Palierne Model Research Articles

Exploring interfacial tension role in the laminar morphology development in reactive compatibilized PP/EVOH

AbstractLaminar-like structures in PP/EVOH (80/20 wt%) blends were developed by in situ reactive compatibilization using a co-rotating intermeshing twin-screw extrusion without the imposition of post-die-forming elongation flows, i.e., draw ratio (DR) = 0. For that, a maleic anhydride-grafted homopolymer polypropylene (PP-g-MA) was added at 1, 1.5, and 3 wt% using a simple mixing protocol. The correlation between the laminar morphology observed via SEM with interfacial parameters was conducted by nonlinear regression of PP/EVOH viscoelastic response (Gʹ and Gʹʹ) applying the Monomodal Palierne Model to estimate interfacial tension. Uncompatibilized PP/EVOH formed a droplet-matrix morphology with high interfacial tension, indicating incompatibility. As PP-g-MA is added, a laminar-like structure is developed. The remaining droplets become smaller at higher content, with lower interfacial tension between the phases. This scenario hampers the stratification of the dispersed phase. At 3 wt% of PP-g-MA, the morphology returns to being a droplet-matrix, although with high adhesion between the phases. Graphical abstract

Feasibility Analysis of Resource Application of Dry Flue Gas Desulfurization Ash in Asphalt Pavement Materials

To verify the feasibility of applying dry flue gas desulfurization ash (DFGDA) to asphalt pavement materials, the asphalt mastic (filler and asphalt composition) prepared by adding different proportions of DFGDA and LSP (limestone powder) into 70# matrix asphalt was studied experimentally. The asphalt mastics were subjected to the penetration test, the softening point test, and the ductility test. Moreover, the rheological properties of asphalt mastic were evaluated with dynamic shear rheometer (DSR) tests and bending beam rheometer (BBR) tests. An interaction ability index C-value based on the Palierne model was proposed to evaluate the interaction ability between DFGDA and asphalt. The influence of DFGDA asphalt on the interaction ability of matrix asphalt was observed and evaluated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that with the increasing proportion of DFGDA, the penetration of asphalt mastic gradually decreased, the softening point increased, and the ductility slightly decreased. At the same temperature, the dynamic shear modulus G* of the asphalt mortar significantly increased with increasing DFGDA content. The incorporation of DFGDA negatively affected the low-temperature plastic deformation resistance of asphalt, but the impact was weakened with the growing DFGDA amount and the powder mastic ratio. The combination mode of DFGDA and matrix asphalt depends on the physical blending, and their interaction ability mainly depends on the miscibility between DFGDA and matrix asphalt. In conclusion, DFGDA can be utilized as a novel filler in asphalt pavement materials.

Emulgels Structured with Dietary Fiber for Food Uses: A Rheological Model.

Emulgels are biphasic emulsified systems in which the continuous phase is structured with a specific gelling agent. In this work, a rheological and microscopic investigation of O/W emulgels prepared by structuring the aqueous (continuous) phase with citrus fiber was carried out with the aim of designing their macroscopic properties for food uses and predicting their characteristics with a rheological model. According to previous investigations, fiber suspensions behave as "particle gels" and, consequently, the derived emulgels' properties are strongly dependent on the fiber concentration and on process conditions adopted to produce them. Therefore, a rotor-stator system was used to prepare emulgels with increasing fiber content and with different levels of energy and power used for mixing delivered to the materials. An investigation of particle gels was then carried out, fixing the operating process conditions according to emulgel results. Furthermore, the effect of the dispersed (oil) phase volume fraction was varied and a modified semi-empirical Palierne model was proposed with the aim of optimizing a correlation between rheological properties and formulation parameters, fixing the process conditions.

Predicting Dynamic Properties of Asphalt Mastic Considering Asphalt-Filler Interaction Based on 2S2P1D Model.

