抄録
Crude second linter and hull linter (cf. Table 1) were purified by the oxygen•alkali method and the ordinary soda method (cf. Table 2).
The linter oxygen•alkali pulp (OAP) was higher in yield, lower in Kappa no., and much higher in brightness than the linter soda pulp (AP). The polymerization degree of OAP was also somewhat higher than that of AP. COD of waste liquor of OAP was less than that of AP (cf. Table 3).
Bleaching of OAP was much easier than that of AP (cf. Fig. 1 and Table 4). PC no. of the bleached OAP (BOAP) was less than that of the bleached AP (BAP) (cf. Table 5). For both BOAP and BAP, d-cellulose content was over 99% and copper no. was below 0.3 (cf. Table 5).
IR absorption spectrum of unbleached OAP (UOAP) was similar to that of unbleached AP (UAP) and also to that of BOAP and BAP (cf. Fig. 2). The lateral order distribution curves showed that AP seemed to have somewhat larger fraction of high-ordered portion than OAP (cf. Fig. 3). X-ray diffractogram of OAP was similar to that of AP. However, the peak intensities in the diffractograms of BOAP and BAP were somewhat lower than those in the diffractogram of UOAP and UAP, respectively, indicating that the crystalline degree of UOAP and UAP was slightly decreased by the bleaching process (cf. Fig. 4 and 5). Specific surface area determined by the N2-adsorption method was 73.7m2/g for second UOAP and 73.1m2 /g for second UAP (Table 6). The polymerization degree distribution of BOAP was wider than that of BAP (Fig. 6 and 7). Scanning electron micrographs of the linter pulps (cf. Fig. 8_??_10) showed that there are no marked difference in morphological properties between OAP and AP.
These results revealed that oxygen-alkali pulping is superior to the ordinary soda pulping in view of economical and environmental point.
