 |
Polymeric Materials
 Polymeric materials are widely extruded into various products, using sophisticated extrusion machines such as extruder and others. The finished products are used for consumer as well as industrial applications. This extrusion process is an integrated one, in which extruder involves one of the components of the complete line. On the basis of the requirement of the product, some pre-blending or few ingredient mixing may be needed before the process of extrusion is carried out.
Before we proceed ahead, it is important to understand the basic meaning of the term “Polymer”. Polymers consists of various atoms that are connected together to form long chains (polymer backbone). The atoms are generally carbon (C), oxygen (O), sulfur (S), or nitrogen (N) that are combined in a unique configuration which is specific for every polymer. Various other atoms may also be present in a definite combination in the polymers.
There are a number of guidelines for the extrusion processing condition for different resin systems. These conditions are the ideal beginning points for various resin systems and may need an optimization for definite extrusion process for obtaining optimal throughput rate along with meeting or surpassing the mentioned quality criteria. The process of optimization of a specific extrusion operation is dependent on following:
| Extruder type—single or twin screw |
Throughput rate |
| Extruder size—small or large |
Downstream process |
| Particular screw design being used |
Resin type and formulation |
| Die design |
Additives in the resin |
| Resin melt flow |
Environmental factors around the extruder |
| |
|
|
Some of the important Polymeric Materials are enlisted below:
- Acrylonitrile Butadiene Styrene (ABS)
- Polyamides (PA) or Nylons
- Polyethylene (PE) Grades
- Polymethyl Methacrylate (Acrylic)
- Polypropylene (PP)
- Polycarbonate (PC)
- Polystyrene (PS)
- Polyvinyl Chloride (PVC)
Polymer Rheology
Rheology can be defined as the science which deals with the materials' deformation and flow. In case of polymers, it is important to understand these two factors both in die and in extruder for the optimal operation of the extrusion process. In the process of co-extrusion, it is pivotal to match the viscosities of resin layer at the processing temperatures. It is important for eliminating all the interfacial instabilities which can make the product simply good-for-nothing. |
|
|
|
