Morphology and mechanical properties of styrene–ethylene/butylene–styrene triblock copolymer/high‐density polyethylene composites

The morphology and mechanical properties of a styrene–ethylene/butylene–styrene triblock copolymer (SEBS) incorporated with high‐density polyethylene (HDPE) particles were investigated. The impact strength and tensile strength of the SEBS matrix obviously increased after the incorporation of the HDPE particles. The microstructure of the SEBS/HDPE blends was observed with scanning electron microscopy and polar optical microscopy, which illustrated that the SEBS/HDPE blends were phase‐separation systems. Dynamic mechanical thermal analysis was also employed to characterize the interaction between SEBS and HDPE. The relationship between the morphology and mechanical properties of the SEBS/HDPE blends was discussed, and the toughening mechanism of rigid organic particles was employed to explain the improvement in the mechanical properties of the SEBS/HDPE blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Degradation of high‐impact polystyrene with processing and its recovery via the addition of styrene–butadiene rubber and styrene–ethylene–butylene–styrene block copolymer

This work was divided into three parts. First, high‐impact polystyrene (HIPS) was submitted to a series of extrusion cycles with the objective of evaluating the consequent variations in its thermal and mechanical properties. The results showed slight variations in both the thermal and mechanical properties of HIPS. Second, degraded HIPS/styrene–ethylene–butylene–styrene (SEBS) blends and degraded HIPS/styrene–butadiene rubber (SBR) blends were prepared to evaluate the influence of the elastomeric concentration on the polymer's properties. The incorporation of SEBS or SBR allowed the recovery of the initial properties shown by virgin HIPS. Finally, blends of degraded HIPS with 2 wt % SEBS or SBR were extruded through four cycles. The mechanical properties remained constant with 2% SEBS added, whereas the mixtures of HIPS with 2% SBR showed an increase in the tensile strength as the number of extrusion cycles increased. The Vicat softening temperature decreased in both cases. The use of differential scanning calorimetry permitted the observation of differences in the crosslinking reactions of different samples as a function of the number of extrusion cycles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Deformation mechanisms and fracture toughness of polystyrene/high‐density polyethylene blends compatibilized by triblock copolymer

A dilatometric technique was used to explore the tensile deformation mechanisms of polystyrene (PS)/high‐density polyethylene (HDPE) blends compatibilized by a styrene–ethylene–butylene–styrene (SEBS) triblock copolymer. The volume change of the sample during a uniaxial tensile process was determined with two extensometers, and it provided useful information concerning the tensile deformation mechanism. A simple model was used in this study in order to obtain quantitative information on the separate contributions of several possible deformation modes to the total deformation. The results indicated that elastic deformation was the main deformation mode for PS. However, elastic deformation was the main mode of deformation prior to yielding for SEBS compatibilized PS/HDPE blends; thereafter the plastic deformations (including shear and crazing) appeared to dominate over the elastic deformation. Moreover, crazing was the main plastic deformation mode for the blend containing 20 wt % HDPE, and shear deformation became predominant when the HDPE content was further increased. Finally, the essential work concept was used to determine the fracture toughness of the typical ductile PS/HDPE/SEBS 10/80/10 blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2024–2033, 2000     

Morphology and mechanical properties of polypropylene/high‐impact polystyrene blends from postconsumer plastic waste

The compatibilizing effect of the triblock copolymer poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) (SEBS) on the morphological and mechanical properties of virgin and recycled polypropylene (PP)/high‐impact polystyrene (HIPS) blends was studied, with the properties optimized for rigid composite films. The components of the blend were obtained from municipal plastic waste, PP being acquired from mineral water bottles (PP_b) and HIPS from disposable cups. These materials were preground, washed only with water, dried with hot air, and ground again (PP_b) or agglutinated (HIPS). Blends with three different weight ratios of PP_b and HIPS (6:1, 6:2, and 6:3) were prepared, and three different concentrations of SEBS (5, 6, and 7 wt %) were used for investigations of its compatibilizing effect. Scanning electron microscopy showed that SEBS reduced the diameter of dispersed HIPS particles in the globular and fibril shapes and improved the adhesion between the disperse phase and the matrix. However, SEBS interactions with PP_b and HIPS influenced the mechanical properties of the compatibilized PP_b/HIPS/SEBS blends. An adequate composition of PP/HIPS, for both virgin and recycled blends, for applications in composite films with characteristics similar to those of synthetic paper was obtained with a minimal amount of SEBS and a maximal HIPS/PP ratio in the range of concentrations studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2861–2867, 2003     

