Elastic Compositions Based on Polyurethane/ Aliphatic Polyesters

Abstract:
Aliphatic polyesters were prepared by melt condensation reaction of a
dicarboxylic acid such as adipic and sebacic with different types of diol
compounds in 1: 1.1 molar ratio. Ethylene glycol, di-, tri-, tetraethylene glycol
and poly(ethylene glycol) with different molecular weights 1000, 4000, 6000 as
well as the prepared hydroxy natural rubber were used as diol compounds.
Polyurethane, with NCO/OH ratio equal 4, was synthesized from the reaction of
toluene diisocyanate with poly(ethylene glycol)1000. The prepared polyurethane
was mixed with different weight percentages of the prepared aliphatic
polyesters. The film samples were tested mechanically, electrically and
chemically. The results show that the weight percentage 10% of the added
polyadipate or polysebacate glycols improves flexibility, electrical volume
resistivity, dielectric constant and dielectric loss of unmodified rigid
polyurethane film sample as well as reduces its swelling by aromatic solvents.
All the above mentioned properties improve by increasing the hydrocarbon
chain length of the glycol portion in the glycol used and the number of
methylene in the aliphatic dicarboxylic acid. Compositions based on hydroxy
natural rubber impart better properties than those based on ethylene glycols.

Elastic Compositions Based on Polyurethane- Aliphatic Polyes