Poly(propylene-co-1-pentene-co-1-heptene) terpolymers: Mechanical and rheological behavior

Abstract

This work describes the important effects of microstructural features on crystalline structure, mechanical behavior and molten state response for poly(propylene-co-1pentene-co-1-heptene) terpolymers. The study was carried out in a wide range of compositions, varying the 1-pentene/1-heptene ratio and the thermal history applied.Molecular features, as propylene sequences and compositional triads, allow predicting the material behavior. Moreover, rheological response has demonstrated the influence of molecular weight, comonomer content and short-chain branches on the properties. The flow activation energy can justify the importance of the material density over the whole spectrum of properties.

Influence of polymorphism and the new trigonal modification on the mechanical response of isotactic poly(propylene-co-1-pentene-co-1-hexene) terpolymers

“…Their dependence on global composition is represented in Figure 7. The trend observed up to 10 mol % is similar to that seen in other copolymers [33,45,46,53,54]. On the contrary, the tendency is completely unusual for the highest content, i.e., in the T14 series.…”

“…This fact seems to indicate that mesomorphic entities, although in a slightly smaller amount, involve a superior reinforcement than imperfect trigonal crystals (characterized by very broad and little intense diffractions, as seen in Figure 1) joined to a more defective mesomorphic polymorph [33]. Crystallites are rather thin due to the fast cooling applied and differences in amount are not too large to balance those from crystallite perfection.…”

“…The overall X-ray degree of crystallinity, f c , can be estimated from the diffractograms in Figure 1 following the procedure described before [6,28,33], which has been briefly detailed in the Supporting Information. The so-obtained data are reported in Table 2 for all the specimens.…”

“…Subsequently, this δ polymorph was also described for propylene-co-1-pentene-co-1hexene terpolymers [30,31] and it has been recently established in propylene-co-1pentene-co-1-heptene terpolymers [32] in spite of that the trigonal lattice was not observed in propylene-co-1-heptene copolymers [33,34] crystallized under different conditions.…”

A Highly Stable Bimetallic Transition Metal Phosphide Catalyst for Selective Dehydrogenation of n‐Heptane

“…Longer chained, linear olefins such as n-hexane, n-heptane and n-octane show higher reactivities compared to their respective alkanes. Therefore, these molecules are utilizable as comonomers in polyethylene syntheses [3][4][5] or for further functionalization to acetals, alcohols and aldehydes, [6][7] which are ingredients in perfumes, pharmaceuticals and agricultural chemicals. [7][8] In dehydrogenation of long-chain alkanes, catalysts often suffer from fast deactivation.…”