Compatibilizers for recycling of the plastic mixture wastes. II. The effect of a compatibilizer for binary blends on the properties of ternary blends

In this article, we discuss the effect of a compatibilizer for binary blends on the properties of ternary blends composed of high‐density polyethylene (HDPE), polypropylene (PP), or polystyrene (PS) and poly(vinyl chloride) (PVC) virgin polymers with a simulated waste plastics fraction. Chlorinated polyethylene (CPE), ethylene–propylene rubber (EPR), and their 1/1 (w/w) mixture were tested as compatibilizers for the HDPE/PP/PVC ternary blend. CPE, styrene‐ethylene‐propylene block copolymer (SEP), or their 1/1 (w/w) mixture were tested as compatibilizers for the HDPE/PS/PVC ternary blend. The composition of the ternary blends were fixed at 8/1/1 by weight ratio. The amount of the compatibilizer was 3 phr. Rheological, mechanical, and thermal properties were measured. For the 8/1/1 HDPE/PP/PVC ternary blends, the tensile strength was slightly decreased, but the impact strength was significantly increased by adding EPR, CPE, or their mixture. EPR exhibited the most significant impact modification effect for the ternary blends. In a similar way, for 8/1/1 HDPE/PS/PVC ternary blends, on adding SEP, CPE, or their mixture, the tensile strength was slightly decreased, but the impact strength was noticeably increased. It was found that the SEP worked much better as an impact modifier for the ternary blends than CPE or the SEP/CPE mixture did. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1048–1053, 2000     

Compatibilization of commingled plastics with maleic anhydride modified polyethylenes and ultraviolet preirradiation

The improvement of the properties of commingled plastics was carried out with a prototype blend of Mexican municipal plastic waste with and without poly(vinyl chloride) (PVC). Compatibilizing agents such as high‐density, low‐density, and linear low‐density polyethylenes modified with maleic anhydride were used. The agents were prepared in the laboratory with peroxide, and their usefulness was compared with that of a commercially modified linear low‐density polyethylene. The blends with PVC were preirradiated with ultraviolet radiation for 12, 24, or 48 h to create oxidized groups to help in situ compatibilization during the blending step of the reactive extrusion process. Compatibilized materials showed a markedly more homogeneous morphology with improved mechanical properties: the elongation at break and impact strength increased with the compatibilization level. The presence of PVC in commingled plastics significantly reduced the beneficial effect of the maleic anhydride modified polyethylene as a compatibilizer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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     

A compatibilized composite of recycled polypropylene filled with cellulosic fiber from recycled corrugated paper board: Mechanical properties,morphology, and thermal behavior

This article deals with the feasibility of using recycled corrugated paper board (rPF) as the reinforcing material for recycled plastics. The composites of recycled polypropylene (rPP) and rPF were prepared by extrusion compounding and injection molding, and the rPP/rPF composites compatibilized by maleic anhydride grafted PP (PP‐g‐MA), maleic anhydride grafted ethylene‐1‐octene copolymer (POE‐g‐MA), and maleic anhydride grafted styrene‐ethylene‐butylene‐styrene copolymer (SEBS‐g‐MA) were also prepared. The crystallization and melting behavior, mechanical properties, thermal stability, and morphology of these composites were studied. The results indicated that rPF promoted the crystallization, enhanced the strength and toughness of rPP/rPF composites to some extent while decreased thermal stability at the same time. PP‐g‐MA and POE‐g‐MA improved the dispersion and interface adhesion of rPF, and further upgraded the mechanical properties and vicat softening temperatures. Among these compatibilizers, PP‐g‐MA was most favorable to the strength improvement while POE‐g‐MA was most favorable to the toughness improvement. As for SEBS‐g‐MA, it had no obvious modification effect. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Blends of bisphenol A polycarbonate and rubber‐toughened styrene–maleic anhydride copolymers

The morphology and mechanical properties of polycarbonate (PC) blends with rubber‐toughened styrene–maleic anhydride copolymer materials (TSMA) were investigated and compared with the properties of blends of PC with acrylonitrile–butadiene–styrene (ABS) materials. The PC/TSMA blends showed similar composition dependence of properties as the comparable PC/ABS blends. Polycarbonate blends with TSMA exhibited higher notched Izod impact toughness than pure PC under sharp‐notched conditions but the improvements are somewhat less than observed for similar blends with ABS. Since PC is known for its impact toughness except under sharp‐notched conditions, this represents a significant advantage of the rubber‐modified blends. PC blends with styrene–maleic anhydride copolymer (SMA) were compared to those with a styrene–acrylonitrile copolymer (SAN). The trends in blend morphology and mechanical properties were found to be qualitatively similar for the two types of copolymers. PC/SMA blends are nearly transparent or slightly pearlescent. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1508–1515, 1999     

