polyurethaansiliconensystemen

Polyurethanes are a versatile class of polymers produced by reacting diisocyanates or polymeric isocyanates with polyols, often with chain extenders and crosslinkers. The resulting materials contain urethane linkages and can be formulated to exhibit a wide range of properties. This breadth allows rigid foams, flexible foams, elastomeric plastics, coatings, adhesives, sealants, and thermoplastic polyurethanes (TPUs).

Common diisocyanates include methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI), while polyols may be polyester- or polyether-based. Foam formulations use blowing agents to create cellular structures, producing either rigid insulation foams or flexible seating foams. Processing approaches include one-shot polymerization and two-step methods using prepolymers. Applications span construction insulation and panels, refrigeration and appliance casings, automotive components, footwear, packaging, coatings for wood or metal, and various adhesives and sealants.

Environmental and safety considerations include exposure risks to diisocyanates during manufacturing, requiring appropriate ventilation and monitoring. Polyurethanes can improve energy efficiency through insulation but pose waste management and recycling challenges. Recycling options include mechanical recycling of thermoplastic polyurethanes and chemical recycling of foams where feasible. The field has evolved since its discovery in the 1930s by Otto Bayer, with commercial production beginning in the 1940s and expanding into numerous industrial sectors since.