Effect of the compatibilizer on the morphology and properties of dynamically cured PP/POE/epoxy blends

Dynamic vulcanization was successfully applied to epoxy resin reinforced polypropylene (PP)/ethylene‐octene copolymer (POE) blends, and the effects of different compatibilizers on the morphology and properties of dynamically cured PP/POE/epoxy blends were studied. The results show that dynamically cured PP/POE/epoxy blends compatibilized with maleic anhydride‐grafted polypropylene (MAH‐g‐PP) have a three‐phase structure consisting of POE and epoxy particles dispersed in the PP continuous phase, and these blends had improved tensile strength and flexural modulus. While using maleic anhydride‐grafted POE (MAH‐g‐POE) as a compatibilizer, the structure of the core‐shell complex phase and the PP continuous phase showed that epoxy particles could be embedded in MAH‐g‐POE in the blends, and gave rise to an increase in impact strength, while retaining a certain strength and modulus. DSC analysis showed that the epoxy particles in the blends compatibilized with MAH‐g‐PP were more efficient nucleating agents for PP than they were in the blends compatibilized with MAH‐g‐POE. WAXD analysis shows that compatibilization do not disturb the crystalline structure of PP in the blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Nonisothermal crystallization and melting behavior of β‐nucleated isotactic polypropylene and polyamide 66 blends

A highly novel nano‐CaCO₃ supported β‐nucleating agent was employed to prepare β‐nucleated isotactic polypropylene (iPP) blend with polyamide (PA) 66, β‐nucleated iPP/PA66 blend, as well as its compatibilized version with maleic anhydride grafted PP (PP‐g‐MA), maleic anhydride grafted polyethylene‐octene (POE‐g‐MA), and polyethylene‐vinyl acetate (EVA‐g‐MA), respectively. Nonisothermal crystallization behavior and melting characteristics of β‐nucleated iPP and its blends were investigated by differential scanning calorimeter and wide angle X‐ray diffraction. Experimental results indicated that the crystallization temperature (T) of PP shifts to high temperature in the non‐nucleated PP/PA66 blends because of the α‐nucleating effect of PA66. T of PP and the β‐crystal content (K_β) in β‐nucleated iPP/PA66 blends not only depended on the PA66 content, but also on the compatibilizer type. Addition of PP‐g‐MA and POE‐g‐MA into β‐nucleated iPP/PA66 blends increased the β‐crystal content; however, EVA‐g‐MA is not benefit for the formation of β‐crystal in the compatibilized β‐nucleated iPP/PA66 blend. It can be relative to the different interfacial interactions between PP and compatibilizers. The nonisothermal crystallization kinetics of PP in the blends was evaluated by Mo's method. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and properties of dynamically cured PP/MAH‐g‐EVA/epoxy blends

A method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin with 2‐ethylene‐4‐methane‐imidazole (EMI‐2,4) was successfully applied in the PP/maleic anhydride‐grafted ethylene‐vinyl acetate copolymer (MAH‐g‐EVA), and the obtained blends named as dynamically cured PP/MAH‐g‐EVA/epoxy blends. The stiffness and toughness of the blends are in a good balance, and the smaller size of epoxy particle in the PP/MAH‐g‐EVA/epoxy blends shows that MAH‐g‐EVA was also used as a compatibilizer. The structure of the dynamically cured PP/MAH‐g‐EVA/epoxy blends is the embedding of the epoxy particles by the MAH‐g‐EVA. The cured epoxy particles as organic filler increases the stiffness of the PP/MAH‐g‐EVA blends, and the improvement in the toughness is attributed to the embedded structure. The tensile strength and flexural modulus of the blends increase with increasing the epoxy resin content, and the impact strength reaches a maximum of 258 J/m at the epoxy resin content of 10 wt %. DSC analysis shows that the epoxy particles in the dynamically cured PP/MAH‐g‐EVA/epoxy blends could have contained embedded MAH‐g‐EVA, decreasing the nucleating effect of the epoxy resin. Thermogravimetric results show the addition of epoxy resin could improve the thermal stability of PP, the dynamically cured PP/MAH‐g‐EVA/epoxy stability compared with the pure PP. Wide‐angle x‐ray diffraction analysis shows that the dynamical cure and compatibilization do not disturb the crystalline structure of PP in the blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Dynamically cured polypropylene/Novolac blends compatibilized with maleic anhydride‐g‐polypropylene

