Reactive compatibilization of PP/PBT blends by a mixture of PP‐g‐MA and epoxy resin

In this study, dual compatibilizers composed of the commercially available maleic anhydride‐grafted polypropylene (PP–MA) and a multifunctional epoxy resin were demonstrated to effectively compatibilize the immiscible and incompatible blends of PP and poly(butylene terephthalate) (PBT). The PP–MA with a low MA content is totally miscible with PP to make the PP phase quasi‐functionalized, so that the multifunctional epoxy has the chance to react with PBT and PP–MA simultaneously to form PP–MA‐co‐epoxy‐co‐PBT copolymers at the interface. These desired copolymers are able to anchor along the interface and serve as efficient compatibilizers. The compatibilized blends, depending on the quantity of dual compatibilizers employed, exhibit higher viscosity, finer phase domain, and improved mechanical properties. Epoxy does not show compatibilization effects for the PP/PBT blends without the presence of PP–MA in the blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2272–2285, 2001     

Dispersion of TiO2 Particles in PET/PP/TiO2 and PET/PP/PP‐g‐MA/TiO2 Composites Prepared with Different Blending Procedures

2 vol.‐% TiO₂ particles were incorporated into PET/PP blends with and without MA‐grafted PP compatibilizer. During extrusion of the PET/PP/TiO₂ composites the TiO₂ particles migrated from the PP matrix to the PET‐dispersed phase irrespective of the blending route. For the PET/PP/PP‐g‐MA/TiO₂ composites, however, the location of TiO₂ depended on the blending sequence. The preferred location of the TiO₂ nanoparticles was confirmed by SEM pictures taken from the chemically etched surface of the blends. The observed migration behavior was traced to differences in the interfacial tensions between TiO₂ and PET and TiO₂ and PP, and to TiO₂ encapsulation in one of the blend components during the related blending procedure.

     

Effect of inclusions and blending on the mechanical performance of recycled multilayer PP/PET/SiOx films

Extending the useful life of materials through recycling has proven to be an efficient means of reducing natural resource use and limiting the production of waste. In the case of polymer‐based materials, in general, and of packaging materials, in particular, material recovery is complicated by the presence of incompatible polymers, as well as a priori undesirable contaminants such as inorganic inclusions. This article investigated the recycling of multilayer packaging material systems, based on polypropylene and silicon oxide‐coated poly(ethylene terephthalate). In particular, the effect of a compatibilization of the blend using maleic anhydride‐grafted polypropylene on the mechanical properties of the recycled material was examined. Without a compatibilizer, and at low compatibilizer concentrations, the blend exhibits a coarse morphology and is brittle. At a concentration of 5% wt of the compatibilizer, a fine morphology is obtained, and the blend shows excellent ductility. Beyond this concentration, a brittle interphase forms between the blend constituents, with a corresponding decrease in ductility. These results were confirmed by a study of strain‐induced crystallization in the blend. Furthermore, the size of the SiO_x inclusions, resulting from the fragmentation of the oxide coating during reprocessing, had no detectable influence on the mechanical properties of the recycled blend, providing that their concentration is lower than 2 × 10⁻³. This study showed that a control of both the microstructure and interface properties considerably improves the mechanical properties of the recycled material, leading to high added‐value applications. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 910–918, 2000     

Effect of functionalized SWCNTs on microstructure of PP‐g‐MA/OMMT/f‐SWCNTs nanocomposite

The aim of this work was to study the effect of functionalized single‐walled carbon nanotubes (f‐SWCNTs) on the microstructure of PP‐g‐MA/organic modified montmorillonite (OMMT)/f‐SWCNTs ternary nanocomposite. Pristine SWCNTs were chemically modified by maleic anhydride to improve the interaction between PP‐g‐MA and nanotubes. The dispersion states of OMMT in the different nanocomposites were investigated by wide angle X‐ray diffraction. The morphologies of the nanocomposites were characterized by scanning electron microscopy. Crystallization behaviors of nanocomposites were studied through differential scanning calorimetry and polarizing optical microscopy. Different than the PP‐g‐MA/OMMT binary nanocomposite, in which the OMMT is mainly in an exfoliated state, the ternary PP‐g‐MA/OMMT/f‐SWCNTs nanocomposite exhibits mostly intercalated OMMT. Furthermore, in the ternary nanocomposite, the crystallization of polymer is mainly induced by f‐SWCNTs rather than by OMMT. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of the type of nylon chain‐end on the compatibilization of PP/PP‐GMA/nylon 6 blends

