The effect of polyamide end-group configuration on morphology and toughness of blends with maleated elastomers

The effect of polyamide end-group configuration on morphology generation and toughness of blends with maleated elastomers was investigated. Two difunctional polyamides, a copolymer containing 15% nylon 6,6 and an amine enriched nylon 6, were compared to monofunctional nylon 6 materials of equivalent molecular weight and melt viscosity. Difunctional polyamides have some chains with amine groups on both ends capable of reacting with the maleated rubber phase resulting in crosslinking-type effects. The elastomers used included styrene-butadiene-styrene block copolymers with a hydrogenated midblock, SEBS, and versions with X% grafted maleic anhydride, SEBS-g-MA-X%, and a maleated ethylene/propylene random copolymer, EPR-g-MA. Blends based on difunctional polyamides form large, complex rubber particles when compounded in a single-screw extruder; however, by compounding with an appropriate twin-screw extruder, the size and complexity of the particles can be reduced to levels similar to blends with the monofunctional nylon 6 controls. Measurement of the extent of reaction between the amine end groups and the grafted maleic anhydride revealed that a larger number of amine groups are consumed for the difunctional polyamides than for their monofunctional controls. The room-temperature Izod impact strength of blends with the difunctional polyamides is greater than are the corresponding blends with the controls; however, subambient toughness depends mainly on the inherent ductility of the polyamide matrix. © 1996 John Wiley & Sons, Inc.     

Comparison of the toughening behavior of nylon 6 versus an amorphous polyamide using various maleated elastomers

The toughening effect of two types of elastomers based on ethylene/α-olefin copolymers, viz, an ethylene/propylene copolymer (EPR) with its maleated version, EPR-g-MA, and an ethylene/1-octene copolymer (EOR) with its maleated versions, EOR-g-MA-X% (X=0.35, 1.6, 2.5), for two classes of polyamides: semi-crystalline nylon 6 versus an amorphous polyamide (Zytel 330 from DuPont), designated as a-PA, was explored. The results are compared with those reported earlier based on a styrenic triblock copolymer having a hydrogenated midblock, SEBS, and its maleated version, SEBS-g-MA, elastomer system. Izod impact strength was examined as a function of rubber content, rubber particle size and temperature. All three factors influence the impact behavior considerably for the two polyamide matrices. The a-PA is found to require a somewhat lower content of rubber for toughening than nylon 6. Very similar optimum ranges of rubber particle sizes were observed for ternary blends of EOR-g-MA/EOR with each of the two polyamides while blends based on mixtures of EPR-g-MA/EPR and SEBS-g-MA/SEBS (where the total rubber content is 20% by weight) show only an upper limit for a-PA but an optimum range of particle sizes for nylon 6 for effective toughening. Higher EPR-g-MA contents lead to lower ductile-brittle transition temperatures (T_db) as expected; however, a-PA binary blends with EPR-g-MA have a much lower T_db than do nylon 6 blends when the content of the maleated elastomer is not high. A minimum in plots of ductile-brittle transition temperature versus particle size appears for ternary blends of each of the matrices with EOR-g-MA/EOR; blends based on SEBS-g-MA/SEBS, in most cases, show higher ductile-brittle transition temperatures, regardless of the matrix. However, blends with EPR-g-MA/EPR show comparable T_db with those based on EOR-g-MA/EOR for the amorphous polyamide but show the lowest ductile-brittle transition temperatures for nylon 6 within the range of particle sizes examined. For the blends with a bimodal size distribution, the global weight average rubber particle size is inappropriate for correlating the Izod impact strength and ductile-brittle transition temperature. In general, trends for this amorphous polyamide are rather similar to those of semi-crystalline nylon 6.     

Elastomer particle morphology in ternary blends of maleated and non-maleated ethylene-based elastomers with polyamides: Role of elastomer phase miscibility

