The morphology and mechanical properties of dynamic packing injection molded PP/PS blends

As a part of long-term project aimed at super polyolefin blends, in this work, we report the mechanical reinforcement and phase morphology of the immiscible blends of polypropylene (PP) and polystyrene (PS) achieved by dynamic packing injection molding (DPIM). The shear stress (achieved by DPIM) and interfacial interaction (obtained by using styrene-butadiene-styrene (SBS) as a compatibilizer) have a great effect on phase morphology thus mechanical properties. The shear-induced morphology with core in the center and oriented zone surrounding the core was observed in the cross-section areas of the samples. The phase inversion was also found to shift towards lower PS content under shear stress, at 70 wt% in the core and 30 wt% in the oriented zone, compared with 80 wt% for static samples (without shear). The tensile strength, tensile modules and impact strength were found largely increase by means of either shear stress or compatibilizer. The PS particle size is greatly reduced with adding of SBS, and the reduced particle size results in greater resistance to deformation, which causes the co-continuous structure at oriented zone change into droplet morphology. The morphology resulting from blending and processing was discussed based on effect of interfacial tension, shear rate, phase viscosity ratio and composition. The observed change of mechanical properties was explained based on the combined effect of phase morphology (droplet-matrix or co-continuous phase) and molecular orientation under shear stress.     

In situ compatibilization of PP/EPDM blends during ultrasound aided extrusion

Blends of isotactic polypropylene (iPP) and uncured ethylene-propylene diene rubber (EPDM) of various concentrations were treated by high power ultrasonic waves during extrusion. Die pressure and power consumption were measured. The effects of different gap sizes, blend ratios and number of ultrasonic horns were investigated. The rheological properties, morphology and mechanical properties of the blends with and without ultrasonic treatment were studied. In situ compatibilization of the blends was observed as evident by their more stable morphology after annealing, improved mechanical properties and IR spectra. The obtained results indicated that ultrasonic treatment induced the thermo-mechanical degradations and led to the possibility of enhanced molecular transport and chemical reactions at the interfaces. Processing conditions were established for enhanced in situ compatibilization of the PP/EPDM blends.     

Reactive compatibilization of PE/PS blends. Effect of copolymer chain length on interfacial adhesion and mechanical behavior

This paper deals with in situ compatibilization of PE/PS blends via Friedel-Crafts reaction, performed at the interphase. Two polyethylenes having different molecular weights, and the same PS, were used along a wide range of catalyst concentration. The influence of the graft copolymer architecture and content on the efficiency of blend compatibilization was studied. The emulsifying effect, morphological aspects and mechanical behavior were also assessed for these blends. The amount of copolymer formed increases with catalyst concentration and the short chain length fraction of the homopolymers. The high molecular weight (MW) copolymers behaved as better compatibilizers as they showed, at the cmc, greater graft copolymer concentration than the low MW ones. A substantial increase in interfacial adhesion and particle size reduction was observed, even at catalyst concentrations as low as 0.3 wt%. In correspondence, mechanical properties, like ductility and yield strength, were enhanced by the effect of this Friedel-Crafts reaction's compatibilization.     

Microstructures and mechanical properties of polypropylene/polyamide 6/polyethelene-octene elastomer blends

A series of polymer blends were designed and manufactured. They are composed of three phases: polypropylene (PP), polyamide-6 (PA6) and polyethylene-octene elastomer (POE) grafted with maleic anhydride. The weight fraction of PA6 was adjusted from 0 to 40% by increments of 10%, and the weight fraction of POE was systematically half that of PA6. The morphology, essentially made of PA6 particles dispersed in the PP matrix, was characterised by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the extruded plates prepared with the blends, the shape of the dispersed PA6 particles showed an elongated ellipsoidal shape, whose aspect ratio increased somehow with alloying content. The POE modifier was observed both as a thin interlayer (less than 100 nm thickness) at the PP/PA6 interface, and as a few isolated particles. The elastic modulus and yield stress in tension are nearly constant for PP and blends. By contrast, the notched Izod impact strength increases very much with alloying content. This remarkable effect is interpreted in terms of POE interphase cavitation, enhanced plastic shear deformation and resistance of PA6 particles to crack propagation.     

