Addition Of Maleic Anhydride Grafted Polypropylene Research Articles

Kenaf Fiber Reinforced Polypropylene Composites Fabricated by Injection Molding

Background: Natural fiber reinforced polymers are finding enormous applications in fields of automobile and house hold applications due to its distinct advantages over synthetic fiber reinforced polymer composites. In order to meet the escalation in demand of natural fiber reinforced composites, quick and versatile processing methods have to be adopted by the industry. Injection molding, being a promising method for this purpose has been chosen for the present study in order to reinforce short kenaf fibers into polypropylene. Methods: Kenaf fiber reinforced PP based composites having a fiber weight fraction of 30% were fabricated using injection molding process. Mechanical properties and fiber distribution of the developed composites were evaluated in comparison to neat polypropylene and maleic anhydride grafted polypropylene (MAPP). Mechanical properties in terms of flexural and tensile strength of the developed composites were evaluated in accordance to respective ASTM standards. Results: The flexural strength of PP/(30)K composite increased marginally, while the flexural strength of PP/(30)K/(5)MAPP composite was found to be significantly higher than both neat PP and PP/(30)K composite. Tensile strength of PP/(30)K composite is found to deteriorate with the addition of untreated short kenaf fibers. However, the addition of MAPP into the matrix improves the tensile strength of the developed composites. The flexural and tensile modulus of the developed composites also increased significantly compared to neat PP indicating increased stiffness of the developed composites. Morphological investigation of the developed composites revealed uniform distribution of short kenaf fibers throughout the composite and improved interfacial bonding in case of PP/(30)K/(5)MAPP composites resulting in better mechanical properties. Conclusion: Short kenaf fiber reinforced polypropylene composites having fiber weight fraction of 30% were successfully developed through injection molding process. Injection molding process for the fabrication of natural fiber reinforced composites is found to be a viable option and short kenaf fibers also have tremendous potential to be used as a reinforcement in natural fiber reinforced composites. Keywords: Injection molding, Kenaf fiber, maleic anhydride grafted PP, natural fiber composites, polypropylene.

New Multi-Scale Hybrid System Based on Maple Wood Flour and Nano Crystalline Cellulose: Morphological, Mechanical and Physical Study

In the first part of this work, composites based on polypropylene (PP) and maple wood flour (MF) were prepared by melt compounding using twin-screw extrusion followed by compression molding. The morphological and mechanical properties of the composites were analyzed for three samples: PP, MF/PP and MF/PP containing maleic anhydride grafted polypropylene (MAPP) as coupling agent. The results showed that MF/PP composites have improved mechanical properties, especially tensile modulus (+33 %), with only 8 % increase in density. The addition of MAPP further improved the mechanical properties, in particular tensile modulus (up to 51 %), which could be related to better fiber/matrix adhesion. In the second step, nano crystalline cellulose (NCC) was added to all samples to produce NCC-MF/PP hybrid composites. From the mechanical analysis performed, the hybrid composites with MAPP have improved properties, especially tensile (+53 %) and flexural (+40 %) moduli. These results confirmed that multi-scale hybrid NCC-MF composites can substantially improve the mechanical properties of polyolefins with limited increase in density (14 %) leading to high specific properties.

Impact of Surface Modification and Nanoparticle on Sisal Fiber Reinforced Polypropylene Nanocomposites

The use of plant fibers, polymer, and nanoparticles for composite has gained global attention, especially in the packaging, automobile, aviation, building, and construction industries. Nanocomposites materials are currently in use as a replacement for traditional materials due to their superior properties, such as high strength-to-weight ratio, cost effectiveness, and environmental friendliness. Sisal fiber (SF) was treated with 5% NaOH for 2 hours at 70°C. A mixed blend of sisal fiber and recycled polypropylene (rPP) was produced at four different fiber loadings: 10, 20, 30, and 40 wt.%, while nanoclay was added at 1, 3, and 5 wt.%. Maleic anhydride grafted polypropylene (MAPP) was used as the compatibilizer for all composites prepared except the untreated sisal fibers. The characterization results showed that the fiber treatment, addition of MAPP, and nanoclay improved the mechanical properties and thermal stability and reduced water absorption of the SF/rPP nanocomposites. The tensile strength, tensile modulus, and impact strength increased by 32.80, 37.62, and 5.48%, respectively, when compared to the untreated SF/rPP composites. Water absorption was reduced due to the treatment of fiber and the incorporation of MAPP and nanoclay.

