Cellulose triacetate

Abstract: Two separate assay systems were used to evaluate the biodegradation potential of cellulose acetate: an in vitro enrichment cultivation technique (closed batch system), and a system in which cellulose diacetate (CDA) films were suspended in a wastewater treatment system (open continuous feed system). The in vitro assay employed a stable enrichment culture, which was initiated by inoculating a basal salts medium containing cellulose acetate with 5% (v/v) activated sludge. Microscopic examination revealed extensive degradation of CDA (DS = 2.5) fibers after 2–3 weeks of incubation. Characterization of the CA fibers recovered from inoculated flasks demonstrated a lower average degree of substitution and a change in the mol wt profiles. In vitro enrichments with CDA (DS = 1.7) films were able to degrade > 80% of the films in 4–5 days. Cellulose acetate (DS = 2.5) films required 10–12 days for extensive degradation. Films prepared from cellulose triacetate remained essentially unchanged after 28 days in the in vitro assay. The wastewater treatment assay was less active than the in vitro enrichment system. For example, approximately 27 days were required for 70% degradation of CDA (DS = 1.7) films to occur while CDA (DS = 2.5) films required approximately 10 weeks before significant degradation was obtained. Supporting evidence for the biodegradation potential of cellulose acetate was obtained through the conversion of cellulose [1-14C]-acetate to 14CO2 in the in vitro assay. The results of this work demonstrate that cellulose acetate fibers and films are potentially biodegradable and that the rate of biodegradation is highly dependent on the degree of substitution. © 1993 John Wiley & Sons, Inc.

Abstract: The degree of substitution (DS) of highly acetylated cellulose acetate (CA) was quantitatively evaluated by FTIR. Seven standard samples, the DS ranging from 1.80 to 2.85, prepared by mixing appropriate amounts of commercial cellulose triacetate and commercial cellulose were analyzed for their DS by a FTIR method, and the relationship between the DS and the ratios of specific peak absorbance intensity or integral area calculated from FTIR spectra was confirmed to be a polynomial fitting of the second degree. The DS values of CA prepared by heterogeneous acetylation under different conditions determined by FTIR based on the resulting quadratic polynomial equations were compared with those determined by a titration method. The results showed that the DS value was well predicted by FTIR spectra and the average percentage errors were lower than 2.31%. The specific peak parameter ratio can effectively evaluate and monitor the acetylation process. Additionally, the results of dynamic analysis indicated that the heterogeneous acetylation reaction followed a second-order kinetic model when the DS value exceeded 2.0.