In this article, the dynamic vulcanization process was applied to polypropylene (PP)/Novolac blends compatibilized with maleic anhydride‐grafted PP (MAH‐g‐PP). The influences of dynamic cure, content of MAH‐g‐PP, Novolac, and curing agent on mechanical properties of the PP/Novolac blends were investigated. The results showed that the dynamically cured PP/MAH‐g‐PP/Novolac blend had the best mechanical properties among all PP/Novolac blends. The dynamic cure of Novolac improved the modulus and stiffness of the PP/Novolac blends. The addition of MAH‐g‐PP into dynamically cured PP/Novolac blend further enhanced the mechanical properties. With increasing Novolac content, tensile strength, flexural modulus, and flexural strength increased significantly, while the elongation at break dramatically deceased. Those blends with hexamethylenetetramine (HMTA) as a curing agent had good mechanical properties at HMTA content of 10 wt %. Scanning electron microscopy (SEM) analysis showed that dynamically cured PP/MAH‐g‐PP/Novolac blends had finer domains than the PP/MAH‐g‐PP/Novolac blends. Thermogravimetric analysis (TGA) results indicated that the incorporation of Novolac into PP could improve the thermal stability of PP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Peroxide‐catalyzed swell grafting of maleic anhydride onto polypropylene

A new grafting method was developed to incorporate maleic anhydride directly onto solid‐state polypropylene powders. Maleic anhydride grafts altered the nonpolar characteristics of polypropylene so that much better mixing was achieved in blends and composites of polypropylene with many other polymers and fillers. Maleic anhydride was grafted onto polypropylene by the peroxide‐catalyzed swell grafting method, with a maximum extent of grafting of 4.60%. Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, tensile testing, and impact testing were used to characterize the isotactic polypropylene (iPP), maleic anhydride grafted polypropylene (MAH‐g‐iPP), and (isotactic polypropylene)/(calcium carbonate) composites (iPP/CaCO₃). The crystallinity and heat of fusion of the MAH‐g‐iPP decreased as the extent of grafting increased. The mechanical properties of the CaCO₃ filled polypropylene were improved by adding MAH‐g‐iPP as a compatibilizing agent. The dispersion of the fillers in the polymer matrix and the adhesion between the CaCO₃ particles and the polymer matrix were improved by adding the compatibilizer.     

Dynamically cured polypropylene/epoxy blends

The dynamic vulcanization process, usually used for the preparation of thermoplastic elastomers, was used to prepare polypropylene (PP)/epoxy blends. The blends had crosslinked epoxy resin particles finely dispersed in the PP matrix, and they were called dynamically cured PP/epoxy blends. Maleic anhydride grafted polypropylene (MAH‐g‐PP) was used as a compatibilizer. The effects of the reactive compatibilization and dynamic cure were studied with rheometry, capillary rheometry, and scanning electron microscopy (SEM). The crystallization behavior and mechanical properties of PP/epoxy, PP/MAH‐g‐PP/epoxy, and dynamically cured PP/epoxy blends were also investigated. The increase in the torque at equilibrium for the PP/MAH‐g‐PP/epoxy blends indicated the reaction between maleic anhydride groups of MAH‐g‐PP and the epoxy resin. The torque at equilibrium of the dynamically cured PP/epoxy blends increased with increasing epoxy resin content. Capillary rheological measurements also showed that the addition of MAH‐g‐PP or an increasing epoxy resin content increased the viscosity of PP/epoxy blends. SEM micrographs indicated that the PP/epoxy blends compatibilized with PP/MAH‐g‐PP had finer domains and more obscure boundaries than the PP/epoxy blends. A shift of the crystallization peak to a higher temperature for all the PP/epoxy blends indicated that uncured and cured epoxy resin particles in the blends could act as effective nucleating agents. The spherulites of pure PP were larger than those of PP in the PP/epoxy, PP/MAH‐g‐PP/epoxy, and dynamically cured PP/epoxy blends, as measured by polarized optical microscopy. The dynamically cured PP/epoxy blends had better mechanical properties than the PP/epoxy and PP/MAH‐g‐PP/epoxy blends. With increasing epoxy resin content, the flexural modulus of all the blends increased significantly, and the impact strength and tensile strength increased slightly, whereas the elongation at break decreased dramatically. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1437–1448, 2004     

