Characterization of Polymer Blends

The above four terms define the key differences between a polymer and PAB.The specific tests developed for the characterization of polymer blends focus on the detection of miscibility, construction of phase diagrams, evaluation of compatibUization and the characterization of interphase. 

The commercial nomenclature is not as precise as the scientific one. A polymer is rarely labeled as a blend or an alloy, unless the concentration of the minor component exceeds the locally accepted limiting concentration. For example, toughened PC may be called a blend when the elastomer content exceeds 5 or 45 wt%. Evidently, these products are blends and should be treated as such.  

All liquids, single or multicomponent, are heterogeneous in terms of the density fluctuations function thus the miscibility is defined mathematically by AG , 0, but operationally one likes knowing which size of heterogeneity, di. Silberberg and Kuhn proposed that in miscible blends the size of heterogeneity should not exceed that of the radius of gyration (s = 

3-10 nm. The customary scattering methods for detecting miscibility are applicable above that limit, s 15 nm.  

Traditionally, turbidity or opacity has been used for detecting the cloud-point curve (CPC), which approximated the bimodal of the phase diagram. Evolution of this approach involved application of laser light scattering, which combined with small specimen size and precise temperature control led to the pulse-induced critical scattering (PICS) for spinodal determination. Unfortunately, the method is limited to the size of heterogeneity 100 nm and the difference in refractive index of the two phases 0.01. ° i 

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Manea, C. and Mulder, M. 2002. Characterization of polymer blends of poly-ethersulfone/sulfonated polysulfone and polyethersulfone/sulfonated poly-etheretherketone for direct methanol fuel cell applications. Journal of Membrane Science 206 443-453. 

LC CC was independently applied to the characterization of oligomers by the group of Evreinov and coworkers in Moscow [170]. Experimental confirmation of characterization of polymer blends and block copolymers were again done in St. Petersburg [166]. Zimina continued her studies also in United Kingdom [172,173]. These researchers are considered founders of LC CC. 

EG-LC was successfully applied to many polymer separations, especially those aimed at the characterization of polymer blends and statistical copolymers [20,22,23,25-29,31,32,210-216]. Sato et al. [216] have demonstrated potential of EG-LC in the separation of chemically identical polymers according to their physical architecture. 

Kuhn R (1983) Characterization of polymer blends, block copolymers, and graft copolymers by fractionation procedures using demixing solvents. Polym Sci Technol 20 45-58. 

For homogenous systems, the ultrasonic velocity is related to the ratio of modulus to density. Thus, one may expect that any method that determines density changes with adequate precision can provide indication of miscibility [Singh and Singh, 1983]. The ultrasonics can also be used as a screening method for the optimization of processing and its parameters, e.g., for the online characterization of polymers blends [Piau and Verdier, 1993 Verdier and Piau, 1995 Gendron et al, 1995]. 

The use of infrared spectroscopy for the characterization of polymer blends is extensive [Olabisi et al, 1979 Coleman and Painter, 1984 Utracki, 1989 Coleman et al, 1991]. The applicability,... 

Preparation of samples for the observation under TEM is more tedious and exacting than that used for SEM. The specimens have to be hardened and stained with Br, OsO, or RuO, microtomed into ca. 20 slices, mounted on a grid and polymeric film support and measured. Frequently, the SEM and TEM methods are being used in parallel. In all cases microscopy is considered but one method of characterization of polymer blends [Karger-Kocsis and JGss, 1987 Kyotani and Kanetsuna, 1987 Hsu andGeil, 1987]. 

Polymer chemists use DSC extensively to study percent crystallinity, crystallization rate, polymerization reaction kinetics, polymer degradation, and the effect of composition on the glass transition temperature, heat capacity determinations, and characterization of polymer blends. Materials scientists, physical chemists, and analytical chemists use DSC to study corrosion, oxidation, reduction, phase changes, catalysts, surface reactions, chemical adsorption and desorption (chemisorption), physical adsorption and desorption (physisorp-tion), fundamental physical properties such as enthalpy, boiling point, and equdibrium vapor pressure. DSC instruments permit the purge gas to be changed automatically, so sample interactions with reactive gas atmospheres can be studied. 

As the molecular size of most gases is much smaller than any scale of structure expected in polymer blend morphology, diffusion and permeability of gases can be employed to determine the phase behavior of a polymer blend. Therefore, the study of transport phenomena in blends would be motivated not only by the requirements of producing improved barrier materials but also by the continuous interest in the nature and characterization of polymer blend morphology. 

Linares, A., Acosta, J. L. (2004). Stmctural Characterization of Polymer Blends Based on PolysulfonesJ.ylpp/. Polym. Sci., 92(5), 3030-3039. 

In the first chapter, an overview of thermodynamic behaviors of non-equilibrium polymers is discussed. In the consecutive chapters, different properties of polymer blends are discussed, including surface tension, transition, crystallization, morphology, and flow behaviors. Miscibility and molecular characterizations of polymer blends are also covered in this book. Applications to various systems are reviewed, and both experimental concerns and references are supplied. 

Robeson, LM. (2007) Chapter 5 Characterization of polymer blends, in Polymer Blends, Hanser, Munich. 

Information on short-distance spatial proximity between different segments of molecules can be obtained using the proton spin-diffusion NMR method. This is a particularly valuable method for the characterization of polymer blends. For example, in case of PS/PVME cast films, the method provided information on blend composition, fraction of interacting groups (phenyl from PS with ether from... 

The use of infrared spectroscopy for the characterization of polymer blends is extensive (Olabisi et al. 1979 Coleman and Painter 1984 Utracki 1989 He et al. 2004 and references therein Coleman et al. 1991, 2006). The applicability, fundamental aspects, as well as principles of experimentation using infrared dispersive double-beam spectrophotometer (IR) or computerized Fourier transform interferometers (FTIR) were well described (e.g., Klopffer 1984). 

For characterization of polymer blends, low strain dynamic rheological measurements are preferred over steady-state shearing (e.g., in a capillary viscometer). Since... 

J. Sharma, Characterization of polymer blends by x-ray scattering SAXS and WAXS, in Characterization of Polymer Blends Miscibility, Morphology and Interfaces, Wiley-VCH Verlag GmbH Co. KGaA, 2015, pp. 209-236. 

Main applications of thermal analysis are (1) Soil and clay analysis (2) Determination of Glass transition (3) Compositional effects on glass transition (4) Heat capacity determination (5) Characterization of polymer blends (6) Study the effects of additives added to polymer (7) Polymer degradation analysis (8) Crystallinity and crystallization rate study and (9) Reaction kinetic studies. 

Another interesting coupled LC method for the characterization of polymer blends utilizes dual SEC/IC separation mechanisms simultaneously [47, 89,117-119]. In this method, one component is separated by the SEC mechanism while the other is separated by the IC mechanism simultaneously. Figure 13 shows an ex-... 

Badia Jose-David, Santonja Blasco Laura, Martmez-FeUpe Alfonso, and Ribes-Greus Amparo. Dynamic mechanical thermal analysis of polymer blends. In Characterization of Polymer Blends, Sabu Thomas, Yves Grohens, Parameswaranpillai Jyotishkumar (eds.), 365-392. Weinheim, Germany Wiley-VCH, 2015. 

Vesely, D. (1996) Microstructural characterization of polymer blends, Polym. Eng. 

Characterization of Polymer Blends Miscibility, Morphology, and Interfaces, First Edition. 

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