Maleic Anhydride Polypropylene Research Articles

Mechanical Properties of VGCF/MAPP and Atmospheric Plasma-Treated VGCF/PP by Melt-Mixing Process

The effects of atmospheric plasma treatment and matrix modification by maleic anhydride PP (MAPP) addition, respectively, on the mechanical properties of vapor grown carbon fiber (VGCF)/polypropylene (PP) were investigated. Raw VGCF/PP, raw VGCF/MAPP, atmospheric plasma-treated (APT) VGCF/PP were melt mixed and extruded using a twin-screw extruder. The tensile modulus, shear modulus, and shear strength of APT VGCF/PP showed higher values than those of raw VGCF/PP. The tensile strength, flexural modulus, and flexural strength of raw VGCF/MAPP demonstrated higher values than all the other samples of raw VGCF/PP. The mechanical properties were improved with the atmospheric plasma treatment and coupling agent due to the improved adhesion at VGCF/PP interface. SEM micrographs revealed an excellent dispersion of VGCF in PP and MAPP, respectively. From the twin-screw extruder processing, the VGCF particles were relatively well aligned as well.

Preparation and Properties of Wheat Straw Fiber-polypropylene Composites. Part II. Investigation of Surface Treatments on the Thermo-mechanical and Rheological Properties of the Composites

Composites made of polypropylene (PP) and wheat straw fiber treated by alkalization, acetylation, and maleic anhydride polypropylene (MAPP) were prepared, and the dynamic mechanical, thermal, and rheological properties of the treated composites have been investigated. The PP composites reinforced with the treated wheat straw fiber exhibited higher brittleness. The melt flow studies were carried out at the temperature of 170, 180, and 190°C and shear rate of 0.01—0.1 s—1. The PP composites reinforced with the alkalized wheat straw fiber showed the high melt viscosity due to the strong chemical interaction among polymer and wheat straw fiber. The introduction of MAPP to the system increased the flow behavior of the polymer dispersed the wheat straw fiber uniformly, and decreased the melt viscosity. The PP composites introduced by 2 wt% MAPP showed the lowest storage flexural modulus (E′) over the entire temperature range from 25—150°C, due to better compatibility between the wheat straw fiber and matrix. The PP composites made of with 20 wt% alkalized and MAPP treated wheat straw fiber showed the highest E′. The differential scanning calorimeter (DSC) study revealed that introducing the wheat straw fiber to PP matrix increased the melting temperature and crystallization temperature. The PP composites reinforced with the alkalized and MAPP treated fiber had the highest rate of crystallization as a consequent of the co-effect of alkalization and esterfication.

Real time assessment of the compatibilization of polypropylene/polyamide 6 blends during extrusion

The reactivity of maleic anhydride and acrylic acid polypropylene graft copolymers with amine groups and their effect in the compatibilization of polymer blends was analyzed in real time during the reactive processing of compatilized polypropylene/polyamide 6 (PP/PA6) blends. The presence of compatibilizers in the blend produces a block copolymer PP-PA6, which stays in the blends interface, lowering the interfacial tension and reducing the PA6 particle size, affecting the light extinction phenomena. The in-line optical detector is able to indirectly quantify the conversion of the compatibilization reaction of the blends. The signal intensity of the detector increases with the increase of the PA6 content due to the increase in the number of particles. Quantitative off-line FTIR analyses of the compatibilized blends have shown that the amount of block copolymer formed when polypropylene grafted with acrylic acid (PP-g-AA) is used as compatibilizer increases with its content in the blend. There is a good correlation between the in-line optical measurement and the off-line amidic bond content formed. Non-reacted compatibilizers are always present in the reactive blends whose content is proportional to its initial concentration. The PA6 particle size data obtained from scanning electron microscopy analysis showed good correlation with the in-line measurements. POLYM. ENG. SCI., 2010. © 2009 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.

Effect of Clay Types on the Mechanical, Dynamic Mechanical and Morphological Properties of Polypropylene Nanocomposites

In the present investigation Polypropylene–Maleic anhydride grafted polypropylene–organically modified MMT (PP-MAPP-OMMT) nanocomposites were prepared by melt mixing in a twin screw extruder followed by injection molding. The effect of clay chemistry and compatibilizer on the properties of the nanocomposites has been studied. Sodium montmorillonite has been organically modified using quaternary and alkyl amine intercalants. A comparative account with commercial quaternary ammonium modified clays i.e Cloisite 20A, Cloisite 15A and Cloisite 30B has been presented. Storage modulus of PP matrix also increased in the nanocomposites, indicating an increase in the stiffness of the matrix polymer with the addition of organically modified nanoclays. The morphology of the nanocomposites has been examined using wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). Morphological findings revealed efficient dispersion of organically modified nanoclays within the PP matrix. MAPP compatibilized PP/Cloisite 15A nanocomposites displayed finely dispersed exfoliated nanomorphology as compared with other systems.