Toughening of PP/EPDM blend by compatibilization

To improve the mechanical properties of blends of polypropylene (PP) and terpolymer of ethylene–propylene–diene (EPDM), a triblock copolymer, (PP‐g‐MAH)‐co‐[PA‐6,6]‐co‐(EPDM‐g‐MAH), was synthesized by coupling reaction of maleic anhydride (MAH)‐grafted PP (PP‐g‐MAH), EPDM‐g‐MAH, and PA‐6,6. The newly prepared block copolymer brought about a physical interlocking between the blend components, and imparted a compatibilizing effect to the blends. Introducing the block copolymer to the blends up to 5 wt % lead to formation of a β‐form crystal. The wide‐angle X‐ray diffractograms measured in the region of 2θ between 10° and 50° ascertained that incorporating the block copolymer gave a new peak at 2θ = 15.8°. The new peak was assigned to the (300) plane spacings of the β‐hexagonal crystal structure. In addition, the block copolymer notably improved the low‐temperature impact property of the PP/EPDM blends. The optimum usage level of the compatibilizer proved to be 0.5 wt %. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1267–1274, 2000     

Synthesis and characterization of high‐density polypropylene‐grafted polyethylene via a macromolecular reaction and its rheological behavior

High‐density polyethylene grafted isotactic polypropylene (PP‐g‐HDPE) was prepared by the imidization reaction between maleic anhydride grafted polyethylene and amine‐grafted polypropylene in a xylene solution. The branch density was adjusted by changes in the molar ratio between maleic anhydride and primary amine groups. Dynamic rheology tests were conducted to compare the rheological properties of linear polyolefins and long‐chain‐branched polyolefins. The effects of the density of long‐chain branches on the rheological properties were also investigated. It was found that long‐chain‐branched hybrid polyolefins had a higher storage modulus at a low frequency, a higher zero shear viscosity, a reduced phase angle, enhanced shear sensitivities, and a longer relaxation time. As the branch density was increased, the characteristics of the long‐chain‐branched structure became profounder. The flow activation energy of PP‐g‐HDPE was lower than that of neat maleic anhydride grafted polypropylene (PP‐g‐MAH) because of the lower flow activation energy of maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MAH). However, the flow activation energy of PP‐g‐HDPE was higher than that of PP‐g‐MAH/HDPE‐g‐MAH blends because of the presence of long‐chain branches. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of compatibilizer on micromehanical deformations and morphology of dispersion in PP/PDMS blend

Role of maleic anhydride grafted polypropylene (PP‐g‐MAH) in interface modification in polypropylene (PP)/poly(dimethylsiloxane) (PDMS) elastomer blend has been investigated in this article through its effects on morphology of dispersion, micromechanical deformations such as voiding, crazing, shear yielding, fibrillation, and tensile behavior. During tensile deformation, PP/PDMS blend without the compatibilizer showed debonding at the elastomer‐matrix interface and it induced shear yielding and subsequently fibrillation in the matrix. The compatibilizer improved the interfacial adhesion between the PDMS domains and PP matrix, which prevented the debonding at elastomer‐matrix interface and the resulting shear yielding, and fibrillation was absent and rather caused extensive crazing in the matrix. Addition of PP‐g‐MAH reduced the size of dispersed PDMS domains, and narrowed the domain size distribution, which is attributed as an effect of interfacial adhesion produced by PP‐g‐MAH. Stress–strain curve and fibrillation also show similar effect of the interfacial adhesion caused by the compatibilizer. All these observations consistently lead to conclude that PP‐g‐MAH acts as a good compatibilizer for PP/PDMS blend. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Effect of maleic anhydride grafted polybutadiene on the compatibility of polyamide 66/acrylonitrile‐butadiene‐styrene copolymer blend

The addition of maleic anhydride grafted polybutadiene (PB‐g‐MAH) can greatly improve the compatibility of polyamide 66 (PA66)/acrylonitrile‐butadiene‐styrene copolymer (ABS) blends. Unlike the commonly used compatibilizers in polyamide/ABS blends, PB‐g‐MAH is compatible with the ABS particles' core phase polybutadiene (PB), rather than the shell styrene‐acrylonitrile (SAN). The compatibility and interaction of the components in the blends were characterized by Fourier transform‐infrared spectra (FTIR), Molau tests, melt flow index (MFI), dynamic mechanical analyses (DMA), and scanning electron microscopic (SEM) observations. The results show that PB‐g‐MAH can react with the amino end groups in PA66 while entangle with the PB phase in ABS. In this way, the compatibilizer anchors at the interface of PA66/ABS blend. The morphology study of the fracture sections before and after tensile test reveals that the ABS particles were dispersed uniformly in the PA66 matrix and the interfacial adhesion between PA66 and ABS was increased significantly. The mechanical properties of the blends thus were enhanced with the improving of the compatibility. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

