Synergistic flame retardancy of solid acid, hindered N‐alkoxy amine, and halogen compound for polypropylene

Abstract

Polypropylene (PP) is a thermoplastic resin widely used in various industrial applications. However, the flammability of PP is a severe drawback that lowers operational safety. This study demonstrates the development of flame‐retardant PP. The co‐adding with various solid acids and a hindered N‐alkoxy amine (NOR116 – Flamestab® NOR 116 FF) affects the combustion behavior of PP in a vertical flame test. The co‐adding of silica alumina (SA) and NOR116 with PP promoted the melt drip, suppressed upward combustion heat, and shorter the combustion time. The decomposition products of NOR116 induced the cleavage of the main chain of PP, and it quenched the radicals on the surface of the SA particles because SA has abundant acidic sites and large pores, facilitating the adsorption of a substantial quantity of NOR116. The molecular weight of PP was controlled to 103 ~ 104 before the combustion to achieve an increase in the melt flow ability and suppress the upward combustion. Furthermore, a small amount of a halogen‐based flame retardant was incorporated into the PP/SA/NOR116 sample, and the specimens could instantly self‐extinguish on the gas phase by radical trap.

Effect of microstructure tuning by rapid heat cycle molding on the photodegradation behavior of isotactic polypropylene

“…Isotactic polypropylene (iPP) is widely used in many engineering applications such as automotive parts and domestic appliance housings due to its excellent properties. 1,2 However, as a typical semicrystalline polymer, it is susceptible to various environmental factors, such as sunlight, temperature, and oxygen, 3 which will lead to the degradation of the polymer. 4 The unstable tertiary hydrogen atoms in iPP molecular chains are prone to occur a series of complex photodegradation under the UV light.…”

“…17 Due to its advantages of high productivity, precision, and low cost, it is widely used in many engineering fields, such as automotive, electronics, and medical. 2,24 However, with the expansion of iPP applications and increased industrial demands for higher quality products, 25,26 conventional injection molding (CIM) often struggles to meet the growing demand. In recent years, some scholars had introduced the technique of controlling the rapid dynamic change of mold temperature, called rapid heat cycle molding (RHCM), into CIM to improve the quality of products.…”