Effect Of Maleated Polypropylene Research Articles

Online Pre-Treatment of Thermomechanical Pulp with Emulsified Maleated Polypropylene for Processing of Extruded Thermoplastic Composites

The effectiveness of maleated polypropylene (MAPP) in emulsified form for the pre-treatment of thermo-mechanical pulp (TMP) before extrusion with polypropylene fibres was evaluated. MAPP in pellet form, which was applied during the compounding step, served as a benchmark. In addition, commercial softwood flour was included as a reference. The influence of the temperature during the defibration process and the presence or absence of the coupling agent on composite performance were evaluated. Composites were processed with a high wood content of 70 wt.%, which is common for extruded profiles. It was found that TMP based on Robinia (Robinia pseudoacacia L.) conferred higher strength properties to the composites compared to TMP based on Scots pine (Pinus sylvestris L.), which was attributed to the higher length/diameter ratio of fibres in Robinia. However, under the conditions of this study, strength properties were superior and water uptake and swelling were reduced when wood flour was used instead of TMP. On the other hand, in many formulations, larger improvements in flexural and tensile strength due to MAPP were found for the TMP-based composites compared to the wood flour-based composites. This could be due to the larger surface/volume ratio for TMP compared to wood flour and more efficient stress transfer from fibres to the matrix. Results from X-ray photoelectron spectroscopy (XPS) showed that TMP surfaces were more hydrophobic than wood flour due to coverage with lignin, which reduced the effectiveness of MAPP. Esterification between the emulsified MAPP and fibre surfaces was determined using Fourier-Transform Infrared (FTIR) spectroscopy, but some non-activated maleic anhydride remained. Under the conditions of this study, MAPP added during compounding provided better performance compared to MAPP which included a non-ionic emulsifier and which was added during the refining process. Lower temperature (150 °C) during defibration was shown to be beneficial for the strength properties of composites compared to high temperature (180 °C) when MAPP was included in the formulations.

The Effect of Maleated Polypropylene on the Non-Isothermal Crystallization Kinetics of Wood Fiber-Reinforced Polypropylene Composites.

The influence of maleated polypropylene (MAPP) on the non-isothermal crystallization behavior of wood fiber (WF)-reinforced PP composites (WPCs) was investigated by a differential scanning calorimeter (DSC). The results showed that MAPP as a nucleation agent accelerated the crystallization rate of the PP matrix in WPC under the cooling process. The corresponding crystallization kinetics and activation energy were further analyzed using the Avrami method, Avrami–Ozawa method, Kissinger method, and Friedman method. The results demonstrated that MAPP significantly changed the crystal growth mechanism of the PP matrix to heterogeneous nucleation for acicular and tabular crystal growth during the annealing step. A remarkably lower cooling rate can achieve a certain relative crystallinity degree at the unit crystallization time for WPC with 3 wt % MAPP (WPCM3). Similarly, the lowest crystallization activation energy was observed for the WPCM3 among all WPCs by the Kissinger method. Furthermore, based on the Friedman method, the addition of MAPP easily caused the PP matrix to crystallize in the WPC at the initial stage of relative crystallinity.

Effect of maleated polypropylene as a compatibilizer and hyperbranched polyester as a processing aid on polypropylene‐wood flour biocomposites

This work focused on two difficulties associated with preparation of polypropylene/wood flour (PP/WF) composites, viz. the compatibility of PP with WF and processing of the composites with high melt viscosity. Maleic anhydride‐grafted polypropylene (MAPP) was used in the preparation of PP composites to provide the compatibility between polymer and filler. Hyperbranched polyester (HBPE) was incorporated to check feasibility of it as a processing aid in the same. The PP/WF composites were formulated by melt compounding on a Brabender Plastograph EC. Blending effect of compatibilizer and processing aid HBPE on PP/WF biocomposites have been carried out on the basis of torque analysis, mechanical properties, morphology, and thermal stability. The investigation showed that HBPE improves the processibility of PP/WF composites than MAPP with respective to torque value. The mechanical and thermal properties slightly vary with change in relative proportion of MAPP and HBPE. J. VINYL ADDIT. TECHNOL., 24:179–184, 2018. © 2016 Society of Plastics Engineers

The Effect of Binder on Mechanical Properties of Kenaf Fibre/Polypropylene Composites Using Full Factorial Method

The effect of maleated polypropylene (MAPP) as binder on the mechanical properties of kenaf fibre/polypropylene (KF/PP) composites is studied. Ratios between kenaf fibre and PP having 10:90, 30:70 and 50:50 in weight ratio were selected. Further, MAPP having 1, 3 and 5 percent in percentage of weight ratio was mixed in KF/PP composites. Hot press machine was used to produce tensile test samples of KF/PP composites. The mechanical properties that are tensile strength, tensile modulus and elongation at break of KF-PP composites were obtained from tensile test result. It is found that the tensile strength and tensile modulus increase with increasing the kenaf fibre loading and higher percentage of MAPP. Further, the elongation at break for KF/PP composites shows lower result when increasing of kenaf fibre loading. However, when percentage of MAPP added in KF/PP composites increases, the elongation at break increased slightly. Thus, result shows that kenaf fibre/PP composites with binder were better in tensile strength, tensile modulus however the elongation at break shows weak result unless the binder was added.

