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Temperature dependence of Flory-Huggins interaction parameter, v , for SMA8/PMMA ( s ); SMA14/ PMMA ( h ); and SMA32/ PMMA ( n ). Open symbols represent values of v calculated using Eq. (3) and closed symbols represent those obtained from Eq. (4). The lines are calculated using v A±B/T (see Table 2 for values of A and B) for (б) SMA8/PMMA; (± ±) SMA14/ PMMA; (± áá ±) SMA32/PMMA
Source publication
We investigated the thermo- rheological behavior of high glass transition, high molecular weight and small dynamic asymmetry
blends of poly(styrene-co-maleic anhydride) (SMA) and poly (methyl methacrylate) (PMMA) with varying amounts of maleic anhydride (MA) content, namely
8 wt%, 14 wt% and 32 wt%, in the SMA component. The phase separation (bino...
Citations
... In addition, the interfacial compatibility between the additive and PLA matrix was investigated by Cole/Cole curves (η' vs. η″, where η″=G'/ω and η'=G″/ω) [29]. According to the literature [30], the arc in the high-frequency region of the Cole/Cole curve indicated the relaxation behavior of the coacervate, while the arc in the low-frequency region indicated the relaxation of the dispersed phase droplets. ...
In this work, we improved the compatibility between layered double hydroxide and poly (lactic acid) (PLA) by organically modified Ni-Zn-Al-layered double hydroxides (T@5S-LDHs) through intercalation and amidation. The structural changes of T@5S-LDHs before and after modification were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and static contact angle. PLA/T@5S-LDHs nanocomposites films were prepared by blown molding process. The addition of T@5S-LDHs was found to further improve the crystallization ability of PLA through polarizing microscopy analysis. The molecular dynamics simulations showed that the interaction force increased from 279.9 to − 863.6 kcal/mol, which indicated that T@5S-LDHs had strong compatibility with PLA. In the natural degradation behavior, the molecular weights of PLA and PLA/T@5S-LDHs nanocomposites films decreased from 95,542 to 97,569 g/mol to 71,174 and 82,438 g/mol before and after natural degradation, respectively. The relevant degradation index R.M.I increased from 1.1200 to 1.0665 to 1.3424 and 1.1835 between the 28 and 56 days of degradation, respectively. Meanwhile, the carbonyl index of the both films decreased from 3.744 to 3.200 to 2.393 and 2.827 before and after degradation, respectively, which demonstrated that T@5S-LDHs effectively mitigated the degradation behavior of PLA and could prolong the service lifetime of PLA films to some extent.
... The approach here proposed, focused on the range of concentration and temperature of industrial relevance, can be used as a simple and effective way to obtain a detailed phase map of a multicomponent mixtures exhibiting complex phase behaviour, as was partially done in literature (Chopra et al. 2002;Ilyin et al. 2020;Pasquino et al. 2013). In fact, the approach here presented can be systematically applied to fine tune the characterisation, extending the number of temperatureconcentration values, and to identify, with any needed precision, values of transition among phases. ...
Surfactant-water mixtures display a complex rheological behaviour, with changes in parameters such as viscosity and moduli of several orders of magnitude as a consequence of phase changes, depending on their concentration and temperature: this criticism heavily affects different industrial processes. In our work, linear rheological behaviour of aqueous mixtures of a commercial anionic surfactant, sodium lauryl ether sulphate, is investigated in a range of temperature (30–60 °C) and surfactant concentration (20–72%wt) of technological relevance. Four phases with different texture are identified by polarised light microscopy: micellar, hexagonal, cubic and lamellar, all showing a shear-thinning behaviour. Rheological parameters of cubic phase show a net jump in a relatively narrow temperature range, suggesting a temperature-induced phase change. The systematic analysis of the rheological behaviour of this widely used surfactant system, reported here for the first time, can be of fundamental support for many industrial applications.
