Modulus changes blending with

P-plastomers, even more than the E-plastomers, have been blended with a number of substrates [23]. The most-important one is blend with iPP which forms compatible blends with P-plastomer for a wide range of relative weights fractions of P-plastomer and iPP as well as a wide range of molecular weights for both of the components. The formation of the blends with iPP leads to changes in the elastic and tensile response with elongation modulus, monotonicaUy increasing with the amount of iPP. 

In Fig. 8.5, course of changes of the storage modulus E, loss modulus E and vibration damping factor g5 for iPP and iPP/Engage I blends with content of 85/15, 70/30 and 55/45% in relation to temperature has been shown. For iPP/EOE blends two, clear relaxation transitions in the range of glass transition are visible, near glass points of iPP and EOE. 

There have been very few studies reported on the viscoelastic properties of rubber-resin pressure sensitive adhesive systems. In 1973, M. Sherriff and co-workers (1) reported on the effect of adding poly (j3-pinene) resin to natural rubber. Based on a G master curve, they showed that the resin shifted the entry to the transition zone to a lower frequency and reduced the modulus in the rubbery plateau. G. Kraus and K.W. Rollman (2) reported in 1977 on their study of resins blended with styrene-isoprene-styrene block copolymers. They showed that the addition of a resin increased the glass transition temperature of the rubbery mid-block and decreased the plateau modulus. Accordingly, a satisfactory tackifying resin should produce these changes. 

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