The relationship between the various phases of asphalt materials, from asphalt binder to mastic and mixture, has received great attention over the years, with efforts being made to establish linkages among these phases. Many methods for predicting the rheology properties of asphalt mastics from those of asphalt and filler volume fractions exist. However, most prediction methods are based on an empirical formula and on the micromechanical model. Very few research studies focus on the constitutive model. In addition, relatively little research has explored the influence of asphalt–filler interaction on mastic’s rheology properties, which is believed to be an important factor. In this study, the 2S2P1D (two springs, two parabolic elements, and one dashpot) model was applied to link the behavior of asphalt binder, filler volume fraction, asphalt–filler interaction and asphalt mastic. First, the interaction between asphalt and filler was evaluated, and the interaction parameter C of the Palierne model was used as an assessment indicator to calculate the effective filler volume fraction of asphalt mastic. Then, the relation between the 2S2P1D model parameters of asphalt mastic and those of asphalt binder and the effective filler volume fraction was analyzed. Finally, a simple relationship associating the 2S2P1D model parameters , of mastic and that of asphalt binder and the effective filler volume fraction was developed. The proposed expression was validated, and the result showed that it was an efficient model for the shear complex modulus prediction of virgin asphalt mastic.

Design of ultrastretchable and super-elastic tailorable hydrophilic thermoplastic elastomeric materials

In this work, new ultrastretchable and super-elastic hydrophilic thermoplastic elastomeric (TPEs) materials were developed for the first time from the thermoplastic polyurethane (TPU) and epichlorohydrin-ethylene oxide-allyl glycidyl ether (GECO) rubber using straightforward melt-blending and dynamic vulcanization approaches, which allows the creation of tailorable hydrophilic TPE materials. The resulting materials can absorb up to ∼80% water within 4 h. The absorbed water convert itself into hexagonal ice crystals in the TPE matrix which was directly evident from differential scanning calorimetry and cryo-transmittance electron microscopy. The phase components of developed TPE were found to be interactive which was analysed from the torque and loss tangent values. Interaction was further enhanced after dynamic vulcanization which was predicted from the rheological Palierne model. Interestingly, interfacial tension between the TPU and GECO was significantly reduced after dynamic vulcanization which suggested stronger inter-domain interaction between the phase components. It was revealed that the resulting TPE possess droplet-matrix phase morphological structure which was supported from the theoretical Kerner model prediction. Surprisingly, resulting materials showed extraordinary elastomeric properties than that of TPEs reported earlier, such as very high strain at break (∼800–1000%) and lowest tension set (∼2–6%) which enables the creation of ultrastretchable and super-elastic materials. • A new kind of ultra-stretchable, superelastic and tailorable hydrophilic TPE was developed. • The developed TPE showed extraordinary elastic properties having high strain at failure (1000%) and low-tension set (∼2%). • The hexagonal ice crystals were formed in the TPE matrix by absorbed water.

Surface tension and interfacial tension of polyolefins and polyolefin blends

AbstractThis paper focuses on the calculation of the interfacial tension of two systems: low‐density polyethylene with isotactic polypropylene and high‐density polyethylene with syndiotactic polypropylene. For this, three methods to measure the interfacial tension are compared: the use of Palierne's model, and Gramespacher and Meissner's model, both based on additional elasticity or long relaxation times brought by shape recovery of dispersed phase, and ab‐initio calculation, which requires the knowledge of the surface tension of the neat polymer measured at the same temperature. For that, a database collected from the literature is built in the first section of this paper, whether for the studied systems or for other systems of various olefinic homopolymers or copolymers with polypropylene. The results show the effectiveness of the Gramespacher and Meissner's model to calculate the interfacial tension of the studied systems for which the results were in agreement with ab‐initio calculation and Palierne's model. Extension of the ab‐initio calculation to olefinic copolymers was proposed.

