Addition Of Maleated Polypropylene Research Articles

Using furniture factory waste sawdust in wood-plastic composite production and prototype sample production

This study investigated the possibility of furniture factory waste sawdust (FFWS) utilization in polypropylene (PP) composites and producing furniture support leg prototypes. Test samples were manufactured using a single screw extruder and injection molding machine utilizing 10, 15, 20, 25, 30, and 35% by weight of FFWS and 0% or 3% maleated polypropylene (MAPP). Selected mechanical and physical properties of manufactured samples were determined. The presence of FFWS and MAPP significantly improved mechanical properties compared to neat PP. The higher FFWS amount increased the flexural strength, flexural modulus, tensile modulus, impact resistance, and density. Tensile strength and elongation at break decreased with filler amount, but the addition of MAPP caused a dramatic increase in tensile strength. In addition, flexural strength, flexural modulus, tensile strength, elasticity modulus, and density values of the composites containing MAPP had higher values than the ones without MAPP. However, impact resistance and elongation at break values were slightly decreased with the addition of MAPP. Optimization results showed that formulation mixtures containing 20% filler and 3% MAPP fit best for prototype furniture legs manufacturing.

Complex Effects of Hemp Fibers and Impact Modifiers in Multiphase Polypropylene Systems

Natural fibers-reinforced polymer composites have progressed rapidly due to their undeniable advantages. Most of the commercial polypropylene (PP)-based materials are characterized by either high impact toughness or high stiffness, while the manufacture of PP composites with both good toughness and stiffness is challenging at present. In this work, poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) and poly(styrene-b-butadiene-b-styrene) (SBS) copolymers were used in different amounts as modifiers in PP/hemp fibers (HF) composites, with the aim to use them for electrical vehicle parts. The interface in these multiphase systems was controlled by the addition of maleated polypropylene (MAPP). SEBS and SBS showed different effects on the elongation at break of the blends and the corresponding composites due to the HF that stiffened the multiphase systems. Similarly, a different action of MAPP was observed in the composites containing SEBS or SBS: higher Young's and storage moduli were obtained for the composite containing SBS, while greater elongation at break and impact strength values were recorded for the SEBS-containing system. In addition, a remarkable dispersion in the MAPP-containing composite and two times smaller average particle size were revealed by the SEM analysis for the SEBS particles compared to the SBS ones. The higher affinity of SEBS for PP compared to that for SBS and the different morphological characteristics of the systems containing SEBS and SBS may explain the different effects of these impact modifiers on the mechanical properties of the composites. The composites developed in this work were designed as substitutes for the fully synthetic polymeric materials or metal components used in the manufacturing of automotive parts.

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.

Torque rheological properties of polypropylene/cocoa pod husk composites

The torque rheological properties of plastic wood composites are important to practical processing, but the research in this field is rare. In present, a Brabender plastrograph torque rheometer was used to analyse the rheological behavior of polypropylene (PP)/cocoa pod husk (CPH) composites. The effect of processing parameter, filler content, and addition of maleated polypropylene (MAPP) on torque rheological properties was investigated. The torque rheological data found that the processing torque increased with the increases of rotor speed, filler content, and addition of MAPP. The PP/CPH composites melt behavior as pseudoplastics and shear thinning occurred at higher shear rate. The decrease of power law index ( n) evidenced the pseudoplasticity of PP/CPH composites increased at higher filler content and presence of MAPP. The increase of viscosity on PP/CPH was due to filler–filler interaction at higher filler content and strong filler–matrix adhesion after addition of MAPP. The activation energy of PP/CPH composites also increased with higher amount of CPH and addition of MAPP.

Effects of geometry and temperature on mode I interlaminar fracture of filled polypropylene-elastomer nanocomposite

In this study, organically modified Na-MMT clay was used for the preparation of blend nanocomposites containing different ratios of polypropylene (PP) and ethylene propylene diene monomer (EPDM) elastomer in a twin screw extruder. Maleic-grafted PP (MAPP) was used as compatibilizer for making PP hydrophilic. Surface modification of Na-MMT was made by using amino propyl trimethoxy silane (APS) and trimethyl amine as coupling agent with surface grafting catalyst, respectively. A fracture mechanics approach has been adopted by mode I test and the effects of specimen geometry have been investigated. Increase in interlaminar fracture energy value, G c, was observed as the crack propagated through the composite, i.e. a rising ‘R-curve’ for both blend and nanocomposites. Deep fracture studies were carried out at different temperatures (−60 °C to 60 °C) using Izod impact and SENT tests. Fracture energy, fracture stress and brittle ductile transition were determined from crack initiation and propagation process, which showed significant improvement in impact and fracture energy at positive temperature. The wide-angle X-ray diffraction (XRD) patterns showed increased d-spacing of clay layers, indicating enhanced compatibility between PP and clay with the addition of maleated polypropylene (MAPP). Morphology/impact property relationships and an explanation of the toughening mechanisms were made by comparing the impact properties with scanning electron micrographs (SEMs) of fracture surfaces. The transmission electron microscopy (TEM) photomicrographs illustrated the intercalated and partially exfoliated structures of the hybrids with clay, MAPP and elastomer.