Dynamic mechanical properties of nanoclay filled TPU/PP blends with compatibiliser

Abstract

Blends of thermoplastic polyurethane (TPU) and polypropylene (PP) are highly incompatible because of large differences in polarities and high interfacial tensions. On one hand, PP is added to TPU to improve TPU's thermal stability, chemical properties, mechanical properties (modulus, strength and hardness) and processing performance and to reduce TPU's cost. On the other hand, TPU is blended with PP to improve PP's properties (e.g. abrasion, flexibility, tear strength, shock absorbing capabilities, impact strength, adhesion and paintability/printability). Earlier works in polyurethane/organoclay nanocomposites, PP/organoclay nanocomposites and TPU/PP blends were studied. In our experimental work, both ester and ether based TPU nanocomposites were prepared by melt blending using 3?wt-% Cloisite 10A (organically modified montmorillonite clay) as the nanoscale reinforcement and blended with PP with/without PP-graft-maleic anhydride as the compatibiliser. Blends of nanoclay filled TPU/PP were evaluated for dynamic mechanical properties such as storage modulus E′, loss modulus E″ and dissipation factor tanδ.     

Reactive compatibilization of LLDPE/PS blends with a new type of Lewis acid as catalyst

The reactive compatibilization of LLDPE/PS (50/50 wt%) was achieved by Friedel–Crafts alkylation reaction with a combined Lewis acids (Me₃SiCl and InCl₃·4H₂O) as catalyst. The graft copolymer at the interface was characterized by Fourier transform infrared spectroscopy and the morphology of the blends was analysized by scanning electron microscopy. It was found that the combined Lewis acids had catalytic effect on Friedel–Crafts alkylation reaction between LLDPE and PS, and the catalytic effect was maximal when the molar ratio of InCl₃·4H₂O to Me₃SiCl was 1:5. The graft copolymer LLDPE–g–PS was formed via the F–C reaction and worked as a tailor-made compatibilizer to reduce the interfacial tension. The mechanical properties of reactive blend with combined Lewis acids as catalyst was notably improved compared to that of physical LLDPE/PS blend and serious degradation had been decreased compared to the reactive blend system with AlCl₃ as catalyst; we interpreted the above results in term of acidity of combined Lewis acids.     

Effects of nanosilica filler surface modification and compatibilization on the mechanical,thermal and microstructure of PP/EPR blends

Polypropylene/ethylene-propylene rubber/nanosilica (PP/EPR/nano-SiO₂) composites were prepared by a melt blending masterbatch process using a Brabender mixer. In order to improve the interfacial adhesion and achieve diverse desired properties of the composites, nanosilica surface silylation by means of two silane coupling agents: N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (AEAPTMS) and 3-methacryloxypropyltrimethoxysilane (MPTMS) was explored. The composites were also compatibilized using three compatibilizers: methyl methacrylate grafted PP (MMA-g-PP), glycidylmethacrylate grafted PP (GMA-g-PP) and maleic anhydride grafted PP (MAH-g-PP). The properties of the blends and the composites were examined using tensile and Izod impact tests, differential scanning calorimetry (DSC), thermogravimetric analysis (ATG) and scanning electron microscopy (SEM). According to the mechanical property evaluations, the incorporation of nano-SiO₂ particles into PP/EPR blend improved the tensile strength and Young’s modulus of the composites. The elongation and Izod impact strength were adversely affected. A significant improvement in the mechanical properties was obtained for the composites with AEAPTMS-SiO₂ and MAH-g-PP. The DSC results indicated that the incorporation of the modified silica and MAH-g-PP increased the crystallinity of the composites. However, no significant variation in the crystallinity was observed as a result of the addition of MMA-g-PP and GMA-g-PP. The TGA results revealed that the composites exhibit a higher thermal stability than that of the neat matrix. SEM micrographs of the fractured surfaces revealed a two-phase morphology with EPR nodules being dispersed in the PP matrix. SEM also indicated that the incorporation of MAH-g-PP into PP/EPR composites contributes to a better dispersion of the EPR phase and nano-SiO₂ particles in the polymer matrix.     

