Synthesis of a maleic anhydride grafted polypropylene–butadiene copolymer and its application in polypropylene/styrene–butadiene–styrene triblock copolymer/organophilic montmorillonite composites as a compatibilizer

A maleic anhydride grafted propylene–butadiene copolymer (MPPB) was prepared. Fourier transform infrared spectroscopy and ¹H‐NMR results indicate that the maleic anhydride molecules reacted with the double bond in the butadiene unit of the propylene–butadiene copolymer (PPB), and the grafting percentage increased with the butadiene content in the initial copolymer. The gel permeation chromatography results show that the introduction of butadiene in the copolymer prevented the degradation of PPB. The MPPB was applied in polypropylene (PP)/styrene‐butadiene‐styrene triblock copolymer (SBS)/organophilic montmorillonite (OMMT) composites as a compatibilizer. In the presence of 10‐phr MPPB, the impact strength of the composite was improved by about 20%. X‐ray diffraction patterns indicated the formation of the β‐phase crystallization of PP in the presence of MPPB, and a significant decrease in the spherulite size was observed. Transmission electron microscopy (TEM) images showed that the OMMT was better dispersed in the matrix upon the inclusion of MPPB. A better distribution of the rubber phase and a rugged fracture surface were observed in the scanning electron microscopy images as the MPPB proportion was increased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polypropylene/polypropylene‐grafted acrylic acid copolymer/ethylene–Acrylic acid copolymer ternary blends for hydrophilic polypropylene

Ternary blends of polypropylene (PP), a polypropylene‐grafted acrylic acid copolymer (PP‐g‐AA), and an ethylene–acrylic acid copolymer (EAA) were prepared by melt blending. The surfaces of films with different contents of these three components were characterized with contact‐angle measurements. Scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis were used to characterize the microstructure, melting and crystalline behavior, and thermal stability of the blends. The contact angles of the PP/PP‐g‐AA blends decreased monotonically with increasing PP‐g‐AA content. With the incorporation of EAA, the contact angles of the PP/PP‐g‐AA/EAA ternary blends decreased with increasing EAA content. When the concentration of EAA was higher than 15 wt %, the contact angles of the ternary blends began to increase. Scanning electron microscopy observations confirmed that PP‐g‐AA acted as a compatibilizer and improved the compatibility between PP and EAA in the ternary blends. Differential scanning calorimetry analysis suggested that acrylic acid moieties could act as nucleating agents for PP in the polymer blends. Thermogravimetric analysis and differential thermogravimetry confirmed the optimal blend ratio for the PP/PP‐g‐AA/EAA ternary blends was 70/15/15. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 436–442, 2006     

Properties of dynamically vulcanized ethylene–propylene–diene copolymer/polypropylene blends

In this study, vulcanized thermoplastic elastomers were produced through the formation of crosslinks with peroxide for different ratios of ethylene–propylene–diene copolymer to polypropylene. Mixing was performed with a twin‐screw extruder. Afterward, the yield, tensile strength, elastic modulus, elongation, Izod impact strength, hardness, melt flow index, Vicat softening point, heat deflection temperature, and density of the crosslinks were determined. The thermal transition temperatures and microstructure were determined with differential scanning calorimetry and scanning electron microscopy, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3895–3902, 2007     

Mechanical,thermal, and morphological properties of maleic anhydride‐g‐polypropylene compatibilized and chemically modified banana‐fiber‐reinforced polypropylene composites

Composites were prepared with chemically modified banana fibers in polypropylene (PP). The effects of 40‐mm fiber loading and resin modification on the physical, mechanical, thermal, and morphological properties of the composites were evaluated with scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Infrared (IR) spectroscopy, and so on. Maleic anhydride grafted polypropylene (MA‐g‐PP) compatibilizer was used to improve the fiber‐matrix adhesion. SEM studies carried out on fractured specimens indicated poor dispersion in the unmodified fiber composites and improved adhesion and uniform dispersion in the treated composites. A fiber loading of 15 vol % in the treated composites was optimum, with maximum mechanical properties and thermal stability evident. The composite with 5% MA‐g‐PP concentration at a 15% fiber volume showed an 80% increase in impact strength, a 48% increase in flexural strength, a 125% increase in flexural modulus, a 33% increase in tensile strength, and an 82% increase in tensile modulus, whereas the heat deflection temperature increased by 18°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of maleic anhydride grafted polypropylene on the mechanical and morphological properties of chemically modified short‐pineapple‐leaf‐fiber‐reinforced polypropylene composites