Recycling of high density polyethylene/poly(vinyl chloride)/polystyrene ternary mixture with the aid of high energy radiation and compatibilizers

Ternary mixtures of waste plastics of high density polyethylene (HDPE), poly(vinyl chloride) (PVC), and polystyrene (PS) was recycled using a single‐screw extruder. Poly(ethylene‐co‐vinyl acetate) and poly(styrene‐b‐ethylene/butylenes‐b‐styrene) were introduced as compatibilizers for HDPE/PVC and HDPE/PS, respectively. After the polymer blends was prepared via extrusion, they were subjected to high energy irradiation. The morphology and the mechanical properties of the hybrid blends were examined. Scanning electron micrographs and transmission electron micrographs showed that both compatibilizers and irradiation improved the uniformity and dispersion of the system. The heterogeneous crosslinking generated by irradiation resulted in an optimum impact strength. High elongation at break was achieved by using compatibilizers. The improvement of tensile strength was moderate. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2756–2762, 2003     

Thermoplastic composites from maleic anhydride modified post-consumer plastics

In attempts to identify potential applications for refined commingled postconsumer plastics, a feedstock containing about 80% polyethylene (PE) and lesser amounts of poly(ethylene terephthalate) (PET), polystyrene (PS), polypropylene (PP), and poly(vinyl chloride) (PVC) was modified through functionalization with maleic anhydride in a co-rotating intermeshing twin-screw extruder. The modified and unmodified blends were compounded with various fillers and reinforcements such as glass fibers, mica flakes, talc, and calcium carbonate. Injection molded composites based on the modified matrix had, in general, superior mechanical and thermal properties. These findings are discussed in view of the improved adhesion resulting from reactions and/or enhanced polar interactions at phase boundaries. Several compounds prepared in this work had overall property data comparable to, or approaching those, of equivalent commercial HDPE molding compounds that are commonly used in “durable” applications.     

Crystallization and dynamic mechanical properties of polypropylene/polystyrene blends modified with maleic anhydride and styrene

Polypropylene (PP)/polystyrene (PS) blends modified with reactive monomers, such as maleic anhydride (MAH) and styrene (St), and in situ formed PP/PS blends were prepared by melting extrusion. The crystallization and melting behavior and the dynamic mechanical properties of the PP/PS blends, including the structure of the grafted copolymer, were investigated with differential scanning calorimetry, dynamic mechanical analysis, and Fourier transform infrared. The results indicated that the addition of MAH hardly influenced the crystallization temperature of PP in the blends, but the addition of MAH and St increased the crystallization temperature of PP in its blends. The blends showed no remarkable variety for the melting temperature, but the shapes of the melting peaks were influenced by the addition of the reactive monomers. In addition, a significant increase in the storage and loss moduli of all the modified PP/PS blends was observed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2038–2045, 2005     

Comparative study of maleated polypropylene as a coupling agent for recycled low‐density polyethylene/wood flour composites

The effects of the type of coupling agent and virgin polypropylene (PP) content on the mechanical properties and water absorption behavior of recycled low‐density polyethylene/wood flour (WF) composites were investigated. The fractured surfaces of these recycled wood/plastic composites (rWPCs) were examined to gain insight into the distribution and dispersion of WF within the polymer matrix. The results indicate that the use of 100% recycled polymer led to inferior mechanical properties and to a greater degree of moisture absorption and swelling when compared to recycled polymer–virgin PP wood/plastic composites. This could have been related to the poor melt strength and inferior processability of the recycled polymer. The extent of improvement of the mechanical properties depended not only on the virgin PP content in the matrix but also on the presence of maleic anhydride (MA) modified PP as the coupling agent. Higher concentrations of MA group were beneficial; this improvement was attributed to increased chemical bonding (ester linkages) between hydroxyl moieties in WF and anhydride moieties in the coupling agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Novel reactive compatibilization strategy on immiscible polypropylene and polystyrene blend

Polypropylene (PP) and polystyrene (PS) are immiscible and incompatible. Since both PP and PS components possess no reactive functional group, reactive compatibilization of a PP/PS blend is impossible unless certain reactive functional groups are imparted to either PP or PS. In this study we provide a simple approach to reactively compatibilize the nonreactive PP/PS blend system by physically functionalizing PP and PS with the addition of maleic anhydride grafted PP (PP‐g‐MA) and styrene maleic anhydride random copolymer (SMA), respectively. An epoxy monomer, serving as a coupler and possessing four epoxy groups able to react with the maleic anhydride of PP‐g‐MA and SMA, was then added during melt blending. Observations of the finer PS domain sizes and improved mechanical properties support the plausibility of reactive compatibilization of this nonreactive PP/PS blend by combining physically functionalized PP and PS with tetra‐glycidyl ether of diphenyl diamino methane (TGDDM) in a one‐step extrusion process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

