Maleic Anhydride Groups Research Articles

Dielectric Study of Molecular Mobility in Poly(propylene-graft-maleic anhydride)/Clay Nanocomposites

Polymer/clay nanocomposite materials based on poly(propylene-graft-maleic anhydride) (PPgMAH) and two different organophilic modified clays were investigated by dielectric relaxation spectroscopy (DRS). In contrast to ungrafted polypropylene (PP), PPgMAH shows a dielectrically active relaxation process which can be assigned to localized fluctuations of the polar maleic anhydride groups. Its relaxation rate exhibits an unusual temperature dependence, which could be attributed to a redistribution of water molecules in the polymeric matrix. This is confirmed by a combination of Raman spectroscopy and thermogravimetric experiments (TGA) with real-time dielectric measurements under controlled atmospheres. In the nanocomposites this relaxation process is shifted to higher frequencies up to 3 orders of magnitude compared to the unfilled polymer. This indicates a significantly enhanced molecular mobility in the interfacial regions. In the nanocomposite materials a separate high-temperature process due to Maxwell−...

Filler-Induced Structural Order and Mechanical Properties of Polystyrene-Silica Nanocomposites

This study is concerned with the relationship between wide angle X-ray scattering (WAXS) analysis and physical properties of amorphous polystyrene (PS)-silica (SiO2) composites. Nanoporous SiO2 for the fillers was prepared by the hydrothermal reaction and the structures of the composites were examined by WAXS. In their WAXS patterns, two characteristic peaks, inner peak and outer peak, were observed at q ≈ 7 nm−1 and 15 nm−1 corresponding to the intermolecular structure of PS chains and the intramolecular order of benzene rings, respectively. The ratio (Iin⁄Iout=P) in intensity of the inner peak (Iin) to outer peak (Iout) affords the structural parameter to well characterize the intermolecular and intramolecular structures of PS molecules and the P values are observed to change widely from 0.183 to 1.16 depending on the material compositions. The elongation at the break point increases monotonously with increasing P, whereas the yield strength and the Young's modulus decrease with P for P=0.497 or below but remain almost constant for larger P values. The elongation of 4.5% for (PS+MPS) / SiO2 is enormously larger than those for PS and the other composites, in contrast to a slight decrease of the other two properties relative to those for PS. It is also revealed that a strong interaction works between the COO or COOH groups of maleic anhydride modified polystyrene (MPS) and the OH groups of SiO2, which makes the PS polymer molecules to stack regularly on SiO2 nanofillers, leading to control the physical properties of the composites.

Side Chain Extension of Maleated Polypropylene with Diamine

Abstract In this study melt reaction of maleated polypropylene (PP-g-MA) with hexamethylene diamine (HMDA) and poly(propylene glycol)-bis-(2-propylamine) (Jeffamine D-400) was carried out. Three kinds of PP-g-MA (Polybond 3002, Polybond 3150 and Polybond 3200) having different maleic anhydride content of 0.2, 0.5, 1.0 wt.% respectively were used. FTIR spectra show that branches and crosslinks were formed through the formation of amide and imide linkages between maleic anhydride group and diamine, and titration results show that the reactivity of HMDA to maleic anhydride group is higher than that of Jeffamine D-400. For Polybond 3002, increases in melt index and decreases in molecular weight was found after reaction as a result of chain degradation. Hence increases in viscosity and moduli were not found in reacted Polybond 3002. Polybond 3150 and Polybond 3200 with higher MA content shows increase in molecular weight after reaction, and gels were detected when high concentration of HMDA was reacted. Increases in shear viscosities and modulus were observed in Polybond 3150 and Polybond 3200. In elongational viscosity measurement, when higher concentration of HMDA used, strain hardening was observed in Polybond 3150 and Polybond 3200.

