Silicon tetrachloride (refs
. 76 and 77) and tin tetrachloride (refs
1/[degrees]K, one can calculate the compound's specific energy of activation ([E.sub.A]) through what is called an Arrhenius plot (refs
. 21 and 22).
Their relative values are shown in figure 5 together with data taken from the literature (refs
. 13-16) on several attempts at barrier enhancement using melt processing technology.
The understanding and ability to model twin-screw extrusion operations has increased dramatically in recent years (refs
. 19, 21-26).
According to Bassi et al (ref
. 3) the durometer had historical priority over the IRHD instruments by more than 30 years.
Up to now there is only little specialized literature available concerning rubber-thermoplastics combinations (refs
. 4-7 and 9).
Two later processes used oleophilic quaternary ammonium salts, typical cationic surfactants, to pacify the silica (refs
. 21 and 22).
That is, gum rubber is treated as a high viscosity fluid (refs
. 16 and 17).
Others have been used to produce PE homo-, co- and tar-polymers, isotactic, syndiotactic and atactic PP, syndiotactic polystyrene and cyclic olefin copolymers (ref
In the mid-1950s this work was stimulated by papers describing synthesis on a semi-commercial scale using both Ziegler type catalysts (ref
. 5) and lithium metal catalysts (ref
. 1) proposed that the strain energy function (W) be expressed as a polynomial of strain invariants, W = W([I.sub.1],[I.sub.2],[I.sub.3]).
However, when we examined the complete capillary rheometer barrel pressure curve, we could see that the wax was not very effective at reducing the shear stress at very high shear rates, in the range that is important in injection molding operations (refs
. 39 and 40).