Phase structure and viscoelastic properties of compatibilized blends of PET and HDPE recyclates

Immiscible blends of recycled poly(ethylene terephthalate) (R‐PET), containing some amount of polymeric impurities, and high‐density polyethylene (R‐PE), containing admixture of other polyolefins, in weight compositions of 75 : 25 and 25 : 75 were compatibilized with selected compatibilizers: maleated styrene–ethylene/butylene–styrene block copolymer (SEBS‐g‐MA) and ethylene–glycidyl methacrylate copolymer (EGMA). The efficiency of compatibilization was investigated as a function of the compatibilizer content. The rheological properties, phase structure, thermal, and viscoelastic behavior for compatibilized and binary blends were studied. The results are discussed in terms of phase morphology and interfacial adhesion among components. It was shown that the addition of the compatibilizer to R‐PET‐rich blends and R‐PE‐rich blends increases the melt viscosity of these systems above the level characteristic for the respective binary blends. The dispersion of the minor phase improved with increasing compatibilizer content, and the largest effects were observed for blends compatibilized with EGMA. Calorimetric studies indicated that the presence of a compatibilizer had a slight affect on the crystallization behavior of the blends. The dynamic mechanical analysis provided evidence that the occurrence of interactions of the compatibilizer with blend components occurs through temperature shift and intensity change of a β‐relaxation process of the PET component. An analysis of the loss spectra behavior suggests that the optimal concentration of the compatibilizers in the considered blends is close to 5 wt %. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1423–1436, 2001     

Effects of component addition protocol on the reactive compatibilization of HDPE/PET blends

Polyethylene terephtyalate (PET) and high-density polyethylene (HDPE) constitute a major portion of the thermoplastic materials currently being used in the packaging industry. Blends of HDPE/PET can be compatibilized by utilizing ester groups or terminal carboxyl and hydroxyl groups present in PET. An ethyleneglycidyl methacrylate copolymer (EGMA) was found to be very effective in compatibilizing this blend by forming a compatibilizer in-situ. The in-situ formation of the compatibilizer and its distribution could be affected by different sequences and modes of component addition. To determine the best protocol of component addition for such a reactive compatibilization process, different sequences and modes of component addition were tried out in an intensive batch mixer and in a twin-screw extruder. All these experiments resulted in blends with vastly different dispersion of the minor phase and mechanical properties. In general, sequences where the reactive polymer was grouped with the nonpolar component of the blend initially resulted in the best compatibilization.     

Mechanical and fracture characterization of 50:50 HDPE/PET blends presenting different phase morphologies

Uncompatibilized and compatibilized blends of poly(ethylene terephthalate) (PET) and high‐density polyethylene (HDPE) (50:50 PET/HDPE) have been prepared and characterized. A commercial grade of ethylene/methacrylic acid copolymer was used as compatibilizing agent and added to the blends in two different proportions, 1% and 7%. Compounded blends were processed following three different procedures: compression molding, extrusion, and extrusion followed by annealing. In every case, there is evidence that suggests that HDPE constitutes the matrix and PET is the dispersed phase. The PET phase shape was related to the processing procedure of the blends. PET adopted a globular morphology in the compression molded samples but it took the form of microfibers (microfibrillar‐like reinforced composites) in extruded samples, which were flattened during the postextrusion annealing process. According to the results obtained in tensile and fracture tests, extruded blends having 7% of ethylene/methacrylic acid copolymer appeared as the optimum combination of processing method and compatibilizer content. POLYM. ENG. Sci., 45:354–363, 2005. © 2005 Society of Plastics Engineers     

Degradability of extruded polyethylene/chitosan blends compatibilized with polyethylene‐graft‐maleic anhydride under natural weathering

The impact of chitosan on the natural weathering behavior of two blends obtained by mixing either polyethylene (PE) with chitosan or PE, chitosan and polyethylene‐graft‐maleic anhydride (PEgMA) as a compatibilizer is analyzed. In order to follow the weathering behavior of both the uncompatibilized and compatibilized systems, the blend films are exposed to outdoor conditions for 6 months. The weathering behavior of the films is monitored by mechanical tests, spectroscopic Fourier transform infrared, and morphological analyses at different weathering periods of time. The presence of chitosan in the blends accelerates significantly the degradation of the films. Apparently, PEgMA also accelerates the photo‐oxidation rate of the films. This behavior appears to be related to the photo‐oxidative instability of maleic anhydride, and also to the better dispersion of chitosan in the PE matrix, which is due to the interactions in the PE/chitosan interface caused by the addition of the compatibilizer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41045.     

