Compatibilizing effects of poly(styrene-graft-ethylene oxide) in blends of polystyrene and butyl acrylate polymers

The compatibilizing effect of poly(styrene-graft-ethylene oxide) in polystyrene (PS) blends with poly(n-butyl acrylate) (PBA) and poly(n-butyl acrylate-co-acrylic acid) (PBAAA) was investigated. No significant effects of the graft copolymer on the domain size were found in the PBA blends. By functionalizing PBA with acrylic acid, the average size of the polyacrylate domains was reduced considerably by the graft copolymer. Thermal and dynamic mechanical analysis of the PS/PBAAA blends revealed that the PBAAA glass transition temperature (T_g) decreased with increasing graft copolymer content. The effect of the graft copolymer in the PS/PBAAA blends can be explained by interactions across the interface due to the formation of hydrogen bonds between the poly(ethylene oxide) (PEO) side chains in the graft copolymer and the acrylic acid segments in the PBAAA phase. Hydrogen bonding was confirmed by IR analysis of binary blends of PEO and PBAAA. Partial miscibility in the PEO/PBAAA blends was indicated by a PEO melting point depression and by a T_g reduction of the PBAAA phase. The thermal properties of the PEO/PBA blends indicated only very limited miscibility. © 1996 John Wiley & Sons, Inc.     

Compatibilization of PS and PA6 Blends by Means of Poly(oxyalkylene)amine Modified Styrene-Maleic Anhydride Copolymer

The compatibilization effect of SMA-co-M2070-co-DAP comb-like copolymers, SMMD, on immiscible blends of polystyrene (PS) and polyamide-6 (PA6) is examined in terms of phase structure, thermal behavior, dynamic mechanical analysis, and mechanical properties. A series of SMMD copolymers are synthesized and confirmed by the FT-IR analysis. These compatibilizers have different amphiphilic properties depending on the content of hydrophilic poly(oxyethylene) segments (M2070) and the molar ratio of MA/amine. The morphologies of PS/PA6, affected by the increasing amount of SMMD compatibilizer, show a more regular and finer dispersion. The sizes of dispersed particles have no marked changes over the saturation level of compatibilizer. The glass transition temperatures of the blends are between that of PS and PA6, while the added SMMD copolymer is mainly located at the interface. Using these SMMD copolymers, the compatibilized blends show some improvements in mechanical properties, including Izod impact strength and flexural properties. The graft poly(oxyethylene) and amide functionalities in SMMD structures in forming hydrogen bonding with PA6 and, the polystyrene backbone in π–π interaction with PS facilitate the compatibilizing effect.     

Polymer blends of polyamide-6 and poly(phenylene oxide) compatibilized by styrene-co-glycidyl methacrylate

Incompatible polymer blends between polyamide-6 (PA6) and poly(phenylene oxide) (PPO) have been compatibilized in situ by the styrene-glycidyl methacrylate (SG) reactive copolymers. The epoxy functional groups in SG copolymers can react with the PA6 amine and carboxylic endgroups at interface to form various SG-g-PA6 copolymers. These in situ-formed grafted copolymers tend to anchor along interface to function as compatibilizer of the blends. The styrene and the SG segments of the grafted copolymers are miscible (or near miscible) with PPO; whereas the PA6 segments are structurally identical with PA6 phase. The compatibilized blend, depending on quantity of the compatibilizer addition and the glycidyl methacrylate (GMA) content in the SG copolymer, results in smaller phase domain, higher viscosity, and improved mechanical properties. About 5% GMA is the optimum content in SG copolymer that produces the best compatibilization of the blends. This study demonstrates that SG reactive copolymers can be used effectively in compatibilizing polymer blends of PA6 and PPO. © 1996 John Wiley & Sons, Inc.     

离聚体增容PA1010／SBS共混物的研究

采用磺化丁基胶锌盐(ZnSIIR)离聚体作为PA1010/SBS共混物的增容剂,研究了共混体系的结构、形态、相容性及对材料冲击性能的影响。结果表明,ZnSIIR的加入有效改善了SBS在PA1010中的相容性;对PA1010结晶起成核作用,并加快其结晶速率;共混物缺口冲击强度得到提高,且在PA1010/SBS为90/10、ZnSIIR为SBS的10％左右时效果较佳。     

Blend composition dependence of the compatibilizing efficiency of graft copolymers for immiscible polymer blends