PET/PP blending by using PP‐g‐MA synthesized by solid phase

In attempts to improve the compatibility of polypropylene (PP) with polyethylene terephthalate (PET), a maleic anhydride grafted PP (PP‐g‐MA) was evaluated as a compatibilizer in a blend of 30/70 wt % PP/PET. PP‐g‐MA was produced from isotactic homopolymer PP utilizing the technique of solid phase graft copolymerization. Qualitative confirmations of the grafting were made by Fourier transform infrared spectroscopy (FTIR). Three different weight percent of compatibilizer, PP‐g‐MA, i.e., 5, 10, and 15 wt % have been used in PP/PET blends. The compatibilizing efficiency for PP/PET blend was examined using differential scanning calorimetry (DSC), optical microscopy (OM), scanning electron microscopy (SEM) of crycrofractured surfaces, and energy dispersive X‐ray spectrum (EDAX). The results show that the grafted PP promotes a fine dispersed phase morphology, improves processability, and modifies the crystallization behavior of the polyester component. These effects are attributed to enhance phase interaction resulting in reduced interfacial tension. Also, the results show that the compatibilizing effects of the three amounts of grafted PP in blend are different and dependent on the amount used. Adding 10 wt % of compatibilizer into blend produced the finest dispersed morphology. Elemental analysis results show that PP is matrix. DSC determination revealed that the melting temperature (T_m) of the PET component declined to some extent by comparison with neat PET. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 3986–3993, 2007     

Effect of maleic anhydride/vinyltrimethoxysilane‐co‐grafting polypropylene on the properties of wood‐flour/polypropylene composites by electron‐beam preirradiation

The electron‐beam preirradiation and reactive extrusion technologies were used to prepare maleic anhydride (MAH)/vinyltrimethoxysilane (VTMS)‐co‐grafting polypropylene (PP) as a high‐performance compatibilizer for wood‐flour/PP composites. The grafting content, chemical structure, and crystallization behavior of the compatibilizers were characterized through Fourier transform infrared spectroscopy, differential scanning calorimetry, and an extraction method. The effects of the compatibilizers on the mechanical properties, water absorption, morphological structure, and torque rheological behavior of the composites were investigated comparatively. The experimental results demonstrate that MAH/VTMS‐g‐PP markedly enhanced the mechanical properties of the composites. Compared with MAH‐g‐PP and VTMS‐g‐PP, MAH/VTMS‐g‐PP clearly showed synergistic effects on the increasing mechanical properties, water absorption, and compatibility of the composites. Scanning electron microscopy further confirmed that the adhesion and dispersion of wood flours in the composites were effectively improved by MAH/VTMS‐g‐PP. These results were also proven by the best water resistance of the wood‐flour/PP composites with MAH/VTMS‐g‐PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Compatibilization of polypropylene/Poly(acrylonitrile‐butadiene‐styrene) blends by polypropylene‐graft‐cardanol

The polypropylene‐graft‐cardanol (PP‐g‐cardanol) was prepared by reactive extrusion with polypropylene (PP) and natural renewable cardanol which could increase the interfacial energy of PP and inhibit the degradation of PP during the process of reactive extrusion and usage. In this article, PP‐g‐cardanol and polypropylene‐graft‐maleic anhydride (PP‐g‐MAH) were used as compatibilizers of the polypropylene (PP)/poly(acrylonitrile‐butadiene‐styrene) (ABS) blends. PP/ABS (70/30, wt %) blends with PP‐g‐cardanol and PP‐g‐MAH were prepared by a corotating twin‐screw extruder. From the results of morphological studies, the droplet size of ABS was minimized to 1.93 and 2.01 μm when the content of PP‐g‐cardanol and PP‐g‐MAH up to 5 and 7 phr, respectively. The results of mechanical testing showed that the tensile strength, impact strength and flexural strength of PP/ABS (70/30) blends increase with the increasing of PP‐g‐cardanol content up to 5 phr. The complex viscosity of PP/ABS (70/30) blends with 5 phr PP‐g‐cardanol showed the highest value. Moreover, the change of impact strength and tensile strength of PP/ABS (70/30) blends were investigated by accelerated degradation testing. After 4 accelerated degradation cycles, the impact strength of the PP/ABS (70/30) blends with 5 phr PP‐g‐cardanol decrease less than 6%, but PP/ABS (70/30) blends with 5 phr PP‐g‐MAH and without compatibilizer decrease as much as 12% and 32%, respectively. The tensile strength of PP/ABS (70/30) blends has a similar tendency to that of impact strength. The above results indicated that PP‐g‐cardanol could be used as an impact modifier and a good compatibilizer, which also exhibited better stability performance during accelerated degradation testing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41315.     