Thermal and mechanical properties of polypropylene filaments reinforced with multiwalled carbon nanotubes via melt compounding

This study examined the thermal and mechanical properties of polypropylene filaments reinforced with multi-walled carbon nanotubes (MWNTs). The MWNTs were functionalized with maleic anhydride polypropylene to increase the interfacial interactions between the CNTs and polypropylene. PP/MWNT composites with different concentrations of MWNTs were prepared by melt compounding using a twin screw extruder. The composites of the filament were then post drawn and heat treated. Tensile tests showed increased strength with the addition of only 0.1 wt% while there were only slight changes in elongation. The thermal properties were also slightly enhanced by the MWNTs.

Accelerated Ultraviolet Weathering of Recycled Polypropylene—Sawdust Composites

Accelerated ultraviolet (UV) weathering of hot-press molded recycled polypropylene (rPP)—sawdust composites was investigated with combinative UV radiation and water spray testing to assess the durability performance. The water absorption and thickness swelling of the composites were increased after accelerated weathering. The surface of the composites underwent significant color changes (ΔE) and lightening (ΔL*) after weathering. The Young’s modulus and flexural strength were decreased after weathering. Microstructural observations revealed a decrease in interfacial bonding between the wood flour and polymer matrix with increased exposure to weathering. The crystallinity and melting temperature of the PP—wood flour composites were decreased while neat rPP showed a 6% increase in the crystallinity after weathering. The crystallinity of rPP in the control composites without maleic anhydride polypropylene (MAPP) was slightly lower than for neat rPP, while MAPP-containing composites showed an increase in the crystallinity of rPP.

Effects of material compositions on the mechanical properties of wood–plastic composites manufactured by injection molding

The objective of this study was to investigate the effects of material compositions on the mechanical properties of wood–plastic composites (WPCs) manufactured by injection molding. Using a ratio of wood flour/plastic matrix/MAPP (maleic anhydride polypropylene)/zinc stearate of 47:47:3:3, the tensile strength and modulus of rupture ( MOR) of WPCs manufactured with LDPE (low-density polyethylene) and PP (polypropylene) were found to be larger than those of LDPE and PP themselves. However, contrasting findings were obtained when the polymer matrix was ABS (acrylonitrile-butadiene-styrene). In comparison to the mechanical properties of RPP (recycled polypropylene) itself, the MOR increased and the tensile strength decreased for WPCs manufactured with RPP. The tensile strength, MOR, and storage modulus of WPCs made from PP mixed with 47% wood flours (<180 μm) and 3–4.5% MAPP were larger than those of the other WPCs manufactured in this study. However, the polymer damping peaks showed a contrary result.

Effect of particulate fillers on mechanical and abrasive wear behaviour of polyamide 66/polypropylene nanocomposites

This article presents the mechanical and three-body abrasive wear behaviour of Polyamide 66/Polypropylene (PA66/PP) blend, nanoclay filled PA66/PP and short carbon fiber (diameter 6–7 μm and length 3–4 mm) reinforced PA66/PP nanocomposites. All particulate-filled PA66/PP composites were prepared by using twin screw extrusion followed by injection molding. Maleic anhydride polypropylene (MAgPP) was used as the compatibilizer. The mechanical properties of particulate-filled PA66/PP composites were studied, and the three-body abrasive wear behaviour was assessed by rubber wheel abrasion test under different loads/abrading distances. The results indicate that addition of nanoclay/short carbon fiber in PA66/PP have significant influence on wear under varied abrading distance/loads. Further, it was found that nanoclay filled PA66/PP composites exhibited lower wear rate compared to short carbon fiber filled PA66/PP composites. In addition, the worn surface morphology of the samples was also discussed.

Rheological properties of polypropylene/hemp fiber composites

AbstractThis study investigates the effect of hemp fibres on the shear and elongational rheology of polypropylene (PP). The parameters studied were hemp content (0‐30%) and maleic anhydride polypropylene (MAPP) addition (0‐0.6%). Shear rheology revealed that fibre content mainly influences low shear rate properties like yield stress and zero‐shear‐viscosity while coupling agent addition mainly influences intermediate to high shear rate parameters like relaxation time, power‐law index and Yasuda parameter. On the other hand, elongational rheology results showed a strain softening behaviour of the composites with increasing consistency and decreasing strain at break as fibre concentration increases. MAPP addition is also shown to improve the fibre‐polymer compatibility, but at the same time produces a plasticizing effect having a significant effect on rheological properties. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers

