Polycaprolactone hydrolytic stability

Among the polyurethane, polyester, and polyamide thermoplastic elastomers, those with polyether-based elastomer segments have better hydrolytic stability and low temperature flexibility, whereas polyester-based analogues are tougher and have the best oil resistance (43). Polycaprolactones and aliphatic polycarbonates, two special types of polyesters, are used to produce premium-grade polyurethanes (12). 

It is considered that the polyurethanes based on oleochemical polyols, dimer acids and dimer alcohols, PTHF and PC-polyols lead to polyurethanes with excellent hydrolytic stability. Polycaprolactone (PCL) polyols and poly (butylene adipate) lead to polyurethanes with good hydrolytic stability, but use of poly (diethylene glycol adipate) give polyurethanes with poor hydrolytic resistance. 

Polycaprolactones possess good low-temperature impact strength for paintable body panels, good fuel and oil resistance, and hydrolytic stability for seals, gaskets, and belting. Polycaprolactones have fast crystallization rates, high crystallinity, and are generally easily processed into complex parts. 

Polyester polyadipates have improved oil and chemical resistance, but slightly lower hydrolytic stability than polycaprolactones which are used for seals, gaskets, and beltings. 

Polyesters have, as a generalization, certain property advantages over polyethers with respe t to strength, oil resistance, etc. Hence many attempts have been made to achieve polyester types of improved hydrolytic stability resulting in the development and establishment of the polycaprolactone series and of the carbonate types, both shown in Table 1.5. 

COMPARISON OF HYDROLYTIC STABILITY OF POLYURETHANE ELASTOMERS BASED ON POLYETHER AND POLYCAPROLACTONE... 

Series Seals, gaskets, caster wheels, belting, animal ID tags, other fabricated products, office furniture, cell phones and PDA overmolding Polycaprolactone-based ester excellent resistance to fuels and oils best hydrolytic stability of ester TPUs... 

---