Lipase‐Catalyzed Synthesis and Curing of High‐Molecular‐Weight Polyricinoleate

Abstract

High-molecular-weight polyricinoleate, with an M(w) of 100,600, was enzymatically prepared by the polycondensation of methylricinoleate using immobilized lipase from Pseudomonas cepacia (IM-PC) in bulk in the presence of 4 A molecular sieves at 80 degrees C for 7 d. Polyricinoleate was a viscous liquid at room temperature with a glass transition temperature (T(g)) of -74.8 degrees C, showed no crystallinity and was biodegraded by activated sludge. Polyricinoleate was readily cured using a dicumyl peroxide at 170 degrees C for 30 min to produce a chloroform insoluble crosslinked polyricinoleate with a hardness of 50A using durometer A.

Poly (Ricinoleic Acid) Based Novel Thermosetting Elastomer

“…Polyricinoleate was prepared by the lipase-catalyzed polymerization of methyl ricinoleate in bulk 21) . The general procedure for the enzymatic polymerization was as follows.…”

“…The obtained polymer was dissolved in chloroform and precipitated from methanol to remove any unreacted monomer and by-product oligomer. The molecular structure was analyzed by FT-IR, 1 H and 13 C NMR spectroscopies 21) .…”

“…Epoxy derivatives are used to stabilize poly(vinyl chloride) resins, and hydroxylated oil yields quick-drying alkyds 20) . We recently reported that ricinoleic acid was enzymatically polymerized to yield a high molecular weight polyricinoleate with an M w of greater than 90,000 21) . The produced polyricinoleate was a viscous liquid at room temperature having a glass transition temperature (T g ) of -74.8 and was biodegraded by activated sludge.…”

“…The initial low torque value was due to the softening of the polyricinoleate by heating. Polyricinoleate itself showed no T m and T c , and was a liquid polymer at room temperature 21) . Thus, the initial viscosity of these compounds was low and the minimum torque value (torque min ) was about 0.1 dNm within the first few minutes.…”

“…Thus, carbon black-filled rubber compounds are now widely used in various applications including automotive tires and vibration mounts. On the other hand, cured polyricinoleate itself had a very low tensile strength without the carbon black 21) . These results indicated that the mechanical properties of the cured polyricinoleate were significantly reinforced by the addition of carbon black.…”