Plastics mechanical treatment

Plastic working of a metal such as steel is the permanent deformation accompHshed by applying mechanical forces to a metal surface. The primary objective is usually the production of a specific shape or si2e (mechanical shaping), although increasingly it also involves the improvement of certain physical and mechanical properties of the metal (mechanical treatment). These two objectives can be readily attained simultaneously. 

Similar surface abrasion processes can be applied on all thermosetting plastics. Mechanical abrasion methods consist of abrasion by fine sandpaper, carborundum or alumina abrasives, metal wools, or steel shot. The following surface treatment procedure is usually recommended for most thermosetting plastics ... 

Many interrelated factors influence the texture of plastic fats. Fatty acid and glyceride composition are basic factors in establishing the properties of a fat. These factors, in turn, are related to solid fat content, crystal size and shape, and polymorphic behavior. Once the crystal network is formed, mechanical treatment and temperature history may influence the texture. 

Iron ore catalysts, modified by mechanical treatment were found to show a catalytic activity in the process of hydropyrolysis of biomas / plastic mixtures. Some synergistic effects were observed in this process resulting in the increase of conversion degree and yield of light liquid fraction and in the decrease of hydrocarbons content in gaseous products. 

The typical dependence of mechanical properties of Ti-Si binary alloys in as-cast and as-deformed states is shown in Fig. 3. It is seen that in as-cast state room temperature plasticity decreases with increase of silicon content, reducing practically to zero at silicon content of 2-3 wt. % then it raises a little at eutectic formation. Unfortunately, our attempts to increase room temperature plasticity in as-cast condition more or less substantially via employing various kinds of heat treatment procedures were not successful. At the same time, using thermo-mechanical treatment (forging at temperature 1050 °C), it was possible to increase plasticity of deformed alloys essentially. 

It is the stress existing in a body at rest, in equilibrium, at uniform temperature, and not subjected to external forces. Often caused by the stresses remaining in a plastic part as a result of thermal and/or mechanical treatment in fabricating parts. Usually they are not a problem in the finished product. However, with excess stresses, the product could be damaged quickly or after in service from a short to long time depending on amount of stress and the environmental conditions around the product. 

FIG. VI. 1. Failure assessment diagrams for elastic-plastic fracture mechanics treatments [VI.16]. (a) Level 2 assessment diagram, (b) Level 3 assessment diagram. 

The stresses remaining in a plastic part as a result of thermal or mechanical treatment. 

Tempering. The mechanical treatment of moistened clay, or body, to disperse the water more uniformly and so to improve the plasticity tempering is usually done... 

Pommet M., Morel M.-H., Redl A., Guilbert S. Aggregation and degradation of plasticized wheat gluten during thermo-mechanical treatments, as monitored by rheological and biochemical... 

Mineral fillers require surface modification when used as reinforcements in plastics. Surface treatment improves mechanical strength and... 

The mechanical properties of Pu metal are highly variable because of the dominant influences of structure and deformation mechanism, which can be significantly altered by thermal and mechanical treatments. The a, and y forms of Pu, having crystal structures with low symmetry, are hard and strong, and lack ductility. When the mechanism for plastic deformation is restricted to slip, ductility is poor because the extent of slip is very limited in these polymorphic... 

When plastic substrates are coated by PEDOTiPSS and subsequently mechanically treated after coating, for example, by thermoforming, special binders are needed to prevent cracks in the coating during mechanical treatment and to maintain the overall conductivity. In such a case polymeric binders are preferred with a softening point that is below the softening point of the underlying polymer substrate. Especially some polyurethane dispersions appear to fulfill this requirement. 

---