Morphology and Mechanical Properties of Polyamide 6/Acrylonitrile-Butadiene-Styrene Blends Containing Carbon Nanotubes

The blends of polyamide 6/acrylonitrile-butadiene-styrene (PA6/ABS), with added styrene-maleic acid copolymer (SMA) compatibilizer, were prepared through melt mixing in an internal mixer. The effects of blend composition and various process conditions, as well as the addition of multi-wall carbon nanotubes (MWCNTs) to the blends, on the morphology and mechanical properties were investigated. The morphology of the blends and blend nanocomposites were observed by scanning electron microscopy (SEM) and analyzed using an image analysis technique. The mechanical behavior of the blends was investigated by tensile and also impact testing. The results showed that the blend composition as well as the processing conditions significantly affected the morphology and mechanical properties of the PA6/ABS blends. Among the various compositions, the blend with 36?wt.% of ABS and 4?wt.% of SMA compatibilizer exhibited the best mechanical properties. Comparing various speeds and times of mixing, it was found that less mixing speed and longer mixing times resulted in the favorable morphology and conditions for achievement of the desired toughness for the polyamide 6. By adding different amounts of MWCNTs to the blends, it was found that the presence of the carbon nanotubes changed the viscosity of the resulting nanocomposite and thus changed the morphology. These nanocomposites also showed an improvement in mechanical properties. The MWCNTs acted as a second compatibilizer, resulting in a synergistic effect on the mechanical properties of the PA6/ABS blend nanocomposites.     

The Effect of Blending Sequence on Nanoclay Partitioning and Microfibrillar Morphology in Blend Nanocomposite Fibers

The aim of this article was to provide an insight into the effect of nanoclay partitioning on the droplet deformation and fibril formation in melt-compounded polypropylene/poly (butylene terephthalate)/organoclay blend nanocomposite fibers prepared by different blending sequences. An attempt was also made to investigate the effect of compatibilizer on the partitioning of nanoclay in these blend systems. Melt viscoelastic behavior, wide angle X-ray diffraction and transmission electron microscopy, along with scanning electron microscopy, revealed that the localization of nanoclay in the poly (butylene terephthalate) dispersed phase reduced the droplet deformation and fibril formation. It was demonstrated that the best microstructure of the blend nanocomposites for the fibrillation process was to have the maximum percentage of exfoliated nanoclay in both polymeric phases. Incorporation of compatibilizer can develop the microfibrillar morphology due to its assisting role in transferring a higher fraction of nanoclay platelets from droplets into the matrix and also increasing the extent of melt intercalation in the matrix.     

Effect of Nanoclay on the Morphology and Properties of Nylon 6 and Poly(Methyl Methacrylate) (PMMA) Blends

The effect of organomodified nanoclay on the morphology and properties of a (70/30 w/w) nylon 6/poly(methyl methacrylate) (PMMA) blend prepared by a melt processing method was investigated. The number average domain diameter (D_n ) of the dispersed PMMA phase was found to decrease with the addition of a small amount [0.5 per hundred resin (phr)] of clay in the blend. A much finer dispersion of the minor phase in the presence of a higher amount (5 phr) of clay indicated better mixing efficiency and improved morphology in the blend. X-ray diffraction indicated the exfoliation of the clays in the nylon 6 matrix, whereas PMMA chains only intercalated into the clay layers. However, the same effect of the clay was not observed in a (30/70 w/w) nylon 6/PMMA blend when nylon 6 became the dispersed domains. In the (30/70 w/w) nylon 6/PMMA blend, the addition of organomodified nanoclay (up to 2 phr) increased the D_n of the nylon 6 domains by preferential location of the clays inside the nylon 6 domains. Addition of styrene-maleic anhydride (SMA) copolymer effectively reduced the D_n of disperse phases in both compositions of the nylon 6/PMMA blends. Thus, in nylon 6/PMMA blends, clay platelets could prevent the coalescence of dispersed domains during melt mixing as long as it was dispersed in the matrix phase of the blend. Mechanical properties and thermal stability of the blends were also improved in the presence of clay.     