Thermal behavior and intermolecular interactions in blends of poly(3‐hydroxybutyrate) and maleated poly(3‐hydroxybutyrate) with chitosan

AbstractThe thermal behavior and intermolecular interactions of blends of poly(3‐hydroxybutyrate) (PHB) and maleated PHB with chitosan were studied with differential scanning calorimetry, Fourier transform infrared (FTIR), wide‐angle X‐ray diffraction (WAXD), and X‐ray photoelectron spectroscopy (XPS). The differences in the two blend systems with respect to their thermal behavior and intermolecular interactions were investigated. The melting temperatures, melting enthalpies, and crystallinities of the two blend systems gradually decreased as the chitosan content in the blends increased. Compared with that of the PHB component with the same composition, the crystallization of the maleated PHB component was more intensively suppressed by the chitosan component in the blends because of the rigid chitosan molecular chains and the intermolecular hydrogen bonds between the components. FTIR, WAXD, and XPS showed that the intermolecular hydrogen bonds in the blends were caused by the carbonyls of PHB or maleated PHB and chitosan aminos, and their existence depended on the compositions of the blends. The introduction of maleic anhydride groups onto PHB chains promoted intermolecular interactions between the maleated PHB and chitosan components. In addition, the intermolecular interactions disturbed the original crystal structures of the PHB, maleated PHB, and chitosan components; this was further proven by WAXD results. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 35–47, 2005

Phase morphology development and stabilization in polycyclohexylmethacrylate/polypropylene blends: uncompatibilized and reactively compatibilized blends using two reactive precursors

The phase morphology developed in immiscible polypropylene (PP)/polycyclohexylmethacrylate (PCHMA) blends has been studied using an in situ reactively generated polystyrene-graft-polypropylene compatibilizer from maleic anhydride grafted polypropylene (MA- g-PP) and amine end-capped polystyrene (PS-NH2) reactive precursors during melt-blending. The imidation reaction responsible for the formation of the compatibilizer is similar to the reaction occurring in polyamide/MA-PP (MA-EPR or MA-EPDM) blends which are industrially important. In the present blend PP/PCHMA/(PP-MA-PS-NH2), no undesired reaction occurs between the maleic anhydride groups and the backbone of the PCHMA chain, as is usually the case with polyamide homopolymer. This type of reaction, although considered non significant, has consequences on the phase morphology development as it affects the viscosity of the polyamide matrix when chain scission takes place. PP/PCHMA blends covering the whole range of compositions were prepared. The composition window at which the blends exhibit a droplet-in-matrix phase morphology and that where the two phases are co-continuous were determined using a selective phase extraction in combination with scanning electron microscopy. The generation in situ of the PP- g-PS compatibilizer substantially changed the state of the phase morphology developed. In the blends having a droplet-in-matrix type of morphology, the particle sizes were significantly reduced (by a factor of more than 10). Two types of MA- g-PP reactive copolymers differing in maleic anhydride content (1 and 8 wt%) have been separately employed with the same grade of PS-NH2. Emphasis was put on a detailed investigation of the behaviour and structural stability of the blends exhibiting a co-continuous phase morphology when the compatibilizer is generated. Significant differences were found in relation to the maleic anhydride content of the MA-PP reactive compatibilizer precursor.

Grafting of maleic anhydride onto linear polyethylene: A Monte Carlo study

AbstractMonte Carlo simulation was used to study the graft of maleic anhydride (MAH) onto linear polyethylene (PE‐g‐MAH) initiated by dicumyl peroxide (DCP). Simulation results revealed that major MAH monomers attached onto PE chains as branched graft at higher MAH content. However, at extremely low MAH content, the fraction of bridged graft was very close to that of branched graft. This conclusion was somewhat different from the conventional viewpoint, namely, the fraction of bridged graft was always much lower than that of branched graft under any condition. Moreover, the results indicated that the grafting degree increased almost linearly to MAH and DCP concentrations. On the other hand, it was found that the amount of grafted MAH dropped sharply with increasing the length of grafted MAH, indicating that MAH monomers were mainly attached onto the PE chain as single MAH groups or very short oligomers. With respect to the crosslink of PE, the results showed that the fraction of PE‐(MAH)n‐PE crosslink structure increased continuously, and hence the fraction of PE‐PE crosslink decreased with increasing MAH concentration. Finally, quantitative relationship among number average molecular weight of the PE, MAH, and DCP contents was given. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5714–5724, 2004

