Lamellar thickness transition of melt-crystallized polybuten-1 tetragonal phase: configurational change in chain folding directions

Thermomechanical properties of poly(1‐butene) synthesized by Ziegler–Natta catalyzed polymerization of 1‐butene in the presence of nucleating agents

“…Isotactic poly(1‐butene) ( i PB) is a semicrystalline polyolefin with unique properties, such as relatively high heat distortion temperature, stiffness, environmental stress cracking resistance, puncture resistance in films, low tendency to creep, and good abrasion resistance, 1 ensuring that the material is a good candidate for pipe application. It is noted that i PB is a polymorphic polymer, which often crystallizes into the kinetically favored form II from the melt and will then slowly transform into the thermodynamically stable form I spontaneously on aging at room temperature for several days 1–4 . As form I has a density 4.74% higher than that of form II, the slow crystal–crystal transition may not only cause distortion and shrinkage of the molding product but also extend the production cycle, which limits the application of i PB in some aspects 1,5 .…”