Effects of Blend Ratio on Rheology,Morphology, Mechanical and Oil-Resistant Properties in Chlorinated Polyethylene Rubber and Copolyamide Blends

The elastomeric chlorinated polyethylene (CPE) blended with a low melting point copolyamide (PA6/PA66/PA1010, PA) was prepared by a melt mixing technique. The mixing characteristics of the blends were analyzed from the rheographs. The influence of copolyamide (PA) content on the morphology, mechanical properties, crystallization and oil-resistance, and the addition of compatibilizers on the mechanical properties were also systematically investigated. Morphological examinations clearly revealed a two-phase system in which CPE/PA blends exhibit a cocontinuous morphology for 50/50 composition, and the continuous phase of PA turns into a disperse phase for 70/30, 80/20, and 90/10. There is a distinct interface between the two phases. The mechanical properties, crystallization, and oil-resistance have a strong dependence on the amount of PA. The blends with higher proportions of PA have superior mechanical properties; they are explained on the basis of the morphology of the blend and the cystallinity of PA. In addition, compatibilizers, including chlorinated polyethylene-graft-copolyamide (CPE-G-PA), chlorinated polyethylene-graft-maleic anhydride (CPE-G-MAH), ethylene-n-butyl acrylate-monoxide (EnBACO), and ethylene-n-butyl acrylate-monoxide-graft-maleic anhydride (EnBACO-g-MAH) were added into the blends. Tensile strength and elongation at break go through a maximum value at a compatibilizer resin content (on the basis of the total mass of the blend) of 20 wt% while the PA content is 30 wt%.     

Phase Morphology and Mechanical Properties of Polyamide-6/Polyolefin Elastomer-g-Maleic Anhydride Blends

The effects of addition of varying amounts of polyolefin elastomers (POE) (with and/or without grafted maleic anhydride) on the morphology and mechanical properties of polyamide-6 (PA6)-based blends were studied. Scanning electron microscopy (SEM) was employed to obtain some detailed quantitative analyses of the morphology of the fracture behavior for the blends containing 80 wt% PA6 and 20 wt% total elastomer. Impact strength, tensile strength, and flexural strength were also measured for these blends. The results showed that POE and PA6 were an incompatible system, but the POE-g-MAH was compatible and had a toughening effect on PA6. PA6-g-POE was formed through the reaction between POE-g-MAH and PA6 during the melt extrusion process, which reduced the size of the dispersed phase and improved the impact and tensile strength of the blends. The impact strength was improved by nine times compared with the pure PA6 or the binary blend PA6/POE when the blend ratio of the ternary blend PA6/POE/POE-g-MAH was 80/16/4.     

Morphology and Mechanical Properties of Acrylonitrile-Butadiene-Styrene (ABS)/Polyamide 6 (PA6) Nanocomposites Prepared via Melt Mixing

Acrylonitrile-butadiene-styrene (ABS)/polyamide 6 (PA6) blends containing various amounts of organomontmorillonite (OMMT) were prepared using a twin-screw extruder followed by injection molding. The effect of OMMT on the microstructure and properties of the ternary nanocomposites is investigated by wide-angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and mechanical properties testing. The results showed the OMMT platelets were preferentially located and exfoliated in the PA6 phase, but some were located at the interface of the ABS and PA6 phase. The effect of the addition of the OMMT on the morphology and mechanical properties was also evaluated. SEM revealed that the dimensions of the dispersed PA6 droplets were greatly reduced when the concentration of the OMMT was less than 4 phr. The domain size was less than the neat ABS/PA6 blends with the increasing of the OMMT content. It was suggested that the OMMT can compatibilize the ABS/PA6 blend. In addition, the flexural strength and modulus increased with increasing OMMT content, but the tensile strength became maximal at 3 phr OMMT. The OMMT had a negligible effect on the impact strength of the ABS/PA6 blend nanocomposite.     

Influence of halloysite nanotubes (HNTs) on morphology,crystallization, mechanical and thermal behaviour of PP/ABS blends and its composites in presence and absence of dual compatibilizer

Halloysite nanotubes (HNTs) filled 80/20 (wt/wt) polypropylene (PP)/acrylonitrile butadiene styrene (ABS) blends and its composites in presence and absence of dual compatibilizer (polypropylene grafted maleic anhydride (PP-g-MA), and styrene-ethylene, butylene-styrene triblock copolymer grafted with maleic anhydrite (SEBS-g-MA)) have been prepared using twin screw extruder followed by injection moulding. Significant refinements in dispersed ABS droplets diameter and interparticle distance between dispersed ABS droplets were observed in case of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence of PP-g-MA and SEBS-g-MA. This has resulted in significant enhancement in tensile and impact properties of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence of PP-g-MA and SEBS-g-MA. Refinement in morphology of dispersed ABS phase results in decrease in crystallinity of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence of PP-g-MA and SEBS-g-MA. In addition, HNTs act as heterogeneous nucleating agent for the growth of PP crystals, and hence crystallization rate of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence and absence of PP-g-MA and SEBS-g-MA increases. Thermal stability also increases in case of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence and absence of PP-g-MA and SEBS-g-MA.     