With the rising cost of petroleum‐based fibers, the utilization of plant fibers in the manufacture of polymer–matrix composites is gaining importance worldwide. The scope of this study was to examine the perspective of the use of pineapple leaf fibers (PALFs) as reinforcements for polypropylene (PP). These fibers are environmentally friendly, low‐cost byproducts of pineapple cultivation and are readily available in the northeastern region of India. Here, both untreated and treated pineapple fibers were used. Maleic anhydride grafted polypropylene (MA‐g‐PP) was used as a compatibilizing agent. The polymer matrix of PP was used to prepare composite specimens with different volume fractions (5–20%) of fibers by the addition of 5% of MA‐g‐PP. These specimens were tested for their mechanical properties, and additional assessments were made via observations by scanning electron microscopy, thermogravimetric analysis, and IR spectroscopy. Increase in the impact behavior, flexural properties, and tensile moduli of the composites were noticed, and these were more appreciable in the treated fibers mixed with MA‐g‐PP. PALF in 10 vol % in PP mixed with MA‐g‐PP was the optimum and recommended composition, where the flexural properties were the maximum. The impact strength and the tensile modulus were also considerably high. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of the delignification of wood fibers on the mechanical properties of wood fiber–polypropylene composites

The effect of the delignification of hornbeam fibers on the mechanical properties of wood fiber–polypropylene (PP) composites was studied. Original fibers and delignified fibers at three levels of delignification were mixed with PP at a weight ratio of 40:60 in an internal mixer. Maleic anhydride (0.5 wt %) as the coupling agent and dicumyl peroxide (0.1 wt %) as the initiator were applied. The produced composites were then hot‐pressed, and specimens for physical and mechanical testing were prepared. The results of the properties of the composite materials indicate that delignified fibers showed better performance in the enhancement of tensile strength and tensile modulus, whereas the hardness of the composites was unaffected by delignification. Delignified fibers also exhibited better water absorption resistance. Notched impact strength was higher for delignified fiber composites, but it was reduced at higher delignification levels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4759–4763, 2006     

Morphology,deformation behavior and thermomechanical properties of polypropylene/maleic anhydride grafted polypropylene/layered silicate nanocomposites

Nanocomposites polypropylene (PP) with 3 and 7 wt % of clay were prepared by melt mixing. Four types of maleic anhydride grafted PP (MAPP) in broad range of MA groups content (0.3–4 wt %) and molecular weights (MW) were used as polar compatibilizers. The effect of the MAPP kind on both the clay dispersion and miscibility with PP was studied. The mixed intercalated/exfoliated morphologies of nanocomposites in the presence of all studied compatibilizers were revealed by XRD and TEM. The oligomer compatibilizer with 4 wt % of MA groups increases the intercalation ability of polymer into clay galleries but this one has limited miscibility with PP and worsens crystalline structure of polymer matrix. The MAPPs with 0.3–1.3% of MA are characterized by the lower intercalation ability but well cocrystallize with PP. Maximum reinforcing effect is attained using high MW MAPP with 0.6% MA and for nanocomposite with 7 wt % (3.8 vol %) of clay it averages almost 1.7 times relative to neat PP and 1.3 times relative to noncompatibilized composite. Dynamic storage moduli of nanocomposites compatibilized by MAPPs with 0.3–1.3% of MA containing 7 wt % of clay increase up to 1.4–1.5 around 30–75°C and over the whole temperature range remain higher compared with both neat PP and uncompatibilized composite. On the contrary, the oligomer MAPP with 4 wt % of MA groups decreases the thermal–mechanical stability of nanocomposite at high temperature compared with both PP and uncompatibilized composites. The study of nanocomposites flammability showed that creating complex composites containing both layered silicate and relatively small amount of magnesium hydroxide can be a successful approach to reduce the combustibility of PP‐based nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of oxidized polypropylene as a new compatibilizer on the water absorption and mechanical properties of wood flour–polypropylene composites

