Rubber blend composites homogeneity

The synthesis of polyoctenamer has been commercialized by Huels.150 In contrast with the transformation of cyclooctene to 1,9-decadiene [Eq. (12.31)], homogeneous catalyst compositions, such as WClg + EtAlCl2, are used to promote ring-opening metathesis polymerization of cyclooctene. A polymer of narrow molecular-weight distribution with high trans content (55-85%) called Vestenamer is produced and used as blend component in different rubbers and thermoplastics. 

Jong et prepared NR composites reinforced with hybrid filler consisting of defatted soy flour (DSF) and CB. Aqueous dispersions of DSF and CB were first mixed, and then blended with NR latex and sulfur dispersion, respectively. The homogenous composite mixtures were quickly freeze-dried and compression moulded to offer the NR composites. They found that the NR composites reinforced with 40% of hybrid filler (the ratio of DSF to CB was 1 1) exhibited a 90-fold improvement in the rubber plateau modulus compared with unfilled NR, showing a significant reinforcement effect by the hybrid filler. 

Lafosse [342] described an oxidant-sorption method for synthesis of P(Py)/Teflon (PTFE) composites. A commercially available, surfactant-stabilized PTFE emulsion is mixed with aqueous Fe(III)-tosylate (oxidant-cum-dopant). Pyrrole is then added to this, yielding a finely divided P(Py)/PTFE composite after several h, precipitated with ethanol. SEM analysis showed the composite to be particles of 0.2 pm diameter which are presumed to be PTFE spherules coated with P(Py), rather than a homogeneous blend. Nevertheless, the composite showed conductivity of ca. 10 S/cm at a percolation threshold of ca. 16 v/v% P(Py), and acceptable microwave absorption properties. A similar emulsion method has been used by Sun and Ruckenstein [343] to synthesize P(Py)/Synthetic Rubber composites, with FeCl3 as oxidant, and several solvents (aqueous/organic combinations) and several nonionic surfactants being employed. Conductivities of the composites were ca. 3 S/cm, Tensile Strengths ca. 10 MPa, and Elongation at Breaks 38% to 166%. 

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