摘要:

Laboratory scale measurements have been made of the ability of certain alkaline salts, commonly used as laundry soap builders, to hold carbon particles in suspension, and thus prevent their deposition on fabric during the washing process. In the absence of soap little difference was noted between any of the builders studied, the suspending power being, on the whole, poorer than that of distilled water. In general, the addition of builders to soap solutions resulted in a decrease in the suspending power of the soap, this effect increasing with increasing builder concentration. The builders fall into three general classifications, viz.: simple electrolytes, silicates, and phosphates. Within each of these groups of builders the suspending power of a built soap solution increases with decreasing pH of the solution. A tentative explanation of the influence of added builders on the suspending power of soap solutions is offered, on the basis of interference with the normal adsorption of soap by the carbon particles, and, in some cases, the superimposed adsorption of the anion of the builder. Classification of the builders with respect to their effect on the suspending power of various pure soaps indicated that sodium hexametaphosphate is superior to all others, while sodium hydroxide and sodium orthosilicate are the poorest. There are only minor differences between the remaining builders, tetrasodium pyrophosphate and trisodium phosphate being the best in this group. This classification, which is based solely on suspending power, is not necessarily indicative of the over-all efficiency of builders in the detergent process as a whole.

ISSN:1923-4287    

DOI:10.1139/cjr50f-033

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

A fibrous holocellulose was isolated from white birch using hot acidified sodium chlorite solutions. Pulps of varying hemicellulose content were prepared by alkaline treatment, and their beating and sheetmaking properties compared with the original holocellulose. Tensile strength increased with hemicellulose content, whereas tearing resistance and fold endurance decreased. Bursting strength reached a maximum at about 15% alkali-extractable hemicellulose content. Pulps obtained in yields of 46–53%, i.e., containing 10–20% hemicellulose, possessed the best over-all strength.A bleached sulphite pulp prepared from the same chips in a yield of 43.6% contained 20.7% alkali-extractable hemicellulose. The over-all yield of α-cellulose was about 6% lower, based on the wood, than in the case of the holocellulose, thus indicating greater fiber damage during the sulphite process. Hand sheets made from the sulphite pulp were inferior to sheets made from a chlorite pulp of the same hemicellulose content in bursting and tensile strengths but had better tearing and fold properties.The presence of hemicellulose was found to increase the rate at which the average fiber length was reduced during beating, thus indicating a correlation between fiber flexibility and hemicellulose content.Since pulps of high strength were prepared, it was concluded that greater quantities of white birch pulp at the appropriate hemicellulose content could be incorporated in many commercial furnishes.

ISSN:1923-4287    

DOI:10.1139/cjr50f-034

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The voluminous starch sludge or "squeegee" fraction, obtained with all known methods of wheat starch manufacture, consists of strongly hydrated pentosan masses in which starch granules are embedded. The pentosans of the bran and endosperm both contribute to the formation of these heterogeneous complexes. The "squeegee" starch fraction is not abolished by allowing the crude starch slurries to ferment, by exposing them briefly to mildly acid or alkaline solutions, or to C2−C12monohydric alcohols. The pentosan and protein contents of this low quality starch fraction may be greatly reduced by 24–48 hr. digestion in dilute acid at pH 2.0 before recovering the starch on the centrifuge.

ISSN:1923-4287    

DOI:10.1139/cjr50f-035

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

Monthly samples of cleaned weed seed screenings and of screenings oil (commercially solvent extracted) examined over a six-month period indicated that the composition of the screenings varied widely but that of the oil was remarkably constant. The composition of the weed seed was: wild mustard, mostlyBrassica arvensts(53–79% av. 68%) mixed weed seeds (13–35%, av. 23%), crop seeds (4–10%, av. 6.6%), and broken and unidentified seeds (1–6% av 3%) The average characteristics of the oil were: iodine value, 124; saponification number, 182; free tatty acid (as oleic), 2%; relative light transmission (cf. mineral oil), 5% at 440 mμ, 18% at 540 mμ, 26% at 660 mμ. Appearance of the oil and response to processing were similar to those of rape and mustard seed oils. Small scale taste panel tests indicated that processed screenings oil was generally not as palatable as corn or cottonseed salad oils, but that screenings shortening was generally as acceptable as the control (commercial vegetable shortenings) the screenings shortening had a satisfactory smoke point and good baking volume properties.

ISSN:1923-4287    

DOI:10.1139/cjr50f-036

出版商:NRC Research Press    

年代:1950

数据来源: NRC