The mechanical properties of Stanyl® depend on temperature, moisture content, and aging time

The composition of the compound, particularly the type and amount of reinforcement and additives, has a large influence on the absolute level of these properties.

Stiffness
Due to its high crystallinity, Stanyl retains a high level of stiffness up to temperatures very close to its melting point. This provides wider safety margins for critical applications than standard engineering plastics (e.g. PA6, PA66, and polyesters). Other high heat resins (e.g. PPA and PPS) have a very high modulus at room temperature but show a significant drop in stiffness at elevated temperatures [above 100°C (210°F)] In practice, Stanyl has a higher stiffness at temperatures >100°C (210°F).

The stiffness advantage offered by Stanyl at elevated temperatures can be exploited by designing components with reduced wall sections, some 10 to 15% thinner than those necessary compared to PPA or PPS with the same level of glass fiber reinforcement. The weight savings achieved with Stanyl are important for automotive and aviation applications where weight is a vital issue. By adding reinforcements, stiffness levels can be increased further.  Additional information on stiffness can be accessed the product database.

Flexural modulus versus temperature.

Creep resistance
For optimum performance and maximum lifetime, engineering plastics, which are subjected to long-term loading, must have a high creep resistance (i.e. low plastic deformation under load). Stanyl's high crystallinity results in an excellent retention of stiffness at elevated temperatures [above 100°C (210°F)] and hence in a creep resistance which is superior to that of engineering plastics and other heat-resistant materials.

Creep behavior is one of the factors that limit the maximum application temperature of a material. When Stanyl and PA66 or PPA are compared at the same temperature exposure, several alternatives exist:

• Decrease the wall thickness by using Stanyl (with an equivalent level of reinforcement
  
  - Reduces material usage and cost
  
  
  
• Use a Stanyl grade with a lower level of reinforcement than is possible with PA66 (for equal wall thickness)
  
  - Giving greater design freedom due to a higher elongation at break
  - Facilitating the use of snap-fits
  - Lowering material consumption per part due to a lower density.

Creep modulus of 30% reinforced polyamides at 120°C load 10MPa.

Effect of glass fiber reinforcement on the creep modulus of Stanyl at 140°C (285°F).

Only Stanyl offers a real performance improvement over PA66.

Creep behavior of glass fiber reinforced Stanyl versus competitive glass fiber reinforced materials at 160°C and load 20 MPa.  

Toughness and fatigue
Toughness, or ductility, is usually measured by impact resistance (related to high speed) and (tensile) elongation (low speed). While tensile and flexural strength decrease with increasing temperature, toughness increases. Therefore, toughness is usually most critical at lower temperatures. For automotive applications indeed the low temperature impact at -30 or -40°C is critical. For many E&E applications toughness at room temperature or elevated temperatures is important in processes such as pin insertion, winding operation and soldering.  Due to its fine crystalline structure, Stanyl exhibits unmatched toughness/ductility in comparison with many other engineering plastics/heat resistant resins notched Izod or Charpy impact values remain at a high level even at temperatures below 0°C (32°F).  This is expressed further in the Product Database.

The effect of different amounts of glass fiber reinforcement is different for both toughness parameters. With increasing reinforcement percentages, the elongation at break decreases while the Izod or Charpy impact resistance increases.

The Izod or Charpy impact resistance of glass fiber reinforced Stanyl is also unmatched. This makes Stanyl the material of choice for demanding applications and facilitates further assembly steps, for instance using inserts and snap-fits. The very high elongation at break of Stanyl offers the best solution for thin-walled parts, film hinges, and insert molding (eg in gears and pulleys).

The high crystallinity and fine crystalline structure of Stanyl lead to a fatigue resistance superior to that of most other engineering and heat-resistant resins.

Impact ( 23°C DAM) and temperature resistance of unreinforced thermoplastics.

Impact resistance of glass fiber reinforced thermoplastics.

Tensile and temperature behavior of 30% glass fiber reinforced thermoplastics.

Stanyl offers a significant improvement in fatigue resistance compared to PA66, PPA and PPS for high temperature applications.  Fatigue resistance is particularly important for gears, charge-air coolers, air ducts, and chain tensioners.

Fatigue behavior of glass fiber reinforced Stanyl versus polyamide 66 and PPA.