Polyamide and polypropylene (PP) are two important classes of commercial polymers; however, their direct mixing leads to incompatible blends with poor properties. Polypropylene functionalized with glycidyl methacrylate (PP‐GMA) was used as a compatibilizer in blends of PP and nylon 6, because of the possible reaction of ? NH₂ and ? COOH groups with the epoxide group of GMA. Two types of nylon 6 with different ratios between ? NH₂ and ? COOH groups were used. The one with higher concentration of ? COOH groups was less compatible with PP in a binary blend. When PP‐GMA was used as a compatibilizer, a better dispersion of nylon in the PP matrix was obtained together with better mechanical properties for both nylons used in this work. © 2001 Society of Chemical Industry     

Thermal evaluation of PHB/PP‐g‐MA blends and PHB/PP‐g‐MA/vermiculite bionanocomposites after biodegradation test

This study aimed to evaluate the thermal behavior of polyhydroxybutyrate (PHB)/polypropylene grafted with maleic anhydride (PP‐g‐MA) blends and PHB/PP‐g‐MA/vermiculite bionanocomposites submitted to the biodegradation test according to ASTM G 160‐03. The blends and bionanocomposites were prepared by melt intercalation method using a single screw extruder, and then, compression molded. The thermal analyzes were performed by thermogravimetry (TG) and differential scanning calorimetry. It was verified the decrease of onset degradation temperature and the melting temperature mainly after 86 days of exposure to the simulated soil. This behavior was more pronounced in bionanocomposites because of interactions between the maleic anhydride groups and the clay favoring biodegradation, making the systems more amorphous and propitious to the attack of microorganisms. POLYM. ENG. SCI., 56:555–560, 2016. © 2016 Society of Plastics Engineers     

Artificial weathering effect on the structure and properties of polypropylene/polyamide‐6 blends compatibilized with PP‐g‐MA

The degradation of uncompatibilized and compatibilized PP/PA‐6 (70/30 wt %) with PP‐g‐MA under accelerated UV light was investigated using Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy, melt flow index (MFI) tester, tensile test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). FTIR analysis of the structure of the compatibilized and uncompatibilized blends after exposure to UV light showed the formation of photoproducts corresponding to both components. The MFI and mechanical results obtained revealed that photooxidation started primarily in PA‐6 rather than PP. In addition, the uncompatibilized blends exhibited a higher degradation rate compared to neat polymers for long exposure time, and the addition of PP‐g‐MA increased slightly their ageing rate in accordance with TGA data. Further, DSC analysis showed an increase in the crystallinity index and a decrease in the melting temperature of PP and PA‐6 after UV exposure either as neat polymers or as blend components. SEM micrographs of the cryo‐fractured surfaces of the samples illustrated the formation of cracks and fractures after UV irradiation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41722.     

Mechanical properties and morphology of PP/ABS blends compatibilized with PP‐g‐2‐HEMA

Polypropylene (PP) and acrylonitrile–butadiene–styrene blends of different composition were prepared using a single‐screw extruder. The binary blend of PP/ABS was observed to be incompatible and shows poor mechanical properties. PP‐g‐2‐hydroxyethyl methacrylate (2‐HEMA) was used as a compatibilizer for the PP/ABS blends. The ternary compatibilized blends of PP/ABS/PP‐g‐2‐HEMA showed improvement in the mechanical properties. Electron micrographs of these blends showed a homogeneous and finer distribution of the dispersed phase. The mechanical performance increased particularly in the PP‐rich blend. The 2.5‐phr (part per hundred of resin) compatibilizer was observed to bring improvement to the properties. The suitability of various existing theoretical models for the predication of the tensile moduli of these blends was examined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 72–78, 2003     

