical properties such as stiffness and strength. These wood fibre composites are microcellular processed to create a new class of materials with unique properties. Recent studies have demonstrated the feasibility of developing microcellular structures in polymer–wood fibre composites. An experimental investigation was conducted to research the microcellular behaviour in the injection moulding foam processing of polypropylene–wood fibre composites using chemical foaming agents. The effects of fibre type (hard and soft wood fibre) and different chemical foaming agents (endothermic, exothermic and endo/exothermic) on the density, physico-mechanical properties, surface roughness and cell morphology of foamed PP–wood fibre composites are studied. A compatibiliser maleic anhydride polypropylene copolymer (MAH-PP) was used with the intension of improving the mechanical properties of foamed composites. The structures of the foamed composites were examined using scanning electron microscopy and optical microscopy to determine the cell size, shape and distribution of cells to account for this behaviour. The density of microfoamed hard wood fibre–PP composites reduced around 30% and decreased up to 0.741 g/cm3 with the using of exothermic chemical foaming agent. Optical microscopy showed that the cells are round and cell sizes are affected by chemical foaming agents. Tensile and flexural tests are performed on the foamed composites to investigate the dependence of these properties on the density (specific properties) of foamed specimens and compared with non-foamed composites and MAH-PP has improved the physico-mechanical properties up to 80%. Chemical foaming agents have also an effect on surface roughness of the composites which decreased surface roughness of the foamed composites compared to the non-foamed composites. Water absorption and thickness swelling of the composites investigated also.

Mechanical properties of flax fibre/polypropylene composites. Influence of fibre/matrix modification and glass fibre hybridization

Abstract The effect of fibre treatments and matrix modification on mechanical properties of flax fibre bundle/polypropylene composites was investigated. Treatments using chemicals such as maleic anhydride, vinyltrimethoxy silane, maleic anhydride-polypropylene copolymer and also fibre alkalization were carried out in order to modify the interfacial bonding between fibre bundles and polymeric matrix. Composites were produced by employing two compounding ways: internal mixing and extrusion. Mechanical behaviour of both flax fibre bundle and hybrid glass/flax fibre bundle composites was studied. Fracture surfaces were investigated by scanning electron microscopy. Results suggest that matrix modification led to better mechanical performance than fibre surface modification. A relevant fact is that silanes or MA grafted onto PP matrix lead to mechanical properties of composites even better than those for MAPP modification, and close to those for glass fibre/PP.

Effects of the chemical foaming agents, injection parameters, and melt‐flow index on the microstructure and mechanical properties of microcellular injection‐molded wood‐fiber/polypropylene composites

AbstractWood‐fiber‐reinforced plastic profiles are growing rapidly in nonstructural wood‐replacement applications. Most manufacturers are evaluating new alternative foamed composites, which are lighter and more like wood. Foamed wood composites accept screws and nails better than their nonfoamed counterparts, and they have other advantages as well. For example, internal pressures created by foaming give better surface definition and sharper contours and corners than nonfoamed profiles have. In this study, the microfoaming of polypropylene (PP) containing hardwood fiber was performed with an injection‐molding process. The effects of different chemical foaming agents (endothermic, exothermic, and endothermic/exothermic), injection parameters (the mold temperature, front flow speed, and filling quantity), and different types of PP (different melt‐flow indices) on the density, microvoid content, physicomechanical properties, surface roughness, and microcell classification of microfoamed PP/wood‐fiber composites were studied. A maleic anhydride/polypropylene copolymer (MAH‐PP) compatibilizer was used with the intention of improving the mechanical properties of microfoamed composites. The microcell classification (from light microscopy) and scanning electron micrographs showed that an exothermic chemical foaming agent produced the best performance with respect to the cell size, diameter, and distance. The polymer melt‐flow index and the variation of the injection parameters affected the properties and microstructure of the microfoamed composites. The density of the microfoamed hardwood‐fiber/PP (with a high melt‐flow index) composites was reduced by approximately 30% and decreased to 0.718 g/cm3 with an exothermic chemical foaming agent. Tensile and flexural tests were performed on the foamed composites to determine the dependence of the mechanical properties on the density and microvoid content of the foamed specimens, and these properties were compared with those of nonfoamed composites. MAH‐PP improved the physicomechanical properties up to 80%. With an increase in the mold temperature (80–110°C), the surface roughness was reduced by nearly 70% for the foamed composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1090–1096, 2005

