Microfibrillar morphology

A more quantitative measure of the microfibrillar morphology can be obtained by SAXS measurements. A detailed analysis of the small-angle scattering from PBT films and derivation of the relevant equations will be given elsewhere. The main features of the analysis are given below. 

We suggest that both the lamellar and the microfibrillar morphologies are formed by a nucleation and growth process. A low nucleation density of crystal solvates results in a lamellar morphology, whereas a high nucleation density of the crystalline PBT results in formation of microfibrils. 

Semi-fluorinated Alkanes. Semi-fluorinated alkanes have been shown to form gels when dissolved in alkanes such as decane and octane, due to a microfibrillar morphology. This gel phase occurs when the mixture is heated above the melting point of the semi-fluorinated alkane, and then allowed to cool (. Upon cooling from above the melting point, the semi-fluorinated alkane solidihed in the form of needles in the presence of the remaining solution. 

An unusual (1— 3)- 3-D-xylan appears to be the skeletal material for a number of seaweeds, and occurs with microfibrillar morphology, just as for cellulose. However, the birefringence of the fibrils is n ative, whereas for cellulose it is positive, and this observation suggests a helical structure, seen, by examination of molecular models, to be quite plausible. An x-ray fiber diagram for the material conditioned at 98% relative humidity is shown in Fig. 19. The principal characteristic of this diagram is that the most intense reflections are not on the equator this is a feature of molecules of the helical type, such as those of nucleotides or proteins. From an analysis of the x-ray data, Frei and Preston concluded that a double... 

In summary, then, a suitable processing history that includes extensional flow can yield a reinforcing, microfibrillar morphology of the dispersed LCP phase. Modulus values that are similar to those of short glass fiber-reinforced plastics can... 

Garmabi H and Naficy S (2007) Developing electrically conductive polypropylene/polyam-ide-6/carbon black composites with microfibrillar morphology, J Appl Polym Sci 106 3461-3467. 

The aim of the present woik was preparation of microfibrillar-phase morphology in the PP/PE blends with polypropylene as a minority component. For these purposes an extrasion line based on conventional singlescrew extrader and semihyperbolic-converging die was employed. It was proved that the formation of fibrillar structure in one processing step can be achieved using blends with various content of polypropylene (the blends with 20, 30 and 40 wt.% of PP were studied) and both compounded and hand-mixed materials (twin-screw extruder compounded and non-compounded materials were processed). Since the structure and properties of polymer parts are mutually interconnected, the extruded tapes with microfibrillar morphology were examined by several methods of structure analysis and measurements of properties. The results can be summarized as follows ... 

IN-SITU FORMATION OF MICROFIBRILLAR MORPHOLOGY IN POLYMER BLENDS.332... 

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