The elastomer particle morphology in ternary blends of maleated and non-maleated ethylene-based elastomers with polyamides has been examined. The elastomers used include an ethylene/propylene copolymer, EPR, with a maleic anhydride (MA) grafted version, EPR-g-MA, and an ethylene/1-octene copolymer, EOR, with maleated versions EOR-g-MA-X% where X is 0.35, 1.6 or 2.5. The polyamides used were nylon 6 and an amorphous polyamide, Zytel 330 from DuPont. The morphology development was explored from both thermodynamic and kinetic points of view where the former refers to miscibility of the elastomers and the latter might include the ratio of the elastomers, the matrix type, the order of mixing, mixing intensity, i.e. the extruder type, and graft structure, etc. Both sources influence the morphology developed. For ternary blends with EPR-g-MA/EPR, the morphology (particle size and distribution) seems to be well controlled via the level of maleation in the rubber phase. The two polyamides generate comparable rubber particle sizes at the same of MA level. For ternary blends with EOR-g-MA/EOR, the morphology strongly depends on the level of MA; the rubber particle size, in general, is much smaller in nylon 6 blends than in Zytel 330 blends. Morphology of ternary blends with EOR-g-MA/EOR is much more complex than that of blends with EPR-g-MA/EPR due to the co-existence of miscibility limits and the kinetic factors. Miscibility of maleated EOR elastomers is examined via transmission electron microscopy (TEM) using a special staining technique; a miscibility boundary, as revealed by TEM, occurs around Δ(%MA)=0.9−1.25 MA%. If the two elastomers are miscible, a unimodal particle size distribution always appears in blends regardless of the kinetic factors; however, if immiscibility prevails, either a unimodal or bimodal particle size distribution may develop depending on the ratio of the elastomers and the matrix type. The order of mixing and the mixing intensity do not seem to change the modality of the size distribution.     

Toughening of nylon 6 with grafted rubber impact modifiers

Recent work has shown that nylon 6/acrylonitrile–butadiene–styrene (ABS) blends can be made tough by the addition of some polymer additives that are chemically reactive with nylon 6 and physically compatible with the styrene-acrylonitrile copolymer (SAN) phase of ABS. Imidized acrylic polymers (IA) represent a successful example of such additives that improve the dispersion of ABS in the nylon 6 matrix and render the blends tough. This article examines the possibility of toughening nylon 6 with ethylene/propylene/diene elastomer grafted with SAN copolymer (EPDM-g-SAN). This EPDM-g-SAN consists of 50% rubber and 50% SAN by weight. However, it was found that the same IA that works well to disperse ABS materials of similar rubber content is not as effective for EPDM-g-SAN, primarily because the EPDM forms the continuous phase, not SAN, and, thus, interfaces with nylon 6 during melt blending. Maleated elastomers like maleic anhydride grafted ethylene–propylene copolymer (EPR-g-MA) and styrene–(ethylene-co-butylene)–styrene triblock copolymer (SEBS-g-MA) were more effective for dispersing EPDM-g-SAN in the nylon 6 matrix than IA. Various mechanisms that improve the dispersion are discussed. © 1995 John Wiley & Sons, Inc.     

Effect of rubber particle size and rubber type on the mechanical properties of glass fiber reinforced, rubber-toughened nylon 6

The effects of rubber type and particle size on the mechanical properties of glass fiber reinforced blends of nylon 6 and EPR/EPR-gMA or SEBS/SEBS-g-MA were investigated; rubber particle size in the two systems could be controlled by varying the ratio of EPR to EPR-g-MA or SEBS to SEBS-g-MA. Unreinforced materials with the highest levels of toughness did not necessarily lead to the highest fracture energy when reinforced with 15 wt% glass fibers. Materials toughened with SEBS/SEBS-gMA, which are tougher in the absence of glass fibers had lower fracture energies when 15 wt% glass fibers are present. In general, smaller rubber particles led to higher fracture energies. Fracture analysis according to a modified essential work of fracture analysis reveals that SEBS/SEBS-g-MA have high values of the dissipative energy density, u_d, in the absence of glass fibers. When 15 wt% glass fibers are added, u_d is essentially zero for all the materials tested. The limiting specific fracture energy, u₀, on the other hand, was higher for both unreinforced and glass fiber reinforced EPR/EPR-g-MA toughened blends than for SEBS/SEBS-g-MA based materials. Transmission electron microscopy observations of fractured specimens indicate that glass fibers decrease the size of the damage zone of rubber toughened nylon 6. Shear yielding was seen in fractured specimens of reinforced nylon 6 blends containing either SEBS/SEBS-g-MA or EPR-g-MA, but the size of this shear yielded zone was larger for EPR/EPR-g-MA. In addition, EPR/EPR-g-MA based materials displayed craze-like deformations, while SEBS-g-MA materials did not exhibit this deformation process.     

