摘要:

Fibrous holocellulose pulps were prepared in approximately quantitative yield from flax shives and wheat, oat, and fiber flax straw that had been macerated in a buhrstone mill and delignified by sodium chlorite. Paper hand sheets that were formed from pulps subjected to prolonged beating were glassinelike in character. Strength of all straw holocelluloses developed slowly on beating. All papers had relatively low densities compared with the usual values for papers from wood pulps. Tear resistance was initially low for all straw holocelluloses, especially flax shives, and decreased with beating. Color reversion, due almost entirely to light, was rapid in all test sheets. Possible uses for straw holocellulose papers are suggested, although, at present, the process is too expensive to be commercially feasible.

ISSN:1923-4287    

DOI:10.1139/cjr48f-015

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Irish moss (Chondrus crispus) from Canada's east coast was used to study possible improvements in the production and storage of gelose. The optimum pH for the extraction of gelose from Irish moss was between 6 and 7. Fine leaf particles, which prevent rapid filtration, were readily removed by supercentrifuging. Comparison of drum drying and drying from the frozen state showed that the former caused a marked lowering of viscosity but had little effect on suspending power or jelly strength. The logarithm of the viscosity determined by means of a MacMichael viscosimeter was related directly to the concentration; therefore, viscosity measurements can be corrected for the moisture content of the samples. The effect of storage temperature on deterioration was greater than the effect of relative humidity. Samples stored at 0° and 40° F. for 12 weeks showed no significant changes in viscosity or suspending power, whereas those stored at 80° and 120° F. deteriorated very rapidly. Material was vacuum ice-dried to 2% moisture without damage but the quality decreased when the extracts were stored at high temperatures.

ISSN:1923-4287    

DOI:10.1139/cjr48f-016

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

A modified Othmer equilibrium still was used to obtain vapor–liquid equilbrium data for thelevo-2,3-butanediol–water system at 14.7, 45, and 75 p.s.i. absolute. Comparison with similar data reported in the literature for themeso-2,3-butanediol–water system showed a greater volatility for thelevo-isomer. There is an inflection in the equilibrium curves at lower diol concentrations.

ISSN:1923-4287    

DOI:10.1139/cjr48f-017

出版商:NRC Research Press    

年代:1948

数据来源: NRC