Exploitation of the hard/soft segments ratio in thermoplastic polyurethane (TPU) for the tuning of electrical and mechanical properties of expanded graphite (EG) based composites

0507000 - ÚMCH 2020 RIV DE eng J - Článek v odborném periodiku
Piana, Francesco - Pionteck, J.
Exploitation of the hard/soft segments ratio in thermoplastic polyurethane (TPU) for the tuning of electrical and mechanical properties of expanded graphite (EG) based composites.
SN Applied Sciences. Roč. 1, č. 8 (2019), č. článku 878. ISSN 2523-3963
Grant CEP: GA TA ČR(CZ) TE01020022
Institucionální podpora: RVO:61389013
Klíčová slova: composites * elastomers * nanoparticles
Obor OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)
Způsob publikování: Open access
https://link.springer.com/content/pdf/10.1007%2Fs42452-019-0908-3.pdf

Composite materials based on three kinds of commercial thermoplastic polyurethanes (TPUs) and electrically conductive expanded graphite (EG) were prepared by melt-mixing. The TPUs differed mainly in hard/soft segment ratio, resulting in different polarity and crystallinity. These parameters were exploited to prepare composite materials with different percolating path structure, whose characteristics were thoroughly analysed. Test specimens were prepared by compression moulding and their electrical, thermal and mechanical properties, as dependent on filler content, were analysed. The electrical behaviour was correlated to the morphologies. The results showed how EG promoted and modified the crystallization, resulting in enhanced hardness but reduced toughness of the material. Moreover, EG segregation was observed in the TPU with the highest HS content which already promoted percolating paths at EG concentration below 2 wt% (1.1 vol%) and showed a resistivity between 105 and 104 Ω cm, while in TPU with low crystallinity the percolation was shifted to above 4 wt% EG and the resistivity reached values slightly over 105 Ω cm at 8 and 10 wt% EG. These peculiarities enabled easy management of a broad range of industrial application such as antistatic coatings, mechanically reinforced insulators, and electrical conductive connectors using a few pristine materials.
Trvalý link: http://hdl.handle.net/11104/0298456