This work is concerned with the dependence of the compatibilizing efficiency of graft copolymers on the composition of immiscible polymer blends. A series of graft copolymers of polystyrene (PS) and polyamide 6 (PA6), denoted as PS‐g‐PA6, with different molecular structures were used as compatibilizers. The PS‐g‐PA6 was more efficient for the PS/PA6 (80/20) blend than for the PS/PA6 (20/80) one, indicating that a graft copolymer whose backbone and grafts match the matrix and the disperse phase polymers, respectively, has higher compatibilizing efficiency. This is in disagreement with the literature. Moreover, whatever the blend composition, for PS‐g‐PA6 graft copolymers with the same backbone and the same number of grafts per backbone, the longer the grafts, the higher their compatibilizing and stabilizing efficiency; for a given backbone/graft mass ratio, the longer the grafts and concomitantly the smaller the number of grafts per backbone, the higher the compatibilizing and stabilizing efficiency of the graft copolymer. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

In situ polymer/polymer composites from poly(ethylene terephthalate), polyamide-6, and polyamide-66 blends

In situ reinforced binary and ternary polymer/polymer composites are obtained by the melt blending of poly(ethylene terephthalate) (PET), polyamide-6 (PA-6), and polyamide-66 (PA-66) in an extruder in the presence of a catalyst, followed by drawing of the extrudate and annealing of the drawn blends. The blends were studied by DSC, X-ray, SEM, and mechanical testing. After drawing, all the components were found to be oriented, forming microfibrils with diameters of about 1–2 μm. The chemical nature of the homopolymers affects the blends' morphologies; while the PA-66/PA-6 blend is homogeneous, phase separation is established in the case of PET/PA-6. The decrease in the enthalpy of melting of the blend components as well as the depression of their peaks of crystallization from the melt, compared to pure homopolymers, are indications that block copolymers have been formed via interchange reactions during the blending process. On the one hand, these copolymers improve the compatibility of the homopolymers, and on the other hand, they alter the chemical composition of the blends. After thermal treatment at 245°C, i.e., above the T_m of PA-6, the latter undergoes some disorientation, while PET and PA-66 retain their microfibrillar shape, and in this way, a compositelike structure is created. The presence of chemical bonds between the separate phases via copolymers favors the cocrystallization of PA-66 and PA-6 as well as the cooperative crystallization of PET, PA-6, and PA-66, both modes fostering improved compatibility (adhesion) of the blend components. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 723–737, 1998     

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.     

高密度聚乙烯／尼龙1010共混体系的研究

采用接枝共聚方法,合成了高密度聚乙烯与马来酸酐,甲基丙烯酸和丙烯酸丁酯的接枝共聚物增容剂,研究了增容剂中接枝单体的种类及含量和增容剂用量等因素对高密度聚乙烯／尼龙1010共混体系力学性能的影响,结果表明在不同类型的接枝共聚物中以聚乙烯马来酸酐接枝共聚物对HDPE／PA1010共混体系的增容效果最好,在接枝单体含量和增容剂用量分别为4％－6％和5％左右时,共混体系的力学性能最好。     

Tracer‐compatibilizer: Synthesis and applications in polymer blending processes

This article reports on a route to synthesizing fluorescent labeled graft copolymers, on the one hand; and on a concept of tracer‐compatibilizer for facile build‐up of emulsification curves of polymer blends, on the other hand. For these purposes, blends composed of polystyrene (PS) and polyamide 6 (PA6) are chosen. The synthesis of the corresponding tracer‐compatibilizer consists of three steps: (1) copolymerization of styrene with 3‐isopropenyl‐α,α'‐dimethybenzyl isocyanate (TMI); (2) conversion of a fraction of the isocyanate moieties of the resulting copolymer into anthracene ones upon reacting with 9‐(methylamino‐methyl)anthracene (MAMA); and (3) polymerization of ε‐caprolactam (CL) from the remaining isocyanate moieties. The resulting fluorescent labeled graft copolymer, denoted as PS‐g‐PA6‐Ant, is used to build up emulsification curves of PS/PA6 blends in a twin screw extruder (TSE), showing great usefulness of the concept of tracer‐compatibilizer. POLYM. ENG. SCI. 2012. © 2011 Society of Plastics Engineers     

Improved compatibility between polyamide and polypropylene by the use of maleic anhydride grafted SEBS

