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| Transparent Armor Window |
Polyamide is certainly higher in price than other transparent sheets, but it has an interesting range of properties that make it suitable for some technically demanding applications.
Like Polycarbonate, Polyamide can be used to make very high quality optical grade clear sheet. In fact the light transmission is 90% compared to 89% for Polycarbonate. Sheets of the same size as Polycarbonate can be easily manufactured. Also, Polyamide is almost as unbreakable at Polycarbonate which means it can withstand environments that would damage polymer sheets made out of Acrylic.
Where Polyamide really excels is in properties such as the heat distortion temperature, tensile modulus, density and solvent resistance. We will look at each of these in turn and compare them to the other Polymers.
Heat distortion temperature.
Material Heat distortion temperature (C) Glass transition temperature (C)
Acrylic 95 110
Polycarbonate 137 148
Polyamide 180 190
These figures show that Polyamide can withstand much higher temperatures than both Acrylic and Polycarbonate before they will start to distort under a load. In many applications, the heat distortion temperature is not an issue, but occasionally the part must be able to operate in higher temperature environments without distorting. In these applications, Polyamide is an excellent option.
Tensile modulus
Material Tensile modulus (psi)
Polycarbonate 348,000
Polyamide 232,000
Polycarbonate is a very flexible material, much more so than Acrylic which is rigid by comparison. This flexibility makes it very useful in applications such as security glazing and transparent armor. While Polyamide grades are available with a number of different Tensile modulus characteristics, the one that HighLine Polycarbonate LLC is currently using to make sheet has a lower tensile modulus than even Polycarbonate, making the Polyamide sheet more flexible than Polycarbonate sheet. This property means that in certain configurations, it can be a better material for bullet resistant applications than Polycarbonate. Of course there is a price-performance balance that means that Polyamide is not suitable for all applications.
Where flexibility is needed, Polyamide is certainly an option to be considered.
Density
Polycarbonate and Acrylic have similar densities of around 1200 kg/m3. Polyamide has a density of around 1060 kg/m3. This means that Polyamide is about 10% lighter. Where weight is important, Polyamide is an option.
Solvent resistance
Polycarbonate, while very resistant to a number of chemicals, does not perform well when exposed to certain other chemicals such as Ketones. One of the strengths of Polyamide is that it has exceptional solvent resistance performance. As well as being resistant to Ketones, Polyamide is not attacked by most fuels, oils and lubricants. This chemical resistant makes it a good choice in transportation and aerospace applications.
As far as we know, HighLine Polycarbonate is the only manufacturer to currently offer clear Polyamide sheet to the market. If you would like more information on this unique material, please contact us.
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