Isotactic poly(butene‐1) trigonal crystal growth in the melt

Abstract

Crystal growth of the trigonal form of isotactic poly(butene‐1) (it‐PB1) was successfully observed in the melt at atmospheric pressure. The growth rate of trigonal crystals was obtained by in situ optical microscopy. It is one hundredth that of it‐PB1 tetragonal crystals. The growth rate of trigonal crystals, as well as that of tetragonal crystals, shows supercooling dependence derived from the nucleation theory. The value of the kinetic constant K of trigonal crystals is about 3.3 times larger than that of tetragonal crystals. The value of the pre‐exponential factor G0 of trigonal crystals was found to be 41 times as large as that of tetragonal crystals. The difference between these K values can be attributed to the conformational entropy of the ethyl side groups in a nucleating stem. The discrepancy found in the values of G0 could be explained by introducing pinning and nucleation barriers, which originate from the crystal thickness δlc, which does not depend on the crystallization temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 684–697, 2007

Polymer Crystallization Processes as Seen from the Growth Front’s Perspective

“…24 Note that the growth rates of the three forms are significantly different-actually orders of magnitude different ( Figure 2). 25 Keeping again in mind that the crystallization conditions are identical, these differences (selection processes, growth rates) indicate that the crystallization process, even if it implies a ''precursor'' phase or molecular conformation, is mainly controlled by the growth front. Only the growth front can (110) twin together with an untwinned crystal, both imaged here in dark field electron microscopy.…”

Trigonal–Tetragonal Crystal Phase Island Structure of isotactic Polybutene-1

“…Tetragonal crystallization is a substantially two-dimensional spherulitic growth that spreads over the matrix of the molten iPB1 films by branching out in the plane parallel to the thin films. We reported that the crystal growth rate G I of the trigonal phase is much slower than the crystal growth rate G II of the tetragonal phase in our previous work [7]. The ratio G I / G II is about 1/200 and 1/100 at 75 and 70°C, respectively.…”

“…Our previous report presents another solution to this problem [7]. Using solution-grown trigonal crystals as nuclei, we demonstrated that the trigonal phase could grow in the melt via self-seeding at atmospheric pressure.…”

Surface free energies of isotactic polybutene-1 tetragonal and trigonal crystals: the role of conformational entropy of side chains

“…In these works, however, in situ observations of the trigonal crystal growth could not be performed. In our previous work, we developed another method to crystallize the trigonal phase in the melt via self-seeding using solution grown trigonal crystals as nuclei and performed in situ observations of its growth process (Yamashita et al, 2004(Yamashita et al, , 2007.…”