Recycled poly(ethylene terephthalate)/linear low‐density polyethylene blends through physical processing

Poly(styrene‐ethylene/butylene‐styrene) (SEBS) was used as a compatibilizer to improve the thermal and mechanical properties of recycled poly(ethylene terephthalate)/linear low‐density polyethylene (R‐PET/LLDPE) blends. The blends compatibilized with 0–20 wt % SEBS were prepared by low‐temperature solid‐state extrusion. The effect of SEBS content was investigated using scanning electron microscope, differential scanning calorimeter, dynamic mechanical analysis (DMA), and mechanical property testing. Morphology observation showed that the addition of 10 wt % SEBS led to the deformation of dispersed phase from spherical to fibrous structure, and microfibrils were formed at the interface between two phases in the compatibilized blends. Both differential scanning calorimeter and DMA results revealed that the blend with 20 wt % SEBS showed better compatibility between PET and LLDPE than other blends studied. The addition of 20 wt % of SEBS obviously improved the crystallizibility of PET as well as the modulus of the blends. DMA analysis also showed that the interaction between SEBS and two other components enhanced at high temperature above 130°C. The impact strength of the blend with 20 wt % SEBS increased of 93.2% with respect to the blend without SEBS, accompanied by only a 28.7% tensile strength decrease. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of HDPE/SEBS‐g‐MAH and its effect on mechanical properties of HDPE/wood flour composites

In this article, high density polyethylene/styrene‐ethylene‐butylene‐styrene block copolymer blends (HDPE/SEBS) grafted by maleic anhydride (HDPE/SEBS‐g‐MAH), which is an effective compatibilizer for HDPE/wood flour composites was prepared by means of torque rheometer with different contents of maleic anhydride (MAH). The experimental results indicated that MAH indeed grafted on HDPE/SEBS by FTIR analysis and the torque increased with increasing the content of maleic anhydride and dicumyl peroxide (DCP). Styrene may increase the graft reaction rate of MAH and HDPE/SEBS. When HDPE/SEBS MAH was added to HDPE/wood flour composites, tensile strength and flexural strength of composites can reach 25.9 and 34.8 MPa in comparison of 16.5 and 23.8 MPa (without HDPE/SEBS‐g‐MAH), increasing by 157 and 146%, respectively. Due to incorporation of thermoplastic elastomer in HDPE/SEBS‐g‐MAH, the Notched Izod impact strength reached 5.08 kJ m^?2, increasing by 145% in comparison of system without compatibilizer. That HDPE/SEBS‐g‐MAH improved the compatibility was also conformed by dynamic mechanical measurement. Scanning electron micrographs provided evidence for strong adhesion between wood flour and HDPE matrix with addition of HDPE/SEBS‐g‐MAH. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Studies on morphology and mechanical properties of PP/HIPS blends from postconsumer plastic waste