Effects of clay contents on the dynamic mechanical and rheological properties of polypropylene/MAH‐g‐POE/clay composites

A series of polypropylene/maleic anhydride grafted polypropylene octane elastomer (MAH‐g‐POE)/clay (PPMC) nanocomposites were prepared with a novel compatilizer MAH‐g‐POE and different contents of octadecyl amine modified montmorillonite, and the effects of clay contents on the dynamic mechanical and rheological properties of these PPMC composites were investigated. With clay content increasing, the characteristic X‐ray diffraction peak changed from one to two with intensity decreasing, indicating the decreasing concentration of the intercalated clay layers. The gradual decrease of crystallization temperature of PPMC composites with the increase of clay loading should be attributed to the preferred intercalation of MAH‐g‐POE molecules into clay interlayer during blending, which is also reflected by scanning electron microscopy observations. By evaluating the activation energy for the glass transition process of MAH‐g‐POE and polypropylene (PP) in the PPMC composites, it is found that clay intercalation could cause the restriction effect on the glass transition of both MAH‐g‐POE and PP, and this restriction effect appears stronger for PP and attained the highest degree at 5 wt % clay loading. The melt elasticity of PP could be improved apparently by the addition of MAH‐g‐POE, and 5 wt % clay loading is enough for further enhancing the elastic proportion of PP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Study on the microstructure and properties of bromobutyl rubber (BIIR)/polyamide‐12 (PA12) thermoplastic vulcanizates (TPVs)

In this study, polyamide‐12 (PA12)/brominated isobutylene‐isoprene (BIIR) TPVs with good mechanical properties and low gas permeability were prepared by dynamic vulcanization in a twin‐screw extruder. The effects of three kinds of compatibilizers on the microstructure and properties of BIIR/PA12 TPV were studied. The compatibility between BIIR and PA12 was improved when maleated hydrocarbon polymeric compatibilizer is added. The reaction between maleic anhydride and amine in polyamide leads to the in situ formation of hydrocarbon polymer grafted polyamide which subsequently can be used to lower the interfacial tension between BIIR and polyamide. The compatibilizing effect of maleic anhydride modified polypropylene (PP‐g‐MAH) on BIIR/PA12 blends is the best among these compatibilizers because the surface energy of PP‐g‐MAH is very close to that of BIIR. The dispersed rubber phase of the blend compatibilized by PP‐g‐MAH shows the smallest size and more uniform size distribution, and the resulting TPVs show the best mechanical properties. The effects of fillers on the properties of BIIR/PA12 TPV were also investigated. The size of the BIIR phase increases with the increase in the content of CaCO₃. The modulus and tensile strength of TPVs increased with the increase in the content of CaCO₃ because of the reinforcing effect of CaCO₃ on TPVs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43043.     

The effect of graft copolymers of maleic anhydride and epoxy resin on the mechanical properties and morphology of PP/ABS blends

In this work, maleic anhydride‐grafted polypropylene (PP‐g‐MAH) and maleic anhydride‐grafted poly(acrylonitrile‐butadiene‐styrene) (ABS‐g‐MAH) at 2 : 1 mass ratio were added as a compatibilizer in the PP/ABS blends. The compatibilizing effect was evaluated by adding the graft copolymers together with epoxy resin/imidazole curing agent (E51/2E4MZ). The reaction in reactive extrusion, morphological structure, and properties of PP and ABS blends were investigated by using infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X‐ray spectrum, transmission electron microscope (TEM), dynamic thermomechanical analysis (DMA), differential scanning calorimetry (DSC), and mechanical properties tests. The results showed that the compatibilizing effect was greatly improved because of the addition of the graft copolymers together with epoxy resin/imidazole curing agent (E51/2E4MZ) because the link structure of PP‐g‐MAH and ABS‐g‐MAH was formed by the reaction of anhydride group with epoxy group catalyzed by the imidazole. The size of the dispersed phase decreased dramatically, the interfacial adhesion between ABS particles and PP matrix was improved, and the tensile strength and flexural modulus of the PP/ABS blends increased further. The optimizing properties were obtained at 3 phr E51/2E4MZ. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40898.     