Extruder‐made TPO nanocomposites. I. Effect of maleated polypropylene and organoclay ratio on the morphology and mechanical properties

AbstractPP/PP‐g‐MA/MMT/EOR blend nanocomposites were prepared in a twin‐screw extruder at fixed 30 wt % elastomer and 0 to 7 wt % MMT content. Elastomer particle size and shape in the presence of MMT were evaluated at various PP‐g‐MA/organoclay masterbatch ratios of 0, 0.5, 1.0, and 1.5. The organoclay dispersion facilitated by maleated polypropylene serves to reduce the size of the elastomer dispersed phase particles and facilitates toughening of these blend nanocomposites. The rheological data analysis using modified Carreau‐Yasuda model showed maximum yield stress in extruder‐made nanocomposites compared with nanocomposites of reactor‐made TPO. Increasing either MMT content or the PP‐g‐MA/organoclay ratio can drive the elastomer particle size below the critical particle size below which toughness is dramatically increased. The ductile‐brittle transition shift toward lower MMT content as the PP‐g‐MA/organoclay ratio is increased. The D‐B transition temperature also decreased with increased MMT content and masterbatch ratio. Elastomer particle sizes below ∼1.0 μm did not lead to further decrease in the D‐B transition temperature. The tensile modulus, yield strength, and elongation at yield improved with increasing MMT content and masterbatch ratio while elongation at break was reduced. The modified Mori‐Tanaka model showed better fit to experimental modulus when the effect of MMT and elastomer are considered individually. Overall, extruder‐made nanocomposites showed balanced properties of PP/PP‐g‐MA/MMT/EOR blend nanocomposites compared with nanocomposites of reactor‐made TPO. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

Effect of hybridization and compatibilization on the mechanical properties of recycled polypropylene‐hemp composites

AbstractHemp fibers and particles, with different sizes and contents, were used to make hybrid composites based on recycled polypropylene (PP). In particular, the effect of maleated polypropylene (MAPP) addition on the morphology and mechanical properties is reported. The results show that better adhesion is obtained with MAPP addition. In general, fiber content and size had a substantial effect on the tensile, flexural, torsion, and impact properties of the resulting composites. Although, adding MAPP to the samples improved the impact strength of the composites, the values were always lower than neat PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Studies on the properties of rice-husk-filled-PP composites: effect of maleated PP

Rice husk is a by-product of rice milling process that usually finds inadequate final disposal (burning, land filling). Thermoplastics composites filled with rice husk flour are materials that offer an alternative for using this agricultural resource viewing the production of low dense materials with some specific properties. In this work composites of polypropylene (PP) and rice husk flour (RHF) were prepared by melt extrusion. Maleic anhydride-modified PP (MAPP) was added as a coupling agent. It was verified that tensile strength decreased with filler loading. The presence of MAPP improved this property showing a strong dependence on the MAPP/RHF ratio (MAPP/RHF = 0.03 produced the best results). The density of the composites slightly increased with filler and coupling agent in comparison to pure PP. The presence of MAPP diminished more than 20% water uptake in highly-loaded composites.

Effects of vinyltrimethoxy silane on thermal properties and dynamic mechanical properties of polypropylene–wood flour composites

AbstractThe viability of vinyltrimethoxy silane was investigated as a coupling agent for the manufacture of wood–plastic composites (WPC). The effect of silane pretreatment of the wood flour on the thermal and the dynamic mechanical properties and thermal degradation properties of the composites were studied. Moreover, the effect of organosilane on the properties of composites was compared with the effect of maleated polypropylene (MAPP). DSC studies indicated that the wood flour acts as a PP‐nucleating agent, increasing the PP crystallization rate. In general, pretreatment with small amounts of silane improved this behavior in all the WPCs studied. Thermal degradation studies of the WPCs indicated that the presence of wood flour delayed degradation of the PP. Silane pretreatment of the wood flour augmented this effect, though without significantly affecting cellulose degradation. Studies of dynamic mechanical properties revealed that the wood flour (at up to 30 wt %) increased storage modulus values with respect to those of pure PP; in WPCs with a higher wood flour amount, there was no additional increase in storage modulus. Pretreatment of the wood flour with silane basically had no effect on the dynamic mechanical properties of the WPC. These results show that with small amounts of vinyltrimethoxy silane similar properties to the MAPP are reached. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Effect of maleated polypropylene as coupling agent for polypropylene composites reinforced with hemp strands

AbstractNew composites based on poly(propylene) as polymer matrix and hemp strands as natural reinforcement have been developed by injection‐molding. The materials were previously mixed in a two roll mill to induce the dispersion of the fiber inside the polymer. To improve the adhesion between both components, maleated poly(propylene) was added as coupling agent, at 4% wt/wt with respect to hemp strands. The addition of this amount of this coupling agent to the formulation modified with 40 wt % of hemp strands increases the ultimate tensile strength (σt) and flexural strength (σf) up to 49 and 38%, respectively, compared with the composite without coupling agent. The interaction between the surface of hemp strands and the coupling agent was determined by FT‐IR spectroscopy assuming that a covalent bond was established, avoiding the adverse effect of the poor compatibility at the interface for this kind of composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 833–840, 2006

