Rapid phase transition of polybutene-1 from form II to form I induced by pressure

Abstract

Extremely slow phase transition from form II to form I has been the greatest bottleneck of isotactic polybutene-1 preventing from its extensive applications. In the past decade, although various methods were proposed, the acceleration for the phase transition was limited. High pressure seems to be a potential approach but is regarded impractical, because earlier studies claimed that to accelerate phase transition the pressure needed to be over 90 MPa, which was too high for real processing. The pressure could be overestimated because of higher phase transition temperature employed, therefore, it is necessary to investigate the pressure-induced phase transition again. Surprisingly, it is found that at room temperature, the pressure inducing fast phase transition actually does not need such high. As low as 0.7 MPa, the acceleration effect appears. At 2 MPa or higher, phase transition can be completed within 5 min. This means that form II totally can transform to form I in real processing process only if applying a slightly higher pressure. This study provides a simple and effective method to settle such a long-standing problem persecuting the academic world and the industrial world for polybutene-1.