Polypropylene/graphite nanocomposites by thermo‐kinetic mixing

AbstractPolypropylene (PP)/graphite nanocomposites have been prepared by melt‐mixing PP with different levels of graphite (G) and graphite oxide (GO) using maleated PP(PP‐g‐MA) and graphite oxide (GO) as interface modifiers. Melt‐mixing was achieved using a Gelimat, a high‐speed thermo‐kinetic mixer. The Gelimat system is specifically designed to handle difficult compounding and dispersion applications by completely mixing, heating and compounding products within a few minutes. Therefore, the thermal history of the compounded polymer is very short, which limits degradation. Interfacial modification by addition of maleated PP and graphite oxide is essential for producing PP/G nanocomposite. The graphite oxide then interacts with the maleic anhydride group of the PP‐g‐MA. The structure and properties of PP/PP‐g‐MA/GO/G nanocomposites were compared by different techniques. Evidence of the nanoscale dispersion of graphite sheets within the PP were provided by wide‐angle X‐ray diffraction (WAXD) and supported by scanning electron microscopy (SEM). The high mechanical shear stresses generated by the Gelimat greatly reduced the ordering initially measured by WAXD between graphite sheets and sheet aggregates, indicating a dispersion of the graphite in the polymer to the extent that graphite particles could hardly be observed by SEM. It was found that the addition of PP‐g‐MA and GO leads to excellent dispersion of G within the PP matrix. The flow behavior of the material was also studied by means of a parallel‐plate rheometer. The addition of graphite to PP caused a drastic change in the flow behavior of PP. The thermal degradation behavior, studied using thermogravimetric analysis (TGA), showed higher thermal stability of the nanocomposite than that of pure polypropylene. The dispersion of the graphite in the resin promoted the nucleation of β crystallites in PP. The β crystallites, normally less abundant than α crystallites in pure PP, were found to constitute the dominant phase in the nanocomposite. Polym. Eng. Sci. 44:1162–1169, 2004. © 2004 Society of Plastics Engineers.

Silicate layer exfoliation in polyolefin/clay nanocomposites based on maleic anhydride modified polyolefins and organophilic clay

AbstractSilicate layer exfoliation processes in maleic anhydride (MA) modified polyolefins were studied by using X‐ray diffraction measurements, scanning electron microscopy, and transmission electron microscopy observations. Modified polyolefins grafted with 0.09–4.5 wt % MA groups intercalate into the organophilic clay galleries modified with stearyl ammonium ions. Molten MA‐modified polypropylene continuously intercalates into the galleries and the silicate layers exfoliate spontaneously without shear. However, the silicate layers maintain arranging parallel together, although the interlayer spacing expands over 10 nm. By adding shear, the silicate layers homogeneously disperse into MA‐modified polypropylene matrix. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 464–470, 2004

Influence of Modifiers on the Physicomechanical Properties of Sawdust-Polyethylene Composites

Polymer-wood composites based on recycled polyethylene (RPE) are investigated. Dispersed alder sawdust was utilized as a filler. To improve the compatibility between the nonpolar matrix and the polar wood fibers as a reinforcement, two types of modifiers were used, which differed in their chemical nature and mechanical interaction with the constituents of the composites. The modifiers of the first type (paraffin and OP) improved the dispersibility of sawdust (SD), and those of the second type (Exxelor 1015 and OREVAC) contained groups of maleic anhydride, which interacted with the OH-groups of SD. The effect of the modifiers on the moisture sorption by SD, the dispersibility of the filler in the matrix, and the strength characteristics (ultimate strengths and moduli in tension and bending) of dry and moist RPE–SD composites and on their moisture sorption is estimated. The best results were obtained for the composites modified with paraffin, which is due to the more efficient employment of the strength and rigidity of well-dispersed SD fibers. In their strength characteristics, the RPE-based composites investigated are comparable to composites based on low-density polyethylene.