Morphological, mechanical, and physical properties of composites made with wood flour-reinforced polypropylene/recycled poly(ethylene terephthalate) blends

Wood flour (WF)-filled composites based on a polypropylene (PP)/recycled polyethylene terephthalate (r-PET) matrix were prepared using two-step extrusion. Maleic anhydride grafted polypropylene (MAPP) was added to improve the compatibility between polymer matrices and WF. The effects of filler and MAPP compatibilization on the water absorption, mechanical properties, and morphological features of PP/r-PET/WF composites were investigated. The addition of MAPP significantly improved mechanical properties such as tensile strength, flexural strength, tensile modulus, and flexural modulus compared with uncompatibilized composites, but decreased elongation at break. Scanning electron microscopic images of fracture surface specimens revealed better interfacial interaction between WF and polymer matrix for MAPP-compatibilized PP/r-PET/WF composites. MAPP-compatibilized PP/r-PET/WF composites also showed reduced water absorption due to improved interfacial bonding, which limited the amount of absorbable water molecules. These results indicated that MAPP acts as an effective compatibilizer in PP/r-PET/WF composites. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Effect of Hot-Compressed Water Treatment of Bamboo Fiber on the Properties of Polypropylene/Bamboo Fiber Composite

A water-soluble fraction of bamboo ranging from 9.2 to 23.5 wt% was obtained by hot-compressed water (HCW) treatment as the temperature increased from 140 to 180 °C. Both untreated and HCW-treated bamboo fibers (BF) were then compounded with polypropylene (PP), either with or without the addition of 5 phr maleic anhydride-grafted PP (MAPP), to net a total BF content of 50, 30, or 10%. It was found that both the HCW treatment and the MAPP addition effectively improved the tensile properties of the composite. Furthermore, the re-compounding of 70/30 and 90/10 composites from a 50/50 master batch proved to be more effective in improving the tensile properties than the direct compounding of PP and non- or HCW-treated BF to the same composition.

Crystallisation and mechanical properties of poly(3-hydroxybutyrate-co-hydroxyvalerate)/polypropylene blends

Poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) was melt blended with polypropylene (PP) with maleic anhydride grafted PP (MPP) used as the reactive compatibiliser. The PHBV/PP (97·5/2·5) blend exhibited optimum elongation at break. Scanning electron microscopy exhibited that the PP phase was dispersed evenly within the PHBV matrix; a reduction in the domain size of the PP phase and plastic deformation of PP were observed with the addition of MPP. Differential scanning calorimetry studies showed that PP enhanced the crystallisation of PHBV, while MPP weakened it. Polarised optical microscopy results demonstrated that small spherulites of PP were effective PHBV nucleation agents, whereas MPP restrained the nucleation of PHBV. The results of tensile tests revealed that the elongation of the blends improved after the addition of MPP and increased with increasing concentration of MPP. The blend containing 2·5 wt-%PP with MPP content of 3 wt-% exhibited the best toughness, increasing 295·7% compared with pure PHBV.