The Effect of Multiple Compatibilizers on the Impact Properties of Polypropylene/Polystyrene (PP/PS) Blend

Effects of compatibilizers on impact properties of polypropylene/ polystyrene (PP/PS) blends were studied and carried out through melt blending using co- rotating twin-screw extruder. A combination of two compatibilizers, maleic anhydride grafted polypropylene (PP-g-MA) and styrene maleic anhydride (SMA) was applied into PP/PS blends. Results from the Izod impact strengths, SEM observations and contact angle measurements in PP(50)/PS(50) blends indicated a better compatibilization effect with the use of dual compatibilizers. This was most probably due to improved adhesion between phases in PP/PS blend systems. The use of dual compatibilizers in the blend compositions produced higher impact properties in the PP/PS blend systems compared to single compatibilizer system.     

Morphology and mechanical properties of polyamide 12 blends with styrene/ethylene–butylene/styrene rubbers with and without maleation

Blends of polyamide 12 (PA12) with styrene/ethylene–butylene/styrene (SEBS) and maleic anhydride grafted SEBS (SEBS‐g‐MA) were prepared by twin‐screw extrusion and injection molding. The morphology, mechanical properties, and dynamic mechanical properties of the blends were studied. The morphology of the blends was evaluated from the etched surfaces of cryogenically fractured specimens with scanning electron microscopy. The morphological parameters showed that the PA12/SEBS‐g‐MA blends (PM series) exhibited a finer and more uniform rubber dispersion than the PA12/SEBS blends (PS series) because of the interfacial chemical reactions. SEBS functionalization via maleic anhydride grafting strongly affected the morphological parameters, such as the domain size, interfacial area per unit of volume, and critical interparticle distance, but the distribution of the rubber domains in the blends was less affected. Tensile and impact studies showed that the PS blends had worse mechanical properties than the PM blends. The tensile strength and elongation at break of the PM blends were considerably greater than those of the PS blends. The fracture toughness and energy values determined for notched Charpy specimens in high‐speed impact tests were markedly higher for the PM blends than for the PS blends. A similar observation was obtained from instrumented falling weight impact studies. Dynamic mechanical analysis confirmed the incompatibility of the blend components because the glass‐transition temperatures of PA12 and the rubber phase (SEBS and SEBS‐g‐MA) were not affected. © 2005 Wiley Periodicals, Inc. J Appl polym Sci 95: 1376–1387, 2005     

聚丙烯固相接枝物增容PA6/PS共混体系

采用FTIR和WAXD研究了聚丙烯固相接枝苯乙烯（St)和马来酸酐（MAH）的结构，并研究了它对聚酰胺6／聚苯乙烯（PA6／PS）共混体系力学性能的影响及其非等温结晶动力学，研究结果表明，PP上可固相接枝St,MAH;gPP(PP接枝St和MAH双组分接枝物）增容PA6／PS的非等温结晶动力学与MandelKern理论基本吻合。     

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     

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

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

Mechanical,thermal, and morphological properties of recycled polycarbonate/recycled poly(acrylonitrile‐butadiene‐styrene) blend nanocomposites

The present work aims within the context of plastic recycling is to upgrade the properties of plastic waste particularly the two engineering plastics polycarbonate (PC) and poly (acrylonitrile‐butadiene‐styrene) (ABS) from electrical and electronic equipment. Recycled polycarbonate (RPC) and recycled poly (acrylonitrile‐butadiene‐styrene) (RABS) were obtained from E‐waste suppliers. RPC/RABS blends compatibilized with both maleic anhydride‐grafted polypropylene (MAP) and solid epoxy resin was prepared by microinjection molding. The effect of compatibilizer addition on the morphology and mechanical properties of RPC/RABS blends were analyzed. Further, to upgrade the mechanical and thermal properties two types of organically modified nanoclays closite 30B (C30B) and closite 15A (C15A) were incorporated into the optimized blend compositions. The effect of organoclay on the mechanical, thermal, and morphological properties of the RPC/RABS blend nanocomposites was investigated. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Polystyrene and polyester polyurethane elastomer blends compatibilized by SMA

