Bluehill v2

Flexural test was conducted according to ASTM D790 utilizing three-point bending test with Instron Universal Testing Machine (Instron Corporation, Canton, MA, USA), Model No. 5567 (Figure 3). All test specimens were cut in accordance with the procedure specified, with 3 and 15 mm as the average depth and width, respectively, and 48 mm as the effective support span. The total length of the specimens was 110 mm, thereby allowing sufficient overhang on each end to avoid slipping through the supports.
All test specimens were tested at ambient temperature, with a cross-head motion of 12.8 mm/min to obtain 0.1 min⁻¹ strain condition, considering that failure was not observed within 0.05 strain under 0.01 min⁻¹ strain condition. The test was continued until the strain exceeded 0.1. Time, load, and deflection were measured using Blue Hill v2.5 software (Instron Corporation, Canton, MA, USA). The average of three measurements was used for each dimension. The modulus of elasticity, flexural stress, and strain at maximum stress were obtained as the average of five readings.

The uniaxial tension test was performed on an Instron Universal Testing Machine (Instron Corporation, Canton, MA, USA), Model No. 5566 under quasi-static condition with displacement-controlled condition in accordance with ASTM D412. Dumbbell test specimens (3 mm thick) were obtained from precast PU sheets in the same direction of the sheet to minimize the influence of anisotropy or grain directionality caused by the flow’s direction during preparation and processing. All dumbbell test specimens (Figure 1) were cut using Die C in accordance with the procedure described in the ASTM specifications. The dimensions were measured by using a vernier caliper with an accuracy of 0.01 mm, including the average of three measurements used for the dimensions of each specimen.
All test specimens were automatically clamped into the grip. A uniform rate of 50 mm/min was used for grip separation during the test (Figure 2). All test specimens were tested at ambient temperature, and data were measured using Blue Hill v2.5 software (Instron Corporation, Canton, MA, USA). The time, load, and extension data were recorded up to failure, and tensile characteristics were calculated by using obtained data.