Effect Maleic Anhydride Polypropylene on Properties of Calcium Carbonate Filled Polypropylene/Ethylene Propylene Diene Terpolymer Composites

Inorganic filler, calcium carbonate (CaCO3) was used as filler in the polypropylene (PP)/ ethylene propylene diene terpolymer (EPDM) composites. The composites were compatibilized with Maleic anhydride grafted polypropylene (MAPP) in order to improve the properties. The addition of CaCO3 at has increased the modulus of elasticity of composites but tensile strength and elongation at break of uncompatibilized composites decreased with increasing CaCO3. The result shows that the compatibilized composites higher tensile strength and Modulus of elasticity but lower elongation at break compared to uncompatibilized composites. At 10 wt% CaCO3 showed higher tensile strength of uncompatibiled and compatibilized composites. The morphology study from SEM analysis reveals that compatibilized composites show better interfacial adhesion between the filler and the matrix. The addition of MAPP has improved crystallinity of compatibilized composites.

Effect of fibre loading on mechanical and thermal properties of sisal and kenaf fibre-reinforced injection moulded composites

Kenaf and sisal fibres were selected for the development of natural fibre-reinforced thermoplastic composites because they are in abundance in South Africa. These materials can be used in the building industry, where good mechanical and fire resistance properties are required for structural and non-structural applications. High load bearing, moisture and fire can negatively affect the properties of these composites and decrease their performance. The effect of water glass, maleic anhydride-grafted-polypropylene (MAPP) treatment and fibre loadings on mechanical and thermal properties as well as fire resistance of kenaf and sisal fibre-reinforced polypropylene composites were investigated. The fibre-reinforced polypropylene composites were produced by injection and compression moulding processes. A significant improvement of the tensile strength and modulus of kenaf fibre composites was more pronounced when compared to sisal fibre composites. However, the water glass has a slight negative influence on mechanical properties of fibre/polypropylene matrix composites but showed better fire resistance and thermal properties when compared to the untreated fibre/polypropylene composites. Generally, the impact strength of fibre/polypropylene composites decreased with the addition of MAPP. The low impact strength could be the results of weak interfacial bond strength between the fibre and the matrix. The total heat release was reduced by water glass treatment due to the non-flammable polysilicate coating, while the average mass loss rate was slightly reduced by MAPP.

A comparative study of the effect of different rigid fillers on the fracture and failure behavior of polypropylene based composites

Polypropylene (PP) composites with 5wt% of different rigid particles (Al2O3 nanoparticles, SiO2 nanoparticles, Clay (Cloisite 20A) nanoparticles or CaCO3 microparticles) were obtained by melt mixing. Composites with different CaCO3 content were also prepared. The effect of fillers, filler content and addition of maleic anhydride grafted PP (MAPP) on the composites fracture and failure behavior was investigated. For PP/CaCO3 composites, an increasing trend of stiffness with filler loading was found while a decreasing trend of strength, ductility and fracture toughness was observed. The addition of MAPP was beneficial and detrimental to strength and ductility, respectively mainly as a result of improved interfacial adhesion. For the composites with 5wt% of CaCO3 or Al2O3, no significant changes in tensile properties were found due to the presence of agglomerated particles. However, the PP/CaCO3 composite exhibited the best tensile behavior: the highest ductility while keeping the strength and stiffness of neat PP. In general, the composites with SiO2 or Clay, on the other hand, displayed worse tensile strength and ductility. These behaviors could be probably related to the filler ability as nucleating agent. In addition, although the incorporation of MAPP led to improved filler dispersion, it was damaging to the material fracture behavior for the composites with CaCO3, Al2O3 or Clay, as a result of a higher interfacial adhesion, the retardant effect of MAPP on PP nucleation and the lower molecular weight of the PP/MAPP blend. The PP/MAPP/SiO2 composite, on the other hand, showed slightly increased toughness respect to the composite without MAPP due to the beneficial concomitant effects of the presence of some amount of the β crystalline phase of PP and the better filler dispersion promoted by the coupling agent which favor multiple crazing. From modeling of strength, the effect of MAPP on filler dispersion and interfacial adhesion in the PP/CaCO3 composites was confirmed.