Graphical Abstract
... Another possible way of investigating the miscibility conditions of polymer blends is through the Han plot, in which the log G′ versus log G″ are reported, generally resulting in a linear correlation [44]. The compatibility of the polymer blend can be demonstrated if the slope of the obtained curves at different relative concentrations of the constituents is the same [45,46]. On the contrary, if these curves show different slopes, then the analyzed blend is considered to be immiscible [47,48]. ...
... Another possible way of investigating the miscibility conditions of polymer blends is through the Han plot, in which the log G versus log G are reported, generally resulting in a linear correlation [44]. The compatibility of the polymer blend can be demonstrated if the slope of the obtained curves at different relative concentrations of the constituents is the same [45,46]. On the contrary, if these curves show different slopes, then the analyzed blend is considered to be immiscible [47,48]. ...
High-performance composites suffer from fatigue crack propagation during service. Traditional repair methods can be expensive and time-consuming. Therefore, research on composites with self-healing capabilities has considerably increased in the past decade. The aim of this work is to develop a polyamide 6 (PA6) matrix with self-healing properties. Polycaprolactone (PCL) was used as healing agent and melt compounded with PA6. PCL caused a decrease of the mechanical properties of PA6, due to its immiscibility and low mechanical properties. Nevertheless, acceptable fracture toughness values in quasi-static mode were obtained. Samples were thermally mended at 80 and 100 °C, and the healing efficiency was assessed by comparing the fracture toughness of virgin and repaired samples both in quasi-static and in impact mode. The blend with a PCL content of 30 wt% showed limited healing efficiency values (up to 6%) in quasi-static mode, while an interesting repair capability (53%) was detected under impact conditions. This discrepancy was explained through microstructural analysis and correlated to a different fracture morphology. In fact, under quasi-static mode, the PA6 matrix was severely plasticized, while under impact a brittle fracture surface was obtained. This morphology favored the flow of PCL during the thermal healing process.
... In general, superposition shows reliable results provided the spectrum of relaxation times is temperature independent and the thermal activation is unchanged over the whole time-temperature range. There are examples of polymer systems which show deviations from TTS (Bousmina et al., 2002;Chopra et al., 2002;Lin et al., 2020;Yokokoji et al., 2021). ...
We present a basic principle and good practices of the rheology of polymers, particularly for teachers or lecturers at colleges or universities for educational purposes, as well as for beginner researchers who may refer to this article as their self-learning resources. Basic consideration of the experimental methods using parallel-plate oscillatory rheometer and step-by-step guidelines for the estimation of the power law dependence of storage, G′ and loss, G″ modulus as well as the estimation of the relaxation time at f cross G′−G′′
${f}_{\,\mathrm{cross}}^{\,{G}^{\prime }-{G}^{\prime \prime }}$
at terminal zone using various approaches such as commercial graphical software, manual graphical approach and commercial rheometer software are highlighted. Good practices for data interpretation using different approaches are described and compared where the outcomes revealed the manual graphical approach or commercial graphical software yield comparable results with the commercial rheometer software. In order to have better insight, several examples and exercises which are applicable for teaching and self-learning activities are also provided.
... For homogeneous polymers, only one circular arc was in the Cole-Cole plot. The appearance of another arc or trailing on the right of the main arc indicated phase separation [7,35]. As shown in Figure 5a, no arcs occurred in the LDPE/PS (70/30, wt%) composite. ...
Melt blending is an effective way to prepare new composite materials, but most polymers are incompatible. In order to reduce the interfacial tension and obtain fine and stable morphology with internal symmetric micro-textures, suitable compatibilizers should be added to the blend. The two immiscible polymers, low-density polyethylene (LDPE) and polystyrene (PS), were compatibilized by styrene/ethylene/butylene/styrene block copolymers grafted with maleic anhydride (SEBS-g-MAH) and organomontmorillonite (OMMT). The scanning electron microscope results indicated that the size of the PS phase decreased with increasing the content of SEBS-g-MAH. By introducing OMMT into LDPE/PS/SEBS-g-MAH composites, the compatibility of composites was further improved. The rheological analysis and Cole–Cole plot analysis indicated that the addition of SEBS-g-MAH and OMMT increased the interaction between the two phases. The tensile strength, elongation at break, and impact strength of the LDPE/PS/SEBS-g-MAH (70/30/7, wt%) composite increased by 64%, 255%, and 380%, respectively, compared with the LDPE/PS (70/30, wt%) composite. A small amount of OMMT could synergistically compatibilize the LDPE/PS composite with SEBS-g-MAH. After adding 0.3% OMMT into the LDPE/PS/SEBS-g-MAH system, the tensile strength, elongation at break, and impact strength of the composite were further increased to 18.57 MPa, 71.87%, and 33.28 kJ/m2, respectively.
