Rheological behaviour blends

In the present investigation it has not been possible to undertake a systematic investigation of all the variables that might affect the viscosity of a glass fibre slurry, but an attempt has been made to identify the more important parameters. Polyol blends as described in a preceding paper in this volume (1) were used. Three specific aspects of rheological behaviour have been investigated. 

Thus, it appears that chemical reactivity or ionic-cross interactions could lead to in situ compatibilising or miscibility enhancement during melt-mixing. However, several questions remain. How does the reactivity modify the thermodynamic balance, the reciprocal miscibility or the rheological behaviour of the melt Or, how the covalent or ionic bonding influence the interfacial adhesion processability and final mechanical properties of the immiscible blends ... 

The second types of blends that can be produced are miscible blends where the blend may have a higher viscosity than PP and appears to be remarkably elastic. The chemical structure of the miscible block appears to be more important in governing the observed viscosity of the system where it has increased the viscosity of the system For instance. Song et. al has shown that the rheological behaviour of blend PP and POE (polyethylene-l-octene) is highly... 

The influence of electron beam irradiation on rheological properties and morphology of polypropylene and polypropylene/ethylene-propylene rubber blends was studied. Electron beam irradiation of isotactic PP causes pronounced chain scission (degradation) at dosis < 100 kGy. Melt viscosity can be controlled easily up to this dose for pure PP. For the blende however, an anomalous rheological behaviour is observed. 

Irradiation of PP/EPDM blends causes pronounced differences in rheological behaviour compared with irradiated PP, which cannot be explained only by crosslinking of the EPDM phase. A possible explanation is the formation of grafted copolymers from PP onto the EPDM rubber particles. In blends a higher crosslinked fraction (based on 100% EPDM) is found than in irradiated EPDM (Table 1). The authors, however, are well aware that this is not an absolute prove of the presence of a graft copolymer and certainly is not a quantitative method to measure the amount of grafting. In order to get more evidence IR and NMR experiments will be performed in the future. 

Rheological measurements showed that the viscoelastic behaviour of a blend containing 1 wt % 28b was similar to that of pure PCL at high frequencies, but at lower frequencies (coaT<2 rad s" ) the storage shear modulus was much higher than that of PCL (Fig. 69). No interpretation of the detailed rheological behaviour of the blends was offered. 

Xu H S, Li Z M, Wang S J and Yang M B (2007) Rheological behaviour of PET/HDPE in situ microfibrillar blends influence of microfibrils flexibility, J Polym Sci Part B Polym Phys 45 1205-1216. 

The rheological performance of rubber blends manifests the ease or diiSculty of their fabrication. Mooney viscosity measurement is usually used to determine the rheological behaviour of an uncured batch at a specific temperature. Other rheometers like plate-plate or capillary may be used for rheological characterization. 

Rheological Behaviour of Natural Rubber Based Blends... 

For the NR based blends, therefore, the rheological behaviour must be considered case by case such as blending with thermoplastics and blending with other rubbers. In the case of the chemically modified NR based-blends, it was not only the type of polymer used to blend with NR, but also the variation of the chemical modification of NR would control the different rheological property of the blends. Special-property NR based blends obtained from the... 

Oommen et al. had studied melt rheological behaviour of the blends between NR and poly(methyl methacrylate) based on the effect of blend ratio, processing conditions and graft copolymer concentration as a function of shear stress and temperature. It was clarified that the viscosity of the blends increased with the increase of the amount of NR. On the other hand, the flow behaviour of the blends was found to be influenced by dynamic vulcanization of the rubber phase. 

The rheological behaviour of NR and polystyrene (PS) blends had been carried out in the presence and absence of the NR-g-PS compatibilizer using a capillary rheometer and a melt flow indexer. ... 

The influence of dichlorocarbene modified natural rubber (DCNR) on the rheological behaviour of blends based on NR and hydrogenated nitrile rubber (HNBR) was studied.The NR used in this study was ISNR 5 grade from India. The HNBR used was a Zetpol 2010 grade (Nippon Zeon, Japan) with... 

The melt rheological behaviour in terms of Mooney viscosity, apparent shear stress, and apparent shear viscosity at 100 of two types of blends that included a blend between maleated STR 5L (MNR) and cassava starch and a... 

Rheological behaviour of the TPVs that were prepared from dynamic vulcanization of NR-g-PMMA and PMMA blends using various vulcanization systems including conventional vulcanization (CV) and efficient sulphur vulcanization (EV) systems were studied by Nakason et al The ingredient formulas of each vulcanization systems are summarized in Table 18.6. 

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