New butadiene based di-block stereoregular polymers for the development of innovative compounds

New polybutadienes, BDSPs, showing the properties of a thermoplastic elastomer, i.e. the behavior of a viscoelastic liquid at processing and moulding temperatures, and elastomeric properties at application temperature, without necessarily passing through a cross linking process, have been developed. This feature particularly applies in the tire production and most importantly allows recycling. It also brings advantage to many other applications requiring not-crosslinked elastomers, with considerable bene t for environmental sustainability. The new polymers have been obtained through a specific and original polymerization catalysis which, having living character and high stereoselectivity, allows to obtain butadiene based stereo regular di-block polymers having cis-1,4/1,2syndiotactic structure. The cis-1,4 block is amorphous with low melting temperature (Tm) (well below room temperature), while the 1,2 syndiotactic block is crystalline with high Tm (above room temperature); the melting temperature of the crystalline block can be managed in the range 70° ÷ 140°C.