Study on the Application Properties of WPU and OMMT in RTV Mold Rubber

Abstract

The purpose of this work was to research on the application properties of waterborne polyurethane (WPU) and organic montmorillonite (OMMT) in room-temperature-vulcanizated silicone rubber (RTV) used as mold materials.

The first part dealt with the application of WPU in RTV matrix. The composite with 3% WPU showed the highest tensile strength and elongation at break, 4.1 MPa and 1441%, respectively. These properties were improved about 28% and 55% compared with that pure RTV. The COLE and COVE of RTV/WPU-3 was 0.2×10⁻⁴∼1.2×10⁻⁴K⁻¹ and 2.7×10⁻³∼4.4×10⁻³K⁻¹, respectively. These values were lower compared with that of pure RTV.

The second part dealt with the application of OMMT in RTV/WPU composites. When 3% OMMT was added, the tensile strength and elongation at break were increased to 5.6 MPa and 1534%, respectively. The COLE and COVE of RTV/WPU-3/OMMT-7 was 0.32×10⁻⁴∼0.94×10⁻⁴ K⁻¹ and 0.32×10⁻³∼2.3×10⁻³K⁻¹. These values showed an obvious decrease compared with that of RTV/WPU-3 composite. After the addition of 3% OMMT, the acid and alkali resistance of these composites were improved. X-ray diffraction (XRD) and scanning electron microscope (SEM) were also used in the investigation of the microtopography of these RTV composites.