Dynamically cured polypropylene/epoxy blends

AbstractThe dynamic vulcanization process, usually used for the preparation of thermoplastic elastomers, was used to prepare polypropylene (PP)/epoxy blends. The blends had crosslinked epoxy resin particles finely dispersed in the PP matrix, and they were called dynamically cured PP/epoxy blends. Maleic anhydride grafted polypropylene (MAH‐g‐PP) was used as a compatibilizer. The effects of the reactive compatibilization and dynamic cure were studied with rheometry, capillary rheometry, and scanning electron microscopy (SEM). The crystallization behavior and mechanical properties of PP/epoxy, PP/MAH‐g‐PP/epoxy, and dynamically cured PP/epoxy blends were also investigated. The increase in the torque at equilibrium for the PP/MAH‐g‐PP/epoxy blends indicated the reaction between maleic anhydride groups of MAH‐g‐PP and the epoxy resin. The torque at equilibrium of the dynamically cured PP/epoxy blends increased with increasing epoxy resin content. Capillary rheological measurements also showed that the addition of MAH‐g‐PP or an increasing epoxy resin content increased the viscosity of PP/epoxy blends. SEM micrographs indicated that the PP/epoxy blends compatibilized with PP/MAH‐g‐PP had finer domains and more obscure boundaries than the PP/epoxy blends. A shift of the crystallization peak to a higher temperature for all the PP/epoxy blends indicated that uncured and cured epoxy resin particles in the blends could act as effective nucleating agents. The spherulites of pure PP were larger than those of PP in the PP/epoxy, PP/MAH‐g‐PP/epoxy, and dynamically cured PP/epoxy blends, as measured by polarized optical microscopy. The dynamically cured PP/epoxy blends had better mechanical properties than the PP/epoxy and PP/MAH‐g‐PP/epoxy blends. With increasing epoxy resin content, the flexural modulus of all the blends increased significantly, and the impact strength and tensile strength increased slightly, whereas the elongation at break decreased dramatically. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1437–1448, 2004

Melt rheology and morphology of uncompatibilized and in situ compatibilized nylon‐6/ethylene propylene rubber blends

AbstractMelt rheology and morphology of nylon‐6/ethylene propylene rubber (EPR) blends were studied as a function of composition, temperature, and compatibilizer loading. Uncompatibilized blends with higher nylon‐6 content (N90 and N95) and rubber content (N5 and N10) had viscosities approximately intermediate between those of the component polymers. A very clear negative deviation was observed in the viscosity–composition curve over the entire shear rate range studied for blends having composition N30, N50, and N70. This was associated with the interlayer slip resulting from the high‐level incompatibility between the component polymers. The lack of compatibility was confirmed by fracture surface morphology, given that the dispersed domains showed no sign of adhesion to the matrix. The phase morphology studies indicated that EPR was dispersed as spherical inclusions in the nylon matrix up to 30 wt % of its concentration. A cocontinuous morphology was observed between 30 and 50 wt % nylon and a phase inversion beyond 70 wt % nylon. Various models based on viscosity ratios were used to predict the region of phase inversion. Experiments were also carried out on in situ compatibilization using maleic anhydride–modified EPR (EPR‐g‐MA). In this reactive compatibilization strategy, the maleic anhydride groups of modified EPR reacted with the amino end groups of nylon. This reaction produced a graft copolymer at the blend interface, which in fact acted as the compatibilizer. The viscosity of the blend was found to increase when a few percent of modified EPR was added; at higher concentrations the viscosity leveled off, indicating a high level of interaction at the interface. Morphological investigations indicated that the size of the dispersed phase initially decreased when a few percent of the graft copolymer was added followed by a clear leveling off at higher concentration. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 252–264, 2004

Cytochrome-C release in hepatocellular carcinoma cell apoptosis induced by cyclooxygenase-2 inhibition: evidence for involvement of mitochondria dependent signalling

Electrospun and ethanol-dispersed polystyrene-poly(styrene-co-maleic anhydride) (PS-PSMA) nanofibers (NFs) were used as a platform for the selective capture and three-dimensional culture of EpCAM-positive cells in cell culture medium and whole blood. The NFs were treated with streptavidin to facilitate bond formation between the amino groups of streptavidin and the maleic anhydride groups of the NFs. A biotinylated anti-EpCAM monoclonal antibody (mAb) was attached to the streptavidin-conjugated NFs via the selective binding of streptavidin and biotin. Upon simple mixing and shaking with EpCAM-positive cancer cells in a wide concentration range from 10 to 1000,000 cells per 10 mL, the mAb-attached NFs (mAb-NFs) captured the Ep-CAM positive cells in an efficiency of 59%-67% depending on initial cell concentrations, with minor mechanical capture of 14%-36%. Captured cells were directly cultured, forming cell aggregates, in the NF matrix, which ensures the cell proliferation and follow-up analysis. Furthermore, the capture capacity of mAb-NFs was assessed in the presence of whole blood and blood lysates, indicating cluster formation that captured target cells. It is anticipated that the antibody-attached NFs can be employed for the capture and analysis of very rare EpCAM positive circulating cancer cells.