PP／PS合金技术进展

PP和PS是不相容的聚合物 ,直接机械共混的产物性能较差 ,通过添加相容剂 ,如嵌段共聚物或接枝共聚物能提高共混物性能。在线增容技术已用于PP、PS反应性增容 ,生产高性能的合金。     

Miscibility,phase behavior,and mechanical properties of ternary blends of poly(vinyl chloride)/polystyrene/chlorinated polyethylene-graft-polystyrene

The effectiveness of chlorinated polyethylene-graft-polystyrene (CPE-g-PS) as a polymeric compatibilizer for immiscible poly(vinyl chloride)/polystyrene (PVC/PS) blends was investigated. The miscibility, phase behavior, and mechanical properties were studied using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), Izod impact tests, tensile tests, and scanning electron microscopy (SEM). DSC and DMA studies showed that PVC is immiscible with chlorinated polyethylene (CPE) in CPE-g-PS, whereas the PS homopolymer is miscible with PS in CPE-g-PS. The PVC/PS/CPE-g-PS ternary blends exhibit a three-phase structure: PVC phase, CPE phase, and PS phase that consisted of a PS homopolymer and PS in CPE-g-PS. The mechanical properties showed that CPE-g-PS interacts well with both PVC and PS and can be used as a polymeric compatibilizer for PVC/PS blends. CPE-g-PS can also be used as an impact modifier for both PVC and PS. SEM observations confirmed, after the addition of CPE-g-PS, improvement of the interfacial adhesion between the phases of the PVC/PS blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 995–1003, 1998     

MAH—g—PP对PP／EVAL共混体系的增容作用

系统研究了不同组成及配比的马来酸酐接枝聚丙烯（ＭＡＨ－ｇ－ＰＰ）及其用量对聚丙烯（ＰＰ）与乙烯－乙烯醇共聚物（ＥＶＡＬ）的共混体系（ＰＰ／ＥＶＡＬ）力学性能借用Ｂｒａｂｅｎｄｅｒ塑化仪测试了ＰＰ／ＥＶＡＬ／ＭＡＨ－ｇ－ＰＰ共混体系的加工性能。结果表明,ＭＡＨ－ｇ－Ｐ接枝物对ＰＰ／ＥＶＡＬ共混体系有较好的增容作用,适量加入,可使ＰＰ／ＥＶＡＬ共混体系的力学性能明显提高,而加工性能基本不变。     

POE/SAN的原位增容

通过扭矩测定,傅里叶变换红外光谱、差示扫描量热法分析等方法研究了苯乙烯-丙烯腈共聚物(SAN)与聚烯烃弹性体(POE)大分子间的Friedel-Crafts烷基化反应。结果表明:适量无水AlCl3可以引发SAN与POE发生Friedel-Crafts烷基化反应,生成的POE-g-SAN接枝共聚物起到了原位增容POE/SAN共混物的作用,提高了其力学性能;当m(POE)/m(SAN)为60.0∶40.0,反应温度为180℃,AlCl3用量为0.4 phr时,POE/POE-g-SAN/SAN共混物性能较好;进一步提高AlCl3用量,SAN分子结构中侧链氰基与铝离子络合作用增强,导致SAN分散相聚集,POE/POE-g-SAN/SAN共混物刚性下降。     

The effect of mercapto‐modified EVA on rheological and dynamic mechanical properties of NBR/EVA blends

The effect of mercapto‐modified ethylene vinyl acetate copolymer (EVALSH) on the rheological and dynamic mechanical properties of acrylonitrile butadiene rubber (NBR) and ethylene vinyl acetate copolymer (EVA) blends was evaluated at different blend compositions. The addition of 5 phr of EVALSH in the blends resulted in an increase of the melt viscosity and a substantial decrease of the extrudate swell ratio. These results can be attributed to the interactions occurring between the double bond of the NBR phase and the mercapto groups along the EVALSH backbone. The power–law index also presents a slight increase in the presence of EVALSH, indicating a decrease in the pseudoplastic nature of the compatibilized blends. The reactive compatibilization of NBR/EVA blends with EVALSH was also confirmed by the decrease of damping values and an increase of glass transition temperature, in dynamic mechanical analysis. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2335–2344, 2002     

液晶离聚物在ABS/PBT共混体系中的增容研究

合成了一种含有磺酸基的液晶离聚物（LCI）,并研究了LCI作为相容剂对丙烯腈-丁二烯-苯乙烯三元共聚物/聚对苯二甲酸丁二醇酯（ABS/PBT）共混体系力学性能的影响。采用扫描电镜（SEM）、差示扫描量热仪（DSC）和热失重（TGA）分析对ABS/PBT/LCI共混物的热性能、微观形态和相容性进行了研究。研究结果表明LCI的加入,改善了二者的相容性,从而提高了共混物的拉伸强度、断裂伸长率以及缺口冲击强度。     

Continuous ultrasonic process for in situ compatibilization of polypropylene/natural rubber blends

