Preparation of polypropylene/acrylonitrile–styrene copolymer alloys by one‐step reactive blending

The compatibilization of polypropylene/acrylonitrile–styrene (PP/AS) blends through the addition of peroxide (DCP) was investigated in this study. The grafting reaction between PP and AS with the addition of peroxide occurred during the reactive‐blending process. The in situ‐formed grafting copolymers of PP‐g‐AS and AS‐g‐PP were then characterized by FTIR. The optimum concentration of the initiator, DCP, was 0.2 wt %, and the reaction temperature should be above 195°C. It was found that, when AS was the major component of the blends, the grafting of AS onto PP was the main process; conversely, when PP was the major component, PP was grafted onto AS. These results can be explained by the main‐chain scission of PP during the reactive‐blending process. With increase of the AS component, the total degree of grafting increased at first and then decreased after the composition of the blends reached 50/50. The maximum degree of grafting was found to be 6 wt % for the 50/50 PP/AS/DCP blend. PP was more degradable than was AS in the presence of peroxide at high temperatures. The MFR values of the PP/AS/DCP blends were slightly greater than were those of the simple PP/AS blends, which means that blending is an effective way to protect PP from degradation. SEM micrographs of the cross section of PP/AS/DCP showed a fine dispersion and a smaller domain size of the dispersed‐phase particles, implying that the in situ‐formed grafting copolymers act as a compatibilizer to reduce the interfacial tension between the PP and AS phases. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1284–1290, 2001     

Improving the toughening in poly(lactic acid)‐thermoplastic cassava starch reactive blends

Poly(lactic acid) (PLA), a physical blend of PLA and thermoplastic cassava starch (TPCS) (PLA‐TPCS), and reactive blends of PLA with TPCS using maleic anhydride as compatibilizer with two different peroxide initiators [i.e., 2,5‐bis(tert‐butylperoxy)‐2,5‐dimethylhexane (L101) and dicumyl peroxide (DCP)] PLA‐g‐TPCS‐L101 and PLA‐g‐TPCS‐DCP were produced and characterized. Blends were produced using either a mixer unit or twin‐screw extruder. Films for testing were produced by compression molding and cast film extrusion. Morphological, mechanical, thermomechanical, thermal, and optical properties of the samples were assessed. Blends produced with the twin‐screw extruder resulted in a better grade of mixing than blends produced with the mixer. Reactive compatibilization improved the interfacial adhesion of PLA and TPCS. Scanning electron microscopy images of the physical blend showed larger TPCS domains in the PLA matrix due to poor compatibilization. However, reactive blends revealed smaller TPCS domains and better interfacial adhesion of TPCS to the PLA matrix when DCP was used as initiator. Reactive blends exhibited high values for elongation at break without an improvement in tensile strength. PLA‐g‐TPCS‐DCP provides promising properties as a tougher biodegradable film. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46140.     

Rheology‐morphology correlation in PET/PP blends: Influence of type of compatibilizer

Rheological and morphological properties of melt processed poly(ethylene terephthalate) (PET)/polypropylene (PP) blends are presented. Two types of compatibilizer namely, PP‐g‐MA <MA= maleic anhydtide> and Elvaloy PTW, an n‐butyl acrylate glycidyl methacrylate ethylene terpolymers, were incorporated at different levels to the PET/PP blend system. Scanning electron microscopy revealed that the dispersed particle sizes were smaller in PET‐rich blends than PP‐rich blends. With increasing compatibilizer level, the refinement of morphology was observed in both the systems. However, the blends compatibilized with PTW showed a more refined (smaller) particle size, and at high PTW content (10 wt%), the morphology changed towards monophasic. The significant changes in morphology were attributed to the highly reactive nature of PTW. Investigation of rheological properties revealed that the viscosity of the PET/PP blends followed typical trends based on mixing rule, which calculates the properties of blends based on a linear average. Incorporation of PP‐g‐MA into the blends resulted in a negative deviation in the viscosity of the system with respect to that of the neat blend. With increasing PP‐g‐MA level, the deviation became more pronounced. Although incorporation of the compatibilizer into the PET/PP blends refined the morphology, it led to a drastic drop of viscosity, which could be attributed to inherently lower molecular weight of the compatibilizer. In the case of the blends compatibilized by PTW, a strong positive deviation in rheological properties was observed that confirmed the stronger interaction between the blend components due to reactive compatibilization process, which led to the more refined morphology in this series of blends. J. VINYL ADDIT. TECHNOL., 19:25–30, 2013. © 2013 Society of Plastics Engineers     