The effect of oxidized polypropylene (OPP) as new compatibilizer on the water absorption and mechanical properties of wood flour–polypropylene (PP) composites were studied and compared with maleic anhydride grafted polypropylene (MAPP). The oxidation of PP was performed in the molten state in the presence of air. Wood flour, PP, and the compatibilizers (OPP and MAPP) were mixed in an internal mixer at temperature of 190°C. The amorphous composites removed from the mixer were then pressed into plates that had a nominal thickness of 2 mm and nominal dimensions of 15 × 15 cm² with a laboratory hydraulic hot press at 190°C. Physical and mechanical tests showed that the wood flour–PP composites with OPP exhibited higher flexural and impact properties but lower water absorption than MAPP. All of the composites with 2% compatibilizers (OPP and MAPP) gave higher flexural and impact properties and lower water absorption compared to those with 4% compatibilizers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Production of polymeric membranes made of polypropylene,poly(ethylene‐co‐vinyl acetate), and poly(vinyl alcohol)

In this study, we prepared and characterized membranes containing polypropylene, poly(ethylene‐co‐vinyl acetate) (EVA), and poly(vinyl alcohol) (PVA). The production process involved blend extrusion and calendering followed by solvent extraction by toluene and water of the EVA and PVA phases. Morphology studies involving scanning electron microscopy determined the pore size distribution at the surface and in the internal regions of the membrane. The resulting membrane properties were related to the processing variables (extension rate, process temperature, and solvent extraction methods) and blend composition. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3275–3286, 2004     

Use of a sodium ionomer as a compatibilizer in polypropylene/high‐barrier ethylene–vinyl alcohol copolymer blends: The processability of the blends and their physical properties

The effect of a sodium ionomer (ion.Na⁺) on the compatibility of polypropylene (PP)/high‐barrier ethylene–vinyl alcohol copolymer (EVOH) blends was studied in terms of the thermal, mechanical, and optical properties and morphology. The rheological behavior, tensile tests, and morphology of the binary blends showed that the miscibility of EVOH with PP was very poor. The miscibility of the polymers improved with the ionomer addition. In general, the ion.Na⁺ concentration did not alter the thermal behavior of the blends, but it did improve the ductility of the injection‐molded specimens. Scanning electron micrographs displayed better adhesion between the PP and EVOH phases in the samples with the ionomer. The mechanical improvement was better in the film samples than in the injection‐molded samples. A 90/10 (w/w) PP/EVOH film with 5% ion.Na⁺ and an 80/20 (w/w) PP/EVOH film with 10% ion.Na⁺ presented better global properties than the other blends studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1763–1770, 2004     

Influence of ethylene vinyl acetate on the spinnability and mechanical properties of poly(propylene)/zeolite‐Ag blend fibers

The spinnability and mechanical properties of poly(propylene) (PP)/zeolite‐supported Ag⁺ (zeolite‐Ag)/ethylene vinyl acetate (EVA) ternary blend fibers were studied. It was found that the spinning temperature of the ternary blend fibers was decreased in the presence of EVA. The addition of 2 wt % EVA substantially improved the spinnability of the blend system by enhancing its flowability. It was also found that the ternary fiber with EVA₂₈ (28 wt % vinyl acetate content) showed balanced improvement of mechanical properties by a concomitant increase in modulus and tensile strength. The improvements of spinnability and mechanical properties suggested that a core–shell structure of zeolite‐Ag/EVA₂₈ particles, with zeolite‐Ag as the core and EVA₂₈ as the shell, was formed and remained during the melt‐mixing process of the blended chips and during the course of fiber processing. EVA probably enhanced the binding between the zeolite‐Ag and the PP matrix, as made evident in SEM microphotographs. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1460–1466, 2005     

Influence of the ethylene–(methacrylic acid)–Zn2+ ionomer on the thermal and mechanical properties of blends of poly(propylene) (PP)/ethylene–(vinyl alcohol) copolymer (EVOH)

The thermal and mechanical properties and the morphologies of blends of poly(propylene) (PP) and an ethylene–(vinyl alcohol) copolymer (EVOH) and of blends of PP/EVOH/ethylene–(methacrylic acid)–Zn²⁺ ionomer were studied to establish the influence of the ionomer addition on the compatibilization of PP/EVOH blends and on their properties. The oxygen transmission rate (O₂TR) values of the blends were measured as well. PP and EVOH are initially incompatible as was determined by tensile tests and scanning electronic microscopy. Addition of the ionomer Zn²⁺ led to good compatibility and mechanical behaviour was improved in all blends. The mechanical properties on extruded films were studied for 90/10 and 80/20 w/w PP/EVOH blends compatibilized with 10 % of ionomer Zn²⁺. These experiments have shown that the tensile properties are better than in the injection‐moulded samples. The stretching during the extrusion improved the compatibility of the blends, diminishing the size of EVOH domains and enhancing their distribution in the PP matrix. As was to be expected, the EVOH improved the oxygen permeation of the films, even in compatibilized blends. Copyright © 2004 Society of Chemical Industry     

