Controlled degradation of polybutene-1 for improved properties under high-temperature environments

Developing new-generation inner-lining materials with enhanced resistance to high temperatures and chemical corrosion is urgent for industrial reactors operating under harsh conditions. In this work, controlled degradation of isotactic polybutene-1 (PB) samples with decreased weight-average molecular weight ( M w ) and narrowed molecular weight distribution ( M w / M n ), significantly increased melt flow rate (MFR) were achieved through peroxide induced chemical degradation. The degraded PB specimens exhibited minor structural moieties, including C C double bonds and –CH(CH 2 –CH 3 )–CH(CH 2 –CH 3 )- groups. Four reaction pathways were proposed to elucidate the microstructural evolution of degraded PB specimens. The degraded PB specimens presented almost constant isotacticity (mmmm = 93-95%), melting temperature ( T m  = 124-131 °C), crystallinity ( X c  = 44-49%), and lamellar thickness ( d c ) around 10-13 nm for PB form Ⅰ. The degraded PB-5 exhibited excellent coating processability, as well as excellent high-temperature properties. Compared with commercial film-grade high-density polyethylene (HDPE), PB-5 showed 59% higher tensile strength, 55% lower creep deformation, and 73% higher resistance to alkali at 85 °C. The blade-coated PB-5 film exhibited the highest surface smoothness and better water vapor barrier property when compared with that of pristine PB and HDPE. This work presented a feasible strategy for the fabrication of degraded PB-5 with superior coating processability and excellent high-temperature properties, which are expected to be used as inner lining materials of industrial reactors.