Blends of i‐PP and SBS. II. Influence of in situ compatibilization on the mechanical properties

This article concerns the in situ compatibilization of immiscible isotatic polypropylene/styrene–butadiene–styrene triblock copolymer blends (i‐PP/SBS) by use of a reactive mixture. For this purpose, maleated PP (PP–MAH) and SBS (SBS–MAH) were used as functionalized polymers and 4,4′‐diaminediphenylmethane was used as a coupling agent between maleated polymers, resulting in a graft copolymer. Binary blends of i‐PP/SBS, nonreactive ternary blends of i‐PP/PP–MAH/SBS, and reactive ternary blends of i‐PP/PP–MAH/SBS–MAH with varying diamine/anhydride molar ratios were prepared. The mechanical properties of the blends were determined by tensile and impact‐resistance tests. The optimum improvement in the mechanical properties was found when the diamine/anhydride molar ratio in the ternary reactive blends was 0.5/1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 516–522, 2003     

Compatibilization of polypropylene/nylon 6 blends with a polypropylene solid‐phase graft

The compatibilization of polypropylene (PP)/nylon 6 (PA6) blends with a new PP solid‐phase graft copolymer (gPP) was systematically studied. gPP improved the compatibility of PP/PA6 blends efficiently. Because of the reaction between the reactive groups of gPP and the NH₂ end groups of PA6, a PP‐g‐PA6 copolymer was formed as a compatibilizer in the vicinity of the interfaces during the melting extrusion of gPP and PA6. The tensile strength and impact strength of the compatibilized PP/PA6 blends obviously increased in comparison with those of the PP/PA6 mechanical blends, and the amount of gPP and the content of the third monomer during the preparation of gPP affected the mechanical properties of the compatibilized blends. Scanning electron microscopy and transmission electron microscopy indicated that the particle sizes of the dispersed phases of the compatibilized PP/PA6 blends became smaller and that the interfaces became more indistinct in comparison with the mechanical blends. The microcrystal size of PA6 and the crystallinity of the two components of the PP/PA6 blends decreased after compatibilization with gPP. The compatibilized PP/PA6 blends possessed higher pseudoplasticity, melt viscosity, and flow activation energy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 420–427, 2004     

Blends of i‐PP and SBS. I. Influence of the in situ compatibilization on the morphology

This article concerns the in situ compatibilization of immiscible isotactic polypropylene/butadiene‐styrene‐butadiene triblock copolymer blends (i‐PP/SBS) by means of a reactive mixture. For this purpose, maleated PP (PP‐MAH) and SBS (SBS‐MAH) were used as functionalized polymers and 4,4′‐diaminediphenylmethane was used as a coupling agent between maleated polymers, resulting in a graft copolymer. Binary blends i‐PP/SBS, nonreactive ternary blends i‐PP/PP‐MAH/SBS, and reactive ternary blends i‐PP/PP‐MAH/SBS‐MAH with varying diamine and anhydride molar ratios were prepared. Torque measurements suggest a graft copolymerization during the melt blending for ternary reactive blends, but the extension of the grafting does not vary with the diamine and anhydride molar ratio, but with the elastomer concentration. The morphology of the blends was investigated by scanning electron microscopy. The morphology of binary and ternary nonreactive blends is similar, exhibiting elastomer domains disperse in the i‐PP matrix, whose sizes increase with elastomer concentration. On the other hand, the elastomer domain size in the ternary reactive blends is practically independent of the blends composition and of the diamine and anhydride molar ratio. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 847–855, 2002     

Relationship between interfacial tension and dispersed‐phase particle size in polymer blends. I. PP/EPDM