回收PP/PET薄膜共混改性的生产工艺探讨

本文对PP涂覆PET薄膜回收生产工艺技术的初步探讨。     

Study on dispersion and intercalation of organoclay in PP and PP‐g‐MA matrices

Understanding the complex mechanism of dispersion and intercalation of the clay tactoids can allow us to control the final morphology, homogeneity, and the macroscopic properties of clay nanocomposites. The objective of this work is a multiscale study of the dispersion state of PP/organoclay and PP‐g‐MA/organoclay composite. The microscopic investigation, WAXS diffractograms, rheological analysis, and mechanical properties were used to characterize the dispersion of organoclay in PP and PP‐g‐MA matrices during melt blending in two different shear rates. The morphological results show a system of aggregating intercalated clay particles which disperse by increasing mixing time with a strain‐controlled process and a very quick intercalation process in early mixing times for PP‐g‐MA/organoclay nanocomposite, while PP/organoclay samples only form microcomposites. The relative network modulus of these intercalated particles as a function of mixing time was obtained; and the tensile modulus of nanocomposite samples were compared with Halpin‐Tsai model prediction. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers     

Morphology and crystallization behavior of the PP/PET nanocomposites

Nanocomposites containing polypropylene (PP), PET, and montmorillonite were prepared in a twin‐screw extruder. X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, polarized optical microscopy, and differential scanning calorimetry were used to characterize the samples. Intercalated and exfoliated morphology were observed in the nanocomposites. The PET domains usually presented spherical shapes and they were the start point to PP crystallization. The average diameter and number of PET domains was evaluated. The influence of addition of PP‐MA as compatibilizer on PP/PET was investigated. The interconnected morphology was observed in the nanocomposite containing PP‐MA. The clay located predominantly in the interphase and in the PET phase. The crystallization process was monitored and the PET crystallization rate was slower in the nanocomposites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Influence of PP‐g‐MA on morphology,mechanical properties and deformation mechanism of copolypropylene/clay nanocomposite

Copolypropylene/organoclay nanocomposites are prepared by melt intercalation method in this research. Two different routes for addition of compatibilizer are examined, i.e. addition in the twin‐screw extruder along with the polymer and the clay powder simultaneously and premixing the compatibilizer with the reinforcement in a batch mixer before addition to the polypropylene (PP) matrix. Morphology, tensile and impact properties and deformation mechanisms of the samples made via two procedures are studied and compared with those of the noncompatibilized system. To study the structure of nanocomposites, x‐ray diffraction and transmission electron microscopy techniques are utilized. The deformation mechanisms of different samples are examined via reflected and transmitted optical microscopy. The results reveal that introduction of compatibilizer and also the procedure in which the compatibilizer is added to the compound, affect structure and mechanical properties of nanocomposite. The elastic modulus of PP‐clay nanocomposite has increased 11.5% with incorporation of compatibilizer. Also, introduction of organoclay without compatibilizer facilitates crazing at the notch tip of PP in 3PB testing. Incorporation of compatibilizer, however, makes difficulties in initiation and growth of crazes at the notch tip. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

An investigation on recycled PET/PP and recycled PET/PP‐EP compatibilized blends: Rheological,morphological, and mechanical properties

The effectiveness of P(E‐co‐MA‐co‐GMA) as a compatibilizer for recycled PET/PP and recycled PET/PP‐EP (polypropylene (ethylene‐propylene) heterophase copolymer) blends was investigated by means of morphological (scanning electron microscopy), rheological (small amplitude oscillatory shear), mechanical (tensile, flexural and impact tests), and thermal (differential scanning calorimetry) properties. Compatibilizer concentration ranged from 1 to 5 wt % with respect to the whole blend. All blends were obtained in a 90/10 composition using a twin screw extruder. Compatibilization effects for PETr/PP‐EP were more pronounced due to ethylene segments present in both PP‐EP and P(E‐co‐EA‐co‐GMA). PETr/PP‐EP has shown greater dispersed phase size reduction, a more solid‐like complex viscosity behavior and larger storage modulus at low frequencies in relation to PETr/PP blend. For both investigated blends, mechanical properties indicated an improvement in both elongation at break and impact strength with increasing compatibilizer content. PETr/PP‐EP blends showed improved performance for the same level of compatibilizer content. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41892.     