Utilization of cocoa pod husk as filler in polypropylene biocomposites

The aim of the research was to utilize cocoa pod husk (CPH) in polypropylene (PP) biocomposites. Maleated polypropylene (MAPP) was used as coupling agent to improve the properties of PP/CPH biocomposites. The addition of MAPP had increased the stabilization torque of PP/CPH biocomposites. The tensile strength and modulus of PP/CPH with MAPP were higher compared to PP/CPH biocomposites without MAPP, except the elongation at break decreased. The crystallinity and thermal stability of PP/CPH biocomposites with MAPP increased. These improvements were due to the enhanced interfacial bonding between CPH and PP matrix, which were proved by SEM analysis.

Preparation and Properties of Polypropylene/Clay Nanocomposites for Food Packaging

Polypropylene (PP)/clay nanocomposites based on PP, organic clay (montmorillonite; MMT), and maleated polypropylene (MAPP) were prepared by melt compounding. The mechanical, thermal, morphological, and gas barrier properties of the resulting PP/clay nanocomposites were investigated at varying concentrations of the components for food packaging. The results revealed that the mechanical strengths, including tensile, flexural, and Izod impact strength, were increased for PP/clay nanocomposites compared to neat PP. The thermal properties showed a tendency for the melting and degradation temperatures to increase with the clay concentration. The effect of the compatibilizer was observed using scanning electron microscopy (SEM). The X-ray diffraction pattern of the nanocomposites revealed increased d-spacing of the MMT layers, indicating that the compatibility of neat PP and clay was improved by the addition of MAPP, and the intercalation and partial exfoliation of the layers. The use of clay increased the mobility distance of the gas molecules, leading to the oxygen permeability of neat PP being reduced by 26% to 55%.

Thermal and mechanical properties of polypropylene/wood‐flour composites

AbstractIn this research, polypropylene/wood‐flour composites (WPCs) were blended with different contents of wood and/or maleated polypropylene (MAPP) and clay. We found that the addition of MAPP or clay in the formulation greatly improved the dispersion of the wood fibers in the composite; this suggested that MAPP or clay may have played the role of an adhesion promoter in the WPCs. The results obtained with clay indicate that it also acted as a flame retardant. The thermal tests carried out with the produced samples showed an increased crystallization temperature (Tc), crystallinity, and melting temperature (Tm) with wood loading. The increase of the two former parameters was explained by the incorporation of wood flour, which played the role of nucleating agent and induced the crystallization of the matrix polymer. On the other hand, the Tm increase was ascribed to the insulating properties of wood, which hindered the movement of heat conduction. The effects of UV irradiation on Tm and Tc were also examined. Tc increased with UV exposure time; this implied that UV degradation generated short chains with low molecular weight that could move easily in the bulk of the sample and, thus, catalyze early crystallization. The flexural strength and modulus increased with increasing wood‐flour content. In contrast, the impact strength and tensile strength and strain decreased with increasing wood‐flour content. All of these changes were related to the level of dispersion of the wood flour in the polymeric matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Hybrid composites made from recycled materials: Moisture absorption and thickness swelling behavior

In this research, hybrid composite materials were made from the combination of recycled newspaper fiber (RNF) and poplar wood flour (PWF) as reinforcement, recycled polypropylene (RPP) as polymer matrix, and maleated polypropylene (MAPP) as coupling agent, by using injection molding. The effects of weight fractions of fibers and coupling agent concentration on the physical properties of the composites in terms of water absorption and thickness were studied. Composites containing more fraction of RNF exhibited maximum water absorption during the whole duration of immersion. This effect can be explained by the presence of a high amount of holocellulose present in the RNF, compared to the PWF. The addition of MAPP exhibited a beneficial effect on both the water absorption and thickness swelling by improving the quality of adhesion between polymer and fibers.