Synthesis and Mechanical Characterization of Nanoparticles Infused Polyurethane Foams; Statistical Analysis of Foam Morphology

Nanocomposite polyurethane foams filled with different loadings (0.1–0.7 wt.%) of nanosized silica (average grain size of about 7 or 12 nm) and organoclay were prepared by a prepolymer method, and their mechanical properties were investigated. Statistical analysis of the size distribution of the foam cells was successfully applied for the characterization of their morphology. It was shown that the developed approach provided detailed analysis of the morphology development in PU foams, including the primary cell formation and their break-up and coalescence. The degree of phase separation in nanocomposite polyurethane foams in its dependence on nanofiller type and content was calculated from the IR spectra. The presence of silica nanoparticles and organoclays gives rise to significant differences in the mechanical (stress–strain) properties of the nanocomposite polyurethane foams with respect to the pure polymer.     

Effect of Phase Arrangement on Solid State Mechanical and Thermal Properties of Polyamide 6/Polylactide Based Co-polyester Blends

The main goal of this work is to correlate morphological parameters of the binary blend of polyamide 6 (PA6) and a polylactide (PLA) based biodegradable co-polyester blend (BioFlex) (scanning electron microscopy, solvent extraction method) with the solid-state mechanical properties (stress strain analysis) as well as thermal (differential scanning calorimetry) and selected physico-chemical characteristics (Fourier transform infrared spectroscopy and water uptake analysis). The blends of PA6/BioFlex were prepared in ratios of 100/0, 90/10, 75/25, 60/40, 50/50, 40/60, 25/75, 10/90 and 0/100 in wt.%. The occurrence of co-continuous morphology was observed within the range of 40 to 60 wt.% of BioFlex. Furthermore, the results show that the co-continuous morphology of PA6/BioFlex blends significantly affected both tensile (E modulus) and thermal properties (melting enthalpy) of the blends. In the case of the tensile properties, the effect of the morphological arrangement was strongly dependent on the deformation range. The presence of BioFlex in the blends reduced the crystallizability of PA6 noticeably. Co-continuous structure formation was observed to have a significant effect on the melting enthalpy of the blend. Composition morphology dependent responses were observed in the case of the FTIR and water uptake studies.     

Influence of surface modification of halloysite nanotubes and its localization in PP phase on mechanical and thermal properties of PP/ABS blends

Halloysite nanotubes (HNTs) have been successfully modified using polyethyleneimine (PEI). HNTs and PEI-modified HNTs-filled 80/20 (wt/wt) polypropylene (PP)/acrylonitrile butadiene styrene (ABS) blends and its nanocomposites in the presence of dual compatibilizer have been prepared by melt mixing technique. The refinement in matrix–droplet morphology, selective localization of PEI-modified HNTs, increase in crystallinity of PP phase, formation of β-form of PP crystals and improved dispersion of PEI-modified HNTs in PP phase has resulted in a remarkable improvement in tensile modulus, impact strength and thermal stability of PEI-modified HNTs-filled 80/20 (wt/wt) PP/ABS blends in presence of dual compatibilizer. The increase in tensile modulus, tensile strength and impact strength for PEI-modified HNTs-filled 80/20 (wt/wt) PP/ABS blends in presence of dual compatibilizer are 28.8, 26.6 and 38.5%, respectively.     

Reactive Compatibilization of Poly(trimethylene terephthalate)/Polypropylene Blends by Polypropylene‐graft‐Maleic Anhydride. Part 1. Rheology,Morphology, Melting,and Mechanical Properties

Poly(trimethylene terephthalate)/polypropylene (PTT/PP) blends were prepared by melt blending. The rheology, morphology, melting, and mechanical properties of PTT/PP blends were investigated with and without the addition of polypropylene‐graft‐maleic anhydride (PP‐g‐MAH). The melt viscosity results showed that the fluid behavior of PTT/PP blends exhibited great disparity to that of PTT but similar to that of PP; the dispersed flexible PP phase in the blends served as a “ball bearing effect” under shear stress, which made the fluid resistance markedly reduced; by contrast, the relatively rigid PTT dispersed phase made only a small contribution to the viscosity. With 5 wt.% PP‐g‐MAH addition during melt processing, both the shear viscosity and the non‐Newtonian index of 70/30 PTT/PP blend were increased over that of the corresponding uncompatibilized one, whereas the shear viscosity of the 30/70 PTT/PP melt decreased slightly indicating that a considerable amount of PP‐g‐MAH did not act as compatibilizer but probably served as plasticizer.