Simple blends with different viscosity ratios of the components as well as compatibilized blends varying both in type and content of compatibilizers were used to study the relation between interfacial tension and dispersed‐phase particle size for PP/EPDM (80/20 wt %) blends in this work. Four compatibilizing systems, poly(ethylene‐co‐methacrylic acid) ionomers (EMA–I), dicumyl peroxide (DCP), DCP combined with EMA–I, and DCP in combination with trimethylol propane triacrylate (TMPTMA), were used. For blends prepared in an internal mixer, a power law relation was found between capillary number and torque ratio of the blends' components. This relation was used to estimate the interfacial tension for the compatibilized blends. The relation between steady‐state torque of the blends as a measure of viscosity and the estimated values of interfacial tension were also investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3148–3159, 2002     

Application of phase dispersion–crosslinking synergism on recycling commingled plastic wastes

A tetra‐component blend, consisting of low‐density polyethylene (LDPE), polyvinyl chloride (PVC), polypropylene (PP), and polystyrene (PS), was studied as a model system of commingled plastic wastes (LDPE/PVC/PP/PS, mass ratio: 70/10/10/10). Effects of chlorinated polyethylene (CPE), ethylene–propylene–diene monomer (EPDM), styrene–butadiene–styrene (SBS), and their mixture (CPE/EPDM/SBS, mass ratio: 2/2/2) on the mechanical properties and morphology of the system were investigated. With addition of several elastomers and their mixture, the tensile strength of the blends decreased slightly, although both the elongation at break and the impact strength increased. Among these elastomers, EPDM exhibited the most significant impact modification effect for the tetra‐component blends. SBS and the mixture have a good phase‐dispersion effect for the tetra‐component blend. By adding a crosslinking agent [dicumyl peroxide (DCP)], the mechanical properties of the tetra‐component blends also increased. When either SBS or the mixture was added to the blend together with DCP, the probability that the crosslinking agent (DCP) would be at the interface improved because of the phase‐dispersion effect of SBS. Therefore, more co‐crosslinked products will form between LDPE and other components. Accordingly, remarkable improvement of the interfacial adhesion and hence the mechanical properties of the tetra‐component blends occurred. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2947–2952, 2001     

Morphological,thermal, rheological,and mechanical properties of PP/EVOH blends compatibilized with PP‐g‐IA

We prepared some blends of polypropylene (PP) and ethylene vinyl alcohol (EVOH) with and without a compatibilizer. As a new compatibilizer, we synthesized polypropylene grafted with itaconic acid (PP‐g‐IA) using Brabender mixing system. We investigated the morphological, thermal, rheological, and mechanical properties of a compatibilized blends (PP/EVOH/PP‐g‐IA) and not compatibilized blends (PP/EVOH). Our experiments showed that carboxylic acid groups in PP‐g‐IA and hydroxyl group in EVOH formed strong in situ hydrogen bond in the compatibilized blends, resulting in better morphological and mechanical properties of the compatibilized blends than those of not compatibilized blends. POLYM. ENG. SCI., 56:1240–1247, 2016. © 2016 Society of Plastics Engineers     

Addition compatibilization of PP/PS blends by tailor‐made copolymers

The thermoplastic polymer blends of commercial interest generally need a phase compatibilization to reduce the interfacial tension, to stabilize the morphology, and to increment the interfacial adhesion. This work deals with the compatibilization of PP/PS blends by addition of a tailor‐made copolymer, which is prepared from the pure homopolymers by a Friedel‐Crafts reaction. This addition compatibilization process comes out as an economic alternative applicable to the recycling of mixed plastics from urban and industrial wastes. The influence of compatibilizer concentration and blending time on the emulsifying effect, morphology, and mechanical properties of the resulting blends are analyzed. The compatibilization process effectiveness is assessed through the improvement in phase adhesion, emulsification and ductility of the compatibilized with respect to the physical blends. An increase of three times in ductility is achieved using very low compatibilizer concentrations (0.5–0.7 wt%). No appreciable detriment in yield strength or modulus is observed in these compatibilized blends. POLYM. ENG. SCI. 46:329–336, 2006. © 2006 Society of Plastics Engineers     

Preparation and characterization of syndiotactic polystyrene/ethylene‐propylene copolymer blends

