Inert‐gas extrusion of rigid PVC foam

Abstract

A novel approach to the extrusion of high‐density, rigid PVC foam uses commercial RPVC compounds with inert‐gas physical blowing agents (carbon dioxide and argon). The process was developed on a segmented single‐screw extruder with L/D of 40. On‐line monitoring of process variables was also carried out. This technique provides an alternative to conventional processing methods using chemical blowing agents.

A Level-Set Method for Computing Solutions to Viscoelastic Two-Phase Flow

“…From this figure we note that the front of the drop is closer to the channel centerlines and hence its velocity is larger than that of the trailing edge, which is closer to the channel wall. Therefore, the drop, as it moves upward in the pressure-driven flow, also rotates in the counterclockwise direction and bends such that the center of curvature of the lower surface moves to the outside [25]. This bending of the drop gives the impression that it is rotating in the clockwise direction even though, as noted above, the rotation is in the counterclockwise direction.…”

Employing response surface approach for optimization of fusion characteristics in rigid foam PVC/clay nanocomposites

“…Blowing agents are generally low‐molecular‐weight ingredients that allow the formation of bubbles. The type and concentration of blowing agents determine the effectiveness of using such materials in rigid PVC foam . The presence of organoclay in the PVC foam itself makes the interpretation of fusion behavior sufficiently difficult.…”

“…Poly(vinyl chloride) (PVC) is one of the most widely used thermoplastics today and PVC compounds, formulated with various additives, are versatile plastics with numerous applications in a variety of industries. PVCbased foamed products can be produced by melt extrusion with the inclusion of a chemical blowing agent, which produces a gas such as nitrogen or carbon dioxide [1][2][3][4][5].…”

“…Fusion achieves more significantly in the case of PVC foams owing to the additional expansion process and presence of specific additives [2,4,5,22]. Although PVC/NC nanocomposites have been occasionally studied [19,21], few works have ever addressed the influence of the NC type and amount on fusion characteristics and properties of rigid PVC/NC nanocomposite foams.…”

Cellular PVC-U: Current Technology and Future Challenges

“…Dey and co-workers [19] have reported a novel method of extruding high density, rigid PVC foam using a commercial PVC compound with inert gas (CO 2 or argon). This process was developed on a segmented single screw extruder with L/D ratio of 40.…”