Blends of polystyrene (PS) with polyester polyurethane elastomer (PU‐es) were compatibilized by addition of poly(styrene‐co‐maleic anhydride) (SMA) containing 7 wt % of maleic anhydride. Binary nonreactive (PS/PU‐es) blends, binary reactive (SMA/PU‐es) blends, and ternary reactive blends (PS/SMA/PU‐es) were prepared with 10 and 20 wt % of PU‐es. The maleic anhydride content in the ternary reactive blends was varied through addition of different SMA amounts from 0.5 to 5 wt %. Polyurethane in the blends was crosslinked by using dicumyl peroxide or sulfur to improve its mechanical properties. The experimental processing conditions, such as temperature and rotor speed in an internal mixer, were analyzed before blend preparation by processing the individual polymers, PS and SMA, and the PS/PU‐es nonreactive blend (90/10), to prevent the degradation of the polymer during melt mixing and to assure macroscopic homogeneity. The torque behavior during the mixture indicated a grafting copolymerization, which was responsible for the significant drop of the PU‐es domain size in the glassy matrix, as observed by scanning electronic microscopy (SEM). The miscibility of the glassy matrix, which was shown to be dependent on the composition and the phase behavior of ternary blends, became very complex as the SMA concentration increased, as concluded from dynamical–mechanical analysis. Blends containing 20 wt % of PU‐es presented an increase up to a factor of 2 in the deflection at break in relation to PS. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2297–2304, 2004     

Recycling of blends of acrylonitrile–butadiene–styrene (ABS) and polyamide

The aim of this work is to evaluate routes to upgrade recycled engineering plastics, especially mixed plastics with acrylonitrile–butadiene–styrene copolymers (ABS) as the major component. A core‐shell impact modifier was successfully used to improve the impact strength of blends of ABS and ABS/polycarbonate (PC) blends recycled from the automotive industry. However, the presence of other immiscible components like polyamide (PA), even in small amounts, can lead to a deterioration in the overall properties of the blends. A styrene–maleic anhydride (SMA) copolymer and other commercial polymer blends were used to promote the compatibilization of ABS and PA. The core‐shell impact modifier was again found to be an efficient additive with regard to the impact strength of the compatibilized ABS/PA blends. The results obtained with fresh material blends were quite promising. However, in blends of recycled ABS and glass‐fiber‐reinforced PA, the impact strength did not exhibit the desired behavior. The presence of poorly bonded glass fibers in the blend matrix was the probable reason for the poor impact strength compared with that of a blend of recycled ABS and mineral‐filled PA. Although functionalized triblock rubbers (SEBS–MA) can substantially enhance the impact strength of PA, they did not improve the impact strength of ABS/PA blends because the miscibility with ABS is poor. The possibilities of using commercial polymer blends to compatibilize otherwise incompatible polymer mixtures were also explored giving promising results. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2535–2543, 2002     

Compatibility effect of reactive copolymers on polypropylene/polyamide 6 blends from commingled plastic wastes

We report the compatibility effect on a recycled polypropylene/nylon (75/25) blend processed with reactive copolymers on the basis of morphological, mechanical, and rheological characteristics. Via a scanning electron microscopy investigation, we found improved surface morphologies with regular and fine domains in a recycled polypropylene/nylon (75/25) blend compatibilized with copolymers containing maleic anhydride as a reactive functional group [styrene–(ethylene/butylene)–styrene‐graft‐maleic anhydride copolymer and polypropylene‐graft‐maleic anhydride]. Large increases in both the mechanical and rheological properties with the addition of the styrene–(ethylene/butylene)–styrene‐graft‐maleic anhydride copolymer could be interpreted with respect to a specific structure at the interface, showing a strong interfacial adhesion between recycled polypropylene and nylon. To confirm the existence of this structure, we used various dynamic rheological parameters: the Cox–Merz rule, storage modulus, and phase angle. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1188–1193, 2006     

Polystyrene and polyether polyurethane elastomer blends compatibilized by SMA: Morphology and mechanical properties

Blends of polystyrene (PS) and the polyether polyurethane elastomer (PU‐et) were prepared by melt mixing using poly(styrene‐co‐maleic anhydride) (SMA) containing 7 wt % of maleic anhydride as a compatibilizer. The polyurethane in the blends was crosslinked using dicumyl peroxide or sulfur. The content of maleic anhydride was varied in the blends through the addition of different SMA amounts. The morphology of the blends was analyzed by SEM and a drastic reduction of both the domain size and its distribution was observed with increase of the anhydride content in the blends. The morphology of the PU‐et blends also showed dependence on the crosslinker agent used for the elastomer, and larger domains were obtained for the elastomer phase crosslinked with dicumyl peroxide. The mechanical properties of the blends were evaluated by flexural and impact strength tests. The blend containing 0.5 wt % of maleic anhydride and 20 wt % of PU‐et crosslinked with sulfur showed the highest strength impact, which was three times superior to the PS strength impact, and the blends containing 20 wt % of PU‐et crosslinked with dicumyl peroxide showed the highest deflection at break independent of the anhydride content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 830–837, 2002