Extrusion with ultrasound applied on intumescent flame‐retardant polypropylene

Abstract

In this work, the effect of processing conditions on the production of an intumescent flame‐retardant system is studied in polypropylene‐based compounds. Two distinct procedures were used: ultrasonic assisted single screw (with a static mixer die) and twin screw extrusion. The flame‐retardant, thermal, mechanical, morphological, and rheological properties were measured. It was found that the flame‐retardant intumescent content can be diminished from 30 phr (as usually used) to 21 phr using the application of ultrasonic waves during extrusion and with the addition of chemically modified clay to obtain a V0 classification according to UL94‐V standards. In addition, the processed materials presented improvements in the mechanical properties such as impact resistance (Izod Notched), strain at break and tenacity upon ultrasound application. The online application of ultrasound through a die that produces extensional flows improved greatly the dispersion and distribution of the particles of the intumescent system and the chemically modified clay in the polymer matrix. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers

Advanced Flame Retardant Materials

“…Therefore, we speculate that the gas phase mechanism is mainly responsible for the improvement of flame retardancy, for the prepared nanocomposites. Fang has proved the statement that some organophosphorus flame retardants are mainly active in the gas phase and not in the condensed phase using TG-FTIR [41]. The addition of ZIF-8@GO into the PLA films results in a slightly lower LOI, but remains in high values.…”

Nanocomposite and biodegradable polymers applied to technical textiles

“…In general, it is believed that the shear is the main flow that generates a high level of exfoliation. However, the nature of the flow at high voltages and with this, the cavitation phenomenon caused by ultrasonic waves [37,38] have been pointed out as the key parameters for dispersing the lamellae of some individual particle types. Denis et al [39] carried out a series of experiments on processing nanocomposites of polymers.…”

“…On the other hand, substantial contributions have been made regarding the flame retardant properties of polymeric materials with modified clays. The process involved a single-screw extruder with a static mixer that produces ultrasonic assisted extensional flows [47].…”

Influence of natural ageing on the flame retardancy and thermal properties of intumescent flame retardant long glass fibre reinforced polypropylene composites

“…But the quite large proportion of filler addition has a great influence on the mechanical properties of the composites. In recent years, intumescent flame retardant (IFR) including acid, carbon and gas source has been considered to be a kind of environmental friendly flame retardant additive with the advantages of low smoke, no halogen, no melt dripping, and excellent flame retardant efficiency, which is considered to be a development direction of flame retardant researches . It is well known that an efficient running IFR system should be consisted by three basic elements including dehydrating, char‐forming and foaming agents.…”