Preparation Of Thermoplastic Polyurethane Elastomer And Its Casting Film Research

In this paper, TPU elastomers obtained from MDI, PBA and BDO were synthesised in a2L reactor by using a prepolymerization methord. Through the discussion on the extent of prepolymerization, prepolymer viscosity, molecule weight of TPU elastomer and mechanical properties, we determined the optimum polymerization process of TPU elastomer as follows:optimal prepolymerization temperature was80℃, prepolymerization time was4h, prepolymer’s best use of time was within48h, and curing temperature was set at100℃and continued12h. Under the above conditions, We designed the isocyanate index of1.00and prepared different properties of TPU elastomer by changing monomer ratio.This paper also examined the processing performance of TPU elastomers with three kinds of different hardness, which provided a reference for TPU elastomer granulation and extrusion casting process. In the processing of TPU elastomer pellets, we investigated the extruder barrel and die temperature, screw speed and the choice of extrusion equipment. Finally, we adopted Φ30diameter single-screw extruder as pellets processing equipment and determined the optimal parameters of extrusion processing. In the processing of TPU elastomer casting films, TPU elastomer pellets were added into a single-screw extruder, melting, plasticizing and extrusion casting, then coolled, shaped and polished by self-made horizontal three roll calendar, we obtained smooth and transparent TPU elastomer casting film. The optimal casting process is: single-screw extruder barrel and adapter temperature were180℃,210℃,210℃,220℃and220℃, the casting mold temperature was set at about220℃, and screw speed was controlled between10-30r/min. Finally, we used X-ray diffraction analysis(XRD), atomic force microscopy(AFM) and scanning electron microscope (SEM) to characterize TPU elastomer casting film, then also investigated the mechanical properties of the film.