Mechanical and thermal properties of talc and calcium carbonate filled polypropylene hybrid composites

The main aim of this work was to study and compare the mechanical and thermal properties of hybrid polypropylene (PP) composites and single‐filler PP composites. With two main types of mineral fillers—calcium carbonate (CaCO₃) and talc—PP composites of different filler weight ratios (talc/CaCO₃) were compounded with a twin‐screw extruder and then injection‐molded into dumbbell specimens with an injection‐molding machine. Tensile, flexural, and impact tests were performed to determine and compare the mechanical properties of the hybrid and single‐filler PP composites. A synergistic hybridization effect was successfully achieved; the flexural strength and impact strength were highest among the hybrids when the PP/talc/CaCO₃ weight ratio was 70:15:15. The nucleating ability of the fillers and its effects on the mechanical properties were also studied with differential scanning calorimetry. Because of the influence of talc as the main nucleating agent, the hybrid fillers showed significant improvements in terms of the nucleating ability, and this contributed to the increase in or retention of the mechanical properties of the hybrid composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3327–3336, 2004     

Flammability and mechanical properties of wood flour‐filled polypropylene composites

Polypropylene (PP) composites filled with wood flour (WF) were prepared with a twin‐screw extruder and an injection‐molding machine. Three types of ecologically friendly flame retardants (FRs) based on ammonium polyphosphate were used to improve the FR properties of the composites. The flame retardancy of the PP/WF composites was characterized with thermogravimetric analysis (TGA), vertical burn testing (UL94‐V), and limiting oxygen index (LOI) measurements. The TGA data showed that all three types of FRs could enhance the thermal stability of the PP/WF/FR systems at high temperatures and effectively increase the char residue formation. The FRs could effectively reduce the flammability of the PP/WF/FR composites by achieving V‐0 UL94‐V classification. The increased LOI also showed that the flammability of the PP/WF/FR composites was reduced with the addition of FRs. The mechanical property study revealed that, with the incorporation of FRs, the tensile strength and flexural strength were decreased, but the tensile and flexural moduli were increased in all cases. The presence of maleic anhydride grafted polypropylene (MAPP) resulted in an improvement of the filler–matrix bonding between the WF/intumescent FR and PP, and this consequently enhanced the overall mechanical properties of the composites. Morphological studies carried out with scanning electron microscopy revealed clear evidence that the adhesion at the interfacial region was enhanced with the addition of MAPP to the PP/WF/FR composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Maleic anhydride grafted polypropylene as a coupling agent for polypropylene composites filled with ink‐eliminated waste paper sludge flour

Ink‐eliminated sludge flour (IESF), a waste residue from the recycling treatment of waste paper, is a promising new kind of filler for thermoplastic polymers with a good price/performance ratio and advantages for environmental protection. In this study, high‐impact polypropylene (PP) and maleic anhydride grafted polypropylene (MAPP) were chosen as a polymer matrix and a coupling agent, respectively, for the preparation of IESF/PP composites, and the structures and properties of the obtained composites were also investigated. The experimental results revealed that IESF not only induced the crystallization orientation of PP along the b axis but also had a restraining effect on the formation of the β phase during the recrystallization of PP from the melt; the addition of MAPP further strengthened this effect to some extent. In addition, the proper addition of MAPP was helpful for improving the thermal stability of the IESF/PP composites. With the strengthening of the interfacial interaction between the IESF and PP matrix by MAPP, the resultant efficient stress transfer from the PP matrix to the IESF particles led to increased tensile and flexural strength. However, the original greater rigidity of MAPP, with respect to PP, reduced the toughness of the composites and caused some negative effects on the impact strength and the elongation at break. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2320–2325, 2004     

Maleic anhydride grafted thermoplastic elastomer as an interfacial modifier for polypropylene/polyamide 6 blends

A maleic anhydride grafted thermoplastic elastomer (TPE_g) was prepared. The effect of the TPE_g on the morphology and performance of polypropylene (PP)/polyamide 6 (PA‐6) blends was studied. The final properties of the blends were tuned through variations in the TPE_g/PA‐6 ratios and TPE_g and PA‐6 percentages in the blends. Scanning electron micrographs showed that the TPE_g greatly improved the homogeneity of the blends, and this led to better mechanical performance. The nonisothermal crystallization behaviors of PP and PA‐6 in the blends, revealed by differential scanning calorimetry, were different from those of pure PP and PA‐6. The crystallization temperature and rate of PP were promoted by the PA‐6 component because of its nucleating effect, whereas stepwise crystallization was detected for PA‐6 in the PP/PA‐6 blends when the TPE_g was added. On the basis of these observations, a schematic model was proposed for these blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1806–1815, 2004     

