GPPS
No. | Width (A), mm | Thickness (W), mm | Energy, J | Joules/Fracture Surface, J/m² | 1 | 11.09 | 3.28 | 0.122 | 3353.93 | 2 | 11.09 | 3.28 | 0.129 | 3546.37 |
HIPS No. | Width (A), mm | Thickness (W), mm | Energy, J | Joules/Fracture Surface, J/m² | 1 | 11.09 | 3.28 | 0.280 | 7697.55 | 2 | 11.09 | 3.28 | 0.316 | 8687.24 |
HDPE No. | Width (A), mm | Thickness (W), mm | Energy, J | Joules/Fracture Surface, J/m² | 1 | 11.09 | 3.28 | 0.205 | 5635.71 | 2 | 11.09 | 3.28 | 0.206 | 5663.20 |
PP No. | Width (A), mm | Thickness (W), mm | Energy, J | Joules/Fracture Surface, J/m² | 1 | 11.09 | 3.28 | 0.124 | 3408.92 | 2 | 11.09 | 3.28 | 0.126 | 3463.90 |
B-7.2 Specimen | Joules/Fracture Strength, J/m² | GPPS | 3450.15 | HIPS | 8192.40 | HDPE | 5649.46 | PP | 3436.41 | 8.1 Out of the four plastic materials, High Impact Polystyrene (HIPS) exhibits the highest impact strength compared with the other three. This suggests that HIPS withstand impact strength best, followed by High density polyethylene (HDPE), General Purpose polystyrene (GPPS) and Polypropylene (PP) in descending order.
The reason why HIPS has a higher impact strength than HDPE is because HIPS is made of a larger monomer, styrene (C8H8 or C6H5CH=CH2) while HDPE is made of a smaller monomer, ethylene (C2H4 or H2C=CH2).
Additionally, HDPE is a linear polymer. HDPE is made of closely packed structure of ethylene hydrocarbon (C2H4n.H2) which undergoes a catalytic process. There are no branching in the molecular structure, resulting in increasing the material’s hardness and its rather high impact strength.
GPPS, also known as the ordinary polystyrene, is a raw material to make HIPS. HIPS is made out of ordinary or general purpose polystyrene and rubber. The addition of rubber to the polymer improves the toughness of the material; hence it can withstand greater impact strength. This concludes the fact that HIPS has higher impact strength than GPPS.
PP
Bibliography: http://www.azom.com/article.aspx?ArticleID=2765#_ISO_and_ASTM http://www.azom.com/article.aspx?ArticleID=4145#_The_Izod_Impact http://www.dynalabcorp.com/technical_info_hd_polyethylene.asp http://www.dynalabcorp.com/technical_info_polypropylene.asp http://www.gopolymers.com/plastic-types/polystyrene-ps-plastic.html http://wiki.answers.com/Q/List_in_increasing_order_of_toughness_HDPE_PMMA_LDPE