Particle Size Of Dispersed Phase Research Articles

Effects of process method and quiescent coarsening on dispersed-phase size distribution in polymer blends: comparison of solid-state shear pulverization with intensive batch melt mixing

We compare how solid-state shear pulverization (SSSP), batch melt mixing (BMM), and static melt-state annealing affect the morphology of an immiscible blend of polypropylene (PP) and ethylene-α-olefin copolymer (EOC). For 85/15 wt% PP/EOC blends, SSSP and BMM led to log-normal distributions of dispersed-phase particle size. The SSSP blend had smaller average particle diameters (e.g., D n = 0.24 μm) and a narrower particle size distribution (e.g., D w/D n = 1.17; D v/D n = 1.56) than the BMM blend (D n = 0.28 μm; D w/D n = 1.25; D v/D n = 1.79). The fact that BMM is subject to thermodynamically and flow-induced coalescence while SSSP is not, can lead to smaller particle sizes and a narrower distribution by SSSP. Although annealing at 200 °C for 30 and 90 min led to continuous growth of average particle size in the BMM blend, the particle-size dispersity remained virtually unchanged. In contrast, after 30-min annealing at 200 °C, the SSSP blend showed less growth in $$D_{{_{n} }}^{{^{3} }}$$ than the BMM blend but a dramatic increase in particle-size dispersity and a loss of the log-normal size distribution. Between 30 and 90 min, there was at most slight growth in $$D_{{_{n} }}^{{^{3} }}$$ , consistent with partial compatibilization caused by in situ block copolymer formation during SSSP, and major reductions in D w/D n and D v/D n close to those of the BMM blend and recovery of the log-normal size distribution. These results suggest that caution should be used in correlating immiscible blend properties to a particular average particle size as that value may not reflect possible complexity of the underlying size distribution.

Thermoplastic polyurethane/polypropylene blends in a co-rotating non-twin screws extruder

Thermoplastic polyurethane (TPU)/polypropylene (PP) blends of different weight ratios were prepared with a self-made co-rotating non-twin screws extruder (NTSE), which rotates at a speed ratio of 2.0, and a traditional twin-screw extruder (TSE), which rotates at a speed ratio of 1.0. The mechanical properties, phase morphology and thermal stabilities were investigated to characterize the effect of different processing methods. The experimental results revealed that the samples prepared with a NTSE had superior mechanical properties compared to those of the samples prepared with a TSE. High-resolution scanning electron microscopy showed a structure feature of fiber morphology of TPU/PP blends prepared with a NTSE and the particle size of dispersed phase of blends prepared with NTSE is smaller than that prepared with TSE, indicating that the NTSE is more efficient in mixing for immiscible polymer blends. Furthermore, thermogravimetric analysis curves indicated the strong interaction of the TPU/PP blends influenced by the flow field in NTSE, compared to that of TSE-extruded.

Improved Mechanical Properties of Compatibilized Polypropylene/Polyamide-12 Blends

Compatibilized blends of polypropylene (PP) and polyamide-12 (PA12) as a second component were obtained by direct injection molding having first added 20% maleic anhydride-modified copolymer (PP-g-MA) to the PP, which produced partially grafted PP (gPP). A nucleating effect of the PA12 took place on the cooling crystallization of the gPP, and a second crystallization peak of the gPP appeared in the PA12-rich blends, indicating changes in the crystalline morphology. There was a slight drop in the PA12 crystallinity of the compatible blends, whereas the crystallinity of the gPP increased significantly in the PA12-rich blends. The overall reduction in the dispersed phase particle size together with the clear increase in ductility when gPP was used instead of PP proved that compatibilization occurred. Young’s modulus of the blends showed synergistic behavior. This is proposed to be both due to a change in the crystalline morphology of the blends on the one hand and, on the other, in the PA12-rich blends, to the clear increase in the crystallinity of the gPP phase, which may, in turn, have been responsible for the increase in its continuity and its contribution to the modulus.

Influence of microstructure and flexibility of maleated styrene-b-(ethylene-co-butylene)-b-styrene rubber on the mechanical properties of polyamide 12

The present investigation deals with the mechanical and morphological properties of binary polyamide 12/maleic anhydride-grafted styrene-b-(ethylene-co-butylene)-b-styrene rubber (PA12/SEBS-g-MA) blends at varying dispersed phase (SEBS-g-MA) concentrations. Tensile behavior, impact strength and crystallinity of these blend systems were evaluated. Influence of microstructure, dispersed phase particle size, and ligament thickness on the impact toughness of the blend was studied. DSC data indicated an increase in crystallinity of PA12 in the blends. Tensile modulus and strength decreased while impact strength and elongation-at-break increased with the elastomer concentration. The enhanced properties were supported by interphase adhesion between the grafted maleic groups of rubber with polar moiety of polyamide 12. Analysis of the tensile data employing simple theoretical models showed the variation of stress concentration effect with blend composition.