Blends containing equal weight fractions of polypropylene (PP) and polyamide (PA-6 and PA-6.6) and up to 25% of a compatibilizing thermoplastic elastomer, either polystyrene-block-poly(ethylene-stat-butylene)-block-polystyrene (SEBS) or SEBS modified by maleic anhydride (SEBS-MA), were prepared by melt mixing. In all these blends, PP formed the continuous matrix phase. Even at high concentrations, unmodified SEBS was found to be a poor compatibilizer, affecting mainly the properties of the matrix. The graft copolymer formed, by reaction between SEBS-MA and polyamide during melt mixing, strongly influenced the blend morphology, by forming an interphase, separating the PA phase domains from the matrix. The crystallization behaviour of PP indicated that full coverage required between 3% and 5% SEBS-MA at the intense mixing conditions used. Above this level, the total surface area of the polyamide domains seemed to increase in direct proportion to the concentration of SEBS-MA. The thickness of the interphase layer was estimated to be about 15 nm. At high concentrations of SEBS-MA, the PA domains agglomerated and formed extended structures held together by the interphase polymer. This was reflected by the stress–strain and rheological behaviour of the blends. In blends with PA domains of small volume, crystallization of PA was delayed. The rate of water absorption was very low in blends containing SEBS-MA, much lower than in corresponding blends containing SEBS.     

Miscible blends of styrene-acrylic acid copolymers with aliphatic,crystalline polyamides

Styrene-acrylic acid copolymers exhibit miscibility with various aliphatic, crystalline polyamides (e.g., nylon 6, 11, and 12) at 20% acrylic acid content in the copolymer. At 8% acrylic acid, phase separation is observed with the crystalline polyamides. At 14% acrylic acid, partial miscibility is observed with each polyamide, resulting in the T_g's of the constituents shifted toward the other constituent. The miscibility of the styrene-acrylic acid copolymers ( > 14 wt % AA) can be ascribed to hydrogen bonding interactions with the polyamides. Styrene-acrylic acid (20% AA) copolymers are miscible with other nylons with alternating amide orientation along the chain (e.g., nylon 6,6 and nylon 6,9). These samples tend to crosslink upon exposure to temperatures above the polyamide melting point unlike the nylon 6, 11, and 12 blends in which branching may only occur. Nylon 11/styrene-acrylic acid blends were chosen for crystallization rate studies. A melting point depression of nylon 11 occurs with addition of the styrene-acrylic acid (20% AA). The Flory-Huggins interaction parameter from the melting point depression is calculated to be -0.27. The crystallization rate of nylon 11 is significantly reduced with the addition of the miscible SAA copolymers (20% AA). The spherulitic growth rate equation predicts this behavior based on a T_g increase with SAA addition.     

The effect of reactive compatibilization of carboxylated polystyrene on morphology and toughness of polyamide-1010/polystyrene blends

The morphology and notched impact behaviour of polyamide-1010/polystyrene (PA1010/PS) (90/10) blends compatibilized by carboxylated polystyrene (CPS) have been studied. It is found that the addition of CPS has a beneficial effect upon the morphology of the resulting blends which leads to a finer dispersion of the PA1010 spherulites and of the PS particles in the PA1010 matrix. However, with increasing CPS content, the shape of the PS domains appears less regular, which may be due to the cracking of the PS spherical domains. Infrared analysis was performed to confirm the formation of PS–PA1010 graft copolymer during the blending process. The notched impact toughness of the compatibilized blends shows a maximum which is almost triple that of the binary blend at approximately 5 wt% of the CPS addition based on the amount of PS. © 1999 Society of Chemical Industry     

Miscibility in blends of linear and branched poly(ethylene oxide) with methacrylate derivative random copolymers and estimation of segmental χ parameters

Miscibility in the blends of poly(ethylene oxide) (PEO) with n-hexyl methacrylate-methyl methacrylate random copolymers (HMA-MMA) and 2-ethylhexyl methacrylate-MMA random copolymers (EHMA-MMA) was evaluated using glass transition and light scattering methods. EHMA-MMA was more miscible with PEO than HMA-MMA. Both blends of PEO with HMA-MMA and EHMA-MMA showed UCST-type miscibility although homopolymer blends PEO/PMMA were predicted to be of LCST-type. This was attributed to an increase in the exchange enthalpy with increasing HMA or EHMA composition in the random copolymer. From the copolymer composition dependence of miscibility the segmental χ parameters of HMA/MMA, EHMA/MMA, EO/HMA and EO/EHMA were estimated using the Flory-Huggins theory extended to random copolymer systems. Miscibility in the blends of branched PEO with HMA-MMA whose HMA copolymer composition was 0.16 was compared with that in the linear PEO blends. The former blends were more miscible with HMA-MMA than the latter one by about 35 °C at the maximum cloud point temperature.     