The reactive compatibilization of syndiotactic polystyrene (sPS)/oxazoline‐styrene copolymer (RPS)/maleic anhydride grafted ethylene‐propylene copolymer (EPR‐MA) blends is investigated in this study. First, the miscibility of sPS/RPS blends is examined by thermal analysis. The cold crystallization peak (T_cc) moved toward higher temperature with increased PRS, and, concerning enthalpy relaxation behaviors, only a single enthalpy relation peak was found in all aged samples. These results indicate that the sPS/RPS blend is miscible along the various compositions and RPS can be used in the reactive compatibilization of sPS/RPS/EPR‐MA blends. The reactive compatibilized sPS/RPS/EPR‐MA blends showed finer morphology than sPS/EPR‐MA physical blends and higher storage modulus (G') and complex viscosity (η*) when RPS contents were increased. Moreover, the impact strength of sPS/RPS/EPR‐MA increased significantly compared to sPS/EPR‐MA blend, and SEM micrographs after impact testing show that the sPS/RPS/EPR‐MA blend has better adhesion between the sPS matrix and the dispersed EPR‐MA phase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2084–2091, 2002     

Interfacial slip‐stick transition induced by reactive compatibilization in ethylene‐co‐butyl acrylate elastomer dispersed polyamide 6 blend subjected to high shear flow and extensional flow

The effect of phase interaction induced by reactive compatibilization during high shear and extensional flow in polyamide (PA6) and ethylene‐co‐butyl acrylate (EBA) blends was studied using advanced dual bore capillary rheometer. The viscosity‐composition behavior of the uncompatibilized PA6/EBA blends exhibited negative deviation behavior from log‐additivity rule. The interfacial slip mechanism, operative between the matrix PA6 and dispersed EBA during shear flow was studied by the use of Lin's and Bousmina‐Palierne‐Utracki (BPU) model for viscosity for the blends under the processing conditions. On the other hand, the compatibilized PA6/EBA‐g‐MAH^0.49/EBA blends with varying dispersed phase volume fraction show positive deviation behavior. The reactive compatibilizers EBA‐g‐MAH^0.49 and EBA‐g‐MAH^0.96 increased the phase interaction with adequate reduction in the dynamic interfacial tension, which favored the particle break‐up and stabilized the morphology in the compatibilized blends. The extensional viscosity of the blends has enhanced because of the inclusion of EBA in all the uncompatibilized and compatibilized blends. The melt elasticity and elasticity function were systematically studied from first normal stress coefficient functions (ψ₁). The variation in the recoverable shear strain (γ_R), shear rate dependent relaxation time (λ) and shear compliance (J_c) under various shear rates were thoroughly analyzed for all the blend compositions. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Real time assessment of the compatibilization of polypropylene/polyamide 6 blends during extrusion

The reactivity of maleic anhydride and acrylic acid polypropylene graft copolymers with amine groups and their effect in the compatibilization of polymer blends was analyzed in real time during the reactive processing of compatilized polypropylene/polyamide 6 (PP/PA6) blends. The presence of compatibilizers in the blend produces a block copolymer PP‐PA6, which stays in the blends interface, lowering the interfacial tension and reducing the PA6 particle size, affecting the light extinction phenomena. The in‐line optical detector is able to indirectly quantify the conversion of the compatibilization reaction of the blends. The signal intensity of the detector increases with the increase of the PA6 content due to the increase in the number of particles. Quantitative off‐line FTIR analyses of the compatibilized blends have shown that the amount of block copolymer formed when polypropylene grafted with acrylic acid (PP‐g‐AA) is used as compatibilizer increases with its content in the blend. There is a good correlation between the in‐line optical measurement and the off‐line amidic bond content formed. Non‐reacted compatibilizers are always present in the reactive blends whose content is proportional to its initial concentration. The PA6 particle size data obtained from scanning electron microscopy analysis showed good correlation with the in‐line measurements. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Morphological study of LLDPE‐NR reactive blending with maleic anhydride