Toughening of Poly(ethylene terephthalate) and Optimizing of the Compatibilization Between PET and EPDM by Functionalized EPDM

Ethylene-propylene-diene elastomer (EPDM), which was grafted with glycidyl methacrylate (GMA) by reactive blending, was used as modifier to toughen poly(ethylene terephthalate) (PET) and enhance the compatibility of PET/EPDM blends. Mechanical properties showed that brittle ductile transition was observed in PET/EPDM-g-GMA blends with the rubber content over 20 wt.%. The introduction of EPDM-g-GMA increased the mechanical properties of the PET/EPDM blends and decreased the particle size of EPDM dispersed phase. DSC analysis showed that the introduction of EPDM-g-GMA made the crystallization of PET difficult. DMA results showed that the compatibility of PET and EPDM phase was improved by EPDM-g-GMA.

두부응고제로서 Homomixer 회전속도를 달리한 염화마그네슘유화물의 제조특성

본 연구는 Homomixer의 회전속도에 따른 염화마그네슘 유화물의 제조특성을 비교하여 두부응고제로서 염화마그네슘유화물의 제조상 최적조건을 확립하기로 하였다. 염화마그네슘유화물의 입자는 Homomixer의 회전속도가 증가할수록 미세화 되었다. 입자크기는 <TEX>$1{\sim}5{\mu}m$</TEX>로 분포하고 있었다. 분산상의 입자크기가 미세화 할수록 점도의 증가와 보관 중 유상분리의 지연으로 상관관계가 있음을 나타내었다. 따라서 염화마그네슘유화물을 제조하는데 있어서 Homomixer의 회전속도는 10,000rpm 이상에서 제조하는 것이 두부응고제로서 두부의 조직 상태와 이수율 등이 가장 좋은 결과를 나타내었다. This study was used homomixer as one of the manufacturing method to establish optimal manufacturing condition with magnesium chloride emulsion as coagulant. The more rotational speed of homomixer was fast, the more particle size of magnesium chloride emulsion was minute. The particle size was distributed between 1 and <TEX>$5{\mu}m$</TEX>. The more minute particle size of emulsion had an effect on increasing viscosity of emulsion and delay of oil phase separation during storage period, so the quality of magnesium chloride emulsion had correlation with dispersed phase particle size. After all the experiments, when manufacturing magnesium chloride emulsion, it used more than 10,000 rpm of rotational speed of homomixer, it showed the best result as coagulant according to the state of texture and the water separation ratio of soybean curd.

Extruder‐made TPO nanocomposites. I. Effect of maleated polypropylene and organoclay ratio on the morphology and mechanical properties

AbstractPP/PP‐g‐MA/MMT/EOR blend nanocomposites were prepared in a twin‐screw extruder at fixed 30 wt % elastomer and 0 to 7 wt % MMT content. Elastomer particle size and shape in the presence of MMT were evaluated at various PP‐g‐MA/organoclay masterbatch ratios of 0, 0.5, 1.0, and 1.5. The organoclay dispersion facilitated by maleated polypropylene serves to reduce the size of the elastomer dispersed phase particles and facilitates toughening of these blend nanocomposites. The rheological data analysis using modified Carreau‐Yasuda model showed maximum yield stress in extruder‐made nanocomposites compared with nanocomposites of reactor‐made TPO. Increasing either MMT content or the PP‐g‐MA/organoclay ratio can drive the elastomer particle size below the critical particle size below which toughness is dramatically increased. The ductile‐brittle transition shift toward lower MMT content as the PP‐g‐MA/organoclay ratio is increased. The D‐B transition temperature also decreased with increased MMT content and masterbatch ratio. Elastomer particle sizes below ∼1.0 μm did not lead to further decrease in the D‐B transition temperature. The tensile modulus, yield strength, and elongation at yield improved with increasing MMT content and masterbatch ratio while elongation at break was reduced. The modified Mori‐Tanaka model showed better fit to experimental modulus when the effect of MMT and elastomer are considered individually. Overall, extruder‐made nanocomposites showed balanced properties of PP/PP‐g‐MA/MMT/EOR blend nanocomposites compared with nanocomposites of reactor‐made TPO. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