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     

Phase behavior of binary blends of PP/PP‐g‐AA: limitations of the conventional characterization techniques

In this study, miscibility/immiscibility issues of a binary blend consisting of polypropylene (PP) and acrylic acid grafted polypropylene (PP‐g‐AA) were investigated using rheometry, DSC, dynamic mechanical and thermal analysis (DMTA), AFM and time‐of‐flight secondary‐ion mass spectrometry (ToF‐SIMS). Phase separation analysis of such blend systems is a challenge and complex due to chemically similar components as well as the low value of acrylic acid groups in the graft copolymer. Thus, it is crucial to determine if the present blend shows some degree of miscibility or develops co‐continuous morphology between the components. The analysis of rheometrical, DSC and DMTA results indicated no sensitivity of these classical techniques for detecting the miscibility or immiscibility of such a system. However, AFM data effectively detected dispersed‐phase domains corresponding to the PP‐g‐AA rich phase. The results, for the first time, indicated that the start of phase separation occurs at a critical copolymer concentration between 2 and 5 wt%. Furthermore it was observed that, as the PP‐g‐AA content increases, the size and continuity of the dispersed phase increase and reach a highly continuous morphology. Additionally, ToF‐SIMS chemical imaging was carried out to aid in the interpretation of the AFM data. © 2016 Society of Chemical Industry     

Synthesis and application of MDPE‐g‐GMA as reactive compatibilizer in blends of MDPE/PET and MDPE/PA6

In the present study, glycidyl methacrylate (GMA) grafted medium density polyethylene (MDPE‐g‐GMA) was synthesized in the molten state and applied as a reactive compatibilizer in MDPE/polyamid6 (PA6) and in MDPE/poly(ethylene terephtalate) (PET) blends. Graft copolymerization of GMA onto MDPE was performed in presence and absence of styrene, with different concentrations of dicumyl peroxide (DCP) as a radical initiator. In the presence of styrene, the MDPE‐g‐GMA with 6% GMA was obtained by addition of only 0.1 phr of DCP. Furthermore, the maximum grafting was reached when 0.6 and 0.7 phr concentration of DCP for styrene containing and styrene free samples were used, respectively. Torque‐time measurement showed faster grafting reaction rate in the presence of styrene. Four MDPE‐g‐GMA samples were selected as compatibilizers in the blends. Furthermore, the effects of melt flow index and grafting content of compatibilizers on mechanical properties and morphology of the blends were investigated through tensile tests and SEM analysis. Tensile test results indicated that the presence of compatibilizers in the blends led to 250 and 133% increase in elongation at break for PA6 and PET blends, respectively. Moreover, the best tensile results for blends were obtained using MDPE‐g‐GMA with high flow ability. The average particle size of the dispersed phase decreased by 350% for PA6 and 300% for PET blends compared with nonreactive blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of blending sequence on the morphology and properties of polyamide 6/EPDM‐g‐MA/epoxy blends

The ternary blends of polyamide 6/maleated ethylene‐propylene‐diene rubber/epoxy (PA6/EPDM‐g‐MA/EP) were prepared by a twin‐screw extruder with four different blending sequences. With the variation of blending sequence, the ternary blends presented distinct morphology and mechanical properties because of different interactions induced by various reactive orders. The addition of epoxy could increase the viscosity of the PA6 matrix, but a considerably larger size of the dispersed rubber phase was observed while first preblending PA6 with epoxy followed by blending a premix of PA6/EP with EDPM‐g‐MA, which was attested by rheological behaviors and SEM observations. It was probably ascribed to the fact that the great increase of the interfacial tension between the matrix and rubber phase aroused a great coalescence of rubber particles. The presence of epoxy in the rubber phase reduced the rubber's ability to cavitate so that the toughening efficiency of the EPDM‐g‐MA was decreased. The results of mechanical testing revealed that the optimum blending sequence to achieve balanced mechanical properties is blending PA6, EPDM‐g‐MA, and epoxy simultaneously in which the detrimental reactions might be effectively suppressed. In addition, thermal properties were investigated by TG and DSC, and the results showed that there was no distinct difference. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Fractionated crystallization of dispersed PA6 phase of PP/PP‐g‐MAH/PA6 blends