The immiscible polypropylene (PP)/natural rubber (NR) blends of various concentrations were prepared by using a twin-screw extruder. The prepared blends were passed through the reactor where they were ultrasonically treated by an extrusion process. Mechanical properties and rheology of the obtained blends were studied, along with morphology by using the scanning electron microscopy and the atomic force microscopy (AFM). Mechanical properties of the treated blends were found to improve significantly in comparison with those of untreated blends. Under most treatment conditions, no significant differences in the viscosity of the treated and untreated blends were observed. The AFM studies revealed the development of interfacial layers, interfacial roughening and improved interfacial adhesion between PP and NR phases in the blends subjected to ultrasonic treatment. At the same time weak adhesion and delamination at the interface were found in the untreated blends. The improved interfacial adhesion, morphology and mechanical properties are believed to be due to the formation of in situ copolymer at the interface of two immiscible polymers caused by an ultrasonic treatment without the use of any chemicals.     

增容聚丙烯/聚苯乙烯共混物的相形态

综述了作为增容剂的接枝共聚物与嵌段共聚物,反应增容,其他技术增容以及共混条件对聚丙烯／聚苯乙烯(PP,PS)共混物的相形态研究进展。PP／PS共混物通过增容可以改善共混物相形态和提高界面粘结,这为提高PP／PS共混物的物理与力学性能提供了依据。     

Morphology and mechanical properties of PET/PE blends compatibilized by nanoclays: Effect of thermal stability of nanofiller organic modifier

Poly(ethylene terephtalate)/poly(ethylene) (PET/PE) blends (80/20 wt %) were prepared by melt‐extrusion and compatibilized by addition of nanoclays. Two commercially available organically modified montmorillonites (Cloisite© 10A and 30B) were chosen as reference and a third one was specially organomodified at lab scale with a thermally stable phosphonium surfactant using conventional cationic exchange reaction. The size of the dispersed polymer phase (PE droplets) and the ductility of the blends depend more on the thermal stability of the surfactant of the organomodified clay than on the enthalpic interactions between the blend components and the surfactants used for the modification of the clays. The highest mechanical properties (yield stress and elongation at break) and the better compatibilization efficiency (smallest dispersed PE droplets) were observed in the presence of phosphonium organomodified montmorillonite compared to other less thermally stable commercial organoclays. The analysis of the thermal stability, morphology, and mechanical properties of PET/PE blends containing the surfactants alone in the absence of clay made it possible to evidence separately the effects of the surfactant and of the nanofiller. The role of the surfactant as compatibilization agent was demonstrated. In the absence of nanofiller, the finest morphological and highest ductility were again obtained with the phosphonium surfactant which is the most thermally stable. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

PP-g-MAH增容PP/PA-66共混物形态结构和性能

用固相接枝法制备了马来酸酐接枝改性聚丙烯(PP g MAH),研究了PP g MAH增容PP/PA 66共混物的形态结构和性能。结果表明,用PP g MAH增容的PP/PA 66共混物的拉伸强度提高约10MPa,弯曲强度、弯曲模量有所提高,缺口冲击强度和伸长率保持不变。     

In situ compatibilization of HDPE/PET blends

The reactive compatibilization of immiscible polymers such as high‐density polyethylene (HDPE) and poly(ethylene terephthalate) (PET) by interfacial grafting of maleic anhydride (MA) without initiator in the molten state was investigated in this study. Grafting reaction of MA onto HDPE was carried out in a Rheocord HAAKE mixer varying reaction parameters such as the temperature, the shear rate, and the time of reaction. Then, the purified copolymers were characterized by infrared spectrometry and the MA content of HDPE‐g‐MA copolymers was determined by volumetric titration. It has been shown that thermomechanical initiation is sufficient to reach grafting yield of 0.3 to 2.5 wt % of MA. We studied then the compatibilization of HDPE/PET blends by interfacial grafting of MA. The in situ interfacial reaction leads to the formation of HDPE‐g‐MA copolymer which acts as a compatibilizer in the blends. The foremost interest of this work is that it provides a simple way of compatibilization of immiscible blends of polyolefin and polyester in one transformation step without using free‐radical initiators. The mechanical properties of the blends are strongly improved by the addition of small quantities of MA. The SEM observations of the compatibilized blends show a deep modification of the structure (i.e., enhanced regularity in the nodule dispersion and better interfacial adhesion). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 874–880, 2001