Breaking thread

Elemans PHM, Janssen JMH and Meijer HEH (1990) The breaking thread method the measurement of interfacial tension in polymer systems. J Rheol 34 1311-22. 

DDRM is particularly useful for the binary polymer blends. The dynamic interfacial tension coefficient, Vj2, is determined from the time evolution of a distorted fluid drop toward its equilibrium form. Measurements of either low viscosity model systems or high viscosity industrial polymer mixtures led to a good agreement with values obtained from the widely used breaking thread method. DDRM enables to measure in polymeric blends of commercial interest — the high viscosity systems that frequently are impossible to characterize by other techniques. Furthermore, for the first time it is possible to follow the time dependence of Vj, thus unambiguously determine its dynamic and equilibrium values. 

PETG (90-80) / EVAc (10-20) internal mixer at 210°C / SEM / NMR model study / rheology / DMA / interfacial tension measurements by breaking thread method / dibutyl tin oxide catalyst (0-1%) Lacroix et al., 1996 a, b... 

Measurements of interfacial tensions of polymer melts were reviewed by Wu (55), Koberstein (65), and Demarquette (66). The measurements usually need long equilibrium time because of the high viscosities of polymer melts. The measurements can be divided into two groups static methods in which interfacial tension is calculated based on the equilibrium profile of the drops and dynamic methods that study the evolution of fiber or drop profiles with time. Static methods include pendant drop method, sessile drop method, and rotating drop method. Dynamic methods include breaking thread method, imbedded fiber method, and deformed drop retraction method. 

Minkova, L., Yordanov, H., Filippi, S., and Grizzuti, N. 2003. Interfacial tension of compatibilized blends of LDPE and PA6 The breaking thread method. Polymer 44 7925-7932. 

Xing et al. (2000) compared five different techniques for the measurement of interfacial tension in a model polystyrene (PS)/polyamide-6 (PA-6) system at a constant temperature. The techniques include three dynamic methods (the breaking thread, the imbedded fiber retraction, and the retraction of deformed drop), one equilibrium method (the pendant drop), and a rheological method based on linear viscoelastic measurements. The advantages, the limitations, and the difficulties of each technique were discussed and compared. 

PA-6/LDPE/EAA (6 wt% AA) Morphology/interfacial tension measmed by breaking thread method/also used EAA partially Zn neutralized Minkova et al. 2002, 2003... 

Table 1.1 Interfadal tension (k) between polymer melts based upon the breaking thread method (Yoon and White [146]).

The variety of experimental methods that have been utilized to efficiently measure the polymer-polymer interfacial tension have been briefly reviewed, with emphasis on the static methods (pendant drop, with the approach being very similar to the case of sessile drop) that have been widely used for polymeric liquids. The breaking thread method and the IFR method have been frequently used as weU, especially for high molecular weight polymers. 

Palmer G, Demarquette NR (2003) New procedure to increase the accuracy of interfacial tension measurements obtained by breaking thread method. Polymer 44 3045—3052... 

The interfacial tension at the interface between two polymers is an expression of different energetics of bulk materials. It reflects differences in thermodynamics, which are related to the x parameter, as shown by Eq. (3.4). The experimental evaluation of the interfacial tension with polymeric melts is extremely difficult due to problems associated with sample preparation and equilibration [77, 78]. Several techniques have been proposed for the measurement. The most commonly used techniques include the pendant drop method, the embedded fiber retraction technique, and the breaking thread method. Classical equilibrium interfacial tension experiments like the pendant drop technique are very difficult to apply to high polymers because of their high melt viscosities (10 -10 Pas). There are many practical problems associated with the pendant drop technique ... 

Even small amounts of reaction have been found to greatly reduce the interfacial tension between polymers. Sundararaj [35] used the breaking thread method to measure... 

Many of the compatibihzation studies include interfacial tension measurements and several examples wiU be noted here. The interfacial tension of LDPE/PA6, determined by the breaking thread method, was measured with the addition of various compatibilizers, including poly(ethylene-co-acrylic acid), poly(ethylene-co-acrylic acid Zn + salt), styrene-ethylene/butylene-styrene (SEES) block copolymer with and without maleic anhydride functionalization [246]. The SEES block copolymer without MA showed no reduction in interfacial tension, whereas the other compatibilizers exhibited significant reductions. 

Breaking Thread Method for Interfacial Tension Determination Figure 5.35 Breaking thread method for the determination of interfacial tension of polymer blends... 

Another method to determine the interfacial tension of immiscible polymer blends is termed the breaking thread method. Thin fibers (in the range of 10s of pm) are embedded in a matrix polymer. Heating to the viscous liquid state results in sinusoidal fiber distortion, ultimately yielding regularly dispersed elKpsolidal to spherical domains as shown in Fig. 5.35. The amplitude, a, follows an exponential relationship ... 

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