Cellulose/syndiotactic polypropylene composites: Effects of maleated polypropylene as a compatibilizer and silanized cellulose on the morphology and tensile properties

AbstractTo improve the interaction between syndiotactic polypropylene (SPP) and fibrous cellulose (FC), the effects of the addition of maleated polypropylene (MAPP) and FC surface modification with 3‐aminopropyltriethoxysilane (APTES) on SPP/FC composites were studied with respect to the morphology and the tensile properties. The addition of MAPP brought about an improvement in the interfacial adhesion between SPP and FC according to scanning electron microscopy observations and tensile testing. This improvement was, however, less effective than the improvement in the interfacial adhesion between isotactic polypropylene (IPP) and FC. SPP and MAPP partially or microscopically phase‐separated because of the IPP‐like polymer chain structure of MAPP. With respect to the compatibility between SPP and FC, FC surface modification with APTES was more suitable. The increase in Young's modulus was remarkable in the SPP/silanized FC composite with APTES. The tensile strength of the SPP/silanized FC composite with APTES was, however, considerably lower than that of the SPP/FC/MAPP composite. These results suggest that interfacial improvement between SPP and FC requires a compatibilizer or a surface modifier with a suitable primary structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Modification of Wood Flour Surfaces by Esterification with Acid Chlorides: Use in HDPE/Wood Flour Composites

Modification of wood fiber/flour (WF) surfaces can improve their compatibility with hydrophobic plastic matrices and reduce composite water uptake. WF was esterified with octanoyl chloride and palmitoyl chloride. Modified WF was analyzed by FT-IR. More extensive esterification occurred in highly polar dimethylformamide (DMF) than in much less polar CHCl3 or methyl tert-butyl ether (MTBE). DMF penetrates into the fiber far more than CHCl3 or MTBE, making more –OH groups available for esterification. Increasing the acid chloride chain length from C8 to C16 decreased the mole fraction of esterification. Longer chains cover surface –OH groups, retarding reactions with nearby hydroxyls after esterification. Longer chain acid chlorides also have lower reactivity and penetrate into the hydrophilic wood fiber more slowly. Modified wood flour surfaces were covered by a hydrophobic layer of ester groups (SEM). Modified wood flour surfaces and WF/HDPE composite fracture surfaces were studied by SEM. C8-modified wood flour (60 wt%)/HDPE composites exhibited far less water absorption after 24 h and 216 h immersions compared with unmodified WF (60 wt%)/HDPE composites. Water absorption continues over the 216 h period. Esterified WF/HDPE composites exhibited lower flexural strengths and moduli. In contrast to C8-esterification, the addition of maleated polypropylene (MAPP) to WF/HDPE composites improved composite mechanical performance and gave similar water absorption properties to C8-esterified WF composites.

Effects of Filler and Coupling Agent on the Properties of Bamboo Fiber-Reinforced Polypropylene Composites

Bamboo fiber (BF) filled polypropylene (PP) composites were manufactured by melt compounding and injection molding. The incorporation of BF to neat PP increased the decomposition temperatures of the composites compared to neat PP. The loading of BF to PP decreased the melting temperature, melting enthalpy, crystallization enthalpy, crystallization temperature, and crystallinity. Tensile modulus, impact resistance, and creep improved as BF loading increased. However, tensile strength and water desorption were decreased by the increase of BF loading. The addition of maleated polypropylene (MAPP) as a coupling agent increased the tensile strength and modulus. The melting enthalpy and crystallization enthalpy were decreased by the addition of MAPP. The loading of MAPP also improved the water desorption, impact resistance, and bamboo fiber dispersion into neat PP matrix, while lowering creep. There was no significant effect of MAPP on the thermal deformation and melting temperature of the composites. The melting enthalpy, crystallization temperature, crystallization enthalpy, and crystallinity were decreased by the addition of MAPP.

Thermal, mechanical and morphological properties of polypropylene/clay/wood flour nanocomposites

Nanocomposites with polypropylene/clay/wood flour were prepared by melt compounding. Thermal, mechani- cal and morphological properties were characterized. The addition of clay, compatibilizer and wood flour considerably improved the thermal stability (i.e., decomposition and melting temperatures) of the hybrids. The tensile modulus and strength of most hybrids were highly increased with the increased loading of clay, MAPP and wood flour, compared to the hybrids without wood flour. The wide angle X-ray diffraction (WAXD) patterns showed the increased d-spacing of clay layers, indicating enhanced compatibility between PP and clay with the addition of maleated polypropylene (MAPP). The transmission electron microscopy (TEM) photomicrographs illustrated the intercalated and partially exfoliated structures of the hybrids with clay, MAPP and wood flour.

Effect of coupling agents on the crystallinity and viscoelastic properties of composites of rice hull ash-filled polypropylene

This paper focuses on the application of silica rich, rice hull ash (RHA) from the rice industry as filler in polypropylene (PP). The dynamic rheological behaviour and the crystallinity of its composites with semi-amorphous polypropylene were used as performance indicators. The effect of coupling agents on RHA/PP compatibility was also investigated. Addition of RHA increased storage modulus (G′), and the onset (Tco) and peak (Tc) crystallinity temperatures, and decreased the degree of crystallinity of the system. Two coupling agents, maleated polypropylene (MAPP) and an amino functional silane, were used to improve the interfacial adhesion of RHA and PP. Addition of MAPP increased G′, Tc and Tco and the crystalline phase of the system. Addition of silane had mixed effects. It increased the rheological properties at higher concentrations, it increased Tc and Tco at all the concentrations and increased crystallinity at lower concentrations and decreased it at higher concentrations. Results from a thermogravimetric analyser were useful in revealing the mechanism by which silane bond to RHA and its effect on the rheology and crystallisation behaviour of the composites.

