Trigonal δ form as a tool for tuning mechanical behavior in poly(propylene-co-1-pentene-co-1-heptene) terpolymers

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

“…On the contrary, the tendency is completely unusual for the highest content, i.e., in the T14 series. The behavior in the T14-75Pe-25He and T14-50Pe-50He terpolymers is quite analogous to that found for the Young´s modulus estimated from stress-strain tests on propylene-co-1-pentene-co-1-heptene terpolymers rapidly cooled, at ratios and total compositions similar [32]. It was associated with the increase in crystallinity because formation of the trigonal form.…”

“…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.…”

“…Dependence of crystallinity on composition was somewhat different in other slowly cooled copolymers of propylene-1-pentene [35] (data also depicted in Figure S1) where the presence of a minimum value is observed at contents around 8-10 mol %, i.e., between the two aforementioned regimes. The existence of a minimum was also described for fast crystallized propylene-1-pentene-1-heptene terpolymers [32].…”

“…They found very low strengths due to the low crystallinity although mechanical parameters, like Young's modulus or yield stress, were not determined. In propylene-1-pentene-1-heptene terpolymers, García-Peñas et al [32] showed that modulus and yield stress exhibited two different trends, depending on the global composition. At low contents, values were decreasing with increasing composition independently of comonomer ratio.…”

Variation of Ultimate Properties in Extruded iPP-Mesoporous Silica Nanocomposites by Effect of iPP Confinement within the Mesostructures

“…Three different polymorphic modifications, α, β and γ, were described together with a phase of intermediate or mesomorphic order obtained by fast quenching [37][38][39][40][41][42][43]. In addition to these four modifications, a trigonal form was firstly reported in the literature [44] in 2005 for isotactic copolymers of propylene with high contents of 1-hexene [45,46] or 1-pentene [47,48], in propylene terpolymers with 1-pentene and 1-hexene [49,50] as comonomers, and in propylene terpolymers with 1-pentene and 1-heptene [51], all synthesized by using metallocene catalysts.…”