Oxyfluorination of Wood-Fiber Reinforced Thermoplastic Composites to Improve Adhesion

Oxyfluorination was evaluated on a series of wood-fiber reinforced thermoplastic composite (WPCs) formulations as a means to improve the adhesion of a water-based acrylic coating. The oxyfluorination increased the acrylic coating peel load to WPCs by 179%, yielding adhesion levels higher than those obtained on control maple. For oxyfluorinated surfaces, the WPC formulation had a significant impact on the acrylic coating paint. Formulations without maleic anhydride polypropylene coupling agent developed better adhesion than formulations with the coupling agent. Formulations with polypropylene also performed better than formulations with high density polyethylene and so did formulations with pine compared with those with maple. Interestingly, the adhesion improvement imparted by oxyfluorination was higher for those formulations that were least amenable to bonding with the acrylic coating, i.e., those containing the coupling agent and high density polyethylene. Contact angle measurements and ATR-FTIR spectroscopy indicated that oxyfluorination improved wettability with polar liquids by generating new oxygenated groups on the surface. A moderate positive linear relationship (r2 = 0.5) was established between the carbonyl/C-H stretch band intensity ratio I1650cm−1 /I2915cm−1 in the infrared spectra of oxyfluorinated WPCs and the coating peel strength. It is, therefore, proposed that oxyfluorination improves the adhesion properties of WPCs by oxidizing the surface, and by increasing wettability with polar liquids, thus allowing the development of stronger interfacial forces.

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

Preparation and characterization of polypropylene and waste tire powder modified by allylamine blends

AbstractWaste tire powder subjected to allylamine modification in the presence of ultraviolet (UV) radiation has been used to prepare polypropylene based thermoplastic vulcanizates with maleic anhydride polypropylene (MA‐PP) as compatibilizer. The effect of increasing the concentration of MA‐PP on performance characteristics like tensile strength, elongation and rheological properties have been investigated. X‐ray diffraction studies of the PP/waste tire powder blend indicate the disappearance of β crystalline peaks on addition of waste tire powder in the PP, whereas it is observed in the allylamine modified rubber powder loaded PP. Differential scanning calorimetry results further supported the above fact. The improvement in mechanical properties of the PP/allylamine modified rubber powder loaded thermoplastic vulcanizates has been explained in terms of βα transformation of PP crystals during straining of the samples and uniform dispersion of allylamine coated rubber powder in the PP matrix. The melt rheological properties of the thermoplastic vulcanizates loaded with modified rubber powder are higher than its counterpart due to the higher dispersion as a result of chemical interaction between the rubber powder surface with the MA‐PP. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Feasibility of Using Heat Treated Wood in Wood/Thermoplastic Composites

Using wood and other natural fibers with thermoplastic materials is always associated with a problem: poor compatibility between wood fibers and thermoplastic matrix. This paper deals with the mentioned problem and tries to solve, or at least ease, it through pre-heat treatment of wood prior to blending of wood fibers with other components of composites. In this study, wood pre-heat treated at different temperatures (175, 190 and 205°C) was used at various loadings (25 and 50%) with high density polyethylene (HDPE) and polypropylene-maleic anhydride copolymer (MAPP) to produce composites. The composite properties, including mechanical performance and morphological character, were investigated. The results of this study show that pre-heat treatment temperature and coupling agent content did not impact the composite properties at 25% wood content. Adding treated wood at 50% level to the composites enhanced the mechanical properties in comparison with untreated wood. The degree of the enhancement depended on pre-heat treatment temperature. Using wood treated at 190°C resulted in composites with the highest modulus of rupture (MOR) and tensile strength. In terms of modulus of elasticity (MOE), composites having wood treated at 205°C showed the highest MOE in both tensile and flexural tests. Adding 2% coupling agent caused an improvement in modulus of rupture (MOR) and tensile strength. An increase in wood content from 25 to 50% deceased strain at maximum load drastically. Morphological study showed that the mode of fracture is a function of wood and coupling agent content, and pre-heat treatment temperature.

Effect of bark flour content on the hygroscopic characteristics of wood–polypropylene composites

AbstractThe effects of the bark content on the water absorption and thickness swelling of wood–plastic composites prepared from polypropylene, wood flour, and bark flour were studied. Samples were made with a laboratory twin‐screw extruder. The results showed that among composites free of maleic anhydride polypropylene, those composites containing a higher bark flour content exhibited lower water absorption and lower thickness swelling. Maleic anhydride polypropylene reduced water absorption and thickness swelling in composites containing wood flour and a lower content of bark flour but had no influence on the hygroscopic properties of composites made with higher bark contents. Adding maleic anhydride polypropylene had no effect on the water diffusion coefficients and swelling rate parameters of composites made with a higher bark flour content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Surface properties and adhesion of wood fiber reinforced thermoplastic composites

