Molecular structure and properties of cellulose acetate chemically modified with caprolactone |
| |
Authors: | Gyö rgy Szá mel,Attila Domjá n,Bé la Puká nszky |
| |
Affiliation: | a Laboratory of Plastics and Rubber Technology, Department of Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary b Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary c Institute of Structural Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary |
| |
Abstract: | Cellulose acetate (CA) with a degree of substitution of 1.7 was modified with caprolactone (CL) under various reaction conditions in an internal mixer. Processing temperature changed from 120 to 220 °C, while reaction time varied between 5 and 45 min. The composition and structure of the polymer was analyzed by various methods including FTIR, MALDI-TOF and NMR spectroscopy and its mechanical characteristics were determined by dynamic mechanical analysis and tensile testing. The results indicate that homopolymerization occurs under relatively mild conditions, while grafting requires higher temperatures and longer times. Grafted polycaprolactone (gPCL) chains are attached mainly to positions 2 and 6 of the glucose ring and their length increases with increasing reaction time and temperature, but the chains are always much shorter than those obtained in solution polymerization. Changes in the degree of substitution during grafting are small indicating that homopolymerization proceeds easier than grafting. Grafting seems to be easier in cellulose acetate with a larger degree of substitution in spite of the smaller number of active -OH groups present. Internal plasticization is more efficient than the external plasticizing effect of monomeric caprolactone. Plasticization results in a decrease of stiffness and strength, but deformability increases only slightly. |
| |
Keywords: | Cellulose acetate Grafting Caprolactone Molecular structure Plasticization Mechanical properties |
本文献已被 ScienceDirect 等数据库收录! |
|