title: Cellulose ester-graft-poly(epsilon-caprolactone): effects of copolymer composition and intercomponent miscibility on the enzymatic hydrolysis behavior.
abstract: Enzymatic hydrolysis was conducted with Pseudomonas lipase for film samples of graft copolymers of cellulose acetate (CA) and butyrate (CB) with poly(epsilon-caprolactone) (PCL), CA-g-PCL, and CB-g-PCL, respectively. The two trunk polymers CA and CB, both having the degree of acyl substitution (DS) of >2, are respectively immiscible and miscible with PCL. A hindrance effect of the cellulose ester trunks on the enzymatic attack to the PCL component was observed for the two copolymer series; the situation was more conspicuous in the use of CB trunks. After the selective hydrolytic degradation of the PCL component, a topographical study by AFM revealed that the CA and CB constituents as residues formed a protuberant structure on the surface of the respective film specimens. The altitude and regularity of the protuberances were variant depending on the initial copolymer composition. In a phase-imaging mode of AFM, a hydrolyzed film of CA-g-PCL with an extremely low graft-density (acetyl DS > 2.95) showed particularly larger CA domains of >25 nm in diameter. The domain sizes were in accordance with a heterogeneity scale in the original intercomponent mixing state estimated by (1)H spin-lattice relaxation time (T(1)(H)) measurements in solid-state (13)C NMR spectroscopy. The present results demonstrate a high potential in application of the PCL-grafted cellulosic copolymers as spatiotemporally biodegradation-controllable materials.
authors: Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
authors: Ryosuke
authors: R
authors: Kusumi
authors: Seung-Hwan
authors: SH
authors: Lee
authors: Yoshikuni
authors: Y
authors: Teramoto
authors: Yoshiyuki
authors: Y
authors: Nishio
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D004798:Enzymes / Q000737:chemistry; D004952:Esters; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D011091:Polyesters / Q000737:chemistry*
chemical_list: D004798:Enzymes; D004952:Esters; D011091:Polyesters; C016240:polycaprolactone; D002482:Cellulose