1. A 1,000 mm long x 100 mm wide x 4 mm thick polymer plate is designed to carry a tensile load 4 kN. In the past, a polystyrene plate of the same dimensions and carrying the same load has failed by brittle fracture due a crack generated at one of its edges close to the mid-length of the plate. Which of the following polymers should you select for this application to replace polystyrene: (1) ABS, (2) Nylon 6,6 and (c) PP copolymer? Give reasons.
2. An aerosol container with diameter = 50 mm and wall thickness = 2.5 mm is to be injection molded using either polymer A (Syt = 65 MPa and Syc = 80 MPa) or polymer B (Syt = 70 MPa and Syc = 77 MPa). Based on the maximum allowable pressure, which polymer will you select?