MATERIAL CHARACTERISATION OF POLYETHYLENE AND POLYSTYRENE
PART 1 1. What date was the video taken? = 21/10/2010 2. What is the initial thickness of the callipers as first shown?= 6490mm 3. What is the time on the when last sample breaks ( ±5 s)? = 2.55 s
Polystyrene is hard but brittle thermoplastic, less flexible and ductile at room temperature than Polyethylene because the phenyl group in its repeating unit increases the strength of intermolecular forces present in crystalline due to its weak polarity. Polystyrene has a modulus of elasticity (initial modulus) of 1.16 ± 0.3 GPa, breaking stress (UTS) 36.12± 6.3 MPa. Polyethylene (HIPS and UHMWPE) are ductile, flexible thermoplastic polymer due to intermolecular forces in the regular arrangement of carbon chains in their crystalline structure, values of mechanical properties of materials in this experiment do not differ largely from published data on polyethylene. From the given data of tensile testing of polyethylene and polystyrene, force vs extension graphs were drawn using Microsoft excel and autograph to establish the modulus of elastics, tensile strength and behaviour of these polymers under stress. The experiment conducted provided good estimates because estimated values mechanical properties of materials are not far from that of established data in (Collister, Jr 2002). Changes to experiment mentioned in the discussion would have to be implemented to increase suitability of values from the experiment.
INTRODUCTION This is report analyses raw data from tensile test of polyethylene and polystyrene materials; thus drawing comparisons with published data of mechanical properties of polyethylene and polystyrene materials. Also how chemical structures affects mechanical properties of polyethylene and polystyrene. Background theory Mechanical properties of a material relate to its resistance to changes, e.g. when loaded, deformed, rise in temperature etc. This depends on the structure and...
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