Comparison of the influence of different compatibilizers on the structure and properties of ethylene vinyl acetate copolymer/modified clay nanocomposites

Nanocomposites of an ethylene vinyl acetate copolymer and clay were prepared by melt blending and extrusion. Two different compatibilizers, ethylene glycidyl methacrylate (EGMA) and maleic anhydride grafted polypropylene (MAPP), were used in these nanocomposites. The structural properties of the composites were characterized with X‐ray diffraction and transmission electron microscopy. The surface morphology was characterized with polarized optical microscopy. The tensile and permeability properties were studied. The thermal stability of the nanocomposites was characterized through thermogravimetric analysis. MAPP‐compatibilized nanocomposites had intercalated and partially exfoliated structures, whereas EGMA‐compatibilized nanocomposites had completely exfoliated structures. The EGMA‐compatibilized nanocomposites were thermally more stable than the MAPP‐compatibilized nanocomposites. The mechanical and permeability properties of the EGMA‐compatibilized nanocomposites were better than those of the MAPP‐compatibilized nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

The effect of maleic anhydride grafting efficiency on the flexural properties of polyethylene composites

Many authors have reported on the property enhancements possible by compounding high density polyethylene (HDPE) with fillers to produce composites. It is accepted that polyethylene combined with materials such as nanoclay or wood flour will not yield favorable properties unless a compatibilizing material is used to form a link. In this work, compatibilized HDPE was produced by grafting maleic anhydride (MA) to its backbone in a twin screw extruder using a peroxide initiated reactive process. Fourier transform infrared spectroscopy (FTIR) was used to examine the effects of varying peroxide and MA levels on the grafting percentage and it was found that a high percentage could be achieved. The gel content of each HDPE‐g‐MA batch was determined and twin bore rheometry analysis was carried out to examine the effects of crosslinking and MA grafting on the melt viscosity. These HDPE‐g‐MA compatibilizers were subsequently compounded with nanoclay and wood flour to produce composites. The composite materials were tested using a three point bending apparatus to determine the flexural modulus and strength and were shown to have favorable mechanical properties when compared with composites containing no compatibilizer. X‐ray diffraction (XRD) was used to examine the effects of grafted MA content on the intercalation and exfoliation levels of nanoclay composites. The results from XRD scans showed that increased intercalation in polymer nanoclay composites was achieved by increasing the grafted MA content. This was confirmed using a scanning electron microscope, where images produced showed increased levels of dispersion and reductions in nanoclay agglomerates. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Structural, morphological and mechanical characteristics of polyethylene, poly(lactic acid) and poly(ethylene-co-glycidyl methacrylate) blends

In this work, uncompatibilized and compatibilized blends of low density polyethylene (LDPE) and poly(lactic acid) (PLA) were subjected to several investigations: Fourier transform infrared (FTIR) spectroscopy, morphological analysis and mechanical testing (tensile, impact, microhardness). The copolymer (ethylene-co-glycidyl methacrylate) (EGMA) was used as compatibilizer. The percentages of PLA in LDPE/PLA samples ranged from 0 to 100 wt% while the EGMA was added to the blend 60/40 (LDPE/PLA) at concentrations of 2, 5, 7, 10, 15 and 20 parts per hundred (phr). FTIR analysis showed the absence of any interaction between LDPE and PLA, but after addition of compatibilizer, reactions between epoxy groups of EGMA and carboxylic or hydroxyl groups of PLA were confirmed. Tensile and impact tests revealed a loss of ductility of LDPE with the incorporation of PLA, except for the composition 80/20 (LDPE/PLA). However, the addition of 15 phr of EGMA led to the maximum increase in the elongation-at-break (about three times the value of uncompatibilized blend) and in the impact strength, but a marginal improvement was observed for tensile strength. SEM micrographs confirmed that the enhancement of mechanical properties is due to the improvement of the interfacial adhesion between different phases owing to the presence of EGMA. The microhardness values of the different blends (uncompatibilized or compatibilized) were in good agreement with the macroscopic mechanical properties (tensile and impact strengths).     

