these luctures divideded into five parts deals with the extensional and shear flow and there applications in different fields such as extrusion and injection mouldind .Also messurments of these flow are included in these luctures.
solutions of different problebs are estimated for studients for purpose of trainining. The defects of folw associated with these operations discussed in details such as melt fracture and sharkskin and effects of these deffects on the final producs of polymers materials for different application. Many parameters must be controlled to improve the mechanical and thermal properties of plastic polymers. Pressure is the important factors in these operations which with the pressure increases the viscosity decreasind ,while when temperatures decreases the the viscosity increasing.
being put on materials and moulding machines it is becoming essential to be
able to make reliable quantitative predictions about performance. In Chapter 4
it was shown that a simple Newtonian approach gives a useful first approximation
to many of the processes but unfortunately the assumption of constant
viscosity can lead to serious errors in some cases. For this reason a more
detailed analysis using a Non-Newtonian model is often necessary and this
will now be illustrated.
Most processing methods involve flow in capillary or rectangular sections,
which may be uniform or tapered. Therefore the approach taken here will be to
develop first the theory for Newtonian flow in these channels and then when the
Non-Newtonian case is considered it may be seen that the steps in the analysis
are identical although the mathematics is a little more complex. At the end of
the chapter a selection of processing situations are analysed quantitatively to
illustrate the use of the theory. It must be stressed however, that even the more
complex analysis introduced in this chapter will not give precisely accurate