New insight into the preparation of flame-retardant thermoplastic polyether ester utilizing β -cyclodextrin as a charring agent

Abstract

The past decade has witnessed remarkable progress of the development and amelioration of thermoplastic polyether ester elastomer (TPEE), showing its promising wide-range utility. Herein we unraveled an unprecedented research to utilize β-cyclodextrin (β-CD) with perfect charring ability in TPEE in substitution of toxic halogen flame retardants. The TPEE/phosphorous–nitrogen flame retardants (P-N FR) (aluminum diethylphosphinate and melamine polyphosphate)/β-CD system was created and the flame retardance effects were determined using the limiting oxygen index (LOI) and the vertical burning test (UL94), while the charring effects of β-CD were measured by thermogravimetric analysis (TGA), laser Raman spectroscopy (LRS), and scanning electron microscopy (SEM). Besides, the mechanical properties and the morphology were tested by the universal testing machine and SEM. Results indicate that with 10 wt% of β-CD added to the TPEE/25 wt% P-N FR systems, the UL94 can reach to V-0 grade and the tensile strength of this blend was kept above 10 MPa, which can be applied in practice. To our delight, β-CD promoted the formation of stable and compact carbonaceous char, preventing the melt dripping and enhancing the properties and the charring mechanism was better studied by real-time Fourier transform infrared spectra. Being easy to construct, sustainable, and economic, the TPEE composite modified by β-CD and P-N FR is a reliable and widely applicable novel fire retardation material.