Fast-Track Crystallization of PB‑1 with Sorbitol-Based Nucleating Agent

TL;DR

This study shows how a nucleating agent affects the crystallization and structure of polybut-1-ene polymers.

Contribution

The study reveals that a sorbitol-based nucleating agent significantly alters crystallization and phase transition in PB-1 polymers.

Findings

The nucleating agent accelerates the phase transition in PB-1 homopolymer.

In copolymers, the nucleating agent increases crystallization temperature and narrows crystallization and melting peaks.

The nucleating agent is soluble in PB-1 melt at high temperatures, affecting crystallization behavior.

Abstract

The work is focused
on crystallization and phase transition of
polybut-1-ene (PB-1) homopolymer and random copolymer in the presence
of commonly used nucleating agent (NA) 1,3:2,4-bis­(3,4-dimethylbenzylidene)
sorbitol, primarily designed for polypropylene. The crystallization
and subsequent phase transition from kinetically preferred tetragonal
form II into thermodynamically stable trigonal form I in defined times
of aging at room temperature is studied. It was found that NA accelerates
phase transition, particularly in homopolymer. In the copolymer, moreover,
the addition of NA dramatically increases the crystallization temperature
and narrows the crystallization peak as well as the melting peak,
which corresponds to the formation of a more uniform structure. At
the same time, the addition of NA increases the haze significantly,
confirming the formation of a two-form structure. However, NA was
found to be soluble in a low concentration (0.2 wt %) in PB-1 melt
at a sufficiently high temperature of melting. The solubility then
affects the crystallization behavior. Finally, it can be confirmed
that the addition of commercial sorbitol-based NA has a significant
effect on the crystallization and phase transition of both the PB-1
homopolymer and the copolymer.

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