The aim of this work was to study the compatibilizing effect of the triblock copolymer poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) (SEBS) on the morphology and mechanical properties of virgin and recycled polypropylene/high‐impact polystyrene (PP/HIPS) blends. The components of the blend were obtained from municipal plastics waste (MPW), with the PP obtained from blue mineral water bottles, symbolized as PP_b, and the HIPS from disposable cups. These materials were preground, washed only with water, dried with hot air, and ground again (PP_b) or agglutinated (HIPS). Blends of PP_b and HIPS in three weight ratios (6:1, 6:2, and 6:3) were prepared, and three concentrations of SEBS (5.0, 6.0, and 6.7% w/w) were used for investigations of its compatibilizing effect. Scanning electron microscopy (SEM) showed that SEBS reduced the diameter of HIPS dispersed particles that were globular and fibril shaped, along with improving the adhesion between the dispersed phase and the matrix. On the other hand, SEBS interactions with PP_b and HIPS influenced the mechanical properties of the compatibilized PP_b/HIPS/SEBS blends. The optimal concentration of SEBS was 5 wt % for application to composite films with similar characteristics to synthetic paper. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 747–751, 2003     

Mechanical behaviors of ethylene/styrene interpolymer compatibilized polystyrene/polyethylene blends

In this study, ethylene/styrene interpolymer was used as a compatibilizer for the blends of polystyrene (PS) and high‐density polyethylene (HDPE). The mechanical properties including tensile and impact properties and morphology of the blends were investigated by means of uniaxial tension, instrumented falling‐weight impact measurements, and scanning electron microscopy. Tensile tests showed that the yield strength of the PS/HDPE/ESI blends decreases considerably with increasing HDPE content. However, the elongation at break of the blends tended to increase significantly with increasing HDPE content. The excellent tensile ductility of the HDPE‐rich blends resulted from shield yielding of the matrix. Izod and Charpy impact measurements indicated that the impact strength of the blends increases slowly with HDPE content up to 40 wt %; thereafter, it increases sharply with increasing HDPE content. The impact energy of the HDPE‐rich blends exceeded that of pure HDPE, implying that the HDPE polymer can be further toughened by the incorporation of brittle PS minor phase in the presence of ESI compatibilizer. The correlation between the impact property and morphology of the blends is discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4001–4007, 2007     

Morphology and mechanical properties of high‐impact polystyrene/elastomer/magnesium hydroxide composites

Ternary composites of high‐impact polystyrene (HIPS), elastomer, and magnesium hydroxide filler encapsulated by polystyrene were prepared to study the relationships between their structure and mechanical properties. Two kinds of morphology were formed. Separation of elastomer and filler was found when a nonpolar poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] triblock copolymer (SEBS) was incorporated. Encapsulation of filler by elastomer was achieved by using the corresponding maleinated SEBS (SEBS‐g‐MA). The mechanical properties of ternary composites were strongly dependent on microstructure. In this study, the composites with separate dispersion structure showed higher elongation, modulus and impact strength than those of encapsulation structure. Impact‐fracture surface observation showed that the toughening mechanism was mainly due to the massive cavitation and extensive matrix yielding. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5184–5190, 2006     

Phase structure and properties of poly(ethylene terephthalate)/high‐density polyethylene based on recycled materials

Blends based on recycled high density polyethylene (R‐HDPE) and recycled poly(ethylene terephthalate) (R‐PET) were made through reactive extrusion. The effects of maleated polyethylene (PE‐g‐MA), triblock copolymer of styrene and ethylene/butylene (SEBS), and 4,4′‐methylenedi(phenyl isocyanate) (MDI) on blend properties were studied. The 2% PE‐g‐MA improved the compatibility of R‐HDPE and R‐PET in all blends toughened by SEBS. For the R‐HDPE/R‐PET (70/30 w/w) blend toughened by SEBS, the dispersed PET domain size was significantly reduced with use of 2% PE‐g‐MA, and the impact strength of the resultant blend doubled. For blends with R‐PET matrix, all strengths were improved by adding MDI through extending the PET molecular chains. The crystalline behaviors of R‐HDPE and R‐PET in one‐phase rich systems influenced each other. The addition of PE‐g‐MA and SEBS consistently reduced the crystalline level (χ_c) of either the R‐PET or the R‐HDPE phase and lowered the crystallization peak temperature (T_c) of R‐PET. Further addition of MDI did not influence R‐HDPE crystallization behavior but lowered the χ_c of R‐PET in R‐PET rich blends. The thermal stability of R‐HDPE/R‐PET 70/30 and 50/50 (w/w) blends were improved by chain‐extension when 0.5% MDI was added. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Ternary blends of high‐density polyethylene–polystyrene–poly(ethylene/butylene‐b‐styrene) copolymers: Properties and orientation behavior in plane–strain compression

