Abstract
The availability of the diisocyanate paraphenylene diisocyanate (PPDI) and cyclohexyl diisocyanate (CHDI) has made possible the synthesis of thermoplastic polyurethanes (TPLTs) which have greater thermal stability than previously obtainable as predicted from their DMTA thermograms.
The ability to combine elevated temperature service with the unique strength and wear resistant properties of polyurethane, together with the automation made possible by thermoplastic injection moulding is considered to represent an advance in current seal materials.
This paper describes the special synthesis and formulation of TPU's based on PPDI and CHDI together with a spectrum of the strength properties used to judge them as potential seal elastomers. Some of these TPU elastomers possess tensile strengths of 50 MPa and compression set values of <25% obtained by using special post-curing techniques.
DMTA data is used to predict these TPU's responses to elevated temperatures.
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