With the increasing of the other component, the melting temperature of the PTT phase showed a slight decrease while the melting temperature of the PP phase showed a slight increase. 5 wt.% PP‐g‐MAH addition had little influence on the melting temperatures of the two components. When PP≤20 wt.%, the cold crystallization temperature of the PTT phase (T_cc (PTT‐phase)) showed little change with the composition; however, it shifted to higher temperature when PP≥30 wt.%. The variations of the T_cc (PTT‐phase), with and without PP‐g‐MAH, suggested that, when PTT was a minor component, the excess PP‐g‐MAH which did not act as compatibilizer might serve as a plasticizer that made the PTT's cold crystallization process to be easier. The SEM results indicated that, for the uncompatibilized blends, the interfaces from particles pulling‐out are clear and smooth, while, for compatibilized blends, the reactive products are at the interfaces. The mechanical properties suggested that PP‐g‐MAH did not result in significant improvement of the toughness of the blend, but the tensile strength increased markedly.     

Compatibilizing Action of a Poly(styrene–butadiene) Triblock Co-polymer in ABS/PET-G Blends

The morphology of blends of poly(acrylonitrile-co-butadiene-co-styrene) (ABS) and poly(ethylene terephthalate glycol) (PET-G) has been investigated with special reference to the effect of blend ratio and compatibilization. Scanning electron microscopy (SEM) examination revealed different morphologies such as dispersed, cocontinuous and phase inverted depending on the composition, which indicates that the binary blends are immiscible and form a two-phase structure. Tensile properties decreased with increase in the ABS content while the impact strength reached an optimum at ca. 70% ABS. Influence of a triblock co-polymer based on styrene and butadiene (SBS) on morphology, mechanical measurements and failure topography was used as criterion of the compatibilization effect. The compatiblizing action of SBS was evidenced by the sharp decrease in domain size of the dispersed phase followed by an increase at higher concentrations. The conformation of the compatibilizer at the interface was further analyzed based on the area occupied by the compatibilizer at the blend interface. The results were in agreement with the theoretical predictions of Noolandi and Hong. The extent of interface adhesion in these blends was analyzed by examination of the fracture-surface morphology. Addition of SBS also improved notched impact, elongation-at-break, tensile strength and modulus of elasticity. These results confirm that SBS is an effective compatibilizer for ABS/PET-G blends.     

Study on Compatibilized Polyethersulfone and Polycarbonate Blends

A multiblock copolymer of polyethersulfone (PES) and polycarbonate (PC) was used as a compatibilizer for a blend of PES/PC. The morphology, thermal properties, mechanical properties, etc. of the resulting ternary blend systems were investigated. The addition of the compatibizer improved the compatibility between PES and PC. It was found that the interfacial adhesion was enhanced; the size of the dispersed phase was reduced and this resulted in an improvement of elongation at break and tenacity of PES/PC blends and tensile strength and tensile modulus were almost constant.     

String formation in sheared polymer blends: coalescence, breakup, and finite size effects

We have discovered a droplet-string transition in concentrated polymer blends which occurs when the size of the dispersed droplets becomes comparable to the gap width between the shearing surfaces. The transition is abrupt and proceeds via the coalescence of droplets in a four-stage kinetic process. Once formed, the strings are stable and exhibit pronounced hysteresis. The string state is stabilized by a suppression of the Rayleigh-Tomotika instability due to both finite size effects and to the shear-induced advection of small-amplitude disturbances.     

Morphological,Thermal and Mechanical Properties of Compatibilized Nylon 6/ABS Blends

Super‐tough nylon 6/ABS blends were prepared by using styrene/acrylonitrile/maleic anhydride co‐polymer (SAM) as a compatibilizer. The variations in morphology, mechanical behavior, and crystallinity associated with the reaction of the SAM with the nylon were characterized. The results showed that the addition of SAM to nylon 6/ABS blends enhanced the interfacial adhesion between nylon 6 and ABS, and this led to the decrease of ABS domain size and the improvement of mechanical properties of their blends. Moreover, it could be found that the crystallinity and phase morphology changed with the variation of SAM.     

Friction and Wear Behavior of Polyamide 66/Poly(vinylidene fluoride) Blends

The tribological performance of PA66 and PVDF blends was investigated by a block‐on ring sliding friction and wear tester. The appropriate amount of PVDF can decrease the friction coefficient and improve the wear resistance of PA66. Moreover, the appropriate amount of PA66 can improve the wear resistance of PVDF. SEM analysis shows that PVDF is noncompatible with PA66, and the blend presents a two‐phase structure. A smooth worn surface is a main reason for improving the frictional and wear properties of the PA66/PVDF blend. Besides, slight debris is an important factor in improving the wear resistance of the PA66/PVDF blend. FT‐IR analysis shows that the oxidation and degradation behavior of PVDF is effectively controlled in the PA66/PVDF blends. Therefore, the blend of PA66 and PVDF is a potential polymer material for tribological applications.     