3D X-ray microtomography study on fibre breakage in noil hemp fibre reinforced polypropylene composites

X-ray microtomography, image processing and Weibull statistical methods were used to characterize the length and width distributions of noil hemp fibres before and after composite fabrication. X-ray microtomography provided direct observations and accurate measurements of length and width of noil hemp fibres within the hemp–polypropylene composite matrix. The effects of the weight content of the noil hemp fibre and the addition of compatibilizer on the fibre breakage and tensile strength of the composites were studied. The results indicated that the tensile strength of the noil hemp fibre reinforced composites without the coupling agent was lower than that of pure polypropylene. Fibre–fibre interaction mechanism indicated that high hemp content caused more fibre breakage. The addition of maleic anhydride grafted polypropylene (MAPP) coupling agent improved the tensile strength of the composites by the enhanced fibre/matrix interfacial adhesion. The addition of MAPP also reduced the fibre breakage due to the better dispersion of fibres.

The Influence of AlkaliTreatment and Compatibilizer Addition on the Tensile Properties and Water Absorption Behavior of Polypropylene/Kenaf Fiber Composites

Composites of polypropylene (PP) and kenaf fiber (KF) were immersed in water at room temperature. The fiber was treated with alkaline solution. A compatibilizer, maleic anhydride-grafted polypropylene (MAPP) was added in some composite formulations. Composite with alkali treated fibers (KFA) showed similar tensile strength but lower tensile modulus than the composite with untreated fiber, KF. Addition of MAPP was crucial to improve the tensile properties and water resistance of either PP/KF or PP/KFA composites. Alkali treatment adversely affected the water absorption behavior of PP/KF composite.

Sunflower seed cake as reinforcing filler in thermoplastic composites

AbstractDimensional stability, mechanical properties, and melting and crystallization behavior of polypropylene composites filled with sunflower seed cake (SSC) were investigated. Injection molded composites were prepared from the SSC flour and polypropylene with and without maleic anhydride‐grafted polypropylene (MAPP) at 30, 40, 50, and 60 wt % contents of the SSC flour. Twenty‐eight days thickness swelling and water absorption values of the specimens increased by 43 and 56% as the filler content increased from 30 to 60 wt %, respectively. The flexural modulus of the polypropylene composites increased from 3157 to 4363 MPa as the SSC flour increased from 30 to 60 wt %. The maximum flexural strength 38.4 MPa was observed for 40 wt % SSC flour filled specimens. However, further increment in the SCC flour decreased the flexural strength to 31.4 MPa. The tensile strength of the specimens decreased from 22.5 to 14 MPa while the tensile modulus increased from 3023 to 3677 MPa as the SSC flour increased from 30 to 60 wt %. The dimensional stability and mechanical properties of the composites were significantly improved by the incorporation of the coupling agent (MAPP). The effect of the MAPP addition was more pronounced for the strength than for the modulus. The melting temperature and degree of crystallinity of the neat polypropylene decreased with increasing content of the SSC flour. The degree of crystallinity of filled composites considerably increased with the incorporation of the MAPP. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Dispersion of a novel phenolic rigid organic filler in isotactic polypropylene matrix by solution-mixing and melt-mixing

A novel phenolic rigid organic filler (named KD) with a high melting point was dispersed in an isotactic polypropylene (iPP) matrix by solution-mixing and/or melt-mixing. A series of KD/iPP blends was prepared with or without addition of maleic anhydride-grafted polypropylene (MAPP) as a compatibilizer. Influences of MAPP and mixing methods on the filler dispersion were studied using polaried optical microscope (POM), scanning electron microscope (SEM) and tensile test. The filler particles are always inclined to form large irregular aggregates in the iPP matrix due to their significant differences in polarity and solubility in solvent. However, an iPP/MAPP/KD (PMK) blend containing filler particles with a quasi-spherical shape (∼97.8 nm in diameter) and narrow particle size distribution (polydispersity index = 1.076) was successfully prepared by incorporating MAPP to reduce the interfacial tension and surface free energy between the dispersion phase and the continuous phase, and adopting a spray-drying method after solution-mixing to suppress the increase of the size of the dispersed phase during the removal of solvent.