Compatible blends of polypropylene with an amorphous polyamide

AbstractCompatible polymer blends of polypropylene (PP) with an amorphous polyamide (aPA) were obtained through reactive compatibilization by adding 20% maleic anhydride‐modified copolymer (PP‐g‐MA) to the blends. The blends were made up of a pure PP phase and an aPA‐rich phase where very small amounts of PP were detected. The dispersed phase particle size decreased considerably indicating that compatibilization occurred. Young's modulus of the compatibilized blends increased with respect to that of the uncompatibilized ones. The compatibilized blends were highly ductile, and the impact strength also improved, proving that compatibilization occurred under a broad range of experimental conditions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013

Effect of pH on the Dispersion Characteristics of Fumed Silica

The effect of pH on the particle distribution and zeta potential of the fumed silica(SiO2) suspended in H2SO4 or NaOH aqueous solution and their relationship were investigated with laser dynamic light scattering(DSL).The experiment showed that the isoelectric point(IEP) and titration end(TE) of silanol were at pH(IEP)=2.09 and pH(TE)=7.47,respectively,and a simple method was given for the determination of Si-OH concentration on SiO2 particle surface based on pH(TE).The dispersed phase particle size measurement showed that between IEP and TE,the hydration radius of SiO2 was stabilized near 230 nm;in H2SO4 medium,when pHpH(IEP),the apparent hydration radius of SiO2 increased with the increased H2SO4 concentration due to the coalescence of dispersed SiO2 aggregates;in NaOH medium,when pHpH(TE),the SiO2 aggregates decomposed and the apparent size of the dispersed phase decreased with increasing the NaOH concentration,which showed that NaOH can promote the dispersion stability of fumed silica in aqueous.

Polypropylene-elastomer (TPO) nanocomposites: 2. Room temperature Izod impact strength and tensile properties

Room temperature Izod impact strength was determined for polypropylene (PP)/ethylene-co-octene elastomer (EOR) blends and nanocomposites, containing organoclays based on montmorillonite (MMT), at fixed elastomer content of 30 wt% and 0–7 wt% MMT. A ratio of maleated polypropylene, PP-g-MA to organoclay of unity was used as a compatibilizer in the nanocomposites. The organoclay serves to reduce the size of the EOR dispersed phase particles and facilitates toughening. The Izod impact strength is also influenced by the molecular weight of PP, elastomer octene content, elastomer MFI in addition to MMT content. Nanocomposites based on a low molecular weight polypropylene (L-PP) containing a higher octene content elastomer showed higher impact strength at lower MMT contents compared to those based on a low octene content elastomer. The effect of elastomer octene content on impact strength of high molecular weight polypropylene (H-PP) nanocomposites is not so significant. Elastomers having a melt flow index (MFI) in the range of 0.5–1.0 showed significant improvement in the impact strength of L-PP based nanocomposites. Most H-PP/EOR blends gave ‘super-tough’ materials without MMT and maintain this toughness in the presence of MMT. The critical elastomer particle size below which the toughness is observed is reduced by decreasing the octene content of the elastomer. For the similar elastomer particle sizes in nanocomposites, the impact strength varies as H-PP > M-PP > L-PP. The tensile modulus and yield strength improved with increasing MMT content; however, elongation at break was reduced. The extruder-made TPO showed a good-balance of properties in the presence of MMT compared to reactor-made TPO having similar modulus and elastomer content.

Effect of organoclay on the morphology, phase stability and mechanical properties of polypropylene/polystyrene blends

The effect of organically modified clay on the morphology, phase stability and mechanical properties of polypropylene (PP) and polystyrene (PS) blends was studied using three molecular weight grades of PP. Maleated polypropylene was used, at a PP-g-MA/organoclay ratio of 1, to preferentially promote dispersion of the organoclay in the PP matrix. The MMT content was fixed at 3 wt% based on the PP/PP-g-MA/MMT phase and the PS content was varied from 0–100 wt% in the blend. All blends were processed using a twin screw extruder. The organoclay resides in the PP phase and at the PP/PS interface. The dispersed PS particle size is significantly reduced by the presence of MMT, with maximum decrease observed for the low viscosity PP compared to its blend without MMT. The blends with MMT did not show any change in onset of co-continuity, though MMT shifts the phase inversion composition toward lower PS contents. The phase stability of the blend was significantly improved by the presence of MMT; for blends annealed at 210 °C for 2 h the dispersed phase particle size increased by as much as 10x without MMT with little change was noted with MMT present in the blend. The tensile modulus of blends improved with the addition of MMT at low PS contents. Blends based on the highest molecular weight grade PP showed increase in the tensile yield stress up to 40 wt% PS in the absence of MMT. The tensile strength at break for blend increased slightly with MMT while elongation at break and impact strength decreased in the presence of MMT. Surface energy analysis model was used to predict the orientation and equilibrium position of the clay platelet at the interface based on the surface energies.