Milling‐induced esterification between cellulose and maleated polypropylene

AbstractThe ball milling of cellulose and maleic anhydride grafted polypropylene (MAPP) induced the formation of ester bonds between OH groups of cellulose and maleic anhydride groups of MAPP, in marked contrast to the melt mixing of the original cellulose and MAPP, through which the esterification was hardly observed. This esterification was hardly dependent on the chemical structure of MAPP. In agreement with the enhanced interfacial adhesion due to the formation of ester bonds, a composite prepared via ball milling revealed an improvement in the tensile strength with respect to a melt‐mixed composite. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1703–1709, 2004

Effect of modified layered silicates and compatibilizer on properties of PMP/clay nanocomposites

AbstractThe preparation and properties of poly(4‐methyl‐1‐pentene) (PMP)/clay nano‐composites are described for the first time. The effect of clay modification and compatibilizer on the formation and properties of the nanocomposites is studied. Layered silicates modified with two types of quaternary ammonium salts are used. The X‐ray diffraction results indicate intercalation of the polymer into the intergallery spacing of the clay. Thermogravimetric analysis shows a delay in the degradation process. Dynamic mechanical analysis shows an increase in the storage modulus for the nanocomposites. The use of compatibilizer containing maleic anhydride and acrylic ester groups is explored. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3233–3238, 2003

Functionalization of Poly(ethylene terephthalate) Film by Pulsed Plasma Deposition of Maleic Anhydride

AbstractPoly(ethylene terephthalate) (PET) films have been functionalized with carboxyl groups by pulsed plasma polymerization of maleic anhydride (MA). The preserved anhydride groups of MA were converted to carboxyl groups by subsequent hydrolysis. Fourier‐transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS) were used to determine the chemical composition of the deposited MA plasma polymers. Atomic force microscopy (AFM) observations visually confirmed the coverage of the PET surface with plasma polymers after water treatment of the processed PET substrate, and the functionality in the XPS spectra of samples before and after water treatment indicated the persistence of functional groups and the good adhesion of the deposited layers on the PET substrate. In accordance with FTIR and XPS results, the density of carboxyl groups increased with decreasing plasma duty cycle. Compared with the pristine PET substrate, a higher roughness was observed on the modified PET surface by AFM. The roughness decreased sharply with decreasing plasma duty cycle.

Stabilization of Thin Polymeric Bilayer Films on Top of Semiconductor Surfaces

The enhanced thermal stability of thin polymer bilayer films against dewetting is investigated. Stabilization results from the addition of a random functional copolymer. The model system consists of a silicon substrate covered with a bilayer of amorphous polyamide (PA), followed by a fully deuterated polystyrene (PSd). While the PA sublayer is stable against dewetting, the addition of a PSd homopolymer film allows dewetting to occur during annealing. By blending the PSd top layer with a fully protonated copolymer poly(styrene-co-maleic anhydride) (SMA2), containing 2% maleic anhydride groups in the chain, its dewetting process is retarded. This increase in stability is investigated as a function of copolymer and annealing time. Scanning force microscopy (SFM) is applied to determine the surface root-mean-square roughness and to check the stabilization effect. Information about the density profile is aquired from specular neutron reflectivity measurements. In addition, grazing incidence small angle neutron scattering (GISANS) is applied. GISANS utilizes the averaging capabilities of scattering methods, which is compared to local information obtained by SFM. Furthermore, GISANS enables the detection of buried structures in contrast to the SFM. An amount of 5% by volume SMA2 is sufficient to stabilize the bilayer film due to the creation of an enrichment layer of SMA2 at the PA:PSd interface. With creation of a brushlike interface, the mobility of the PSd molecules is decreased, which suppresses dewetting.