Utilization of Microcrystalline Cellulose Prepared from Cotton Waste as Reinforcement in Polypropylene Composites

To obtain polypropylene/microcrystalline cellulose (PP/MCC) composites, PP was melt mixed with three loadings (5, 10 and 15 phr) of MCC prepared by hydrolyzing cotton waste with hydrochloric acid. The prepared MCC was characterized for its crystal structure, particle size, thermal stability and morphology. The tensile properties and thermal stability of PP/MCC composites with and without maleic anhydride-grafted polypropylene (MAPP) compatibilizer were investigated using the universal testing machine and thermogravimetric analyzer, respectively. The obtained results showed that the tensile strength, Young’s modulus and thermal stability of the composites were enhanced in a dose dependent manner, whilst the elongation at break was deteriorated with increasing MCC loadings, as compared with the neat PP. However, these properties were all improved with the addition of MAPP into the composites. This work showed that MCC and MAPP could be effectively used as reinforcing agent and compatibilizer, respectively in the PP matrix.

Effect of coupling agents on reinforcing potential of recycled carbon fibre for polypropylene composite

Polypropylene (PP) composites reinforced with recycled carbon fibre have been prepared through extrusion compounding and injection moulding. The reinforcing potential of the recycled fibre was increased by improving the interfacial adhesion between the fibre and PP matrix and this was done by the addition of maleic anhydride grafted polypropylene (MAPP) coupling agents. Three MAPP couplers with different molecular weights and maleic anhydride contents were considered. The effects on the mechanical properties of the composite were studied, and scanning electron microscopy (SEM) was used to study the fracture morphology of the tensile specimens. It was observed that with the addition of MAPP the interfacial adhesion was improved as fewer fibres were pulled-out and less debonding was seen. A microbond test was performed and a significant improvement in interfacial shear strength was measured. This resulted in composites with higher tensile and flexural strengths. The maximum strength was achieved from MAPP with the highest molecular weight. Increased modulus was also achieved with certain grades of MAPP. It was also found that the composite impact strength was improved significantly by MAPP, due to a higher compatibility between the fibre and matrix, which reduced crack initiation and propagation.

Viscoelastic and viscoplastic behavior of a fully recycled carbon fiber-reinforced maleic anhydride grafted polypropylene modified polypropylene composite

The effect of maleic anhydride grafted polypropylene (MAPP) coupling agents on properties of a new composite made of recycled carbon fibers and recycled polypropylene (rCF/[rPP + MAPP]) was studied experimentally. This new material presented significantly improved properties, compared to the previous generation, without the addition of MAPP (Giannadakis K, Szpieg M and Varna J. Mechanical performance of recycled carbon fibre/PP. Exp Mech 2010; published online.). This was mostly attributed to improvement of the fiber/matrix interface. The inelastic and time-dependent behavior of the MAPP modified composite material in tension was analyzed. A series of quasi-static tensile and creep tests were performed to identify the material model, which accounts for: (a) damage-related stiffness reduction, (b)development of stress and time-dependent irreversible strains described as viscoplasticity, (c) nonlinear viscoelastic behavior. The damage-related stiffness reduction was found to be less than 10%. Although damage-dependent stiffness was not the main source of nonlinearity, it was included in the inelastic material model. In creep tests, it was found that the time and stress dependence of viscoplastic strains follows a power law, which makes the determination of the parameters in the viscoplasticity model relatively simple. The viscoelastic response of the composite was found to be linear in the investigated stress domain. The material model was validated in constant stress rate tensile tests.

