Extrusion parameters effects

We have created structured networks in whey proteins using mild heat and shear, to create reversible TWPs. By understanding on a molecular basis, the effects of shear, ways of creating new functionality can be developed. This will enable development of extrusion parameters that permit controlled denaturation of whey proteins. 

HaO/solid ratio used in the washing step, drying protocol, extrusion parameters (type and concentration of peptizing agents, solid/solution ratio and mixing time) and nitridation conditions. Because of the limited space available, this communication only reports the main effects brought by the adjustment of some of these parameters. 

P. I. Bashtannik, V. G. Ovcharenko, Y. A. Boot (1997) Effect of combined extrusion parameters on mechanical properties of basalt fiber-reinforced plastics based on polypropylene, Mech. Compos. Mater. 33,600. 

B. A. C. Siaotong, L. G. Tabil, S. A. Panigrahi and W. J. Crerar, Extrusion Compounding of Flax-Fiber-Reinforced Polyethylene Composites Effects of Fiber Content and Extrusion Parameters. Journal of Natural Fibers. 7 (4), 289-306 (2010). 

Major Regularities of the Effect of Rotation and Core Vibration upon Rheological Properties and Process Parameters of Polymer Extrusion... 

This is not the first attempt to review the effects of processing on the physical chemistry of raw materials. We refer extensively to the previous reviews by Richmond and Smith (1987) and Guy and Home (1988). Both took a forensic approach, examining bulk parameters such as temperature and pressure during extrusion in a single screw machine, then stopped the operation of the extmder and examined the effect on the processed raw material. 

Because direct dynamic measurements of materials state within the barrel are impossible, the structural and molecular changes relevant to extrusion must be measured off-line and related to real process conditions. In principle, we need to explain not only the effect of applied physical parameters of heat, shear and pressure, but also the effect of formulation. This is not yet possible, and for reasons stated above, the behaviour of carbohydrate (starch) dominated systems will be quite different from proteinaceous systems, since their heat denaturation behaviour and glass to rubber transitions are different in detail during their conversion from a moist powder to a continuous melt. ... 

Much of the published work on extrusion has attempted to correlate process conditions and formulation with final product properties. Correlations are almost always found, and may be systematic within the particular set of variables examined, but do not survive when further parameters are examined in other studies. This makes them of limited use in even qualitative explanation of product properties. Re-examination of published data, bearing in mind the effect of material states on the expansion process after the die, shows that there is a systematic explanation that can be related to the material properties of the extruded mass, during the dynamic formation of bubbles and cellular structures. However, because of the transformation of materials within the barrel, both at the microscopic and molecular level, it is unrealistic to expect test methods on raw materials alone to relate directly to product structures and... 

Applications The physical principle of measurement is similar to the scanning acoustic microscopy discussed in the Section 14.23, but applications and the method of data processing are essentially different. Sonic methods were used in the following applications to filled materials the effect of particle size and surface treatment on acoustic emission of filled epoxy, longitudinal velocity measurement of tungsten filled epoxy, and in-line ultrasonic measurement of fillers during extrusion. Numerous parameters related to fillers can be characterized by this non-destructive method. 

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