Investigation of rheological properties of asphalt emulsions

Rheology is critical issue in the workability, stabilization and engineering performance of asphalt emulsions. The objective of this study is to investigate the rheological properties of asphalt emulsions. To achieve this goal, a preshear protocol was introduced and four kinds of asphalt emulsions were tested base on preshear. Firstly, the necessarity of preshear was analyzed and the suitable range of preshear rate and preshear time of the studied asphalt emulsions were given. Then, the rheological properties of asphalt emulsions were studied after preshear. Finally, the palierne model was modified and the storage/loss modulus of asphalt emulsions was accurately predicted by the modified palierne model. The results showed that it’s necessary to preshear asphalt emulsions before testing rheological properties. The viscosity, zero shear viscosity, storage and loss modulus of asphalt emulsions increase with the increase in solid content. The prediction results of the modified palierne model are better than that of palierne model. The storage/loss modulus of asphalt emulsions can be effectively predicted by the modified palierne model. This study has considerable meaning to the promotion of production and manufacturing of asphalt emulsions.

Rheology of a polypropylene/low-density polyethylene blending melt: Fitting dynamic rheological data by Palierne model and Lee and Park model

Rheology of a polypropylene/low-density polyethylene blending melt: Fitting dynamic rheological data by Palierne model and Lee and Park model

Preparation, Characterization and Processing of PCL/PHO Blends by 3D Bioplotting

Abstract Blends of polycaprolactone (PCL) and poly(3-hydroxyoctanoate) P(3HO) were prepared by melt compounding. These immiscible blends exhibited droplet-matrix morphology at compositions up to 30 wt% P(3HO). Even though the addition of amorphous P(3HO) decreased the crystallinity of PCL, the crystallization temperature of the blends increased by 6 to 7 8C. Blends containing up to 30 wt% P(3HO) had higher crystallization rates, and lower crystallization half-times compared to neat PCL. The viscosity of PCL decreased upon addition of P(3HO), making the blends suitable for processing using a 3D bioplotter. Compositions with 10 to 30 wt% P(3HO) were ideal for processing, because of their improved crystallization kinetics, reduced stickiness and good flow properties. Estimation of the interfacial tension by fitting the Palierne model to the linear viscoelastic properties of the blends revealed good compatibility, which gave rise to synergistic effects in the thermal and mechanical properties. The fibres prepared by 3D bioplotting maintained droplet matrix morphology, with finer particle size than the original compounded material. In addition to favourable viscosity and thermal properties, the extruded fibres containing 30 wt% P(3HO) had comparable modulus to the neat PCL, while exhibiting good ductility. These blends may be suitable alternatives to PCL for biomedical applications, because they provide a range of crystallinities, crystallization rates and viscosities.

Prediction of Rheological Properties and Interfacial Tension of Mixtures of Immiscible Polypropylene-Polystyrene (PP3/PS) Blends

Blends of polypropylene (PP3) and polystyrene (PS) were studied and, their rheological behavior was determined and discussed in detail. The interfacial tension between the blend components was evaluated from the rheological data and the storage modulus by using two well-known models: Palierne model and Choi-Schowalter equation. The theoretical predictions were compared with experimental data obtained from PP3/PS blends. The obtained results showed that the Palierne model could predict the rheological and viscoelastic properties of the considered polymer blends. In addition, the interfacial tensions between PP3 and PS were evaluated and compared with those cited in the literature. It was also found that the Palierne model was more accurate than Choi-Schowalter one in determining the interfacial tension.

Rheological Investigation with Palierne’s Model on a Polystyrene/Nylon 6 Blending Melt Compatibilized by a Polystyrene Grafted Maleic Anhydride

The dynamic rheological behaviors are measured by small amplitude oscillatory shear on a rotational rheometer for a polystyrene (PS)/nylon 6 (PA6) blend compatibilized by a polystyrene grafted maleic anhydride (PS-g-MAH). The storage moduli versus angular frequency (G’-ω) data of the blends are fitted by Palierne model. The Palierne model fits the data basically well for the PA6-rich blends and the 70/6/30 (PS/PS-g-MAH/PA6) blend. The fitting results show that the PS-g-MAH has a fine compatibilizing effect on the PS/PA6 blends.