Reactive compatibilizer precursors for LDPE/PA6 blends. III: ethylene-glycidylmethacrylate copolymer

The effectiveness of a commercial ethylene-glycidylmethacrylate copolymer (Lotader GMA AX 8840) as a compatibilizer precursor (CP) for blends of low density polyethylene (LDPE) with polyamide-6 (PA) has been evaluated by an investigation of the thermal properties and the morphology of binary (LDPE/CP and PA/CP) and ternary (LDPE/PA/CP) blends, as well as by solvent fractionation experiments. It has been demonstrated that the epoxy groups of the CP react quite easily, during melt blending, with both the amine and the carboxyl end groups of PA to give CP-g-PA copolymers, which, depending on the relative amounts of PA and CP, may be partially cross-linked. The composition of the graft copolymers has been approximately determined by gravimetric and calorimetric measurements. The compatibilizing efficiency of the CP employed in this work has been found to be comparable to that of the ethylene-acrylic acid copolymers, and lower than that of a maleic anhydride-functionalized polyethylene, which had been used in previous works.     

Efficiency of graft copolymers at stabilizing co-continuous polymer blends during quiescent annealing

This work was aimed at studying the efficiency of graft copolymers at stabilizing the co-continuous morphology of polystyrene (PS)/polyamide 6 (PA6) blends during quiescent annealing. A series of graft copolymers with PS as backbone and PA6 as grafts, denoted as PS-g-PA6, with different molecular structures and compositions were used as compatibilizers. The co-continuous domain size of the blends without PS-g-PA6 increased almost linearly with annealing time. The addition of the PS-g-PA6 not only narrowed down the composition range of co-continuity of PS/PA6 blend but also slowed down and even stopped completely the coarsening of the co-continuous morphology during the quiescent annealing. Moreover, the efficiency of PS-g-PA6 depended very much on its molecular structure and/or composition. For graft copolymers with similar backbone and graft chain number, the longer the grafts, the higher their stabilizing efficiency. For a given backbone/graft composition, graft copolymers having fewer and longer grafts were more efficient at compatibilizing and stabilizing the co-continuous morphology.     

Graft copolymers of poly(methyl methacrylate) and polyamide-6 via in situ anionic polymerization of ε-caprolactam and their properties

Graft copolymers of poly(methyl methacrylate) and polyamide-6 (PMMA-g–PA6) were investigated via in situ anionic polymerization of ε-caprolactam, using PMMA precursors with N-carbamated caprolactam pendants (PMMA–CCL) as macroactivators and sodium caprolactamate as catalyst. Three grades of PMMA–CCLs obtained by free radical copolymerization were used for synthesizing the PMMA-g–PA6 copolymers with different PMMA content. The resulting graft copolymer was characterized by Fourier-transform infrared spectroscopy and selective extraction. Scanning electron microscopy is used to clarify the phase morphology of obtained polymer by fracture surface. The thermal property, crystallinity and dimensional stability of graft copolymer were studied using differential scanning calorimetry, X-ray diffraction and water absorption measurement. The results show the T_g of graft copolymer is higher than that of neat PA6, but the onset and peak points of graft copolymer melting point are shifted to lower temperature. The percentage crystallinity and water absorption of PMMA-g–PA6 copolymer decrease with increasing PMMA content, but the crystal structure of PA6 is scarcely affected by the presence of PMMA. Graft copolymers have improved dimensional stabilities relative to neat PA6. Upon the incorporation of 19.9 wt% PMMA into PA6, the water absorption of PMMA-g–PA6 copolymer has been reduced from 4.8 for neat PA6 to 2.1%.     

Poly(ethylene‐graft‐ethylene oxide) (PE‐PEO) and poly(ethylene‐co‐acrylic acid) (PEAA) as compatibilizers in blends of LDPE and polyamide‐6

