Blends with Ethylene-a-Olefin Copolymers

Dynamic mechanical spectra of the iPP/EBR (75/25) blends are shown in Fig. 9.3. In the blends with phase-separated morphology for example, iPP/ EBR36, double peaks appear in the tensile loss modulus E curve distinctly in the temperature range from 200 to 300K, which are assigned as and in the order of 

Although the crystallization condition affects the morphology to some degree, which will be discussed later, the miscibility in the molten state has strong influence on the morphology in the solid state, in particular, for quenched samples. 

Sample Melting temperature, K Crystal form Long period, nm 

3 Ethylene-Propylene Copolymer and Ethylene-Octene-1 Copolymer 

Carriere and Silvis studied the interfacial tension between iPP and ethylene-octene-1 copolymers (EORs) with various amounts of octene-1 (less than 14 mol%) (6). They found that the interfacial tension decreases monotonicaUy from 1.5 mN m (2.4 mol % of octene-1) to 0.56 mN m (14 mol%). Yamaguchi and Nitta demonstrated that the EOR with 52 mol% of octene-1 is miscible with iPP in the amorphous region whereas the blend with EOR32 having 32 mol% of octene-1 shows phase-separated morphology (26). 

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Semicrystalline polyolefin blends and method of their preparation were described. The blends were reported to show enhanced inter-spherulitic and interlamellar strength. The first polymer should have higher crystallinity and crystallization temperature than the second. Thus, 50-99.9 wt% PP was blended with ethylene-a-olefin copolymers, either a stereo block polypropylene or an ethylene-propylene copolymer, EPR... 

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