Drawing ratio

Tube No OD (ym) Wall thickness (ym) Machine draw ratio True draw ratio Draw speed (m/min) Corona Voltage (kV)... 

In spite of the above diversity of oriented crystalline morphologies, Samuels has shown that the structural state can sometimes be adequately characterized by the crystalline and amorphous orientation factors (37). For polypropylene samples prepared with different draw ratios, draw temperatures, shrinkage temperatures, etc., simple property correlation with these two orientation factors was observed ".. . these results suggest that different fabrication processes are simply different paths along which the sample is moved to equivalent structural states. Thus, general structure-property correlations are achieved by concentrating on the final structural state of the sample and not on the path by which the state was reached." Where applicable, this Is a most useful approach however, when radically different fabrication processes and radically different morphologies are compared, the definition of "structural state" must include more subtle features than the crystalline and amorphous orientation factors. 

Using an economic L/D ratio, draw a line from the L/D scale throi h the mark on Index Line B. Extend the line until it cuts the diameter scale. 

Emulsion polymers Mixing ratio Draw ratio Tenacity (g/tlen) Elongation (%)... 

Solid-state forming basically uses a male metal plug mold that matches a female metal cavity mold and can be used only with crystalline-type resins. Below their glass transition temperatures Tg) amorphous-type resins are generally too stiff to be rapidly formed into stable products. Crystalline types can be permanently deformed at temperatures between their Tg and melting point (Chapter 1). Molecular orientation, the mechanism that allows this to occur, relates to the draw ratio. Draw ratios can vary from 5 1 for PET and nylon to 10 1 for low molecular weight PP. 

PROBLEM 12.17 When treated under SnI conditions, the two allyUc chlorides shown here give the same pair of alcohols in the same ratio. Draw structures for the two alcohols and show the mechanism leading to each product. 

The 295 drawn PET yarns have been produced by applying a wide variety of process conditions especially chip viscosity, winding speed, draw ratio, drawing temperature, and degree of relaxation have been varied. 

A high molecular weight is required for an eventually high draw ratio. Draw ratio scales as DR MW°. In gel spinning the molecular weight is higher than in... 

FIG. 87 Dynamic Yoimg s modulus vs temperature for PE (Rigidex 140-60) samples at different draw ratios (measured at 20 Hz, experimental points shown for Cor = 35). (b) tan S vs temperature for PE (Rigidex 140-60) samples at different draw ratios. Draw ratio curve 1,11 curve 2,15 curve 3, 28 curve 4, 35. (From Ref. 117.)... 

Figure 17. Mechanical properties (measured at room temperature) of gel fibers, spun from a 2 % solution of UHMW PE in decalin, as a function of the draw ratio. Drawing was performed at 120 °C using dried gel filaments. Note the dramatic increase (over 100-fold) in stiffness and strength. 

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