Plastics
Property
Acrylic
Acrylic sheets are vacuum formed into the desired shape & sprayed with a layer of fiberglass to make a durable product.
Acrylic are normally thermoplastic substances, soluble in organic solvents. They vary from polymethylmethacrylate (perspex), a hard glass-clear material, to soft rubbery polymers and waxes.
Chemical Properties
Acrylics tends to be soluble in most aromatic and chlorinated hydrocarbons, esters, ketones and tetrahydrofuran. When cross-linked, they can be insoluble, but will swell in chlorinated hydrocarbons.
They are plasticized by some ester type plasticizer (e.g. dibutylphthalate and trirolylphospate), are swollen by alcohols, phenols, ether and carbon tetrachloride, but are relatively unaffected by aliphatic hydrocarbons, concentrated alkalis, most dilute acids and concentrated hydrochloric acid, aqueous solutions of salts and by oxidizing agents. they are however, decomposed by concentrated oxidising acids and by alkalis in alcoholic solution.
Thermal Properties
| Specific heat | 1.47 J/gK |
| Conductivity | 0.19 W/m °C |
| Coefficient of linear expansion | 0.007/°C (20°C), 0.0105/°C (80°C) |
| Maximum service life temperature | 80°C |
| Decomposes at | 180-190°C |
| Density | 1.19 g/cm3 |
Mechanical Properties
| Young’s modulus | 2940 MPa (decreasing to 1670 MPa at 80°C) |
| Tensile strength | 70 MPa |
| Elongation at break | 4% (cast sheet) |
| Impact strength: Notched Izod | 1.6 kJ/m² |
| Charpy unnotched | 15 kJ/m² |
| Compressive strength | 117 MPa |
Advantages
- Transparent
- Good Surface Finish
- Good Outdoor Weathering Property
- Rigidly Thermoformable
- Easily Machinable
Disadvantages
- Poor Scratch Resistance
- Dissolved By Number Of Organic Solvents
- Attacked By Mineral Acids