Polyamides have been used for a long time, but glass-filled polyamides are a new generation of this material. Their difference from the usual ones is that the introduction of a filler such as fiberglass made it possible to obtain a product that is characterized by higher strength, stiffness, heat resistance, as well as less cracking, which manifests itself in conditions of elevated and lowered temperatures.
Description and Application
Despite the fact that glass-filled polyamide has improved almost all of its characteristics, there are those that have become somewhat worse. This relates to the resistance of the material to its abrasion, as well as its elasticity. Unfilled substances have higher qualities.
As for the use of glass-filled polyamide, parts for precision-type devices are made from it. In addition, it is also used for the manufacture of cam discs, for cases of electric tools. In order to improve the performance of glass-filled polyamide, substances such as graphite and molybdenum disulfide are also added. Thanks to these additives, the coefficient of friction is improved, which means resistance to wear. Talc can also be used as an additive. It is used to obtain deformation type marks.
Types of Polyamide
Today, brands such as PA and PA66 are quite popular. These glass-filled polyamides are notable for their high stiffness, strength, and toughness. Good resistance to various aggressive environments is observed.
As for the benefits that the use of such a polyamide gives, they are as follows:
- Viscosity, stiffness and high resistance to such an effect as thermal warping.
- The coefficient of resistance to friction and wear is also quite high.
- These types of polyamides can be used at temperatures from -60 to +150 degrees Celsius.
- The properties of glass-filled polyamide allow it to function for quite a long time even under conditions of simultaneous exposure to factors such as high temperature, high mechanical stresses, as well as exposure to substances such as oil, gasoline and other aggressive compounds.
This type of polyamide per se belongs to a composite material which consists of a polyamide type resin filled with pieces of glass filaments.
Description of injection molded polyamides
It is worth noting that there is a group of glass-filled thermoplastic polyamides that are obtained during the casting process. They have a number of significant drawbacks. Among them the most prominent is the too low coefficient of elasticity, low coefficient of impact strength. In addition, the processing of such material is accompanied by a strong grinding of fibers of the reinforcing type. During this procedure, severe abrasive wear of the equipment is also observed.
Another property of fiberglass as a filler is its high density and low adhesion. Due to these factors, it turns out that the finished product is characterized by a high weight, and there is also an incomplete use of the safety factor of the fibers. Such products also exhibit low resistance to moisture and strong delamination of products.
GOST glass-filled polyamide
GOST 17648-83 regulates the quality requirements of the finished product, the technological process of its production, as well as safety requirements, acceptance rules and test methods for quality control.
With regard to safety, polyamides of this type belong to the group of solid and combustible substances. This product can be processed safely only at temperatures up to 270 degrees Celsius. In this case, harmful fumes will not be emitted, and the material itself will not be subject to decomposition. Threats to human health are not observed.
If a base with a mark of 66 is used in polyamide, then at a temperature higher than 275 degrees Celsius the material will begin to decompose. At this time, carbon monoxide, ammonia and carbon dioxide will be released. These substances are already hazardous to human health. If polyamide marked 6 or 610 is used as the base, then the maximum processing temperature may increase to 300 degrees before the product begins to decompose.