Ternary blends of high‐density polyethylene (HDPE) with atactic polystyrene (PS) and styrene–ethylene/butylene–styrene block copolymer (SEBS) were deformed by plane–strain compression in a channel die. The samples were deformed up to the true strain of 1.8 (compression ratio of 6) at 100°C. Thermal and mechanical properties of the deformed blends were studied in addition to the study of the deformation process. The basic mechanism of plastic deformation is crystallographic slip, the same as that active in deformation of plain HDPE and binary blends of HDPE and PS. This slip is supplemented by the plastic deformation of an amorphous component. In blends of high SEBS content, the role of deformation of an amorphous component by shear and flow increases markedly due to reduced overall crystallinity of these blends. In such blends an amorphous component includes a semicontinuous embedding of crystallites, and therefore, the deformation process is dominated by deformation mechanisms active in a more compliant amorphous phase. Consequently, with increasing the content of SEBS in the blend, the texture of the oriented blends changes from a single‐component (100)[001] texture to a texture with a strong fiber component in addition to a (100)[001] component. In blends with high content of SEBS, the crystalline lamellae of polyethylene do not undergo fragmentation up to the compression ratio of 6, while in blends with low and moderate content of SEBS, such lamellar fragmentation was detected. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1746–1761, 2000     

Mechanical,thermal, and microstructural properties of polypropylene/polyamide‐6/styrene‐ethylene‐butadiene‐styrene polymer alloys

Interfacial agents as compatibilizers have recently been introduced into polymer blends to improve the microstructure and mechanical properties of thermoplastics. In this way, it is possible to prepare a mixture of polymeric materials that can have superior mechanical properties over a wide temperature range. In this study, an incompatible blend of polypropylene (PP) and polyamide‐6 (PA₆) were made compatible by the addition of 10% styrene–ethylene–butadiene–styrene copolymer (SEBS). The mixing operation was conducted by using a twin‐screw extruder. The morphology and the compatibility of the mixtures were examined by SEM and DSC techniques. Furthermore, the elastic modulus, tensile and yield strengths, percentage elongation, hardness, melt flow index, Izod impact resistance, heat deflection temperature (HDT), and Vicat softening point values of polymer alloys of various ratios were determined. It was found that the addition of SEBS to the structures decreased the tensile strength, yield strength, elastic modulus, and hardness, whereas it increased the Izod impact strength and percentage elongation values. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3485–3491, 2003     

Morphology and flame‐retardancy properties of ternary high‐impact polystyrene/elastomer/polystyrene‐encapsulated magnesium hydroxide composites

The effects of elastomer type on the morphology, flammability, and mechanical properties of high‐impact polystyrene (HIPS)/polystyrene (PS)‐encapsulated magnesium hydroxide (MH) were investigated. The ternary composites were characterized by cone calorimetry, mechanical testing, and scanning electron microscopy. Morphology was controlled with poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS) triblock copolymer or the corresponding maleinated poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS‐g‐MA). The HIPS/SEBS/PS‐encapsulated MH composites exhibited separation of the filler and elastomer, whereas the HIPS/SEBS‐g‐MA/PS‐encapsulated MH composites exhibited encapsulation of the filler by SEBS‐g‐MA. The flame‐retardant and mechanical properties of the ternary composites were strongly dependent on microstructure. The composites with an encapsulation structure showed higher flame‐retardant properties than those with a separation structure at the optimum use level of SEBS‐g‐MA. Furthermore, the composites with a separation structure showed a higher modulus and impact strength than those with an encapsulation structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Toughening of recycled polystyrene used for TV backset