Morphological Aspects of In-Situ Compatiblized Binary Polymer Blends With Variable Viscosity Ratios of Components

The in-situ compatiblized binary polymer blend polypropylene(PP)/polystyrene(PS)/ anhydrous aluminum chloride(AlCl₃) was selected as a model system of a reactive polymer blend to investigate the effect of viscosity ratio of components at a constant shear rate on the phase morphological behavior in in-situ compatibilized systems. The results showed that the well-known interfacial compatibilization effect was related to variations of viscosity ratios of components in the reactive PP/PS blends with different contents of AlCl₃ catalyst. The phase morphology evolution of the in-situ compatiblized reactive blend was determined by both the interfacial compatibilization and the variation of the viscosity ratio of components under the fixed mixing conditions, which showed characteristics obviously different from and much more complex than those in binary polymer blends generally compatiblized by added compatiblizers. The results implied that the variation of the viscosity ratio of components should be checked carefully and taken into account if necessary, when the phase morphology of binary polymer blends is investigated, especially in complex in-situ compatiblized reactive polymer blends.     

AFM lateral force imagining of modified polychloroprene: A study based on roughness analysis

Films of a binary polymer blends comprising polychloroprene (PCP) and piperylene-styrene copolymer (PSC) have been prepared by solution casting. The dependence of the surface morphology of the free blend films on PSC content was studied with both roughness and correlation analysis of lateral force microscopy (LFM) images. Significant changes in roughness and lateral parameter values of different blend film sides have been observed depending on the blend composition. It was shown that up to 15 wt.% PSC is distributed continuously in PCP bulk. The increase of roughness and lateral parameter values at the air/film surface shows the enrichment of PCP in the blends containing 25 wt.% or more PSC. The enrichment of PCP on the air/film surface favours the increase of PSC concentration at the backing/film surface. The films underside morphology becomes similar to that of PSC, when its content reaches 40 wt.%.     

Mechanical Properties and Morphology of LDPE/PP Blends

Two types of polypropylene (PP) with different molecular structure, namely, homogeneous PP (PPH) and PP block‐copolymer (PPC), were blended with a long chain, branched, low density polyethylene (LDPE) in a twin screw extruder and then injection moulded into test specimens; the mechanical properties and morphology of the blends are reported. The tensile strength, elastic modulus, flexural strength, and flexural modulus of the blends increased monotonically with increasing PP content, although exhibiting a slightly negative deviation from the rules of mixtures due to the relatively poor compatibility of the components, which caused the blends to separate into individual phases. Comparatively, these mechanical properties of the LDPE/PPH blend were much higher than that of the LDPE/PPC blend, which was attributable mainly to the fact that the mechanical properties of neat PPH are stronger than that of neat PPC. With respect to the impact strength of the blends, a maximum value appeared in LDPE/PPH blends when PPH content was about 20% and also in LDPE/PPC blends when PPC content was about 40%.     

Effect of Maleated Styrene/Ethylene-co-Butylene/Styrene on the Dispersed Particles Size and Mechanical Properties of Polyamide 6/Poly(styrene-co-acrylonitrile)/Poly(styrene-b-(ethylene-co-butylene)-b-styrene) Ternary Blends

In this study, the effect of several parameters, including composition, order of mixing, viscosity, and interfacial tension, on the phase structure and size of dispersed particles of polyamide 6 (PA6)/poly(styrene-co-acrylonitrile) SAN/poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) ternary blends was investigated. Moreover, the effect of addition of different ratios of reactive SEBS (maleic anhydride grafted-SEBS) and non-reactive SEBS at a fixed order of mixing and composition of 70/15/15 (PA6/SAN/SEBS + SEBS-g-MAH) on the mechanical properties of ternary blends was examined. Scanning electron microscopy (SEM) micrographs showed that among the studied parameters, interfacial tension and viscosity of dispersed phases were the leading factors in the formation of morphology and size of dispersed droplets. Mechanical results revealed that in contrast to the expectation, formation of core/shell structure of PA6/SAN/SEBS ternary blends did not result in a significant increasing of impact strength. The highest impact strength was achieved when a 50/50 weight ratio of SEBS/SEBS-g-MAH was used.