Fractionated crystallization behavior of dispersed PA6 phase in PP/PA6 blends compatibilized with PP‐g‐MAH was investigated by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), polarized light microscopy (PLM), and wide‐angle X‐ray diffraction (WAXD) in this work. The lack of usual active heterogeneities in the dispersed droplet was the key factor for the fractionated crystallization of PA6. The crystals formed with less efficient nuclei might contain more defects in the crystal structures than those crystallized with the usual active nuclei. The lower the crystallization temperature, the lesser the perfection of the crystals and the lower crystallinity would be. The fractionated crystallization of PP droplets encapsulated by PA6 domains was also observed. The effect of existing PP‐g‐MAH‐g‐PA6 copolymer located at the interface on the fractionated crystallization could not be detected in this work. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3742–3755, 2004     

Crystallization behavior of PP/PP‐g‐MAH/GFR PA66 blends: Establishment of their continuous‐cooling‐transformation of relative crystallinity diagrams

Polypropylene/polypropylene‐grafted‐maleic anhydride/glass fiber reinforced polyamide 66 (PP/PP‐g‐MAH/GFR PA 66) blends‐composites with and without the addition of polypropylene‐grafted‐maleic anhydride (PP‐g‐MAH) were prepared in a twin screw extruder. The effect of the compatibilizer on the thermal properties and crystallization behavior was determined using differential scanning calorimetry analysis. The hold time was set to be equal to 5 min at 290°C. These conditions are necessary to eliminate the thermomechanical history in the molten state. The crystallization under nonisothermal conditions and the plot of Continuous‐Cooling‐Transformation of relative crystallinity diagrams of both PP and PA 66 components proves that PP is significantly affected by the presence of PP‐g‐MAH. From the results it is found that an abrupt change is observed at 2.5 wt % of PP‐g‐MAH as a compatibilizer and then levels off. In these blends, concurrent crystallization behavior was not observed for GFR PA66. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1620–1626, 2007     

Study of dynamically cured PP/MAH‐g‐PP/talc/epoxy composites

In the present study, an epoxy resin was dynamically cured in a polypropylene (PP)/maleic anhydride–grafted PP (MAH‐g‐PP)/talc matrix to prepare dynamically cured PP/MAH‐g‐PP/talc/epoxy composites. An increase in the torque at equilibrium showed that epoxy resin in the PP/MAH‐g‐PP/talc composites had been cured by 2‐ethylene‐4‐methane‐imidazole. Scanning electron microscopy analysis showed that MAH‐g‐PP and an epoxy resin had effectively increased the interaction adhesion between PP and the talc in the PP/talc composites. Dynamic curing of the epoxy resin further increased the interaction adhesion. The dynamically cured PP/MAH‐g‐PP/talc/epoxy composites had higher crystallization peaks than did the PP/talc composites. Thermogravimetric analysis showed that the addition of MAH‐g‐PP and the epoxy resin into the PP/talc composites caused an obvious improvement in the thermal stability. The dynamically cured PP/MAH‐g‐PP/talc/epoxy composites had the best thermal stability of all the PP/talc composites. The PP/MAH‐g‐PP/talc/epoxy composites had better mechanical properties than did the PP/MAH‐g‐PP/talc composites, and the dynamically cured PP/MAH‐g‐PP/talc/epoxy composites had the best mechanical properties of all the PP/talc composites, which can be attributed to the better interaction adhesion between the PP and the talc. The suitable content of epoxy resin in the composites was about 5 wt %. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006