A binary blend and ternary reactive blends of 90/10 LLDPE/NR using maleic anhydride (MA) as a reactive agent with and without dicumyl peroxide (DCP) were made at 150°C in an internal mixer. The fracture surfaces of the blends were conventionally observed by TEM and atomic force microscope, revealing that the rubber domains became smaller with the addition of MA and DCP. This suggested that the in situ graft copolymer (LLDPE‐g‐NR) was formed and acted as an in situ compatibilizer to enhance interfacial adhesion. This was further supported by FTIR results. Importantly, after removal of NR phase from the blends, the remaining LLDPE part was dissolved in hot xylene, purified by precipitation in methanol, and carefully prepared by solvent casting for TEM observation. The microstructures of the solvent‐extracted LLDPE from all blends are unlike that of solvent cast‐ pure LLDPE, which shows only crystalline structure. This leads to an unambiguous way to disclose the existence of an in situ graft copolymer. The solvent‐extracted LLDPE from the blends shows mixed morphology of LLDPE crystalline structure and its in situ graft copolymer as nanofibrillar networks of the NR phase protruded from the amorphous region of the LLDPE matrix due to spinodal decomposition by the solvent removal. Adding MA makes more branches and fibril connections of the NR phase, whereas a thinner fibril network and more links of the NR and the LLDPE amorphous region are found in the reactive blend with MA and DCP, where the most compatibilized blend is obtained. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Dynamically cured polypropylene/Novolac blends compatibilized with maleic anhydride‐g‐polypropylene

In this article, the dynamic vulcanization process was applied to polypropylene (PP)/Novolac blends compatibilized with maleic anhydride‐grafted PP (MAH‐g‐PP). The influences of dynamic cure, content of MAH‐g‐PP, Novolac, and curing agent on mechanical properties of the PP/Novolac blends were investigated. The results showed that the dynamically cured PP/MAH‐g‐PP/Novolac blend had the best mechanical properties among all PP/Novolac blends. The dynamic cure of Novolac improved the modulus and stiffness of the PP/Novolac blends. The addition of MAH‐g‐PP into dynamically cured PP/Novolac blend further enhanced the mechanical properties. With increasing Novolac content, tensile strength, flexural modulus, and flexural strength increased significantly, while the elongation at break dramatically deceased. Those blends with hexamethylenetetramine (HMTA) as a curing agent had good mechanical properties at HMTA content of 10 wt %. Scanning electron microscopy (SEM) analysis showed that dynamically cured PP/MAH‐g‐PP/Novolac blends had finer domains than the PP/MAH‐g‐PP/Novolac blends. Thermogravimetric analysis (TGA) results indicated that the incorporation of Novolac into PP could improve the thermal stability of PP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Reactive compatibilization of poly(methyl acrylate‐ran‐acrylonitrile)/poly(ethylene) blends through amine–anhydride coupling

Methyl acrylate/acrylonitrile copolymers (MA/AN) were reactively compatibilized as the dispersed phase into poly(ethylene) (PE) for potential hydrocarbon barrier materials. The MA/AN was made reactive by including p‐aminostyrene (PAS), yielding terpolymers (MA/AN/PAS) with pendant primary amine functionality (number average molecular weight = 65–133 kg mol^?1, dispersity (?)=1.83–2.53, molar composition of PAS in copolymer F_PAS = 0.03–0.14, molar composition of AN = F_AN = 0.27–0.52). The non‐functional MA/AN and amino functional MA/AN/PAS were each melt blended into PE that was grafted with maleic anhydride (PE‐g‐MAnn) at 200 °C at 70:30 wt % PE‐g‐MAnn:co/terpolymer. After extrusion, the dispersed phase particle size (volume to surface area diameter, ) was coarse (12.6 μm) for the non‐reactive blend whereas it was much lower for the reactive blend ( = 1.2 μm). Coarsening after annealing at 150 °C was slow, but the domain sizes increased only slightly for both cases. The reactive blend was deemed sufficiently stable and thus was suitable as a candidate barrier material for further testing against olefins. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44177.     

Polymer blends of poly(ethylene‐2,6‐naphthalate) with polystyrene compatibilized by styrene‐glycidyl methacrylate copolymers. I. Rheology,morphology, and mechanical properties

The compatibilization of blends of poly(ethylene‐2,6‐naphthalate) (PEN) with polystyrene (PS), through the styrene‐glycidyl methacrylate copolymers (SG) containing various glycidyl methacrylate (GMA) contents, was investigated in this study. SG copolymers are able to react with PEN terminal groups during melt blending, resulting in the formation of desirable SG‐g‐PEN copolymers in the blend. These in situ formed copolymers tend to reside along the interface preferentially as the result of interfacial reaction and thus function as effective compatibilizers in PEN/PS blends. The compatibilized blends exhibit higher viscosity, finer phase domain, and improved mechanical properties. It is found that the degree of grafting of the in situ formed SG‐g‐PEN copolymer has to be considered as well. In blends compatibilized with the SG copolymer containing higher GMA content, heavily grafted copolymers would be produced. The length of the styrene segment in these heavily grafted copolymers would be too short to penetrate deep enough into the PS phase to form effective entanglements, resulting in the lower compatibilization efficiency in PEN/PS blends. Consequently, the in situ formation of SG‐g‐PEN copolymers with an optimal degree of grafting is the key to achieving the best performance for the eventually produced PEN/PS blends through SG copolymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 967–975, 2003     