Melt rheology and interfacial properties of binary and ternary blends of PS, EOC, and SEBS

ABSTRACTThis works systematically investigates the interfacial properties of the binary and the ternary blends based on polystyrene (PS), ethylene octene copolymer (EOC), and styrene–ethylene–butylene–styrene (SEBS) by analyzing the melt linear rheological behavior of the blends and neat components. Moreover, the relationship between rheology, phase morphology, and mechanical properties of PS/EOC ternary blends with various quantities of SEBS were studied. The surface shear modulus (β) and interfacial tension values obtained by Palierne model indicated that the EOC/SEBS blend has the best interfacial properties, while the lowest interaction was found for PS/EOC blend. Based on the Palierne model and Harkin's spreading coefficients a core–shell type morphology with EOC phase encapsulated by the SEBS shell dispersed in the PS matrix was determined for the ternary blends. Scanning electron microscopy results revealed that both fibrillar and droplet forms of dispersed phase could be developed during the blending of PS and EOC in presence of SEBS. The extent of fibrillar morphology and interfacial interactions in PS/EOC/SEBS ternary blends was dependent on the SEBS content. The improvement of the mechanical properties of PS/EOC blends in the presence of SEBS was evidenced by the tensile and impact resistance experiments. The tensile strength reinforcement was more pronounced for the ternary blends with more fibrillar dispersed phase. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48791.

A multiple approach in determination of interfacial tension of biodegradable melt-mixed PBAT/EVOH blends: Correlation of morphology, rheology and mechanical properties

The interfacial tension of biodegradable melt-mixed blends of poly(butylene adipate-co-terephthalate), PBAT, and poly(ethylene-co-vinyl alcohol), (EVOH), was measured by breaking thread (BT), imbedded fiber retraction (IFR), and rheological methods. The PBAT-rich blends were prepared under different melt mixing conditions in order to investigate the effect of mixing conditions and possibility of reactive mixing between the blend components on the blend morphology, rheology, mechanical properties and interfacial tension values. The conditions were varied based on a Taguchi design of experiment using four factors namely EVOH content (0–30 wt%), mixing time (2–15 min), rotor speed (50–90 rpm), and mixing temperature (185–200 °C), each varying at three levels. The average size of EVOH droplets in PBAT matrix was determined for each blend by a field emission-scanning electron microscopy technique. The values of interfacial tension of PBAT/EVOH were found to be 2.57 ± 0.22 and 2.73 ± 0.30 mN m−1 by the BT and IFR methods, respectively. The Palierne, Gramespacher, and Bousmina models were fitted to the rheological data to verify the interfacial tension of the blends. The continuous relaxation spectrum of the blends was determined in order to obtain the relaxation time of the EVOH droplets in the PBAT matrix. The Taguchi analysis revealed that the most effective factor is the EVOH content, and other factors do not play a significant role in the ultimate properties of the blends. Finally, based on the obtained mechanical properties, the possibility of reactive mixing under the applied mixing conditions was ruled out by means of repeated differential scanning calorimetry (DSC) and rheological measurements.