In a blend of two immiscible polymers a controlled morphology can be obtained by adding a block or graft copolymer as compatibilizer. In the present work blends of low‐density polyethylene (PE) and polyamide‐6 (PA‐6) were prepared by melt mixing the polymers in a co‐rotating, intermeshing twin‐screw extruder. Poly(ethylene‐graft‐polyethylene oxide) (PE‐PEO), synthesized from poly(ethylene‐co‐acrylic acid) (PEAA) (backbone) and poly(ethylene oxide) monomethyl ether (MPEO) (grafts), was added as compatibilizer. As a comparison, the unmodified backbone polymer, PEAA, was used. The morphology of the blends was studied by scanning electron microscopy (SEM). Melting and crystallization behavior of the blends was investigated by differential scanning calorimetry (DSC) and mechanical properties by tensile testing. The compatibilizing mechanisms were different for the two copolymers, and generated two different blend morphologies. Addition of PE‐PEO gave a material with small, well‐dispersed PA‐spheres having good adhesion to the PE matrix, whereas PEAA generated a morphology characterized by small PA‐spheres agglomerated to larger structures. Both compatibilized PE/PA blends had much improved mechanical properties compared with the uncompatibilized blend, with elongation at break (ε_b) increasing up to 200%. Addition of compatibilizer to the PE/PA blends stabilized the morphology towards coalescence and significantly reduced the size of the dispersed phase domains, from an average diameter of 20 μm in the unmodified PE/PA blend to approximately 1 μm in the compatibilized blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2416–2424, 2000     

Effect of the composition of α-MSAN copolymer on the miscibility of PVC/α-MSAN blends

A series of α-methylstyrene, styrene, and acrylonitrile (α-MSAN) copolymers with different acrylonitrile (AN) contents were synthesized by altering α-MSt, St, and AN ratios with emulsion copolymerization method. By melt-blending these copolymers with PVC resin and di-isooctyl phthalate (DOP), PVC/α-MSAN, and PVC/α-MSAN/DOP blends were prepared. The miscibility and morphology of the blends were investigated by dynamic mechanical analysis (DMA) and scanning electron microscopy. The PVC is immiscible with SAN by melt-mixing, whereas PVC is miscible with α-MSAN (α-MSt/St = 1/1) if AN weight percent is within the window range of 20–25 wt %, and α-MSAN (not containing St) with 35 wt % AN is miscible with PVC even when they are blended by melt-mixing. Replacement of styrene with α-methylstyrene widens the miscibility window with PVC. The miscibility of PVC/α-MSAN blends is substantially improved with the increasing α-MSt content in α-MSAN copolymer containing identical AN content. When DOP was introduced into the PVC/α-MSAN (α-MSt/St = 1/1) blends, a single tan δ peak over room temperature in DMA detection is found as AN content in α-MSAN copolymer is within the range of 15–25 wt %, and SEM observation also shows that the blends are homogeneous. When the AN content in α-MSAN copolymer is over 35 wt %, the presence of DOP causes the phase domain extended. The phase domain size of the PVC/α-MSAN/DOP blends intensively depends on AN content in α-MSAN copolymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Studies on the Effect of Polyamide-6 onto Modified Polyphenylene Oxide Matrix in Presence of Fumaric Acid as a Compatibilizer

Polymer blends of modified polyphenylene oxide (mPPO) and polyamide-6 (PA-6) are immiscible and incompatible in nature. However fumaric acid (FA) is used as a compatibilizer for the compatibilizing of mPPO/PA-6 blend systems. During melt compounding functional groups of the polymer components were reacted in the presence of a compatibilizer in the extruder. The blends were characterized by using FTIR, SEM, and mechanical behavior testing. The concentration of FA compatibilizer varies inversely w.r.t. PA-6 concentration in the blend systems. However the blend composition of PA-6 (10%) shows good miscibility among the other blend systems under present study.     

PVC／ABS共混体系的相容性与形态结构研究

采用种子乳液聚合技术在聚丁二烯（PB）乳胶粒子上接枝共聚苯乙烯（St）、α-甲基苯乙烯（α—MSt）和丙烯腈（AN）单体,合成了一系列不同AN结合量的ABS和α—MABS接枝共聚物。将其与聚氯乙烯（PVC）树脂熔融共混制得了PVC／AtkS共混物,利用扫描电镜（SEM）、透射电镜（TEM）和动态力学分析仪（DMA）对共混物的相容性和相结构进行了表征。结果发现,在PVC／ABS共混体系中,尽管改变接枝SAN共聚物的AN结合量,PVC和ABS接枝共聚物均为不相容体系;在ABS接枝共聚物中引入α-MSt后,当接枝SAN共聚物的AN结合量为18．7％～23．6％（质量分数）时,共混物在室温以上只存在1个tanδ峰,共混物成为相容体系,当AN结合量达到32．1％（质量分数）时,共混物成为部分相容体系。共混物的相区尺寸明显地依赖于接枝SAN共聚物中的AN结合量,与动态力学性能结果表现出良好的吻合。