Hydrolytic Stability Of Polyurethane With Alkyl Side Groups

It is well-known that polyurethane(PU) has excellent mechanical properities, adhesive property, impact resistance, abrasion resistance and flexibility at lower temperatures, these characteristics are utilized in a wide variety of industrial products, such as building materials, sports goods, medical equipments, adhesives and coatings. Depending on the field of application, polyester polyols(PEPO) or polyether polyols have generally been chosen as the soft segment, properties of polyester-based PU are better than those of polyether-based PU, but hydrolytic stability is poor.In this paper, four different kinds of PEPO with alkyl side groups was synthesized from adipic acid and diol by condensation polymerization, the PU was synthesized from polyurethane-prepolymers and the chain extender 1,4-Butanediol(BDO). Mechanical properties and hydrothermal stability of these polyurethane were studied. All the results showed that: although polyesters containing alkyl side groups give polyurethane a significant lower mechanical properties and phase separation, the hydrolytic stability of polyurethane are excellent in spite of greater water swell. In addition, new species of PU were prepared with blends of these PEPO. Synergies as high hydrolytic stability and high mechanical strength were expected for the PU with combined polyols. It was found that the PU derived from PEPO-EHO with a solid content of about 50% showed improved hydrolysis resistance and superior mechanical properties. Novel polyester glycols with alkyl side groups(PEPO-EHO) were used for the improvement of hydrothermal stability of polyurethane, it is concluded that introduction of alkyl side groups is an important procedure for improvement of the hydrolytic stability of polyurethane.