Effect of PBT molecular weight and reactive compatibilization on the dispersed‐phase coalescence of PBT/SAN blends

AbstractPoly(butylene terephthalate) (PBT)/styrene‐acrylonitrile copolymer (SAN) blends were investigated with respect to their phase morphology. The SAN component was kept as dispersed phase and PBT as matrix phase and the PBT/SAN viscosity ratio was changed by using different PBT molecular weights. PBT/SAN blends were also compatibilized by adding methyl methacrylate‐co‐glycidyl methacrylate‐co‐ethyl acrylate terpolymer, MGE, which is an in situ reactive compatibilizer for melt blending. In noncompatibilized blends, the dispersed phase particle size increased with SAN concentration due to coalescence effects. Static coalescence experiments showed evidence of greater coalescence in blends with higher viscosity ratios. For noncompatibilized PBT/SAN/MGE blends with high molecular weight PBT as matrix phase, the average particle size of SAN phase does not depend on the SAN concentration in the blends. However noncompatibilized blends with low molecular weight PBT showed a significant increase in SAN particle size with the SAN concentration. The effect of MGE epoxy content and MGE molecular weight on the morphology of the PBT/SAN blend was also investigated. As the MGE epoxy content increased, the average particle size of SAN initially decreased with both high and low molecular weight PBT phase, thereafter leveling off with a critical content of epoxy groups in the blend. This critical content was higher in the blends containing low molecular weight PBT than in those with high molecular weight PBT. At a fixed MGE epoxy content, a decrease in MGE molecular weight yielded PBT/SAN blends with dispersed nanoparticles with an average size of about 40 nm. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010

Enhanced compatibility of PA6/POE blends by POE‐g‐MAH prepared through ultrasound‐assisted extrusion

AbstractThe effects of POE‐g‐MAH, prepared through different methods, on morphology and properties of PA6/POE/POE‐g‐MAH blends are summarized in this article. The grafting degree of POE‐g‐MAH can be increased through the ultrasound‐assisted extrusion. Experimental results showed that the addition of POE‐g‐MAH can increase the mechanical properties of the PA6/POE blend and decrease the particle size of POE dispersed phase in PA6 matrix due to the compatibilization by POE‐g‐MAH. The PA6/POE blend compatibilized by POE‐g‐MAH prepared through the ultrasound‐assisted extrusion has smaller particle size of POE dispersed phase and higher notched Izod impact strength than that by POE‐g‐MAH with similar grafting degree initiated only by peroxide. This result is ascribed to some anhydride rings attached to the chain terminus of POE due to ultrasound initiation. Rheological and Molau test results also showed enhanced compatibilization of POE‐g‐MAH prepared through the ultrasound‐assisted extrusion on the PA6/POE blend due to a structural difference of POE‐g‐MAH. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Reactive Compatibilization and Properties of Recycled Poly(ethylene terephthalate)/Poly(ethylene-octene) Blends

High toughness recycled poly(ethylene terephthalate) (R-PET)/poly(ethylene-octene) (POE) blends were prepa scanning electron microscopy red by adding glycidyl methacrylate grafted poly(ethylene-octene) (mPOE) as reactive compatibilizer. Evidence for reaction between the carboxyl or hydroxyl end groups of R-PET and the epoxy groups of mPOE under the conditions of processing to form graft copolymers (PET-g-mPOE) is presented. Effects of compatibilizer on morphology and mechanical and thermal properties of the blends were evaluated systematically. The results showed that dispersed phase particle size decreased with increasing mPOE content until the critical compatibilizer concentration (5 wt%) was reached. Notched Charpy impact strength and elongation at break were improved greatly by the addition of compatibilizer. Differential scanning calorimetry (DSC) analysis showed POE could act as a nucleating agent in the R-PET matrix to improve the crystallization temperature, while the graft copolymers formed in compatibilized R-PET/POE blends decreased the nucleation activity.

