Characteristics of Polycarbonate Soft Segment-Based Thermoplastic Polyurethane

Abstract

The pre-experiment of the present study revealed that polyurethane (PU) synthesized using poly (hexamethylene carbonate) glycol (PHC) has high melt viscosity and is difficult to process. Therefore, poly (trimethylene carbonate) glycol (PTC) was employed to synthesize a PU product with low melt viscosity. First, four types of thermoplastic polyurethane (TPU) were formed through one-step solvent-free synthesis. TPU is presented in the format “TPU-X-Y,” with X representing the polyol (PTC or PHC, around 1000 molecular weight) and Y the chain extender (1,3-propane diol [PDO] or 1,4-butane diol [BDO]) used. The TPU was synthesized using a fixed molar ratio of (isocyanate):(polyol):(chain extender) = 2:1:1 and compared. The results indicated that chain entanglement often occurred among the long carbon chains of PHC. The synthesized TPU employed a property of PTC, namely converting polarity into reverse polarity in high temperatures, to resolve the high melt viscosity of TPU of the PHC series, which causes processing difficulties. The synthesized TPU-PTC-PDO exhibited favorable molecular arrangements. Given its polarity, TPU-PTC-PDO has outstanding tensile properties (strength at break: 41.10 ± 10.78 MPa; 100% modulus = 6.73 ± 0.12 MPa), making processing at lower temperatures (180 or 190 °C) feasible. With the inclusion of PTC, the synthesized polycarbonate TPU exhibits the advantages of polycarbonate and is suitable for a wide range of applications.

Keywords

• thermoplastic polyurethane
• poly (trimethylene carbonate) glycol
• poly (hexamethylene carbonate) glycol