Effect of filler content and size on the properties of ethylene vinyl acetate copolymer–wood fiber composites

In this study, the main focus was on the effect of wood fiber (WF) content and particle size on the morphology and mechanical, thermal, and water‐absorption properties of uncompatibilized and ethylene glycidyl methacrylate copolymer (EGMA) compatibilized ethylene vinyl acetate copolymer–WF composites. For uncompatibilized composites, the tensile strength decreased with increasing WF content, whereas for compatibilized composites, the tensile strength initially decreased, but it increased for composites containing more than 5% WF. Small‐WF‐particle‐containing composites had higher tensile strengths than composites containing larger WF particles, both in the presence and absence of EGMA. WF particle size did not seem to have much influence on the degradation behavior of the composites, whereas water absorption by the composites seemed to be higher in composites with smaller particle sizes for both compatibilized and uncompatibilized composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3645–3654, 2007     

Improved compatibility of high‐density polyethylene/poly(ethylene terephthalate) blend by the use of blocked isocyanate group

The blocked isocyanate group (BHI) was synthesized to improve the storage stability of HI (2‐hydroxyethyl methacrylate combined with isophorone diisocyanate) and characterized by Fourier transform infrared spectroscopy (FTIR). High‐density polyethylene grafted with the blocked isocyanate group (HDPE‐g‐BHI) was used as a reactive compatibilizer for an immiscible high‐density polyethylene/poly(ethylene terephthalate) (HDPE/PET) blend. A possible reactive compatibilization mechanism is that regenerated isocyanate groups of HDPE functionalized by BHI react with the hydroxyl and carboxyl groups of PET during melt blending. The HDPE‐g‐BHI/PET blend showed the smaller size of a dispersed phase compared to the HDPE/PET blend, indicating improved compatibility between HDPE and PET. This increased compatibility was due to the formation of an in situ graft copolymer, which was confirmed by dynamic mechanical analysis. Differential scanning calorimetry (DSC) analysis represented that there were few changes in the crystallinity for the continuous PET phase of the HDPE‐g‐BHI/PET blends, compared with those of the HDPE/PET blends at the same composition. Tensile strengths and elongations at the break of the HDPE‐g‐BHI/PET blends were greater than those of the HDPE/PET blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1017–1024, 2000     

Resistance of paper mill sludge/wood fiber/high‐density polyethylene composites to water immersion and thermotreatment

The disposal of paper mill sludge (PMS) is a difficult environmental problem. Thus, PMS has been used as a substitute for wood fiber (WF) to reinforce high‐density polyethylene (HDPE). In this study, we compared PMS–WF–HDPE composites with composites without PMS after water immersion and thermal treatment. Water immersion and thermal treatment were conducted at 25 and 70°C, respectively. The results show that the composites with PMS absorbed less water but lost more of their original flexural properties after immersion; thereby, their strength was compromised. These reduced mechanical properties could be partially restored after redrying. After the thermotreatment, the composites with added PMS lost their weight and flexural properties, whereas the composites without PMS gained flexural strength. The results show that the thermotreatment improved the impact strength of the composites when no more than one‐third of WF was replaced with PMS. Fourier transform infrared spectroscopy and energy‐dispersive X‐ray energy‐dispersive spectroscopy showed that the wood index of the PMS composite decreased more than the index of the non‐PMS composite, whereas the carbonyl index increased more. However, the PMS composite showed a lower increase in the total oxygen/carbon weight ratio. This study suggested that limited amounts of WF could be substituted with PMS to reinforce HDPE. However, WF–PMS–HDPE composites should not be used in hot, humid environments for long periods. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41655.     