Dynamic rheological and morphological study of the compatibility of thermoplastic polyurethane/ethylene–octene copolymer blends

AbstractTwo grafted ethylene–octene copolymers [POEs; i.e., POE‐g‐maleic anhydried (MAH) and aminated POE (denoted by POE‐g‐NH2) were used as compatibilizers in immiscible blends of thermoplastic polyurethane (TPU) and POE. The effects of the compatibilizers on the dynamic rheological properties and morphologies of the TPU/POE blends were investigated. The characteristic rheological behaviors of the blends indicated that the strong interactions between the two phases were due to the compatibilization. Microstructural observation confirmed that the compatibilizers were located at the interface in the blends and formed a stable interfacial layer and smaller dispersed phase particle size. Compared with POE‐g‐MAH, POE‐g‐NH2 exhibited a better compatibilization effect in the TPU/POE blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

In‐line measurements of the morphological parameters of PP/PA6 blends during extrusion in the transient mode

AbstractThe real‐time measurement of the morphology of immiscible polymer blends based on polypropylene (PP) and polyamide 6 (PA6) was performed during melt blending in a twin‐screw extruder. The disperse phase particle size and concentration were obtained in‐line with an optical device placed at the die exit. To validate the response of the optical device, its detector was calibrated in advance in a bench using ceramic particles of well‐controlled size dispersed in water. The optical device was able to measure the changes in particle size and concentration and the data enabled the calculation of the particle extinction cross section. Melt blending experiments in the extruder were performed in a transient mode, where a small amount of the material was added as a pulse to the main melt flow. The pulses containing pellets of the PA6 and polypropylene grafted with acrylic acid (PP‐g‐AA) were added to the PP flow stream in different amounts. The detector's response increased with increasing concentrations in the PA6 and PP‐g‐AA. The disperse phase particle size decreased concomitantly because of the compatibilizing effect of the PP‐g‐AA on the PP/PA6 immiscible blend. That observation confirmed that the detector's response was directly related to the disperse phase particle size. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

Change in disperse phase particle size in petroleum systems in thermal transformations

Change in disperse phase particle size in petroleum systems in thermal transformations

Localized compatibilization in immiscible blends of thermoplastic polyurethane and ethylene‐octylene copolymer

AbstractTo prepare thermoplastic polyurethane (TPU)/ethylene‐octylene copolymer (POE) blends, which are thermodynamically immiscible, maleated POE and aminated POE were incorporated as compatibilizers. Effect of addition of the compatibilizers and their contents on morphology, coalescence, and mechanical properties of TPU/POE blends were investigated. The microstructural observation revealed that the compatibilizers are located at the interface in the blends, forming a stable interfacial layer. As a result, the dispersed phase particle size was greatly reduced and tensile properties of the blends were significantly improved. POE‐NH2 provides the blends with higher compatibility than POE‐MA. The interfacial interaction offered by the compatibilizers was found to be a function of the amount of the reactive groups grafted onto POE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Morphology of Extruded PP/HDPE Foam Blends

A complete three-dimensional morphological analysis is performed to determine the size and deformation of both foam cells and dispersed phase particles in the extrusion foaming of HDPE/PP blends. Each dimension is carefully measured to determine interaction between blending and foaming on the final foam morphology. In this study, blends of 0, 10, 30, 50, 70, 90, and 100% PP in HDPE are foamed using azodicarbonamide (ACA). The effect of using a compatibilizing agent (Kraton D 1102) is also included.

Effect of mixing protocol on compatibilized polymer blend morphology

AbstractWe investigated the effect of mixing protocol on the morphology of compatibilized polymer blends made with premade compatibilizer and reactively formed in‐situ compatibilizer in a custom‐built miniature mixer Alberta Polymer Asymmetric Minimixer (APAM). The compatibilized blends show a finer morphology than uncompatibilized blends if the polymers are mixed together in the dry state and then fed into the mixer. It is found that premelting one polymer, and premixing polymers and compatibilizer, both greatly affect the compatibilized blends' morphology. The effects are complex since the dispersed phase particle size and distribution of the compatibilized blends may be smaller or larger when compared with the uncompatibilized system, depending on the material's physical and chemical properties; for example, diblock molecular weight or the preference of copolymer to migrate to a particular phase can change the final morphology. Good mobility of the copolymer to reach the interface is crucial to obtain a finer morphology. Micelles are observed when a high molecular weight diblock copolymer P(S‐b‐MMA) is used for a PS/PMMA blend. Because of its enhanced mobility, no micelles are found for a low molecular weight diblock copolymer P(S‐b‐MMA) in a PS/PMMA blend. For PS/PE/P(S‐b‐E) blends, finer morphology is obtained when P(S‐b‐E) is first precompounded with PS. Because the block copolymer prefers the PE phase, if the P(S‐b‐E) block copolymer is compounded with PE first, some remains inside the PE phase and does not compatibilize the interface. In the case of reactive blend PSOX/PEMA, premelting and holding the polymers at high temperature for 5 min decreases final dispersed phase particle size; however, premelting and holding for 10 min coarsens the morphology. POLYM. ENG. SCI. 46:691–702, 2006. © 2006 Society of Plastics Engineers.