Optimization of flame retardant system for waste Tetra Pak/bamboo fiber composites with inorganic flame retardants

Tetra Pak (TP)/bamboo fiber (BF) composites were prepared using waste TP and bamboo fiber as the main raw materials. Twelve inorganic flame retardant systems were used to modify the flame retardancy of TP/BF composites. Specimens were evaluated with the limiting oxygen index test, water absorption test, dry shrinkage and wet expansion test, mechanical property test, and Fourier transform infrared spectroscopy (FTIR). The results showed that the composite flame retardant systems outperformed the single flame retardant system, with the limiting oxygen index reaching up to 37.6%. Retardant addition lowered the modulus of elasticity (MOE), modulus or rupture (MOR), and internal bond (IB) and impaired dimensional stability, the extent varying with type and dosage. Among them, the TP/BF composites modified by systems Z3, Z8, Z9, and Z12 satisfied GB/T 11718-2021requirements for ordinary, furniture, and building medium-density fiberboards. FTIR showed the presence of chemical bonds of various functional groups that would be consistent with the development of adhesion within the composite.