Studies on the physico‐mechanical,thermal, and morphological behaviors of high density polyethylene/coleus spent green composites

This study is aimed at utilizing nutraceutical industrial waste and reducing carbon footprints of plastics. Eco‐friendly “green composites” of high density polyethylene (HDPE) were fabricated using coleus spent (CS)—a nutraceutical industrial waste as reinforcing filler and maleic anhydride‐graft‐polyethylene (MA‐g‐PE) as compatibilizer. Composites were fabricated with 5, 10, 15, and 20% (w/w) of CS by extrusion method. The fabricated HDPE/CS composites were evaluated for mechanical and thermal behavior. A slight improvement of about 5% in tensile strength and marked improvement of about 25% in tensile modulus for 20 wt % CS filled HDPE composites was noticed. The effect of CS content on rheological behavior was also studied. Thermal characteristics were performed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA thermogram indicated increased thermal stability of CS‐filled composites. From TGA curves the thermal degradation kinetic parameters of the composites have been calculated using Broido's method. The enthalpy of melting (ΔH_m) obtained from DSC curves was reduced with increase in CS content in HDPE matrix, due to decrease in HDPE content in composite systems. An increase in CS loading increased the water absorption behavior of the composites slightly. Morphological behavior of cryo‐fractured composites has been studied using scanning electron microscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical and thermal properties of exfoliated graphite nanoplatelets reinforced polyethylene terephthalate/polypropylene composites

Exfoliated graphite nanoplatelets (GNP) reinforced composites materials based on blend of poly(ethylene terephthalate) (PET) and polypropylene (PP) were prepared by melt extrusion followed by injection molding. 10 parts per hundred resin (phr) styrene‐ethylene‐butylene‐styrene‐g‐maleic anhydride was added to the base formulation PET/PP (70/30) as a compatibilizer. PET/PP/GNP composites 0–5 phr were prepared and characterized using field emission scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, and Fourier transform infrared (FTIR) spectroscopy analysis. The morphological studies revealed a homogenous dispersion of GNPs in PET/PP blends up to 3 phr loading after which agglomeration occurred. Flexural strength was enhanced by 80% at 3 phr GNPs loading which was the highest value obtained. Interestingly, the highest value for the impact strength was also recorded at 3 phr loading. The thermal stability of the composites were generally improved at all filler loading with the highest at 3 phr. From the overall results, it is clear that the optimum concentration of GNPs in the PET/PP/GNP system in terms of both mechanical and thermal properties was 3 phr loading. Although, the mechanical and thermal properties of the composites were improved, the FTIR analysis did not reveal any chemical interaction between GNP and the polymer matrix. POLYM. COMPOS., 35:2029–2035, 2014. © 2014 Society of Plastics Engineers     

In situ compatibilization of HDPE/PET blends

The reactive compatibilization of immiscible polymers such as high‐density polyethylene (HDPE) and poly(ethylene terephthalate) (PET) by interfacial grafting of maleic anhydride (MA) without initiator in the molten state was investigated in this study. Grafting reaction of MA onto HDPE was carried out in a Rheocord HAAKE mixer varying reaction parameters such as the temperature, the shear rate, and the time of reaction. Then, the purified copolymers were characterized by infrared spectrometry and the MA content of HDPE‐g‐MA copolymers was determined by volumetric titration. It has been shown that thermomechanical initiation is sufficient to reach grafting yield of 0.3 to 2.5 wt % of MA. We studied then the compatibilization of HDPE/PET blends by interfacial grafting of MA. The in situ interfacial reaction leads to the formation of HDPE‐g‐MA copolymer which acts as a compatibilizer in the blends. The foremost interest of this work is that it provides a simple way of compatibilization of immiscible blends of polyolefin and polyester in one transformation step without using free‐radical initiators. The mechanical properties of the blends are strongly improved by the addition of small quantities of MA. The SEM observations of the compatibilized blends show a deep modification of the structure (i.e., enhanced regularity in the nodule dispersion and better interfacial adhesion). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 874–880, 2001     