Rheology of polymer multilayers: Slip in shear, hardening in extension

The nonlinear rheology of multilayer stacks of alternating isotactic polypropylene (PP) and polyethylene (PE) films with N layers was measured in shear and uniaxial extension. We show that the force to extend N − 1 interfaces can lead to strain hardening. We studied three PE/PP pairs: a Ziegler–Natta catalyzed pair and two metallocene pairs, one with high density PE and one with linear low density PE. Interfacial tension was measured on matrix/droplet blends of each pair using small amplitude oscillatory shear measurements fitted with the Palierne model. Multilayer coextrusion was used to fabricate bilayers and sheets with hundreds of layers for each polyolefin pair. Under shear deformation, disentangling of chains in the N − 1 interfaces led to a decrease in the overall shear viscosity, which is interpreted as an interfacial slip velocity and is in agreement with previous studies on multilayer films. Under extensional flows, the multilayers exhibited an increased transient extensional viscosity (tensile stress growth coefficient, η E , M +) and pronounced strain hardening, even when the constituent homopolymers exhibited no strain hardening behavior. A model based on a force summation was developed to predict this behavior with interfacial tension as a fitting parameter; the extracted interfacial tensions agreed reasonably well with those from the Palierne model. The “slip in shear” and “hardening in extension” behaviors highlight the role of interfacial polymer physics during rheological measurements and polymer processing.

Phase behavior and dynamics of Pluronic®-based additives in semidilute solutions of poly(ethersulfone) and poly(N-vinyl pyrrolidone): rheological and dynamic light scattering experiments

The phase behavior and dynamical properties of a pristine Pluronic® F127 and a Pluronic®-based multiblock copolymer, respectively, in semidilute solutions of poly(ethersulfone) (PESU) and poly(N-vinyl pyrrolidone) (PVP) in N-methyl-2-pyrrolidone (NMP) are investigated using shear rheological and dynamic light scattering (DLS) experiments. Pluronic® F127 is used for synthesis of the PESU-based multiblock copolymer. If the concentration of this additive exceeds a critical value, the solutions are characterized by a pronounced elasticity because of the phase behavior of the solutions, i.e., the polymer solution with three polymeric components depicts a miscibility gap which is associated with an interfacial tension in the two-phase regime. The addition of pristine Pluronic® F127 or the Pluronic®-based multiblock copolymer leads to an additional relaxation process. The zero shear rate viscosity data are qualitatively reproduced by the Palierne model. Phase separation above the critical concentration is supported by a relatively low diffusion coefficient as determined by DLS experiments.

Comparing effects of two tri-block copolymers on morphology, thermal, mechanical and rheological properties of polystyrene/low density polyethylene blends

Compatibilized and uncompatibilized immiscible blends of polystyrene and low density polyethylene at various blending ratios were prepared by melt mixing using an internal batch mixer. Two kinds of similar structure tri-block copolymers as compatibilizers were employed: styrene-butadiene butylene-styrene (SBBS) with long blocks of polystyrene, and styrene-ethylene butylene-styrene (SEBS) with long blocks of poly(ethylene-butylene). The influence of the compatibilizers on morphology, thermal and mechanical properties of different blends were analyzed and compared by using scanning electron microscope (SEM), differential scanning calorimetry (DSC), x-ray diffraction (XRD), impact and tensile tests. Also, linear dynamic rheological properties of different blends were analyzed and interfacial tensions between the blend components were calculated by using Palierne model. The Cole-Cole plots were established to bring more insights into the results of viscoelastic measurements. Significant difference appeared in thermal and mechanical properties between the compatibilized blends using SEBS and SBBS. It was found that type and length of blocks in the compatibilizers along with the ratio of the blends controlled the interfacial tension, droplet size and the mechanical properties of the given blends.

Interfacial Tension Properties in Biopolymer Blends: From Deformed Drop Retraction Method (DDRM) to Shear and Elongation Rheology-Application to Blown Film Extrusion

Abstract Shear and elongation rheology have been used in order to quantify the interfacial tension properties of PLA_PBAT blends. A multi-functional epoxide (Joncryl) has been chosen as a compatibilizer. From small amplitude oscillatory shear (SAOS), the results show that the addition of the Joncryl into the blends increased largely the shear rheological properties (elasticity, shear-thinning behavior) and contributed to very long relaxation process. This relaxation process is characterized by the presence of a G′ shoulder at lower angular frequencies. Scanning and transmission electron microscopy (SEM and TEM) observations show a finer morphology thus confirming the improvement of interfacial properties of the compatibilized blends. The interfacial tension has been firstly quantified using the deformed drop retraction method (DDRM). These experiments elucidated some of the effects of phase elasticity on both deformation mechanism and break-up conditions. A decrease of the interfacial tension has been demonstrated for the compatibilized blends. Secondly, the same trend was also highlighted using the emulsion Palierne model (simplified and generalized versions). Finally, the interfacial tension value was extracted from the measurements of extensional properties. A good accuracy with the two latter methods was obtained. This decrease of the interfacial tension nicely demonstrated the role of Joncryl as an efficient compatibilizer for a better handling of blow PLA-PBAT film extrusion process.