The recycled polystyrene (rPS) was toughened with ethylene‐octylene copolymer thermoplastic elastomer (POE) and high‐density polyethylene (HDPE) with various melt flow index (MFI), compatibilized by styrene‐butadiene‐styrene copolymer (SBS) to enhance the toughness of rPS for use as TV backset. The rPS/POE binary blends exhibited an increased impact strength with 5–10 wt % POE content followed by a decrease with the POE content up to 20 wt %, which could be due to poor compatibility between POE and rPS. For rPS/POE/SBS ternary blends with 20 wt % of POE content, the impact strength increased dramatically and a sharp brittle‐ductile transition was observed as the SBS content was around 3–5 wt %. Rheological study indicated a possible formation of network structure by adding of SBS, which could be a new mechanism for rPS toughening. In rPS/POE/HDPE/SBS (70/20/5/5) quaternary blends, a fibril‐like structure was observed as the molecular weight of HDPE was higher (with lower MFI). The presence of HDPE fibers in the blends could not enhance the network structure, but could stop the crack propagation during fracture process, resulting in a further increase of the toughness. The prepared quaternary blend showed an impact strength of 9.3 kJ/m² and a tensile strength of 25 MPa, which can be well used for TV backset to substitute HIPS because this system is economical and environmental friendly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

A study on the effects of SEBS‐g‐MAH on the phase morphology and mechanical properties of polypropylene/polycarbonate/SEBS ternary polymer blends

In this work, five ternary blends based on 70% by weight (wt %) of polypropylene (PP) with 30% wt of polycarbonate (PC)/poly(styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene)(SEBS) dispersed phase consists of 15 wt % PC and 15 wt % reactive (maleic anhydride grafted) and nonreactive SEBS mixtures at various ratios were prepared in a co‐rotating twin screw extruder. scanning electron microscopy (SEM) micrographs showed that the blends containing only nonreactive SEBS exhibited a fine dispersion of core‐shell particles. With decreasing the SEBS/SEBS‐g‐Maleic Anhydride (MAH) weight ratio, the morphology changed from the core‐shell particles to a mixed of core‐shell, rod‐like and individual particles. This variation in phase morphology affected the thermal and mechanical properties of the blends. DSC results showed that the blends containing only nonreactive SEBS exhibited a minimum in degree of crystallinity due to the homogeneous nucleation of core‐shell particles. Mechanical testing showed that in the SEBS/SEBS‐g‐MAH weight ratio of 50/50, the modulus and impact strength increased compared with the PP matrix while the yield stress had minimum difference with that of PP matrix. These effects could be attributed to the formation of those especial microstructures revealed by the SEM studies. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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

The effects of compatibilization on the toughening of polypropylene (PP) by melt blending with styrene/ethylene‐butylene/styrene tri‐block copolymer (SEBS) in a twin‐screw extruder were investigated. The compatibilizers used were SEBS functionalized with maleic anhydride (SEBS‐g‐MA), PP functionalized with acrylic acid (PP‐g‐AA), and bifunctional compound p‐phenylenediamine (PPD). The effects of the compatibilization were evaluated through the mechanical properties as well as through 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 with neat PP; likely the result of the reaction of the bifunctional compound (PPD) with the acid acrylic and maleic anhydride groups, this increase in strength rendered both morphological and mechanical stability to these blends. The addition of PPD to the blends significantly changed their phase morphologies, leading to larger average diameters of the dispersed particles, probably as a result of the morphological stabilization at the initial processing steps during extrusion, with the occurrence of chemical reactions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3466–3479, 2002     

Rheological,mechanical and morphological properties of thermoplastic vulcanizates based on high impact polystyrene and styrene‐butadiene rubber