Mechanical properties of short flax fibre bundle/polypropylene composites: Influence of matrix/fibre modification, fibre content, water uptake and recycling

The aim of this work was to compare the effect of modification way of short flax fibre bundle/polypropylene (PP) composites on mechanical properties. Modification was carried out on fibre surface and also modifying PP matrix using several amounts of maleic anhydride-polypropylene copolymer (MAPP) as compatibilizer. The optimum doses of two different MAPP compatibilizers have been obtained. The effect of fibre bundle loading on composite mechanical properties was also analysed. The influence of water uptake on the sorption characteristics of composites has been studied by immersion in distilled water at room temperature. The effects of fibre bundle loading and also the use of MAPP modification on both water sorption and mechanical properties were also evaluated. Results showed that using MAPP as coupling agent, mechanical properties of composites improved, and water uptake rate clearly decreased. However, after long period of water immersion mechanical properties drastically decreased. On the other hand, mechanical recycling of flax fibre bundle/PP composites has been shown to be feasible.

Flax fiber surface modifications: Effects on fiber physico mechanical and flax/polypropylene interface properties

This study arises on the opportunities of using flax fibers as reinforcement for polypropylene (PP) matrix composites. For this purpose, untreated flax fiber bundles obtained by a retting process have been used. For improving compatibility between flax fiber bundles and PP matrix, fiber surface treatments such as maleic anhydride, maleic anhydride polypropylene copolymer, and vinyltrimethoxy silane have been carried out. On the other hand, alkali treatment has also been carried out for fiber modification. The effect of surface modification on tensile properties of single fibers and also on fiber-matrix interfacial shear strength (IFSS) has been analyzed. Finally, both optical microscopy and atomic force microscopy have been used for characterizing flax fiber microstructural features. The current study completes previous results to elucidate the influence of treatments on fiber surface and flax fiber-PP interface. POLYM. COMPOS. 26:324–332, 2005. © 2005 Society of Plastics Engineers.

Effects of fibre treatment on wettability and mechanical behaviour of flax/polypropylene composites

Chemical treatment of natural reinforcements can enhance their adhesion to polymer matrices. This work reports the effects of different treatments on the fibre–matrix compatibility in terms of surface energy and mechanical properties of composites. The composites were compounded with two kinds of flax fibres (natural flax and flax pulp) and polypropylene. The applied treatments were maleic anhydride (MA), maleic anhydride-polypropylene copolymer (MAPP) and vinyl trimethoxy silane (VTMO). The treatment effects on the fibres have been characterised by Infrared Spectroscopy. Two techniques have been used to determine the surface energy values: the Dynamic Contact Angle method for the long flax fibres and the Capillary Rise method for the irregular pulps. The use of different methods involves a small discordance in the wettability values. Nevertheless, the three treatments reduce the polar component of the surface energy of the fibre. Composites containing MAPP-treated did the highest mechanical properties, whilst the MA and VTMO-treated fibre gave similar values to that for the untreated ones.

Mechanical characterization of polypropylene–wood flour composites

AbstractThe mechanical performance of different wood flour/polypropylene (PP) composites with interface modifications was compared. Wood flour was incorporated into the matrix after esterification with maleic anhydride (MAN) or without any modification but with the addition of a compatibilizing agent [maleic anhydride–polypropylene copolymer (PPMAN)] to modify the polymer–filler interaction. Composites were prepared by injection molding with different concentrations of wood flour. Mechanical properties (except Young's modulus) were not improved either by the wood flour chemical modification or by the use of PPMAN. However, both compatibilization methods were successful in improving the dispersion of the wood flour in the PP matrix. Creep behavior of composite samples was improved by the addition of PPMAN, whereas the composites prepared from MAN‐treated wood flour showed larger deformations than composites made with untreated particles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1420–1428, 2003

Microcellular Wood Fibre Reinforced Polypropylene Composites in an Injection Moulding Process

Microcellular foams of polypropylene containing wood fibres, cell sizes on the order of 10 to 50 μm were produced by injection moulding. The relationships of processing/structure/property were investigated for wood fibre-thermoplastics composites foaming with a chemical blowing agent. Wood polypropylene composites (WPC) of different wood content (30%, 40%, 50% and 60% by weight) were prepared using maleic anhydride-polypropylene copolymer (5% relative to the wood fibre content) as a coupling agent. Measurement of density, cell size, void content, tensile and flexural test of the prepared WPC were carried out. The shape and distribution of the voids were investigated by optical photo examination of longitudinal sections of specimens, using a polishing technique and reflected light microscopy. The density of foamed composites decreased about 24%. The cell morphology and foam properties showed improvement when the coupling agent was added. Water absorption and scanning electron microscope of the composites also investigated.

