Porophors Used in the Extrusion Process

Abstract

The high density polyethylene (HDPE) modification by selected agents which are blowing agents during extrusion process, including the determination of modification effect on the selected physical properties and properties of the surface of HPDE extrusion products have been studied. The paper presents specification of the cellular extrusion process of thermoplastics with endothermic chemical blowing agents. The rotational speed of extruder, melt flow rate (MFR) and microscopic structure have been examined.

Impact of blowing agents in poly(vinyl chloride) cellular extrusion process

“…When, in the proper temperature, the process of gas emission is started, numerous microspheres which are then generated dissolve in the surrounding plastic material due to the operation of pressure and surface development. The emerging cells may be filled in with air or with any other gases, for instance CO 2 and N 2 , yet later they are replaced with air as a result of diffusion [1,2,3]. Stream of the processed plastic material, together with the gas dissolved therein, is transported under pressure to the pre-forming head.…”

“…The effects of polymers extrusion using the blowing agents are new and modified physical and technological properties of cellular products [3,4,5]. These are for example: smaller density of received product, better damping properties, small processing shrinkage, better damping and insulating properties, bigger resistance to fire and the possibility of utilization after using.The examination of the process of extrusion, which was conducted by the Lublin Technical University attended by the authors of this article, among others, refers to the production of the covering of cables of different types and various applications of cellular plastics (example on Fig.…”

“…These are for example: smaller density of received product, better damping properties, small processing shrinkage, better damping and insulating properties, bigger resistance to fire and the possibility of utilization after using.The examination of the process of extrusion, which was conducted by the Lublin Technical University attended by the authors of this article, among others, refers to the production of the covering of cables of different types and various applications of cellular plastics (example on Fig. 1) [3,4,5] Fig. 1: Cross -section view of PVC cellular multilayer: 1 -core zone, 2, 3 -indirect zones, 4, 5 -surface zones.…”

Research on the Influence of Blowing Agent on Selected Properties of Extruded Cellular Products

“…In order to achieve a high degree of the so-called physical blowing agents (gases, volatile liquids) are used. Chemical blowing agents are applied where it is necessary to maintain low levels of capital expenditures on equipment and machinery [3,6,7]. The essence of this process is the introduction of the plastic material (support), the most are concentrated (5-70% concentration) or powders.…”

“…Modification of cable coatings and research on the extrusion process conducted in the Department of Polymer Processing at Lublin University of Technology [3][4][5][6][7][8][9][10][11] are focused especially on manufacturing coatings from cellular plastics, what results in the reduction of plastic purchase costs, energy costs of the process and transportation costs. At the same time, this results in the replacement of conventional extrusion coating by the cellular extrusion process [11][12][13][14].…”