Rubber toughening of an amorphous polyamide by functionalized SEBS copolymers: morphology and Izod impact behavior

Rubber toughening of an amorphous polyamide (Zytel 330) using combinations of triblock copolymers of the type SEBS and a maleic anhydride functionalized version, SEBS-g-MA, was investigated and the results compared with those of nylon 6 and nylon 66. The effects of rubber content and the type of extruder on the morphology, Izod impact behavior and the ductile-brittle transition temperature were explored. The shape and sizes of the rubber particles in blends with this amorphous polyamide were found to be more similar to those in nylon 6 than in nylon 66 blends. The twin screw extruder produced smaller particles with a more narrow distribution of sizes than the single screw extruder. Higher rubber contents generally yielded tougher blends; there is a critical rubber particle size above which the ternary blends are brittle at 20 wt% total rubber. The ductile-to-brittle temperature was found to decrease with increased rubber content and decreased rubber particle size. In general, the trends for this amorphous polyamide are rather similar to those reported earlier for semi-crystalline nylon 6 and nylon 66.     

Rubber toughening of nylon 6 nanocomposites

The rubber toughening of nylon 6 nanocomposites prepared from an organoclay was examined as a means of balancing stiffness/strength versus toughness/ductility. Nine different formulations varying in montmorillonite, or MMT, and maleated ethylene/propylene rubber or EPR-g-MA rubber content were made by mixing of nylon 6 and organoclay in a twin screw extruder and then blending the nanocomposites with the rubber in a single screw extruder. In this sequence, the MMT platelets were efficiently dispersed in the nylon 6 matrix. The MMT platelets did not penetrate into the rubber phase. The addition of clay affected the dispersion of the rubber phase resulting in larger and more elongated rubber particles. The tensile properties and impact strength of these toughened nanocomposites are discussed in terms of the MMT and rubber contents and morphology. There is a clear trade-off between stiffness/strength versus toughness/ductility.     

Effect of glass fiber surface chemistry on the mechanical properties of glass fiber reinforced, rubber-toughened nylon 6

The mechanical properties of nylon 6 and its blends with maleated ethylene-propylene rubber (EPR-g-MA) plus glass fibers were examined as a function of the chemical functionality of the silane surface treatment applied to the glass fibers. Three reactive silane coupling agents, with anhydride, epoxy, or amine functionality, were used and found to have little effect on the mechanical properties when no EPR-g-MA is present. When 20 wt% EPR-g-MA is used as a rubber toughener, however, the yield strength and Izod impact strength were lowest for the amine functional silane and highest for the anhydride silane, while the epoxy silane fell in-between. These results were attributed to the differences in reactivity of the three reactive silanes. An unreactive silane (octyl groups) was used as a release agent on the glass fibers and compared with the anhydride functional silane. The octyl silane did not improve the ductility of the composite, as may have been speculated, and had poor yield strength and impact resistance when compared to the anhydride silane. Both octyl and anhydride treated glass fibers improve the heat distortion temperature such that most of the high temperature stiffness that is lost on addition of EPR-g-MA is regained by adding glass fibers.     

Toughness improvement of novel biobased aromatic polyamide/SEBS/organoclay ternary hybrids

Biobased aromatic polyamide/organoclay (Cloisite30B, C30B) nanocomposites were melt-compounded with reactive and nonreactive styrene–ethylene–butylene–styrene (SEBS) rubbers at different weight contents to form ternary and quaternary blends. The mechanical properties were investigated as a function of the blend composition. The elongation at break and the impact strength increase with increasing SEBS rubber content, whereas the Young's modulus logically decreases proportionally to SEBS amount. Extra addition of SEBS grafted maleic anhydride (SEBS-g-MA) induces a synergistic effect. The SEBS-g-MA makes it possible to limit the aforementioned rigidity loss and to greatly increase the impact strength. The critical strain energy release rate increases significantly when both reactive and nonreactive rubbers are combined. Three types of microstructures appear depending on the blend composition: (1) small and numerous well-dispersed particles when reactive rubber is used, (2) about 10 times bigger and less numerous well-dispersed particles in the case of nonreactive rubber, and (3) a flocculated dispersion of small particles when both reactive and nonreactive rubber are added. Finally, the polyamide performances were significantly increased when the flocculated morphology was noticed due to a better PAXD/SEBS interfacial adhesion given by the SEBS-g-MA compatibilization and to a thinner rubber distribution in the matrix. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48888.     