Crystallization and melting behaviors of maleated polyethylene and its composite with fibrous cellulose

AbstractThe crystallization and melting behaviors of maleated polyethylene (MPE) and its composite with fibrous crystalline cellulose are investigated by differential scanning calorimetry. MPE exhibits a higher crystallization starting temperature, because of the interactions between maleic anhydride (MA) groups for nucleation, and lower melting and crystallization enthalpies, because of the intensive irregularity of MPE chains compared to unmaleated PE (UPE). Fibrous cellulose (FC) slightly facilitates the nucleation of MPE but causes no change in the transition enthalpies of MPE for crystallization and melting in UPE–FC and MPE–FC composites. The kinetics of crystallization show that the Avrami exponent depends on the content of MA groups and FC to a small extent and the activation energy is largely determined by the MA content, suggesting the irregularity and decreased mobility of MPE chains that is due to the interactions between the grafted MA groups in MPE and the FC composite. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3292–3300, 2003

Toughening of polypropylene with styrene/ethylene‐butylene/styrene triblock copolymer: Effects of reactive and nonreactive compatibilization

AbstractThe effects of the compatibilization on the toughening of polypropylene (PP) by melt blending with styrene/ethylene‐butylene/styrene triblock copolymer (SEBS) in a twin‐screw extruder were investigated. The compatibilizers used were an SEBS functionalized with maleic anhydride, a PP functionalized with acrylic acid, and a bifunctional compound, p‐phenylenediamine (PPD). The effects of the compatibilization were evaluated through the mechanical properties and by the determination of the phase morphology of the blends by scanning electron microscopy. Reactive compatibilized blends show up to a 30‐fold increase in impact strength compared to neat PP, which was likely to have been due to the reaction of the bifunctional compound (PPD) with the acid acrylic and maleic anhydride groups, which rendered both morphological and mechanical stability to these blends. The addition of the PPD to the blends significantly changed their phase morphologies, leading to larger dispersed particles' average diameters, probably due to the morphological stabilization at the initial processing steps during extrusion, with the occurrence of the chemical reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1081–1094, 2003

Synthesis and characterization of maleated poly(3‐hydroxybutyrate)

AbstractGraft copolymerization of maleic anhydride (MA) onto poly(3‐hydroxybutyrate) (PHB) was carried out by use of benzoyl peroxide as initiator. The effects of various polymerization conditions on graft degree were investigated, including solvents, monomer and initiator concentrations, reaction temperature, and time. The monomer and initiator concentrations played an important role in graft copolymerization, and graft degree could be controlled in the range from 0.2 to 0.85% by changing the reaction conditions. The crystallization behavior and the thermal stability of PHB and maleated PHB were studied by DSC, WAXD, optical microscopy, and TGA. The results showed that, after grafting MA, the crystallization behavior of PHB was obviously changed. The cold crystallization temperature from the glass state increased, the crystallization temperature from the melted state decreased, and the growth rate of spherulite decreased. With the increase in graft degree, the banding texture of spherulites became more distinct and orderly. Moreover, the thermal stability of maleated PHB was obviously improved, compared with that of pure PHB. Its thermal decomposition temperature was enhanced by about 20°C. In addition, the introduction of the MA group promoted the biodegradability of PHB. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 659–668, 2003

High Stiffness Natural Fiber‐Reinforced Hybrid Polypropylene Composites

Natural fibers are potentially a high‐performance non‐abrasive reinforcing fiber source. In this study, pulp fibers [including bleached Kraft pulp (BKP) and thermomechanical pulp (TMP)], hemp, flax, and wood flour were used for reinforcing in polypropylene (PP) composite. The results show that pulp fibers, in particular, TMP‐reinforced PP has the highest tensile strength, possibly because pulp fibers were subjected to less severe shortening during compounding, compared to hemp and flax fiber bundles. Maleic‐anhydride grafted PP (MAPP) with high maleic anhydride groups and high molecular weight was more effective in improving strength properties of PP composite as a compatiblizer. Coupled with 10% glass fiber, 40% TMP reinforced PP had a tensile strength of 70 MPa and a specific tensile strength comparable to glass fiber reinforced PP. Thermomechanical pulp was more effective in reinforcing than BKP. X‐ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to aid in the analysis. Polypropylene with high impact strength was also used in compounding to improve the low‐impact strength prevalent in natural fiber‐reinforced PP from injection molding.