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Material Information Polymethylmethacrylate
PMMA, Acrylic
Buy small quantities online of Polymethylmethacrylate for research and/or development
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General Description:
Common Brand names :Diakon Lucite Oroglas Perspex Plexiglas
General Description : Often just called "acrylic" - though this really describes a large family of chemically related polymers - PMMA is an amorphous, transparent and colourless thermoplastic that is hard and stiff but brittle and notch-sensitive. It has good abrasion and UV resistance and excellent optical clarity but poor low temperature, fatigue and solvent resistances. Though flammable, it has low smoke emission.
General purpose grades can be extruded and injection moulded. Monomer casting (for a description, see Nylon 6) is also used to achieve much higher molecular weights - which are not melt processable because of their extremely high melt viscosity - with somewhat improved properties. The monomer cast items most commonly encountered are sheets and novelty displays in which e.g. insects or watch parts are embedded.
Thin films are normally made from impact modified grades, which incorporate a small proportion of elastomer(s), in order to improve their flexibility.
Perspex CQ is a particular example of monomer cast sheet which was, until recently, made for intra-ocular use by the original, ca.1940, process because war-time air crew experience had shown that splinters of it that had entered the human eye were biologically inert. They are additive-free and the purest (and probably the highest molecular weight) grade of PMMA available. Almost all of our other PMMA items contain UV absorber; these two items are identified as "free from UV absorber" in the item description.
Applications include sinks, baths, displays, signs, glazing (especially aircraft), lenses and light covers. Cast sheet is also used for guards and the like.
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Chemical Resistance
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| Acids - concentrated | Good-Poor |
| Acids - dilute | Good-Poor |
| Alcohols | Good-Poor |
| Alkalis | Good |
| Aromatic hydrocarbons | Poor |
| Greases and Oils | Good |
| Halogenated Hydrocarbons | Poor |
| Halogens | Poor |
| Ketones | Poor |
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Electrical Properties
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| Dielectric constant @1MHz | 2.6 |
| Dielectric strength ( kV mm-1 ) | 15 |
| Dissipation factor @ 1MHz | 0.014 |
| Surface resistivity ( Ohm/sq ) | 1014 |
| Volume resistivity ( Ohmcm ) | 2-14 x 1015 |
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Mechanical Properties
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| Elongation at break ( % ) | 2.5-4 |
| Hardness - Rockwell | M92-100 |
| Izod impact strength ( J m-1 ) | 16-32 |
| Poisson's ratio | 0.35 - 0.4 |
| Tensile modulus ( GPa ) | 2.4-3.3 |
| Tensile strength ( MPa ) | 80 |
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Physical Properties
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| Abbe number | 57.2 |
| Density ( g cm-3 ) | 1.19 |
| Flammability | HB |
| Limiting oxygen index ( % ) | 17-20 |
| Radiation resistance | Fair |
| Refractive index | 1.49 |
| Resistance to Ultra-violet | Good |
| Water absorption - over 24 hours ( % ) | 0.2 |
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Thermal Properties
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| Coefficient of thermal expansion ( x10-6 K-1 ) | 70-77 |
| Heat-deflection temperature - 0.45MPa ( C ) | 105 |
| Heat-deflection temperature - 1.8MPa ( C ) | 95 |
| Lower working temperature ( C ) | -40 |
| Specific heat ( J K-1 kg-1 ) | 1400 - 1500 |
| Thermal conductivity @23C ( W m-1 K-1 ) | 0.17-0.19 |
| Upper working temperature ( C ) | 50 to 90 |
Properties for Polymethylmethacrylate Film
| Property |
Value |
| Permeability to Oxygen @25C | x10-13 cm3. cm cm-2 s-1 Pa-1 | 0.1 |
| Permeability to Water @25C | x10-13 cm3. cm cm-2 s-1 Pa-1 | 500 |
Properties for Polymethylmethacrylate Monofilament
| Property |
Value |
| Material | | 1.0/2.2 |
| Extension to break | % | <8 |
| Maximum Use temperature | C | 85 |
| Minimum Use temperature | C | -55 |
| Minimum bending radius | mm | 90 - >25 |
| Tensile force | N | >90 |
Click to see Standard Catalogue items from one of the forms
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