Effect of addition of polyoxypropylenediamine on the morphology and mechanical properties of maleated polypropylene/maleated rubber blends

Blends of maleated polypropylene and maleated ethylene propylenediene (EPDM-g-MA) were compounded in a twin-screw extruder with a polyetheramine (PEA), polyoxypropylenediamine, as a compatibilizer. The effect of the compatibilizer concentration and molecular weight on the physical properties was investigated. FTIR data showed that the addition of the compatibilizer caused an imide linkage to form between the amine functionality on the PEA and the maleic anhydride (MA) functionality on both the polypropylene (PP) and the rubber backbone. This bond improved the interfacial adhesion between the rubber and the PP matrix, resulting in an improvement in the toughness of the blends. Other improvements in the physical properties of the blends with a compatibilizer compared to the blends without it included notched Izod impact, elongation at yield, and elongation at break. The optimum improvement in properties was found when the level of the compatibilizer was about 3 wt %. These changes in properties correlated well with the morphology observed via optical and scanning electron microscopy. © 1998 John Wiley & Sons, Inc. J Appl Polm Sci 68: 1451–1472, 1998     

Synergetic toughness and morphology of poly(propylene)/nylon 11/maleated ethylene‐propylene diene copolymer blends

Polypropylene (PP)/nylon 11/maleated ethylene‐propylene‐diene rubber (EPDM‐g‐MAH) ternary polymer blends were prepared via melt blending in a corotating twin‐screw extruder. The effect of nylon 11 and EPDM‐g‐MAH on the phase morphology and mechanical properties was investigated. Scanning electron microscopy observation revealed that there was apparent phase separation for PP/EPDM‐g‐MAH binary blends at the level of 10 wt % maleated elastomer. For the PP/nylon 11/EPDM‐g‐MAH ternary blends, the dispersed phase morphology of the maleated elastomer was hardly affected by the addition of nylon 11, whereas the reduced dispersed phase domains of nylon 11 were observed with the increasing maleated elastomer loading. Furthermore, a core‐shell structure, in which nylon 11 as a rigid core was surrounded by a soft EPDM‐g‐MAH shell, was formed in the case of 10 wt % nylon 11 and higher EPDM‐g‐MAH concentration. In general, the results of mechanical property measurement showed that the ternary blends exhibited inferior tensile strength in comparison with the PP matrix, but superior toughness. Especially low‐temperature impact strength was obtained. The toughening mechanism was discussed with reference to the phase morphology. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of Thermoplastic Elastomer on Melt Rheological and Fracture Behavior of Poly(Lactic Acid)

Poly(lactic acid) (PLA) was melt blended with thermoplastic elastomer, maleic anhydride grafted poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS-g-MA) copolymer with varied concentration (10–40?wt%) using twin screw extruder. Dynamic rheological behavior of PLA/SEBS-g-MA blends investigated a transition from liquid-like behavior to solid-like behavior in the composition range of 10–20?wt% of SEBS-g-MA. The capillary rheometer analysis showed enhanced shear viscosity with increase in SEBS-g-MA content. At 10?wt% of SEBS-g-MA, a maximum in the non-essential work of fracture was observed which reflects resistance to crack propagation. Scanning electron microscopy revealed a transition in deformation mechanisms from voids, to fibrillation and cavitation.     

Influence of microstructure and flexibility of maleated styrene-b-(ethylene-co-butylene)-b-styrene rubber on the mechanical properties of polyamide 12

The present investigation deals with the mechanical and morphological properties of binary polyamide 12/maleic anhydride-grafted styrene-b-(ethylene-co-butylene)-b-styrene rubber (PA12/SEBS-g-MA) blends at varying dispersed phase (SEBS-g-MA) concentrations. Tensile behavior, impact strength and crystallinity of these blend systems were evaluated. Influence of microstructure, dispersed phase particle size, and ligament thickness on the impact toughness of the blend was studied. DSC data indicated an increase in crystallinity of PA12 in the blends. Tensile modulus and strength decreased while impact strength and elongation-at-break increased with the elastomer concentration. The enhanced properties were supported by interphase adhesion between the grafted maleic groups of rubber with polar moiety of polyamide 12. Analysis of the tensile data employing simple theoretical models showed the variation of stress concentration effect with blend composition.     