Melting and nonisothermal crystallization behavior of polypropylene/hemp fiber composites

Melting and nonisothermal crystallization behaviors of polypropylene (PP) and PP/hemp fibers (HFs) composites was investigated by differential scanning calorimetry (DSC) technique. The results show that the incorporation of HFs increases both the melting temperature ( Tm) and crystallization temperature ( Tc) of PP. Moreover, in comparison with PP/HF(70/30) composite, the addition of maleic anhydride-grafted PP (PP-MAH) results in a slight decrease in Tm but a significant increase in Tc of PP. The higher Tc of PP in the composites implies that HFs could act as nucleating agents for the crystallization of PP. Nonisothermal crystallization kinetics analysis was performed using Avrami and Mo models. The values of half-time ( t1/2) and rate constant indicate that the crystallization rate increases with the increasing of cooling rate for all the specimens. However, the crystallization rate of PP/HF(70/30) composite is found to be lower than that of PP at a certain cooling rate. Additionally, the composite containing PP-MAH has the lowest crystallization rate. Lower overall crystallization rate of PP/HF composites compared to PP is probably due to sufficiently high density of nuclei, which hinders the transport of PP molecular chains to crystal surface during nonisothermal crystallization. The crystallization activation energies (Δ E) determined by Kissinger method are 207.4 KJ/m2, 218.5 KJ/m2, and 220.4 kJ/m2 for PP, PP/HF(70/30), and PP/HF/PP-MAH(70/30/5), respectively.

Impact modification of poly(trimethylene terephthalate)/polypropylene blend nanocomposites: Fabrication and characterization

AbstractA poly(trimethylene terephthalate) (PTT)/polypropylene (PP) blend and the nanocomposites were prepared with and without the addition of a compatibilizer precursor [maleic anhydride grafted polypropylene (MAPP)]. A reactive route was used for the compatibilization with the addition of MAPP during melt blending in a batch mixer. Organically modified nanoclays were used as nanoscale reinforcements to prepare the blend nanocomposites. Mechanical tests revealed optimum performance characteristics at a PTT/PP blend ratio of 80 : 20. Furthermore, incorporation of nanoclays up to 3 wt % showed a higher impact strength and higher tensile strength and modulus in the blend nanocomposites compared to the optimized blend. The nanocomposite formation was established through X‐ray diffraction and transmission electron microscopy (TEM). Thermal measurements were carried out with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC thermograms revealed an increase in the crystallization temperature in the presence of the nanoclays in the blend system containing Cloisite 30B. TGA thermograms also indicated that the thermal stability of blend increased with the incorporation of Cloisite 30B. Furthermore, dynamic mechanical analysis measurements showed that the Cloisite 30B nanocomposite had the maximum modulus compared to other nanocomposites. TEM micrographs confirmed an intercalated morphology in the blend nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Flammability and mechanical properties of wood flour‐filled polypropylene composites

AbstractPolypropylene (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

Hybrid Composites from Waste Materials

Hybrid composites of thermoplastic biofiber reinforced with waste newspaper fiber (NF) and poplar wood flour (WF) were prepared. The weight ratio of the lignocellulosic materials to polymer was 30:70 (w:w). Polypropylene (PP) and maleic anhydride grafted polypropylene (MAPP) were also used as the polymer matrix and coupling agent, respectively. The mechanical properties, morphology and thermal properties were investigated. The obtained results showed that tensile and flexural modulus of the composites were significantly enhanced with addition of biofibers in both types (fiber and flour), as compared with pure PP. However, the increasing in WF content substantially reduced the tensile, flexural and impact modulus, but improved the thermal stability. This effect is explained by variations in fiber morphological properties and thermal degradation. Increasing fiber aspect ratio improved mechanical properties. The effect of fiber size on impact was minimal compared to the effects of fiber content. Scanning electron microscopy has shown that the composite, with coupling agent, promotes better fiber–matrix interaction. The largest improvement on the thermal stability of hybrid composites was achieved when WF was added more. In all cases, the degradation temperatures shifted to higher values after addition of MAPP. This work clearly showed that biofiber materials in both forms of fiber and flour could be effectively used as reinforcing elements in thermoplastic PP matrix.