Polymer stiffness V temperature question
Polymer stiffness V temperature question
(OP)
Hi . Not my normal area as my name implies. I would like to know about temperature effects on polymers ( or plastics) , particularly commonly available polymers . I understand that a lot of such polymers become less stiff with temperature but is the reverse possible ( in a common polymer?) . In other words can some become more rigid at higher temperature? Many thanks in advance. Opticsman






RE: Polymer stiffness V temperature question
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Polymer stiffness V temperature question
As Pat mentioned, about the only way to increase modulus at high temperature is if you actually change the polymer chemically by heating, i.e. induce cross-links. For example an uncured epoxy (like glue) will harden a lot on heating due to the cure (cross-linking). Other ways are possible but not likely to be very useful in practice.
RE: Polymer stiffness V temperature question
RE: Polymer stiffness V temperature question
RE: Polymer stiffness V temperature question
The examples are two pot adhesives, polyester resins used in the FRP industry, and thermoplastics going hard and brittle due to thermal ageing.
Another possibility is if a semi crystalline thermoplastic is moulded under conditions that produce amorphous mouldings, the E vs T will increase if the parts are heat treated to increase crystallinity. That is heated to softening point and cooled slowly.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Polymer stiffness V temperature question