Preparation of halogen‐free flame‐retardant expandable polystyrene foam by suspension polymerization

Abstract

In this research, using hexaphenoxycyclotriphosphazene (HPCTP) as the halogen-free flame retardant, we prepared flameretardant expandable polystyrene (EPS) beads by suspension polymerization. The effects of process parameters and the amount of flame retardant on polystyrene (PS)/HPCTP composite beads were investigated. The results show that the change in HPCTP content has little effect on the particle size distribution of composite beads. When the oil-water ratio is 1/4, TCP dosage is 3 wt %, stirring rate is 350 rpm, initiator dosage is 1.25 wt %, and HPCTP dosage is 15 wt %, the size of the composite beads is uniform, and the average particle size is 1.12 mm. HPCTP formed nanodispersed particles in the PS matrix with an average particle size of 44.86 nm. In addition, the thermogravimetric behavior and heat-release properties of composite beads were evaluated. The results showed that HPCTP mainly acted in the gaseous phase, which can effectively decrease the maximum mass-loss rate of the PS/HPTCP composite beads and significantly reduce the heat-release rate and heat-release capacity. The EPS foams were obtained by a prefoaming method. The average cell diameter was 62.15 μm, and the foaming ratio was 11 times.

Study on preparation of highly dispersed graphite composite expandable polystyrene foam by homogeneous dissolution‐suspension polymerization with waste polystyrene

“…With the increase of the dissolved amount of wEPS, the droplets viscosity μ increased, the V 0 decreased, which means the moving speed ( V 0 ) of the graphite in the droplets is more slowly, the graphite dispersed in the droplet uniformly (Figure 1). [ 2,38,39 ]…”

An ultrafast and clean method to manufacture poly(vinyl alcohol) bead foam products

“…10,11 Trapping the blowing agent into the polymer granules is the main approach to manufacture the expandable beads, for example, adding the pentane during the suspensionpolymerization of polystyrene (PS) to produce the expandable PS beads. 12 The expanded beads are commonly prepared via highpressure impregnation and followed by blowing agent releasing, which is suitable for the semi-crystalline thermoplastics, such as polyethylene (PE) and polypropylene (PP). [13][14][15][16] At present, only expandable PS, expanded PE and expanded PP bead have realized commercial bead foaming.…”

“…The bead foaming process contains two steps, that is, the preparation of the beads (expandable and expanded beads) and the welding of beads 10,11 . Trapping the blowing agent into the polymer granules is the main approach to manufacture the expandable beads, for example, adding the pentane during the suspension‐polymerization of polystyrene (PS) to produce the expandable PS beads 12 . The expanded beads are commonly prepared via high‐pressure impregnation and followed by blowing agent releasing, which is suitable for the semi‐crystalline thermoplastics, such as polyethylene (PE) and polypropylene (PP) 13‐16 .…”

Manufacturing and Evaluation of Mechanical, Morphological, and Thermal Properties of Reduced Graphene Oxide-Reinforced Expanded Polystyrene (EPS) Nanocomposites

“…Polystyrene enriched with foaming agents is applicable to the production of expanded polystyrene (EPS) [12][13][14], with cellular structure. Polystyrene in the form of beads containing foaming agents is obtained in the suspension polymerization of styrene with the addition of blowing agents or low boiling liquids, e.g., pentane, butane, or propane [15,16]. Depending on the purpose and the polymerization conditions, beads of various sizes (from 0.3-2.5 mm) are obtained.…”