- Characteristics and Applications of Polyurethane Microcellular Elastomers
Answer:
Characteristics: Polyurethane elastomers are block copolymers composed of soft segments formed by flexible long chains of oligomeric polyols and hard segments made of diisocyanates and chain extenders. These hard and soft segments alternate to create repeating structural units. Apart from containing urethane groups, polyurethane molecules exhibit intermolecular and intramolecular hydrogen bonding. Microphase separation occurs as soft and hard segments form distinct microphase regions. - Key Performance Features of Polyurethane Elastomers
Answer:
①High strength and elasticity over a broad hardness range (Shore A10–Shore D75), maintaining flexibility without the need for plasticizers, thus avoiding issues related to plasticizer migration.
②Superior load-bearing capacity compared to other elastomers of the same hardness.
③Exceptional wear resistance, up to 2–10 times that of natural rubber.
④Excellent resistance to oils and chemicals; aromatic polyurethanes are also radiation-resistant, with good resistance to oxidation and ozone.
⑤High impact resistance, excellent fatigue resistance, and vibration damping properties, suitable for high-frequency flexing applications.
⑥Good flexibility at low temperatures.
⑦While standard polyurethane cannot withstand temperatures above 100°C, specialized formulations can endure up to 140°C.
⑧Relatively low molding and processing costs. - Classification of Polyurethane Elastomers Based on Raw Materials and Manufacturing Processes
Answer:
①By Polyol Type: Includes polyester-based, polyether-based, polyolefin-based, and polycarbonate-based elastomers. Within the polyether category, there are subtypes such as polytetramethylene ether and polypropylene oxide types.
②By Diisocyanate Type: Categorized into aliphatic and aromatic elastomers, with further subdivisions like TDI, MDI, IPDI, and NDI types.
③By Manufacturing Process: Traditionally divided into cast polyurethane (CPU), thermoplastic polyurethane (TPU), and millable polyurethane (MPU). - Molecular Structural Factors Affecting the Performance of Polyurethane Elastomers
Answer:
Polyurethane elastomers are block copolymers comprising soft segments made from flexible oligomeric polyols and hard segments formed by diisocyanates and chain extenders. These alternate to create repeating structures. Hydrogen bonding occurs both within and between molecules, leading to microphase separation between the soft and hard segments. These structural attributes impart outstanding wear resistance and toughness to polyurethane elastomers, earning them the moniker “wear-resistant rubber.” - Performance Differences Between Regular Polyester and Polytetramethylene Ether Elastomers
Answer:
Polyester-Based Elastomers: Contain numerous polar ester groups (-COO-) that form strong intramolecular hydrogen bonds, resulting in higher strength, wear resistance, and oil resistance.
Polytetramethylene Ether-Based Elastomers: Offer better hydrolysis stability, weather resistance, low-temperature flexibility, and resistance to microbial degradation.
Sally Zhang
CEO of Foshan Alforu Technology Co.,Ltd