Blending sequences

Flow behavior of the polymer blends is determined by their structure, which is governed by the degree of dispersion of the component and by the mode of their distribution. For blends having identical compositions, it is possible to produce systems in which one and the same component may be either a dispersion medium or a dispersed phase [1]. This behavior of the polyblend systems depends on various parameters, the most important of which is the blending sequence. It is, therefore, difficult to obtain a uniform composition property relationship for the polymer blends even though the composition remains identical. 

Process States Batch processing usually involves imposing the proper sequence of states on the process. For example, a simple blending sequence might be as follows ... 

Compatibilities between the rubber phase and the blend components play the most important role in determining the final destination of the rubber, although, in a few cases, processing conditions such as blending sequence may... 

Recycle PET/PC/EBA-co-GMA Low-temperature solid-state extrusion/mechanical properties/ SEM/DSC/FTIR/effect of blending sequence on properties Peng et al. 2008... 

This chapter discusses the role of various nanoparticles in inuniscible polymer blends for control of the size of the dispersed polymer phase particles, phase inversitMi and rheological behavior, impact strength, and mechanical performance. Various issues such as the effect of nanoparticle dimensions on the polymer particle size and properties, blending sequence, location of nanoparticles in the blend components, mechanism behind improvement in... 

Figure 17.1 Blending sequences of nanocomposites in internal mixer.

In blending sequence B2, the high viscosity of natural rubber and incompatibility between natural rubber and organoclay (because it does not have any polar groups in its backbone) caused poorer dispersion of the filler, which was first incorporated into the natural rubber phase. Thus agglomerates were formed. 

Figure 17.6 The effect of different blending sequences and organoclay loading on tensile strength of the EVA/SMR L nanocomposites.

Figure 17.7 shows that with increasing loading of organoclay, there is an increase in stress at 100% elongation (MlOO) for all nanocomposites. Samples prepared via blending sequence B1 exhibit the highest improvement in MlOO. 

A 2 phr organoclay filled nanocomposite prepared via blending sequence B3 exhibits more matrix tearing with step-like appearances (indicated by white arrows) and lesser voids compared to nanocomposites prepared via blending... 

Figure 17.8 Tensile fracture surface for neat EVA/SMR L and its nanocomposites (2 and 8 phr) prepared via blending sequence Bl, B2 and B3.

All the blends in Table 12.2 may be divided into three groups based on the presence of the superadditive electrical conductivity and the effect of blending sequence on electric conductivity. 

It is impossible to understand the effect of blending sequence on filler localization at the interface from the single viewpoint of thermodynamics of particle wetting by two liquids. It is due to the fact that in polymer mixtures, for well-known reasons, the most energetically efficient distribution of a filler described by Eq. (12.1) is not achieved. 

Blending sequence Notched impact energy (kJ/ni2) Static fracture toughness (MPa.nd/2) Flexural modulus (GPa)... 

Dasari A, Yu Z-Z and Mai Y-W (2005) Effect of blending sequence on microstructure of ternary nanocomposites. Polymer 46 5986-5991. 

Very few papers have been published on the preparation of polymer blend nanocomposite from organoclays and poly(ethylene oxide)/poly(methyl methacrylate) (PEO/PMMA) blend by the solution blending method." In this section, we discuss how the blending sequence affects the microstructure of the ternary hybrid nanocomposites and especially the dispersion states of the organoclays in the polymer matrix. 

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