... It has been reported that two arcs are formed for many polymer blends. This is consistent with the existence of two phases with different relaxation times [49,50]. In other words, those plots clearly demonstrate two dissimilar relaxation mechanisms associated with different phases [51]. ...
The present work demonstrates the relationship between the tensile and hardness properties, crystalline structure as well as rheological behavior and gel content for the organo-montmorillonite (OMMT) filled poly(ethylene-co-vinyl acetate) (EVA)/acrylonitrile-butadiene rubber (NBR) nanocomposites. The NBR/EVA mixtures containing 5% (wt) OMMT were first provided and then cured with 0–2% (wt) dicumyl peroxide. The results of tensile experiments showed that while the elastic modulus and yield stress linearly increased, strain-at-break linearly decreased with gel content in the range studied. It was also found that the tensile strength and modulus at 100 and 300% strain increased exponentially, however, energy-at-break decreased in the form similar to an inverse S-shaped curve with gel content. The Cole–Cole plots revealed that the relaxation time increased progressively with the increase in gel content. Wide-angle X-ray diffractometry showed that the peak intensity ratio of I110/I200 was reduced by the addition of OMMT and increased somewhat with increasing in gel content. In addition, the Casson plot was employed to calculate the yield stress of the materials. The results indicated that the yield stress of the uncured nanocomoposite was higher than that of the simple blend and the value progressively increased with the increase in gel content.
... Melt rheology is frequently used to study the flow of polymer blends, including effects related to morphological changes [32][33][34][35]. The PMMA/SAN blends were studied in frequency sweeps at 200 • C, 210 • C and 220 • C, respectively. ...
... The PMMA/SAN blends were studied in frequency sweeps at 200 • C, 210 • C and 220 • C, respectively. The temperature 230 • C is a ceiling temperature for PMMA, above it depolymerization followed by gelation would occur, especially in the presence of moisture [33,36]. Cross-linked structures are formed, and they provide long relaxation times. ...
... The LCST transition of polymer blends can be studied using dynamic shear rheology. The transition appears as a drift from semicircle in Cole-Cole plot [33]. The Cole-Cole plot represents the dependence of imaginary part of η*(η") versus real part of η* (η ′ ) (where η" = G'/ω and η ' = G"/ω, and G ′ and G ′′ represent the real and imaginary parts of the shear complex storage modulus, respectively). ...
A new concept of utilization of particle-polymer hybrids as multifunctional additives for polymer blends was introduced in this study. Graphene oxide particles with short densely grafted polystyrene brushes (GO-g-PS) were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). Melt rheology studies revealed that GO-g-PS suppressed the phase separation of miscible poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) (PMMA/SAN) blends. The studies suggested specific interactions of GO-g-PS with the PMMA phase and this was confirmed based on calculations of activation energies of segmental relaxations by broadband dielectric spectroscopy (BDS). These unusual interactions of GO-g-PS with PMMA phase were assigned to the specific and precise architecture of the GO-g-PS particles as well as chemical nature of PS polymer brushes. The short chains of PMMA and PS provide miscibility originating from UCST behavior of PMMA/PS blend of short polymer chains. Additionally, BDS also revealed improved charge transport in PMMA/SAN blend in presence of GO-g-PS hybrid.
... In particular, all samples present information about the relaxation process occurring in polymeric blends. These diagrams, in particular, form or become one semicircle when they indicate miscibility; on the contrary, immiscibility is attributed when more than one semicircle appears [46]. The Cole-Cole diagrams revealed the homogeneity of amorphous PLA, showing a smooth semicircular arc. ...