Effect of maleated polypropylene and impact modifiers on the morphology and mechanical properties of PP/Mica composites

Composites of polypropylene (PP) with mica powder and impact modifiers were produced by internal mixer. A major drawback in the use of mica-filled PP is its low impact resistance. In the present study, the effect of the maleated PP (MAPP) and impact modifiers was evaluated on the composite properties separately and together. Thus, two different styrene-ethylene/butylene-styrene triblock copolymers (SEBS) and one ethylene-propylene-diene terpolymer (EPDM) have been used as impact modifiers in the PP-mica composites. Addition of MAPP had a negative effect on the composite notched impact strength and elongation at break but had a positive effect on tensile strength when used together with impact modifiers. All three elastomers increased the impact strength of the PP-mica composites but the addition of maleated SEBS (SEBS-MA) granted the greatest improvement in impact strength. It was inferred from the scanning electron microscopy that SEBS-MA had a stronger interaction with mica surface than the other impact modifiers. POLYM. COMPOS., 27:614–620, 2006. © 2006 Society of Plastics Engineers

Effect of maleated polypropylene on the performance of polypropylene/cellulose composite

Composites consisting of a polypropylene (PP) and highly crystalline cellulosic microfibers were prepared by melting mixing with the maleic anhydride grafted polypropylene (MAPP) as a compatibilizer. The results show that even with addition of a small amount of MAPP, the mechanical properties of the composites improved dramatically. The improvement is attributed to stronger interfacial adhesion caused by esterification between anhydride groups of MAPP and hydroxyl groups of cellulose, although the number of the ester bonds is too few to be detected by FT-IR spectroscopy. It was also found that tensile strength and Young's modulus increased with the increasing MAPP contents in the composites, and the optimum MAPP content is about 10 wt% for the composite with cellulose content of 30 wt%. SEM indicated that the interfacial adhesion between cellulose fibers and PP improved in MAPP-containing composites. The DSC results showed that MAPP has little effect on melting and crystallization temperatures of PP in the composites. POLYM. COMPOS., 26:448–453, 2005. © 2005 Society of Plastics Engineers

Effect of Ester Linkages on the Mechanical Properties of Wood Fiber-Polypropylene Composites

The esterification reaction between several wood fibers and maleated polypropylenes, and its role in determining the mechanical properties of wood fiberpolypropylene composites was investigated. The modification technique used in this study involved bulk treatment in a thermokinetic mixer. The treatment of wood fiber with maleated polypropylene had a significant effect in increasing the mechanical properties of the composites. However, no direct evidence of ester links was detected between wood fiber and maleated polypropylene by FT-IR. Thus, the effectiveness of maleated polypropylene in improving the mechanical properties was attributed to the compatibilization effect which is accomplished by improving the wettability of wood fiber by the matrix polymer, lowering the fiber to fiber interactions, improving fibers dispersion and orientation, and enhancing the adhesion between wood fiber and polypropylene matrix.

Bonding of air-formed wood fibre/polypropylene fibre composites

The effectiveness of a maleated polypropylene (MAPP) as a coupling agent in wood fibre/polypropylene fibre composites made by non-woven web technology has been evaluated. The composite panels were made with 70 or 85% wood fibre, wiht the MAPP being incorporated in the panels at a level of 1 or 3% by spraying an emulsified form on the wood fibres. Both levels of MAPP significantly increased bending and tensile strength and moduli, and dynamic modulus. At the 70% wood fibre level, impact energy was increased significantly in panels with 3% MAPP. At the 85% wood fibre level, both 1% and 3% MAPP significantly increased impact energy. The MAPP also led to small improvements in water resistance for composites containing 85% wood fibre. The effectiveness of MAPP is believed to be the result of efficient incorporation at the wood/polypropylene interface, thus providing effective coupling of the polar wood component to the non-polar polymer matrix.

Extruded Wood-Flour Polypropylene Composites: Effect of a Maleated Polypropylene Coupling Agent on Filler-Matrix Bonding and Properties

ABSTRACTFull factorial studies were conducted to determine the effects of a coupling agent (a low molecular weight maleated polypropylene (MAPP)) and other composition and processing variables on the mechanical properties of a wood-flour-filled polypropylene (PP) composite. Effects of MAPP on the bonding between PP and wood veneer were also examined. At less than 1 percent by weight, MAPP produced useful increases in strength and modulus properties of the composite, and this effect was somewhat enhanced by small-particle-size wood flour and multiple extrusions. However, MAPP caused small losses in notched impact energy. High extrusion temperature (190°C to 250°C) had little influence on strength, but it decreased notched impact energy. Peel force between PP and wood veneer was increased by pretreatment with MAPP for aspen, but not for birch, aspen being more porous than birch. The effectiveness of MAPP may therefore be related to its ability to penetrate the wood and form a strongly held hydrophobic layer that is attractive to the PP, thereby increasing both the effective bonding area and mechanical interlocking.