The surface chemistry, wettability and topography of wood fiber reinforced thermoplastic composites were evaluated using Fourier transform infrared spectroscopy, contact angle analysis and profilometry. Wood plastic composites have a low surface energy (31 mJ/m 2), a large surface roughness R (rms) (3.5–7.4 μm) and a large wetting hysteresis (63–90 mJ/m 2) that stems from surface roughness, chemical heterogeneity and viscoelastic energy dissipation. Using a 180° peel test the adhesion of an acrylic coating on wood plastic composites was evaluated and a positive linear correlation ( R 2 = 0.89) between peel load and wetting hysteresis indicated that the wetting hysteresis was a good predictor of adhesion. Furthermore, strong linear correlations were found between peel load and surface roughness for formulations using polypropylene ( R 2 = 0.79) and formulations using high density polyethylene ( R 2 = 0.97). Formulations with polypropylene, which had higher surface wood index, also developed higher peel loads. Similarly formulations that did not use a maleic anhydride polypropylene coupling agent, which had higher surface roughness and have higher molecular mobility, also developed higher peel loads. Consequently surface roughness, polarity and viscoelastic energy dissipation mechanisms were proposed to be critical factors of adhesion on wood–plastic composites explaining the parallel between wetting hysteresis and peel load.

Waste Paper Filled Polypropylene Composites: the Comparison Effect of Ethylene Diamine Dilaurate as a New Compatibilizer with Maleic Anhydride Polypropylene

The effect of a new compatibilizer, ethylene diamine dilaurate (EDD) and a commercial compatibilizer, maleic anhydride polypropylene (MAPP) on the processability, mechanical properties, water absorption, thermal properties and morphology of waste paper (WP) filled polypropylene (PP) composites were studied. The results show that WP filled PP with EDD has better processability, higher elongation at break (Eb), impact and flexural strengths but lower tensile strength, Young’s modulus, and water absorption resistance compared to MAPP. Scanning electron microscopy (SEM) study of impact fractured surfaces exhibits the evidence of better impact strength of WP filled PP composites with EDD over MAPP, but the tensile fractured surfaces exhibit opposite characteristics. Fourier transform infrared (FT-IR) spectra provide an evidence of interaction between EDD or MAPP with WP in PP composites. Thermogravimetry analysis show that the addition of EDD or MAPP was found to improve the thermal stability of WP filled PP composites. Differential scanning calorimetry (DSC) also indicates that WP filled PP composites with EDD or MAPP have slightly higher heat fusion (ΔHf (com)) and crystallinity (χcom) than PP/WP composites without compatibilizer.

The effect of fibre and coupling agent content on the mechanical properties of hemp/polypropylene composites

Composites made from hemp and polypropylene were prepared in order to determine the effect of fibre and coupling agent content on their mechanical properties. The samples were prepared by compression molding after an initial melt blending and homogenization step in an internal batch mixer. Different fibre contents (0, 10, 20 and 30 wt%) and sizes (355 and 500 μm) were used with two coupling agents: maleic anhydride polypropylene (MAPP) pellets and wax. For each case, MAPP concentrations between 0 and 7 wt% (fibre basis) were added to determine the optimum amount maximizing mechanical properties. The fractured surfaces of these composites were investigated by scanning electron microscopic technique (SEM) to investigate the fibre/matrix interfacial bonding. The mechanical properties of the composites were characterized in tensile, torsion, and flexion and the results showed that coupling agent addition has a positive effect on all moduli with an optimum content ranging between 2 and 4 wt%. It was also found that the coupling agent wax was more effective that the pellets.

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

Chemical Imaging of Wood—Polypropylene Composites

Recent investigations of wood plastic composites have revealed a detrimental effect of using lubricant systems in production. This includes nullifying part or all of the mechanical benefit of using a polar compatibilizer, maleic anhydride polypropylene (MAPP), in the composite formulation. This investigation utilizes lubricants labeled with deuterium in conjunction with Fourier transform infrared (FT-IR) spectroscopy to allow for the separation of individual lubricants from all other material constituents. All of the deuterium labeled lubricants, used without MAPP, revealed their expulsion from the wood interface during crystallization. MAPP coupling agent was found to exist near the wood, but it is unclear if any covalent bonding with the hydroxyl functionality on the wood surface occurred. The addition of zinc stearate lubricants appears to nullify the activity of the anhydride functionality near the wood surface as evidenced by a shift in the FT-IR spectra to the hydrolyzed form of the coupling agent. Most of the additives collect at the edges of the spherulites in mostly amorphous regions of the material. The consequence of this morphology may be a weak interface between crystallites.