Compatibilized blends of PVC/PA12 and PVC/PP containing poly(lauryl lactam‐block‐caprolactone)

Specially designed block copolymers have played a role as compatibilizing agents in the system of immiscible polymer blends. We applied lauryl lactam (LA)–caprolactone (CL) block copolymer [P(LA‐b‐CL)] as a compatibilizing agent for immiscible poly(vinyl chloride) (PVC) blends with various polymers. These blends possess high thermal performance and toughness. We investigated the effect of P(LA‐b‐CL) as a compatibilizing agent for immiscible PVC blends with poly(ω‐lauryl lactam) [polyamide 12 (PA12)]. We also described the invention of a new compatibilizing agent system involving P(LA‐b‐CL) for PVC/polypropylene (PP) blends. The mechanical and thermal properties of (1) PVC/PA12 blend compatibilized with P(LA‐b‐CL) and (2) PVC/PP blend compatibilized with P(LA‐b‐CL)/PA12/maleic anhydride–modified PP were both enhanced. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1983‐1992, 2004     

The effect of interface characteristics on the static and dynamic mechanical properties of three‐component polymer alloys

The effect of interfacial characteristics on the structure‐property relationships of ternary polymer alloys and blends comprising polypropylene (PP), ethylene‐vinyl alcohol copolymer (EVOH) and glass beads (GB) or fibers (GF) was investigated. The systems studied were based on a binary PP/EVOH immiscible blend, representing a blend of a semi‐crystalline apolar polymer with a semi‐crystalline highly polar copolymer. The ternary systems studied consisted of filler particles encapsulated by EVOH, with some of the minor EVOH component separately dispersed within the PP matrix. Modification of the interfacial properties was done using silane coupling agents for the EVOH/glass interface and compatibilization using a maleic anhydride grafted PP (MA‐g‐PP) for the PP/EVOH interface. Both glass fillers increased the dynamic modulus and decreased the damping of the neat polymers and of their binary blends, especially in the rubbery region. GF has a more profound effect on both the modulus and the damping. Glass surface treatments and compatibilization have only a marginal effect on the dynamic mechanical behavior of the ternary blends. Yet, compatibilization shifted the polymers' T_gS to higher temperatures. Both glass fillers increased the elastic modulus of the binary blends, where GF performed better than GB as a reinforcing agent. GF slightly increased the strength of the binary blends while, GB reduced it. Both fillers reduced the ductility of the binary blends. The blends' mechanical properties were related to the morphology and their components' crystallinity. The compatibilizer increases both stiffness and strength and reduces deformability.     

Compatibilization of polypropylene/ poly(3‐hydroxybutyrate) blends

Blending polypropylene (PP) with biodegradable poly(3‐hydroxybutyrate) (PHB) can be a nice alternative to minimize the disposal problem of PP and the intrinsic brittleness that restricts PHB applications. However, to achieve acceptable engineering properties, the blend needs to be compatibilized because of the immiscibility between PP and PHB. In this work, PP/PHB blends were prepared with different types of copolymers as possible compatibilizers: poly(propylene‐g‐maleic anhydride) (PP–MAH), poly (ethylene‐co‐methyl acrylate) [P(E–MA)], poly(ethylene‐co‐glycidyl methacrylate) [P(E–GMA)], and poly(ethylene‐co‐methyl acrylate‐co‐glycidyl methacrylate) [P(E–MA–GMA)]. The effect of each copolymer on the morphology and mechanical properties of the blends was investigated. The results show that the compatibilizers efficiency decreased in this order: P(E–MA–GMA) > P(E–MA) > P(E–GMA) > PP–MAH; we explained this by taking into consideration the affinity degree of the compatibilizers with the PP matrix, the compatibilizers properties, and their ability to provide physical and/or reactive compatibilization with PHB. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012