Semi-crystalline thermoplastics are characterized by the fact that they are made up of polymer chains that are more or less arranged in regular structures. In the material there are areas where the chains are tightly packed. The forces between the chains are greater in these areas than between the parts of the chains that are in the irregular, amorphous portions.
The milky white propylene plastic is used in bottles, knobs, door handles, and medicine and cosmetics packaging, among other things. It is available as a homopolymer as well as a copolymer. The two differ in that the copolymer PP-PE has a better impact resistance in cold than the homopolymer has. The transmission capacity for this semi-crystalline plastic is 55 – 90%.
Polyethylene plastic is colorless and has unlimited coloring possibilities. This type of semi-crystalline plastic is often used in household items, bottles, fuel tanks, and pipes. The versatile ethylene plastic can be blow-molded, thermoformed, injection-molded, extracted, and machined. It can also be embossed, welded, and vacuum metalized.
Amide plastic is often used in gears, propellers, cable insulation, and door handles, for example. All polyamides are suitable for injection molding, extrusion, and blow molding. Products made of polyamide semi-crystalline plastic can be embossed, welded, processed, and vacuum metalized.
Acetal plastic can be vacuum metalized, extracted, embossed, injection-molded, electroplated, welded, cutting processed, and blow-molded. The semi-crystalline acetal plastic is similar to polyamide in several aspects but differs by being slightly stiffer and harder. This plastic is well suited for automatic turning and is recommended for precision parts with tight tolerances. Acetal plastic withstands an alkaline environment up to a pH of 14
Fluoroplastic is often used in applications in aircraft, electric machines, robots, coating in cookware and as electrical insulation material, to name a few. PTFE is well suited for compression molding and extrusion. It is a very difficult material to work with, but it can be machined.
The milky white vinylidene fluoride plastic is seen in electrical applications in aircraft, electrical machines, electrical insulation materials, and robots. This type of semi-crystalline plastic is suitable for injection molding and extrusion.
Polybenzimidazole is the most technical semi-crystalline plastic available today. It offers maximum heat resistance and mechanical retention above 205 ° C (400 ° F) of unfilled plastic. It has better durability and load-bearing capacity at extreme temperatures than any other reinforced or unreinforced construction plastic.
The ocher yellow polyamidimide plastic is quite unusual on the market, as it is difficult to process. When the semi-crystalline plastic is filled with lubricant, it is used for precision parts in high-tech equipment, bearing holders, bearings, valves, bushings, etc. PAI together with graphite and PTFE has high wear resistance and lower friction.