Processing and mechanical properties of organic filler–polypropylene composites

The addition of organic fillers into thermoplastic polymers is an interesting issue, which has had growing consideration and experimentation during the last years. It can give rise to several advantages. First, the cost of these fillers is usually very low. Also, the organic fillers are biodegradable (thus contributing to an improved environmental impact), and finally, some mechanical and thermomechanical properties can be enhanced. In this study, the effect of the addition of different organic fillers on the mechanical properties and processability of an extrusion‐grade polypropylene were investigated. The organic fillers came from natural sources (wood, kenaf, and sago) and were compared to short glass fibers, a widely used inorganic filler. The organic fillers caused enhancements in the rigidity and thermomechanical resistance of the matrix in a way that was rather similar to the one observed for the inorganic filler. A reduction in impact strength was observed for both types of fillers. The use of an adhesion promoter could improve their behavior. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1906–1913, 2005     

Modification of oil palm empty fruit bunches with maleic anhydride: The effect on the tensile and dimensional stability properties of empty fruit bunch/polypropylene composites

Oil palm empty fruit bunch (EFB)‐filled polypropylene (PP) composites were produced. The EFB filler was chemically modified with maleic anhydride (MAH). The effects of the filler size and chemical modification of EFBs on the tensile and dimensional stability properties of EFB–PP composites were studied. The composites with MAH‐treated EFBs showed higher tensile strengths than those with untreated EFBs. This was attributed to the enhanced compatibility between the MAH‐treated EFBs and PP matrix, as shown in a scanning electron microscopy study. Fourier transform infrared analysis showed evidence of C?C and C?O bonds from MAH at 1630 and 1730 cm^?1, respectively. The MAH‐treated PP composites showed lower water absorption and thickness swelling than those with untreated EFBs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 827–835, 2003     

Preparation and characterization of polypropylene/clay nanocomposites with polypropylene‐graft‐maleic anhydride

Polypropylene (PP)/montmorillonite (MMT) nanocomposites were prepared by the esterification of propylene‐g‐maleic anhydride (MAPP) with MMT modified with α,ω‐hydroxyamines. The structural characterization confirmed the formation of ester linkages and the interaction between the silicate layers. In particular, X‐ray diffraction patterns of the modified clays and MAPP/MMT composites showed 001 basal spacing enlargement as great as 0.14–0.62 nm according to the type of α,ω‐hydroxyamine. Thermal characterization by thermogravimetric analysis for the composites revealed increased onset temperatures of thermal decomposition. The melting peak temperature decreased, and the crystallization peak temperature increased; this indicated that MMT retarded the crystallization of MAPP. Compounding PP with MAPP/MMT composites enhanced the tensile modulus and tensile strength of PP. However, the elongation at break decreased drastically even when the MMT content was as low as 0.4–2.0 wt %. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1229–1234, 2005     

Mechanical and thermal properties of toughened polypropylene composites

The mechanical, thermal, and structural properties of a new flexible composite containing polypropylene fiber (PP) in a random poly(propylene‐co‐ethylene) (PPE) matrix with ethylene–propylene elastomer (EP) was investigated with emphasis on the effect of EP elastomer concentration. The intrinsic composition of the composites, toughening of the matrix with EP and the fiber–matrix interface determined the properties of the composites. Through the incorporation of EP elastomer into the polypropylene–poly (propylene‐co‐ethylene) (all‐PP) composite, tensile and storage modulus (E′) decreased, flexural modulus and loss modulus (E″, damping) increased slightly to 0.15 EP and then decreased. There was an increase in impact resistance for the toughened composites, with about 100% increase in comparison with an untoughened all‐PP composite. The composition corresponding to 0.20 weight fraction EP gave optimum impact and mechanical properties. Creep resistance of the composite decreased with increasing EP content, but recovery showed an increase with increasing EP content up to 0.20. Fracture surfaces of composites after impact tests were studied with scanning electron microscopy. Moreover, the use and limitation of theoretical equations to predict the tensile and flexural modulus of the flexible PP composite is discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007