Influence of the molar masses on compatibilization mechanism induced by two block copolymers in PMMA/PS blends

The compatibilization mechanism of poly(methylmethacrylate) (PMMA)/polystyrene (PS) blends induced by PMMA-b-PS block copolymers of different molar masses (30 and 104 kg/mol) was studied. The blend morphologies with and without copolymers were observed by scanning electron microscopy. The rheological behavior was studied performing small amplitude oscillatory shear experiments. The experimental results were compared to Palierne's model predictions. Shear induced coalescence tests were also conducted. Contrary to what was expected, adding block copolymers did not result in a refinement of the droplet size. However, it induced Marangoni stresses, a decrease in interfacial tension and an inhibition of coalescence of the dispersed phase. During coalescence tests, a decrease in the relaxation time due to Marangoni stresses with time was revealed. This interesting behavior contradicts previous works on the subject, and is believed to be due to a migration of block copolymers to the interface during the tests rather than droplets' coalescence. As such, the morphology was explained by the fact that block copolymers are not entirely at the interface initially. Also, the block copolymer with a higher molecular mass was shown more efficient at inhibiting coalescence, indicating that the compatibilization mechanism is a combination of Marangoni stresses and steric hindrance.

Prediction of complex modulus in phase-separated poly (lactic acid)/poly (ethylene oxide)/carbon nanotubes nanocomposites

This study focuses on the modeling of complex modulus in phase-separated poly (lactic acid) (PLA)/poly (ethylene oxide) (PEO)/carbon nanotubes (CNT) nanocomposites. Palierne model for complex modulus of immiscible blends is developed assuming the significances of CNT and interphase regions. The predictions of developed model are compared to the experimental data from rheological experiment and the predictability of the developed model is studied. Furthermore, the roles of main parameters in the complex modulus of nanocomposites are explained to validate the developed model. The calculations show proper agreements with the experimental data confirming the predictability of the developed model. A higher concentration of continuous matrix and a smaller content of PEO droplets cause thicker and stronger interphase in nanocomposites. High CNT concentration and thin CNT mainly improve the complex modulus. Additionally, both thickness and complex modulus of interphase regions directly control the complex modulus of nanocomposites. This study can afford an insight for researchers to control and optimize the complex modulus in immiscible nanocomposites.

Influence of formulation on morphology and rheology of polypropylene/polyamide blends filled with nanoclay mineral particles

The effect of formulation on the morphological and rheological properties of clay polypropylene/polyamide 12 nanocomposites is investigated. Two clay minerals, organically modified montmorillonite and synthetic talc, and two polypropylenes matrices, a low viscosity polypropylene and a high viscosity polypropylene, are used. The higher polypropylene matrix viscosity strongly influences the interfacial coverage of polyamide nodules, by slowing down the migration of fillers from polypropylene matrix to polyamide nodules. The nature of clay minerals as well as the polypropylene matrix viscosity is shown to influence the change from nodular to non-nodular morphology of nanocomposites. A comparative study of the viscoelastic properties of montmorillonite or synthetic talc high viscosity polypropylene/polyamide 12 nanocomposites is performed through the use of Palierne's model. Surprisingly, the results show that a developed montmorillonite interphase behaves like a weakly developed synthetic talc interphase suggesting that the nature and structure of clay particles located at the interface play a key role in interphase viscoelastic properties.