Preparation of hexakis (4‐aldehyde phenoxy) cyclotriphosphazene grafted kaolinite and its synergistic fire resistance in poly (butylene succinate)

Abstract

Hexakis (4‐aldehyde phenoxy) cyclotriphosphazene (HAPCP) was synthesized firstly and then it was grafted onto the exfoliated kaolinite (Kaol) to prepare K‐HAPCP. The structure of HAPCP and K‐HAPCP was well characterized. K‐HAPCP was used as synergistic agent in poly (butylene succinate) (PBS)/intumescent flame retardants (IFR) composites. The combustion behavior of PBS composites was reflected by limited oxygen index (LOI), vertical burning (UL‐94), and cone calorimeter test. The thermal stability was traced by thermogravimetric analysis. PBS is highly flammable with the LOI value of only 21.9% and cannot pass any UL‐94 grade during vertical burning test. By the presence of 22 wt% IFR and 3 wt% K‐HAPCP, the LOI of PBS composite is sharply increased to 40.3% and the sample can pass UL‐94 V‐0 rating with excellent anti‐dripping properties. Moreover, the degradation behavior is investigated and the probable flame retardant mechanism is also proposed.

Recent developments in fire retardancy of polybutylene succinate

“…(b) PBS chains decompose and react with phosphorus-containing acids to form P-O-C structurecontaining units, accompanied by the generation of conjugated polyenes. (c) melamine releases ammonia and gradually forms melam, melem, and melon with the increase of temperature, which tend to migrate upward [161]. Besides, in order to further improve the flame-retardant efficiency of composite, APP/MA-based IFR system is generally used in conjunction with synergists.…”

“…A number of synergistic agents, such as esterified starch-modified cassava dregs (ES-CD) [164,165], urea-kaolinite [166], hexakis (4-aldehyde phenoxy)cyclotriphosphazene grafted kaolinite (K-HAPCP) [161], fumed silica [167], organically acetyl quaternary ammoniummodified Ca-montmorillonite (OMMT) [168], and graphene [29], have also been conducted on APP/MA-based intumescent PBS systems. The fire performance of those PBS composites based on the combination of different synergists and APP/MA (mass ratio of 5:1 or 2:1) are also been…”

Intumescent polybutylene succinate: Ethylenediamine phosphate and synergists

“…For this reason, suitable synergists are usually introduced into polymer intumescent systems to reinforce the thermal and mechanical properties of the protective carbonaceous layer through physical interactions and/or chemical reactions [25,26]. Recently, attention has been paid to the development of synergists to be incorporated in IFR PBS systems, including fumed silica [27], kaolinite [28], montmorillonite [29], halloysite nanotube [30], and carbon nanotube [31]. It is known that there are major advantages in using zinc borate as synergist in combination with conventional flame retardants (e.g., ammonium polyphosphate [32], magnesium hydroxide [33], and aluminum hypophosphite [34]) in halogen-free polymer systems.…”

Preparation of continuous glass fiber/polyamide 6 composites containing hexaphenoxycyclotriphosphazene: Mechanical properties, thermal stability, and flame retardancy

“…[19][20][21] Thus, phosphazene is recognized as an environmental-friendly halogen-free flame retardant for increasing the flame retardancy of various resins. [22][23][24][25] Several investigations have focused on the design and synthesis of cyclotriphosphazene with different chemical structures. [26][27][28][29][30] However, phosphazene flame retardants containing cyclophosphazene ring units usually form crosslinked network structure with the insoluble and infusible nature.…”