Physico-mechanical studies of wood fiber reinforced composites

Wood polypropylene composites (WPC) of different compositions (30, 40, and 50%) have been prepared using maleic anhydride–polypropylene copolymer of different percentage (5 and 10% relative to their wood fiber content). Tensile, flexural, fracture toughness, and impact test of the prepared WPC were carried out. From the results, it is observed that the hard wood fiber–polypropylene composites, by using maleated polypropylene (MAH-PP), show comparatively better performance to soft wood fiber–polypropylene composites. Tensile strength and charpy impact strength have been increased to a maximum of 50 and 20%, respectively. The damping index has been decreased by 60% when 10% of MAH-PP has been used. Water absorption and scanning electron microscopy of the composites are also investigated.

Laboratory FTX twin-screw extruder offered by US manufacturer

Blends of polypropylene and two polyketone grades with low and medium-high viscosities were prepared by melt extrusion. To obtain good compatibility, a maleic-anhydride–polypropylene copolymer was added to the blends. Polyoxypropylenediamine was added to some of the blends to further enhance compatibility. The blends were analysed with differential scanning calorimetry. In a second step, the blends were compression or injection moulded. Scanning electron microscopy, shear viscosity, density measurements and infrared spectroscopy were used to characterise the moulded blends and their oxygen permeabilities were assessed. Impact strength and hardness were measured on injection-moulded blends. It was shown that the oxygen barrier properties of polypropylene could be greatly enhanced by a small addition of primarily the low-viscosity polyketone. A content of 23.9% by volume of polyketone was sufficient to lower the permeability by 70% compared to pure polypropylene. This was because a polyketone-rich surface layer was formed during compression moulding. The incorporation of polyoxypropylenediamine had a profound effect on the morphology. The polyketone particles in this case were very small, and the absence of “pull-outs” suggested an enhanced phase adhesion between the different components. Further, the incorporation of polyoxypropylenediamine had no impact on the oxygen permeability but the impact toughness and hardness were increased and the shear viscosity was also increased in its presence. This indicated that chemical bonds were formed between polyketone, polyoxypropylenediamine and the maleic-anhydride–polypropylene copolymer. This network suppressed crystallisation of primarily the polyketone component.

Properties of polyketone/polypropylene blends

Blends of polypropylene and two polyketone grades with low and medium-high viscosities were prepared by melt extrusion. To obtain good compatibility, a maleic-anhydride–polypropylene copolymer was added to the blends. Polyoxypropylenediamine was added to some of the blends to further enhance compatibility. The blends were analysed with differential scanning calorimetry. In a second step, the blends were compression or injection moulded. Scanning electron microscopy, shear viscosity, density measurements and infrared spectroscopy were used to characterise the moulded blends and their oxygen permeabilities were assessed. Impact strength and hardness were measured on injection-moulded blends. It was shown that the oxygen barrier properties of polypropylene could be greatly enhanced by a small addition of primarily the low-viscosity polyketone. A content of 23.9% by volume of polyketone was sufficient to lower the permeability by 70% compared to pure polypropylene. This was because a polyketone-rich surface layer was formed during compression moulding. The incorporation of polyoxypropylenediamine had a profound effect on the morphology. The polyketone particles in this case were very small, and the absence of “pull-outs” suggested an enhanced phase adhesion between the different components. Further, the incorporation of polyoxypropylenediamine had no impact on the oxygen permeability but the impact toughness and hardness were increased and the shear viscosity was also increased in its presence. This indicated that chemical bonds were formed between polyketone, polyoxypropylenediamine and the maleic-anhydride–polypropylene copolymer. This network suppressed crystallisation of primarily the polyketone component.