120mm PU Rod Polyurethane Plastic Rod
Core Performance Parameters and Advantages
Mechanical Properties (Core Advantages of Polyether Type)
- Tensile Strength: 25-45 MPa (Rigid type close to 50-70 MPa of nylon PA6, semi-rigid type approximately 15-30 MPa);
- Elongation at Break: 200%-400% (significantly higher than 100%-200% of polyester-type PU, superior flexibility, and strong tear resistance);
- Compressive Strength: 15-35 MPa (can withstand axial or radial pressure, such as bearing loads or impact cushioning);
- Shore Hardness: Rigid type: 70-95A (close to hard rubber, 70A is relatively soft, 95A is close to plastic); Semi-rigid type: 50-70A (flexible support);
- Abrasion Resistance: Akron abrasion ≤0.08-0.12 cm³/1.61km (superior to ordinary plastics such as PVC and PP, close to ultra-high molecular weight polyethylene (UHMWPE), and with a smoother surface after long-term wear);
- Impact resilience: ≥80% (semi-rigid) to ≤60% (rigid, impact resistant but with controllable energy absorption).
Environmental resistance (key difference between polyether and polyester types)
Hydrolysis resistance: Excellent—the ether bonds (-R-O-R') of polyether polyols are more resistant to hydrolysis than the ester bonds (-CO-O-) of polyester polyols. They are less prone to degradation in humid environments (such as high humidity and hot water immersion) after long-term use, while polyester PU may experience molecular chain breakage and strength reduction within a few months under the same conditions;
Low temperature resistance: Maintains high elasticity even at -40℃ to -60℃. (The flexible segments of polyether-type soft segments do not easily crystallize at low temperatures, while polyester-type PU may become brittle below -20℃);
Mold resistance: The polyether molecular structure is not easily attacked by mold (ether bonds have high antimicrobial activity), making it suitable for outdoor or humid and sanitary environments (such as aquaculture equipment);
Oil resistance: Swelling rate to mineral oil and lubricating oil ≤5% (comparable to polyester-type, better than ordinary rubber), but long-term contact with aromatic hydrocarbons (such as benzene, toluene) or ketones (such as acetone) will still cause swelling.
Thermal Properties and Temperature Resistance
Glass Transition Temperature (Tg): Rigid type approximately 100-120℃ (molecular chains begin to soften), semi-rigid type approximately -20℃ to 50℃;
Continuous Service Temperature: -40℃ to 80℃ (ordinary polyether PU), short-term resistance to 100-120℃ (if modified rigid type);
Heat Deflection Temperature (HDT, 1.82 MPa load): Rigid type approximately 80-100℃, semi-rigid type approximately 50-70℃.
Chemical and Weather Resistance
Chemical Resistance: Resistant to weak acids and alkalis (such as dilute sulfuric acid and sodium hydroxide solution), but sensitive to strong oxidants (such as concentrated nitric acid and concentrated sulfuric acid) and chlorinated hydrocarbons (such as carbon tetrachloride);
Weather Resistance: Long-term exposure to ultraviolet light (outdoors) will accelerate aging (yellowing and brittleness), requiring the addition of UV stabilizers (such as carbon black or UV stabilizers);
Water Resistance: Immersion in boiling water or high humidity environments (such as 80% RH) for several months shows almost no performance degradation (polyester PU may experience a 20%-30% strength decrease during the same period).