Thermal and crystallisation behaviours of blends of polyamide 12 with styrene-ethylene/butylene-styrene rubbers

Polyamide 12 (PA12)/styrene-ethylene/butylene-styrene (SEBS) and PA12/maleic anhydride grafted SEBS (SEBS-g-MA) blends were prepared in a twin-screw extruder followed by injection moulding. Thermal and crystallisation behaviours of these blends were evaluated. Thermal properties and morphology of the blends were estimated using thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM), respectively. The phase structure of the blends was interpreted by dynamic mechanical thermal analyser (DMTA). In terms of temperature at maximum rate of degradation (T_max) and integral procedural decomposition temperature (IPDT), it was found that PA12/SEBS-g-MA (PM) blends possessed greater thermal stability than PA12/SEBS (PS) blends. The kinetics of degradation process of PA12 and its blends were studied using Coats-Redfern (CR) method. It was found that there is no appreciable change in the thermal stability of PA12 in the presence of small amount of rubber phase. A good correlation was observed between the thermal properties and phase morphology of the blends. Melting and crystallisation behaviours of the blends were analysed by differential scanning calorimetry (DSC). These results showed that the melting and crystallisation behaviours of PA12 were not significantly affected by blending with rubbers. It was also observed that the functional group present in the rubber phase has little effect on the melting and crystallisation behaviours of PA12.     

Core/shell morphologies in recycled poly(ethylene terephthalate)/linear low-density polyethylene/poly(styrene-<Emphasis Type="Italic">b</Emphasis>-(ethylene-<Emphasis Type="Italic">co</Emphasis>-butylene)-<Emphasis Type="Italic">b</Emphasis>-styrene) ternary blends

Compatibilizer plays very important roles in preparing high performance polymer composites, not only for the ternary immiscible polymer blends, but also for the recycled and reused of waste plastics mixture. Generally, the compatibilizers can be used as the toughening agent in blending polymer materials. In the present work, the poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) or maleic anhydride-grafted poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS-g-MA) acts as the compatibilizer and toughening agent for the preparation of R-PET/LDPE/SEBS (70/20/10) ternary blends. It must be pointed that the ternary blends are costlessly and conveniently prepared from the recycled poly(ethylene terephthalate) (R-PET) and linear low density polyethylene (LLDPE) through a melt blending in a co-rotating twin-screw extruder and injection moulded. The morphologies of the ternary blends are characterized by scanning electron microscopy (SEM). It was found that the blends contains reactive or non-reactive compatibilizer, the morphology originates from the LLDPE particles encapsulated by both SEBS and SEBS-g-MA. So, it results to the reduced interfacial tension between of the R-PET and SEBS-g-MA, in which the grafted chains of PET-g-SEBS-g-MA formed through in situ reaction between R-PET and SEBS-g-MA phases. Therefore, core–shell particles with smaller diameter disperse uniformly in the blends. Moreover, the good compatibilization and corresponding morphologies induce in balanced mechanical and thermal properties. DSC analysis show the dispersed phase particles could act as nucleating agent in the R-PET matrix, which results the improvement of the crystallization temperature. And it was also observed the decreased nucleation activity in graft copolymers in the R-PET/LLDPE/SEBS-g-MA blends. Notched Charpy impact strength and elongation at break are improved by the addition of compatibilizer.     

Recycling of polycarbonate by blending with maleic anhydride grafted ABS

Recycling of used polycarbonate (PC) was conducted via melt blending with maleic anhydride grafted ABS (ABS-g-MA) using a twin-screw extruder. The toughness of waste PC was greatly improved through the modification of ABS-g-MA. The toughening mechanism was explored based on the morphology of the blends. The grafting of MA onto ABS was considered a key factor, which resulted in a special morphology of ABS domains dispersed in PC matrix. At a certain PC/ABS-g-MA weight ratio, the ABS domains connected together forming a network and gave rise to a maximum of the notched impact strength.     