Effect of Moisture Absorption on the Tensile Properties of Steam-exploded Acacia mangium Fiber–Polypropylene osites

Polypropylene-filled alkali-extracted steam-exploded Acacia mangium fiber (AEF–PP) composites are immersed in water at room temperature for three months. All composites, including those with maleated polypropylene (MAPP) are found to absorb water considerably. The results of tensile properties indicate that the properties deteriorate following water absorption. The addition of MAPP to the composite systems (AEF–PP–MAPP) does not help in retaining the tensile properties. Scanning electron microscopy (SEM) examinations of the fracture surfaces of AEF–PP–MAPP composites reveal degradation of interfacial interaction. The composites, however, recover more than 90% of the tensile properties after oven treatment probably due to recovery of interfacial interaction as evident in scanning electron micrographs. The tensile properties recoveries for AEF–PP composites are fewer than for those with MAPP. Permanent damages in composite structures due to water absorption might account for this result.

Synthesis and characterization of polypropylene reinforced with cellulose I and II fibers

AbstractRecently, cellulose fiber–thermoplastic composites have played an important role in some applications. Plastics reinforced with cellulose and natural fibers have been widely studied. However, composites with regenerated cellulose have rarely been investigated. In this study, the lyocell fiber of Lenzing AG (cellulose II) and its raw material a bleached hardwood pulp (cellulose I) were used as reinforcement materials. The mechanical and thermal properties of polypropylene (PP) reinforced with pulp and lyocell fibers were characterized and compared with regard to the content of the fiber and the addition of maleated polypropylene (MAPP). PPs with cellulose I or II as a reinforcement material had similar mechanical properties. However, when MAPP was used as coupling agent, the mechanical properties of the composites were different. The crystallinity of the composites were determined by differential scanning calorimetry. Cellulose I (pulp) promoted the crystallization of PP, whereas cellulose II did not. MAPP reduced this effect in cellulose I fibers, but it induced crystallization when cellulose II (lyocell) was used as a reinforcement material. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 364–369, 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

Fracture toughness of modified polypropylene/poly(styrene‐ran‐butadiene) blends

AbstractFracture toughness of polypropylene (PP)/poly(styrene‐ran‐butadiene) rubber (SBR) blends as a function of concentration of maleic anhydride (MA) in the maleated polypropylene (MAPP) compatibilizer was investigated under uniaxial static and impact loading conditions. The addition of MAPP to the unmodified PP/rubber blend enhanced the tensile modulus and yield stress as well as the Charpy impact strength. The maximum values were recorded at 1.0 wt% grafted MA in the compatibilizer. V‐shaped blunt‐notched specimens exhibited typical ductile behavior and no breakage of the specimens occurred during the impact fracture tests. Sharp‐notched specimens of uncompatibilized and low‐content MA blends broke in a semibrittle manner, supported by a rapid crack propagation process. Increasing MA content in the blends led to semibrittle‐to‐ductile transition characterized by stable crack propagation. Fracture mechanics experiments, supplemented by scanning electron microscopy (SEM), were also employed to obtain a better understanding of the fracture and deformation behavior. Copyright © 2005 Society of Chemical Industry

Mechanical properties and morphology of impact modified polypropylene-wood flour composites

The mechanical properties and morphology of polypropylene/wood flour (PP/WF) composites with different impact modifiers and maleated polypropylene (MAPP) as a compatibilizer have been studied. Two different ethylene/propylene/diene terpolymers (EPDM) and one maleated styrene–ethylene/butylene–styrene triblock copolymer (SEBS–MA) have been used as impact modifiers in the PP/WF systems. All three elastomers increased the impact strength of the PP/WF composites but the addition of maleated EPDM and SEBS gave the greatest improvements in impact strength. Addition of MAPP did not affect the impact properties of the composites but had a positive effect on the composite unnotched impact strength when used together with elastomers. Tensile tests showed that MAPP had a negative effect on the elongation at break and a positive effect on tensile strength. The impact modifiers were found to decrease the stiffness of the composites. Scanning electron microscopy showed that maleated EPDM and SEBS had a stronger affinity for the wood surfaces than did the unmodified EPDM. The maleated elastomers are, therefore, expected to form a flexible interphase around the wood particles giving the composites better impact strength. MAPP further enhanced adhesion between WF and impact-modified PP systems. EPDM and EPDM–MA rubber domains were homogeneously dispersed in the PP matrix, the diameter of domains being between 0.1–1 μm. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1503–1513, 1998