The Study On Thermal Degradation And Flame Retardant Performance Of Thermoplastic Cassava Starch Composites

This paper reviews the status and development of the thermoplasticstarch materials and flame retardant, discusses the properties andapplications of the thermoplastic starch materials and flame retardant. Onthe basis, it firstly studies the preparation and properties of thermoplasticcassava starch plasticized by the mixed plasticizer formamide anddicyandiamide (FDPTPS). Through the optimization design of theformulation, the thermoplastic cassava starch (TPS)/magnesiumhydroxide (MH) composites and the thermoplastic cassava starch (TPS)/ammonium polyphosphate (APP) composites were prepared by meltblending, and the plastics processing performance, retrogradation,microstructure, mechanical properties, thermal stability andflame-retardant properties were studied.Experimental results showed that the mixed plasticizer canplasticized starch effectively, it can form stronger hydrogen bonds withthe hydroxyl of starch, accordingly damaged the interaction between themolecules of starch, it not only improved the mechanical properties ofcomposite materials also had good flame retardant properties. The tensilestrength reached a maximum of20.2MPa, the vertical burning achievedUL94V0level.About TPS/MH composites, MH was not only improved thecompatibility with cassava starch, the machianical properties andthermal stability was also improved, the tensile strength reached amaximum of48.5MPa, the burning performance parameters of heatrelease rate (HRR), mass loss rate (MLR) and smoke rate (SPR) weresignificantly reduced, the burning time extended from22s (pure TPS) to 43s (40phr MH), the smoke rate peak value decreased from0.004m2/s ofpure TPS to0.0005m2/s of40phr MH, showing good flame retardanceand smoke suppression; but also can play a synergistic role, mainlydicyandiamide and magnesium hydroxide produced a synergistic flameretardant effect, and the oxygen index of20phr MH reached40.1%,showing a good flame retardant effect.About TPS/APP composites, there was a synergistic flame retardanteffect between the three components of TPS-dicyandiamide-APP. TGresults shown that APP improving the thermal stability of the compositesgreatly. Combustion performance shown that, even adding a smallamount of APP the fire retardant performance has reached the UL94V0level. The reason was mainly the dicyandiamide and ammoniumpolyphosphate in the whole system respectively played a gas source andan acid source, both with thermoplastic tapioca starch(carbon source)matrix formed an intumescent flame retardant system, and through thecondensed phase and gas phase interaction to improve a flame retardanteffect.