Glass fiber/wood flour modified high density polyethylene composites

Composites of high density polyethylene (HDPE) with the reinforcements of glass fiber (GF) and wood flour (WF) have been studied in this work. High‐density polyethylene‐grafted maleic hydride (HDPE‐g‐MAH) was used as a compatibilizer. In particular, the effect of GF, WF, and HDPE‐g‐MAH on the overall properties of GF/WF/HDPE composites (GWPCs in short form) was systematically studied. The results indicate that HDPE‐g‐MAH as a compatibilizer can effectively promote the interfacial adhesion between GF/WF and HDPE. By the incorporations of GF/WF, the heat deflection temperature can reach above 120°C, and the water absorption can be below 0.7%, also the tensile strength, flexural strength, and impact strength of GWPCs can surpass 55.2 Mpa, 69.4 Mpa, and 11.1 KJ/m², respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Compatibilizers for thermotropic liquid crystalline polymer/polyethylene blends prepared by reactive mixing

This paper describes the effects of composition and processing conditions on the efficiency of the compatibilizer prepared from a thermotropic liquid crystalline polymer (TLCP) and the sodium salt of a poly(ethylene‐co‐r‐acrylic acid) ionomer (EAA‐Na) in TLCP/low‐density polyethylene (LDPE) blends and TLCP/high‐density polyethylene (HDPE) blends. The TLCP‐ionomer graft copolymer formed by a melt acidolysis reaction effectively reduced the interfacial tension between TLCP and polyethylene, which improved impact strength and toughness of the compatibilized blends. Higher processing temperatures for the reactive extrusion produced a more efficient compatibilizer, presumably due to increased graft‐copolymer formation, but the reaction temperature had little effect on the impact strength of compatibilized blends for temperatures above 300°C. The addition of the compatibilizer to TLCP/LDPE blends significantly increased the melt viscosity due to increased interfacial adhesion. The TLCP/EAA‐Na ratio used to prepare the compatibilizer had little effect on the performance of the compatibilizer. Although the compatibilizer can be prepared in situ by blending and extruding a ternary blend of TLCP/EAA‐Na/polyethylene, pre‐reacting the compatibilizer resulted in blends with improved toughness and elongation.     

Effect of microfiber reinforcement on the morphology,electrical, and mechanical properties of the polyethylene/poly(ethylene terephthalate)/carbon nanotube composites

In situ microfiber reinforced conductive polymer composites consisting of high‐density polyethylene (HDPE), poly(ethylene terephthalate) (PET), and multiwalled carbon nanotube (CNT) were prepared in a twin screw extruder followed by hot stretching of PET/CNT phase in HDPE matrix. For comparison purposes, the HDPE/PET blends and HDPE/PET/CNT composites were also produced without hot stretching. Extrusion process parameters, hot‐stretching speed, and CNT amount in the composites were kept constant during the experiments. Effects of PET content and molding temperature on the morphology, electrical, and mechanical properties of the composites were investigated. Morphological observations showed that PET/CNT microfibers were successfully formed in HDPE phase. Electrical conductivities of the microfibrillar composites were in semi‐conductor range at 0.5 wt% CNT content. Microfiber reinforcement improved the tensile strength of the microfibrillar HDPE/PET/CNT composites in comparison to that of HDPE/PET blends and HDPE/PET/CNT composites prepared without hot stretching. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Effects of polyethylene‐grafted maleic anhydride as a compatibilizer on the morphology and tensile properties of (thermoplastic tapioca starch)/ (high‐density polyethylene)/(natural rubber) blends

Effects of polyethylene‐grafted maleic anhydride as a compatibilizer on the tensile properties of (high‐density polyethylene)/(natural rubber)/(thermoplastic tapioca starch) (HDPE/NR/TPS) blends were investigated. The ratio of HDPE/NR was fixed at 70/30, and these materials were blended with TPS in concentrations varying from 5 to 30% by using a Haake Rheomix 600 mixer. Two series of HDPE/NR/TPS blends were prepared, i.e., with and without compatibilizer. Morphology and tensile properties of the HDPE/NR/TPS blends were evaluated as a function of TPS loading. The tensile strength and elongation at break decreased with the increase of TPS content. However, an improvement in the tensile strength was obtained for compatibilized blends as compared to uncompatibilized blends. The degrees of TPS adhesion and dispersion in HDPE/NR blends were revealed by scanning electron microscopy (SEM). Results showed that a smaller‐sized dispersed phase was achieved for compatibilized blends as compared to that for their uncompatibilized counterparts. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers     

