Date de rkeption: 12 Novembre 1975) ZUSAMMENFASSUNG:Die viskoelastischen Eigenschaften von Mischungen aus Polybuten-1 und Polypropen werden im /I-Relaxationsgebiet untersucht. Es gibt nur einen Relaxationspeak, und die Mischungen scheinen in der amorphen Phase vertraglich zu sein. Diese Beobachtungen bestatlgen die von uns bereits fruher aufgestellten Hypothesen iiber den EinfluD der relativen Lange der Alkylgruppe in Polyolefinmischungen.
SUMMARY:Viscoelastic properties of polybutene-I-polypropene blends were investigated in the p-relaxation range. Those blends show only one relaxation peak and are assumed to be compatible in the amorphous phase. These results permit to corroborate our former assumption concerning the influence of the relative length of the alkyl group in polyolefin blends.
In this paper, a model for the conveying of solid polymer in the feeding zone of intermeshing co‐rotating twin screw extruders is proposed. The theoretical model uses an approach that is similar to that commonly used in single screw extruders; however, it takes into account the particular geometry of the screw channel, the partially filled channel, and the special configuration of the two self‐wiping screws. The model thus considers two conveying mechanisms: the first one in the channel, which is analyzed in terms of polymer‐metal friction, and the second one, which is mainly an axial transport in the intermeshing zone. The theoretical predictions of the model are compared with the experimental results obtained on a laboratory extruder with a polymer in powder form, and satisfactory agreement is observed. The model enables the prediction of the evolution of the filling of the screws towards the geometry and the operating conditions. This is an important key to analyzing the thermal aspects in this zone, which can lead to a prediction of the melting capacity of the extruder. Indeed, the filling of the feeding zone defines the heat transport that occurs between the hot barrel and the solid polymer.
SynopsisDifferent polyamides and polysulfonamides were prepared by the interfacial polycondensation method. The influence of the experimental condition was specified. The principal characteristics of polymers are indicated (solubilities, molecular weights, IR spectra, thermal stability). In the case of poly(ethy1ene l,>benaenesulfonamide), a study of the thermal behavior was specially developed.
The dynamic mechanical properties of 1-hexene-propene copolymers were measured in the p-relaxation range, using a DDV-11 Rheovibron viscoelasticimeter. The infrared spectroscopy showed typical bands, from which the copolymer composition could be evaluated and the crystallization ability deduced. The study of the morphology was performed by differential thermal analysis and X-ray diffraction. It led to a model of the copolymers' crystalline structure in which there is still a crystalline fraction up to 60-% 1-hexene concentration (in moles). The experimental results showed that the maximum of tan iJ shifted towards low temperatures as the 1-hexene concentration increased. Its magnitude grows as the crystallinity decreases. The activation energies associated with relaxation were calculated according to the Arrhenius equation; the average relaxation times were calculated by application of the time-temperature correspondence principle.
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