Triptycene Chain Extenders

Title: TRIPTYCENE MONOMER AND TRIPTYCENE CONTAINING POLYESTERS AND POLYURETHANES

 Number/Link: US20150191408

Applicant/Assignee: not yet recorded. Research supported by US Army

Publication date: 9-07-2015

Gist”: A novel primary diol derived from triptycene is useful as chain extender for polyurethanes and polyesters.

Why it is interesting: Polymers with increased mechanical properties and stiffness can be obtained by incorporating rigid structures in the polymer chain.  This however also results in increased glass transition temperature and reduced ductility because of reduced chain flexiblity and entanglements.  According to this invention polyurethanes (and copolyesters) with high modulus and good ductility at low temperatures can obtained by using triptycene-1,4-hydroquinone-bis(2-hydroxyethyl ether) or TD. In and example TD capped with PEG400 is reacted with a 4,4’MDI- PTMEG1000 prepolymer.  The resulting material indeed has a very low softblock Tg of  -65ºC and a much higher Y modulus compared to a PU made with HQEE as chain extender. According to the inventors the PU is highly suitable as a matrix material in KEVLAR or UHMWPE fiber composites.
In my opinion this is a very interesting chain extender as it appears to prevent H-bond formation and increase molar volume thereby substantially decreasing Tg. However lack of availability, and (most probably) price, will prevent this from becoming mainstream anytime soon.

Tryptycene-1,4-hydroquinone-bis(2-hydroxyethyl ether)

Triptycene-1,4-hydroquinone-bis(2-hydroxyethyl ether)

 

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