Herein, we report the melt blending of amorphous poly(lactide acid) (PLA) with poly(styrene-co-methyl methacrylate) (poly(S-co-MMA)). The PLAx/poly(S-co-MMA)y blends were made using amorphous PLA compositions from 50, 75, and 90wt.%, namely PLA50/poly(S-co-MMA)50, PLA75/poly(S-co-MMA)25, and PLA90/poly(S-co-MMA)10, respectively. The PLAx/poly(S-co-MMA)y blend pellets were extruded into filaments through a prototype extruder at 195 °C. The 3D printing was done via fused deposition modeling (FDM) at the same temperature and a 40 mm/s feed rate. Furthermore, thermogravimetric curves of the PLAx/poly(S-co-MMA)y blends showed slight thermal decomposition with less than 0.2% mass loss during filament extrusion and 3D printing. However, the thermal decomposition of the blends is lower when compared to amorphous PLA and poly(S-co-MMA). On the contrary, the PLAx/poly(S-co-MMA)y blend has a higher Young’s modulus (E) than amorphous PLA, and is closer to poly(S-co-MMA), in particular, PLA90/poly(S-co-MMA)10. The PLAx/poly(S-co-MMA)y blends proved improved properties concerning amorphous PLA through mechanical and rheological characterization.
... When the system was homogeneous, the cole-cole curve assumed a single arc shape. When the microphase separation happened, the cole-cole curve would show two peaks or a tail on the right side.[44][45] ...
Most biodegradable thermoplastic materials can’t be used as elastomers due to their relatively poor elasticity. Poly(butylene furandicarboxylate-co-ε-caprolactone) (PBFCL) copolyesters were synthesized from 2,5-Furandicarboxylic acid (FDCA), 1,4-Butanediol and poly(ε-caprolactone) diols. The PBFCLs are susceptible to hydrolysis and enzyme degradation, and the degradation rate could be controlled by the enzymes. PBFCL40 and PBFCL50 (CL molar content) displayed high tensile strength (≥ 50 MPa), good elongation at break (≥ 1050%) and quick shape recovery like an elastomer. Although BF and CL segments were incompatible, the dynamic mechanical and rheological results excluded the possibility of microphase separation under room temperature. In-situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) measurements revealed the evolution of crystals during stretching. Strain induced orientation, melting of original crystals and formation of fibrillar crystal occurred in different strain regions, and the surviving crystals acted as the physical crosslinking points. This viewpoint was further confirmed by measuring the recoverability during cyclic tensile tests in PBFCL40 and PBFCL50 with controlled crystallinity. With controlled crystallinity, samples gained adjustable elasticity.
... It is well-known that the plot of h'' versus h', so-called Cole-Cole plot, can provide valuable information about morphology of polymer blends [27,28]. Figure 6 shows the Cole-Cole plots of blend samples above and below nominal melting point. ...
... Figure 6 shows the Cole-Cole plots of blend samples above and below nominal melting point. It is observed that PP in both temperatures exhibits a single characteristic circular arc, while a tail appears on the right-hand side of the arc for blend systems that is considered as an indication of a second relaxation process [27,28] of interfacial or nematic responses of samples. It is clear that classic compatibilizers change both the position and height of the arc as well as the significance of tail as a result of improved interfacial interactions. ...
The effect of classical compatibilizers and silica fillers, which are a new potential type of compatibilizers, on the rheological properties of PP/LCP blends was investigated.The frequency sweep, shear stress growth and stress relaxation upon cessation of steady shear were performed to probe the effect of the interfacial modification and the role of silica, on the rheological behaviour of the blend. It was found that SEBS-g-MA improves the interfacial interaction more than SEBS due to the possible chemical bonding between maleic anhydride groups and LCP chains. The results showed while the hydrophilic silica fills both matrix and the LCP dispersed phases, the hydrophobic silica has some compatibilizing effect on PP/LCP blend samples.