Morphology and mechanical properties of polyamide‐6/K resin blends

Mechanical properties and morphological studies of compatibilized blends of polyamide‐6 (PA‐6)/K resin grafted with maleic anhydride (K‐g‐MAH) and PA‐6/K resin/K‐g‐MAH were investigated as functions of K resin/K‐g‐MAH and dispersed phase K resin concentrations, and all the blends were prepared using twin screw extruder followed by injection molding. Scanning electron microscopy (SEM) were used to assess the fracture surface morphology and the dispersion of the K resin in PA‐6 continuous phase, the results showing extensive deformation in presence of K‐g‐MAH, whereas, uncompatibilized PA‐6/K resin blends show dislodging of K resin domains from the PA‐6 matrix. Dynamic mechanical thermal analysis (DMTA) test reveals the partially miscibility of PA‐6 with K‐g‐MAH, and differential scanning calorimetry (DSC) results further identified that the introduction of K‐g‐MAH greatly improved the miscibility between PA‐6 and K resin. The mechanical properties of PA‐6/K resin blends and K‐g‐MAH were studied through bending, tensile, and impact properties. The Izod notch impact strength of PA‐6/K‐g‐MAH blends increase with the addition of K‐g‐MAH, when the K‐g‐MAH content adds up to 20 wt %, the impact strength is as more than 6.2 times as pure PA‐6, and accompanied with small decrease in the tensile and bending strength less than 12.9% and 17.5%, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

High‐frequency welding of thermoplastic LLDPE/PA 6/PE‐g‐MAH ternary blends

High frequency (HF) welding of linear low density polyethylene (LLDPE) melt blends with polyamide 6 (PA6) was done at 27.12 MHz using maleic anhydride grafted polyethylene (PE‐g‐MAH) as compatibilizer. HF welding was not possible for the blends at room temperature, but possible at higher temperatures (50, 80°C) although the maximum relaxation frequency was lower than the operating frequency. Greater dielectric constant, dissipation factor, and welding performance were obtained when PA 6 was premixed with PE‐g‐MAH rather than the one‐shot process where all the components were mixed simultaneously. This was interpreted in terms of lowered viscosity of PA 6 phase, which encapsulates the flow effectively and provides great skin effect. Also, the peeling force of resin–resin was greater than resin–nylon mesh due to the higher melting temperature and vacancy of nylon mesh. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Isotactic polypropylene toughened with poly(acrylonitrile–butadiene–styrene): Compatibilizing role of maleic anhydride grafted polypropylene

The β‐nucleating activity and toughening effect of acrylonitrile–butadiene–styrene (ABS) graft copolymer on isotactic polypropylene (iPP) and the compatibilizing role of maleic anhydride grafted polypropylene (PP‐g‐MAH) on the iPP/ABS blends were investigated. The results show that ABS can induce the formation of β‐crystal in iPP, and its β‐nucleating efficiency depends on its concentration and dispersibility. The relative content of β‐crystal form is up to 36.19% with the addition of 2% ABS. The tensile and impact properties of the iPP were dramatically enhanced by introducing ABS. The incorporation of PP‐g‐MAH into the iPP/ABS blends inhibits the formation of β‐crystal. The crystallization peaks of the blends shift toward higher temperature, due to the heterogeneous nucleation effect of PP‐g‐MAH on iPP. The toughness of iPP/ABS blends improved due to favorable interfacial interaction resulting from the compatibilization of PP‐g‐MAH is significantly better than the β‐crystal toughening effect induced by ABS. POLYM. ENG. SCI., 59:E317–E326, 2019. © 2019 Society of Plastics Engineers     

Extrusion foaming behavior of a polypropylene/nanoclay microcellular foam

With maleic anhydride grafted polypropylene (PP‐g‐MAH) as a compatibilizer, composites of block‐copolymerized polypropylene (B‐PP)/nanoclay were prepared. The effects of the PP‐g‐MAH and nanoclay content on the crystallization and rheological properties of B‐PP were investigated. The microcellular foaming behavior of the B‐PP/nanoclay composite material was studied with a single‐screw extruder foaming system with supercritical (SC) carbon dioxide (CO₂) as the foaming agent. The experimental results show that the addition of nanoclay and PP‐g‐MAH decreased the melt strength and complex viscosity of B‐PP. When 3 wt % SC CO₂ was injected as the foaming agent for the extrusion foaming process, the introduction of nanoclay and PP‐g‐MAH significantly increased the expansion ratio of the obtained foamed samples as compared with that of the pure B‐PP matrix, lowered the die pressure, and increased the cell population density of the foamed samples to some extent. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44094.