Mechanical properties of wood flake–polyethylene composites. II. Interface modification

This article discusses the methods of interface modification of composites based on raw wood flakes and high‐density polyethylene (HDPE) and the effects of these modifications on composite properties. An HDPE matrix was modified by a reaction with maleic anhydride (MA) in a twin‐screw extruder and then compounded with wood flakes to produce wood–polyethylene composites. Wood flakes were modified by a reaction with a silane coupling agent in an aqueous medium before being compounded with HDPE to produce silane‐modified WPCs. Differential scanning calorimetry and Fourier transform infrared spectroscopy data provide evidence for the existence of a polyethylene (PE)–silane‐grafted wood structure, which acts as a compatibilizer for wood flakes and PE. The results of MA‐modified composites indicate that some maleated HDPE is reacting with wood through esterification to form a compatibilizer for wood flakes and HDPE. Significant improvements in tensile strength, ductility, and Izod impact strength were obtained. Scanning electron micrographs provide evidence for strong interactions between the wood flakes and the matrix agent. The results indicate that 1–2 wt % MA modification on HDPE and 1–3 wt % silane treatment on wood flakes provide WPCs with the optimum properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2505–2521, 2002     

Melt-neutralization of maleic anhydride grafted on high-density polyethylene compatibilizer for polyamide-6/high-density polyethylene blend: effect of neutralization level on compatibility of the blend

Blends of polyamide-6 (PA-6) and high-density polyethylene (HDPE) with blend ratios of 80/20 (wt/wt) and 20/80 (wt/wt) were studied using zinc-neutralized maleic anhydride (MAH) grafted HDPE as compatibilizers. MAH groups were hydrolyzed and neutralized with different amounts of zinc acetate dihydrate in a twin-screw extruder to produce different levels of zinc-neutralization (0, 14, 41, 69, and 95 %) at one and ten parts per hundred of resin of compatibilizer. Melt neutralization of MAH was confirmed by X-ray fluorescence, FT–IR, and rheological properties. SEM micrographs showed a large reduction in the dispersed phase size in the compatibilized blends. Tensile measurements showed improvement of tensile strength for all compatibilized blends; moreover, the elongation at break of compatibilized blends at 10 phr of compatibilizer was improved. Blending increased the crystallization temperature for the PA-6, and the addition of compatibilizer reduced the crystallization temperature slightly. A significant increase in melt viscosity of the compatibilizer was found with zinc addition and adding compatibilizer increased the viscosity of the blends. However, the addition of zinc to the compatibilizer did not change the viscosity in the PA-6-rich blends and actually led to a decrease in viscosity in the HDPE-rich blends.     

Synergistic compatibilization and reinforcement of HDPE/wood flour composites

Multi‐monomer grafted copolymers, high‐density polyethylene‐grafted‐maleic anhydride‐styrene (HDPE‐g‐(MAH‐St)) and polyethylene wax‐grafted‐ maleic anhydride ((PE wax)‐g‐MAH), were synthesized and applied to prepare high‐performance high‐density polyethylene (HDPE)/wood flour (WF) composites. Interfacial synergistic compatibilization was studied via the coordinated blending of high‐density polyethylene‐grafted‐maleic anhydride (MPE‐St) and polyethylene wax‐grafted‐ maleic anhydride (MPW) in the high‐density polyethylene (HDPE)/wood flour (WF) composites. Scanning electron microscopy (SEM) morphology and three‐dimensional WF sketch presented that strong interactive interface between HDPE and WF, formed by MPE‐St with high graft degree of maleic anhydride (MAH) together with the permeating effect of MPW with a low molecular weight. Experimental results demonstrated that HDPE/WF composites compatibilized by MPE‐St/MPW compounds showed significant improvement in mechanical properties, rheological properties, and water resistance than those compatibilized by MPE, MPE‐St or MPW separately and the uncompatibilized composites. The mass ratio of MPE‐St/MPW for optimizing the HDPE/WF composites was 5:1. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42958.