Influence of interchange reactions on the crystallization and melting behavior of nylon 6,6 blended with other nylons

The thermal behavior of blends of nylon 6,6, with an amorphous polyamide, Trogamid-T, and a semicrystalline polyamide, nylon 6,12, was studied. The blends were prepared both by solution blending and by melt blending, using a Maxwell extruder and a twin screw extruder. The concentration of the blends ranged from 75% to 95% by weight of nylon 6,6. Annealing the blend samples in the molten state in a differential scanning calorimeter (DSC) produced changes in the melting and crystallization behavior. This was attributed to transamidation reactions occurring between the blend components, leading to the formation of in-situ block copolymers. The length of the blocks decreased with annealing time, as suggested by reduced melting (T_m) and crystallization temperatures (T_c) and heat of fusion values. The changes in thermal behavior were dependent on the blending method, additive concentration, presence or absence of a catalyst, melt annealing time, and the extent of melt mixing. The extent of reaction, measured by the depression in equilibrium melting temperature, was linear with respect to the annealing time. The Trogamid-T containing blends appeared to be “nearly miscible” while those with nylon 6,12 were initially immiscible. The glass transition temperature (T_g) vs. the composition curve of the nylon 6,6/Trogamid-T blends showed a positive deviation from linear additivity, with the single T_g decreasing as a function of annealing time in the melt.     

Wide-angle X-ray diffraction investigation on crystallization behavior of PA6/PS/SEBS-g-MA blends

Blends of polystyrene/polyamide 6 (PS/PA6) compatibilized by styrene-ethylene/butylene-styrene (SEBS) elastomer grafted with maleic anhydride were prepared by melt blending. Wide-angle X-ray diffraction (WAXD) scans indicated a skin–core structure formed in the specimens during the injection-molding process. The results showed that the specimens tended to form the α-crystalline form in the core region, but the γ-crystalline form in the skin region. The influences of PS and SEBS-g-MA on the crystallization of PA6 were different in the core region and skin region. In the core region, PS made the PA6 tend to be in the γ-crystalline form, but the influence of PS was contrary in the skin region. SEBS-g-MA had both enhancement and toughening effects on the blends. The mechanical properties of the blends were determined by the combined action of the two aforementioned factors.     

Blends of poly(2,6‐dimethyl‐1,4‐phenylene oxide)/polyamide 6 toughened by maleated polystyrene‐based copolymers: Mechanical properties,morphology, and rheology

Poly(2,6‐dimethyl‐1,4‐phenylene oxide)/polyamide 6 (PPO/PA6 30/70) blends were impact modified by addition of three kinds of maleated polystyrene‐based copolymers, i.e., maleated styrene‐ethylene‐butylene‐styrene copolymer (SEBS‐g‐MA), maleated methyl methacrylate‐butadiene‐styrene copolymer (MBS‐g‐MA), and maleated acrylonitrile‐butadiene‐styrene copolymer (ABS‐g‐MA). The mechanical properties, morphology and rheological behavior of the impact modified PPO/PA6 blends were investigated. The selective location of the maleated copolymers in one phase or at interface accounted for the different toughening effects of the maleated copolymer, which is closely related to their molecular structure and composition. SEBS‐g‐MA was uniformly dispersed in PPO phase and greatly toughened PPO/PA6 blends even at low temperature. MBS‐g‐MA particles were mainly dispersed in the PA6 phase and around the PPO phase, resulting in a significant enhancement of the notched Izod impact strength of PPO/PA6 blends from 45 J/m to 281 J/m at the MBS‐g‐MA content of 20 phr. In comparison, the ABS‐g‐MA was mainly dispersed in PA6 phase without much influencing the original mechanical properties of the PPO/PA6 blend. The different molecule structure and selective location of the maleated copolymers in the blends were reflected by the change of rheological behavior as well. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Influence of interfacial adhesion on toughening of polyethylene–octene elastomer/nylon 6 blends

Super-tough nylon 6 was prepared by using polyethylene–octene elastomer (POE) grafted with maleic anhydride as a toughener. The influences of maleating and a compatibilizer on interfacial adhesion and mechanical properties of nylon 6/POE blends were investigated in terms of mechanical testing, Molau tests, SEM observations, IR analyses, and rheological behavior. The results show that the unmodified POE has hardly any contribution to toughness of nylon 6, whereas the maleic anhydride-grafted POE (POE-g-MA) significantly improves the compatibility of POE with nylon 6 and sharply reduces its size in the nylon 6 matrix due to the in situ formation of a graft copolymer between POE-g-MA and nylon 6 during melt processing. With the POE-g-MA, a transition from brittle to ductile occurs. Besides, the use of a compatibilizer in nylon 6/POE-g-MA system shifts the brittle–ductile transition curve to a lower POE-g-MA content, which is attributed, in part, to the chain-extending effect of CE-96 on the nylon 6 matrix leading to further reduction of the sizes of POE-g-MA in the matrix, in part, to the coupling reaction of CE-96 between POE-g-MA and nylon 6. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1711–1718, 1998