Poor hydrolysis resistance: PBT hydrolyzes under high - temperature, high - humidity conditions, breaking molecular chains and degrading mechanical and electrical properties, especially in long - term water contact.
High notch sensitivity: PBT's impact strength drops sharply at notches, prone to crack initiation and propagation, requiring careful design to avoid sharp notches and stress concentrations.
Moderate flame retardancy: Pure PBT is flammable and often requires flame retardants to meet high - fire - safety requirements.
Relatively high cost: Compared with common plastics like PE and PP, PBT's higher production cost limits its use in cost - sensitive applications.