Abstract
An ammonium polyphosphate (APP) surface-modified by silane coupling agent was used as flame retardant in high-impact polystyrene (HIPS). A series of HIPS nanocomposites containing different mass fractions of APP (k-APP) surface-modified by silane coupling agent (3-aminopropyl triethoxysilane, KH 550) and carboxylic-functionalized MWCNTs (COOH–MWCNTs) were prepared by the melt blending method. A composite only containing APP was also prepared as a reference material. Scanning electron microscopy (SEM) was employed to investigate the dispersion of the fillers into the HIPS matrix, and it was found the hydrophobic groups on the k-APP surface would greatly enhance the dispersion and prevent agglomerations compared with APP. Furthermore, the COOH–MWCNTs also showed good dispersibility into the matrix. Mechanical tests of the nanocomposites revealed that k-APP exhibits a more beneficial effect on both tensile and flexural properties compared with APP. Thermogravimetric analysis (TGA) and cone calorimeter tests (CCT) were conducted to probe the thermal and flammability properties of the nanocomposites, respectively. The synergistic effects of k-APP and COOH–MWCNTs on mechanical, thermal and flammability properties were examined as well.
Highlights
High-impact polystyrene (HIPS) synthesized by grafting is a widely used thermoplastic copolymer in packaging, toys, bottles, electronic appliances, light-duty industrial components, etc. due to its low cost, easy processing, and high impact strength [1]
These results show that the stability of the char layer formed by COOH–multi-walled carbon nanotubes (MWCNTs) is worse than that formed by combination of k-ammonium polyphosphate (APP) and COOH–MWCNTs, which is another cause intensifying incomplete combustion of the HIPS/k-APP/COOH–MWCNTs nanocomposites and leading to more CO yield compared with the HIPS/k-APP nanocomposites and the HIPS/COOH–MWCNTs nanocomposites
The elongation at breakage decreased, the other mechanical properties of HIPS/k-APP/COOH–MWCNTs nanocomposites increased with increasing COOH–MWCNTs content
Summary
High-impact polystyrene (HIPS) synthesized by grafting is a widely used thermoplastic copolymer in packaging, toys, bottles, electronic appliances, light-duty industrial components, etc. due to its low cost, easy processing, and high impact strength [1]. High-impact polystyrene (HIPS) synthesized by grafting is a widely used thermoplastic copolymer in packaging, toys, bottles, electronic appliances, light-duty industrial components, etc. Due to its low cost, easy processing, and high impact strength [1]. To reduce the fire risk, some flame-retardant additives are added, such as clays, double hydroxides, phosphorous compounds, nanomaterials [4,5,6,7] Some additives, such as ammonium polyphosphate (APP), provide the flame retardancy by promoting polymers to carbonization and forming a barrier char layer to isolate air [7]. Some other additives, such as aluminum trihydroxide (ATH) and magnesium hydroxide (MH), play the role of coolant and thinner with the aid of endothermic decomposition and release of water in the gas phase [8].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