Thermoplastic vulcanizates (TPVs) based on high impact polystyrene (HIPS)/styrene‐butadiene rubber (SBR) blends were prepared by dynamic vulcanization technique. The rheological, mechanical and morphological properties of the dynamically vulcanized blends were investigated systematically. As determined by capillary rheometer, the apparent viscosity of the blends decreases as the shear rate increases, indicating obvious pseudoplastic behavior. At low shear rate, the apparent viscosity of these blends is considerably higher than that of neat HIPS and decreases with the increase of HIPS concentration. The increase of HIPS content in the dynamically vulcanized blends contributes to the increase of tensile strength and hardness properties, while elongation at break and tensile set at break reach a maximum at 30 and 50 wt % of the HIPS content, respectively. The etched surfaces of the HIPS/SBR TPVs were investigated using field‐emission scanning electron microscopy, the morphological study reveals continuous HIPS phase and finely dispersed SBR elastomeric phase in the TPVs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Blends of polyamide1010 with unmodified and maleic‐anhydride‐grafted high‐impact polystyrene

The crystallization behaviors, dynamic mechanical properties, tensile, and morphology features of polyamide1010 (PA1010) blends with the high‐impact polystyrene (HIPS) were examined at a wide composition range. Both unmodified and maleic‐anhydride‐(MA)‐grafted HIPS (HIPS‐g‐MA) were used. It was found that the domain size of HIPS‐g‐MA was much smaller than that of HIPS at the same compositions in the blends. The mechanical performances of PA1010–HIPS‐g‐MA blends were enhanced much more than that of PA1010–HIPS blends. The crystallization temperature of PA1010 shifted towards higher temperature as HIPS‐g‐MA increased from 20 to 50% in the blends. For the blends with a dispersed PA phase (≤35 wt %), the T_c of PA1010 shifted towards lower temperature, from 178 to 83°C. An additional transition was detected at a temperature located between the T_g's of PA1010 and PS. It was associated with the interphase relaxation peak. Its intensity increased with increasing content of PA1010, and the maximum occurred at the composition of PA1010–HIPS‐g‐MA 80/20. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 857–865, 1999     

Photodegradation of thermodegraded polypropylene/high‐impact polystyrene blends: Mechanical properties

The influence of the addition of high‐impact polystyrene (HIPS) on polypropylene (PP) photodegradation was studied with blends obtained by extrusion with and without styrene–butadiene–styrene (SBS) copolymer (10 wt % with respect to the dispersed phase). The concentrations of HIPS ranged from 10 to 30 wt %. The blends and pure materials were exposed for periods of up to 15 weeks of UV irradiation; their mechanical properties (tensile and impact), fracture surface, and melt flow indices were monitored. After 3 weeks of UV exposure, all of the materials presented mechanical properties of the same order of magnitude. However, for times of exposure greater than 3 weeks, an increasing concentration of HIPS resulted in a better photostability of PP. These results were explained in light of morphological observations. This increase of photostability was even greater when SBS was added to the blends. It was more difficult to measure the melt flow index of the binary PP/HIPS blends than that of PP for low concentrations of HIPS; this was most likely due to energy transfer between the blend domains during photodegradation. This phenomenon was not observed for the ternary blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Compatibilization of polyethylene/poly(propylene)/polystyrene blends

The compatibilization of mixtures of polyolefins or of polyolefins with polystyrene using either liquid polybutadiene (l-PB)/organic peroxide or styrene-butadiene-styrene (SBS) block copolymers was investigated. Tensile impact strength was chosen as a measure of compatibility. Binary blends LDPE/high-impact polystyrene (HIPS) and LDPE/poly(propylene) (PP) as well as LDPE/HDPE/PP/HIPS blends were prepared by blending in the chamber of a Brabender Plasticorder. Composition of the blends corresponds to real commingled plastic waste. It was found that l-PB-based compatibilizer enhanced the impact strength of LDPE/HIPS blends with LDPE contents higher than 60 wt.-% only. Also SBS copolymer enhanced the impact strength of LDPE/PP blends with LDPE contents higher than 40 wt.-%. Both the compatibilizers substantially increased the toughness of LDPE/HDPE/PP/HIPS blends with composition similar to the municipal plastic waste.