Cellulosic materials, yellowing

This material is a cationic, substantive, fatty type softener. Supplied as a soft flowable off-white liquid designed specifically for use on cotton and cellulosic material, as well as blends of synthetics and cellulosics shows minimum yellowing. 

As early as 1917, the need to obtain chemicals from cellulosic materials had already been eminent. For example. Palmer Cloukey (1918) in producing alcohol from various species of hardwoods studied the effect of moisture content in the wood on alcohol yield. By destructively distilling beech, yellow birch and maple that had been subjected to seasoning for between 4 and 18 months they observed that beech gave high alcohol yields when the moisture content was high, while excess moisture lowered the yields for yellow birch and maple. 

Yilmaz [13] reported that alkaline extracted corn husk fibers posed higher thermal resistance with the onset of the major degradation step of210 - 225°C compared to water retted and enzyme treated corn husk fiber with that of 185°C. This might be due to the stronger effect of alkalization in removing extra-cellulosic material. She also reported lower yellowness of alkalized corn husk fibers compared to water retted ones which also... 

This safety glass turned yellow after several years of exposure to light. The bonding layer was replaced in 1933 by cellulose acetate, made from the reaction of cotton with acetic acid. By 1939 this was replaced by poly(vinyl butyral) (PVB), which is still in use today as the adhesive placed between sheets of glass to produce laminated safety glass. This is one of a very few modern-use materials that has retained the same basic materials for over 60 years. 

Acidity has long been recognized as a major factor contributing to the deterioration of cellulose-containing materials. In an effort to combat the harmful influence of acidity, researchers have developed a variety of deacidification techniques capable of decreasing the acid content of most paper-containing objects that are found in museums and libraries. These techniques often are used by conservators in the care of books and works of art on paper (I). Nevertheless, the nature of the chemical processes that cause papers to yellow and to lose strength remains somewhat obscure, and the role of acidity in these processes also is not well understood. 

Chlorine retention is a special problem with amine and amide-containing finishes. When fabrics treated with these finishes are laundered with chlorine bleach, unsubstituted nitrogen atoms can react to form chloramines (Fig. 5.10). Chloramines hydrolyse to form hypochlorous acid that can decompose to materials that will degrade cellulose by significant strength loss and marked yellowing. DMDHEU products show less chlorine retention than do TMM or DMU products. Chlorine retention of A -methylol-based finishes is used for antimicrobial effects (Chapter 15.4 and Fig. 15.3 and 15.4). 

This material is a nonionic softener designed to produce satisfactory softening on cellulosic and blends of synthetics and cellulosic fibers. The outstanding feature of this softener is its tremendous resistance to yellowing under extreme conditions of time and temperature. This product is recommended for use with thermosetting resin finishes particularly where high cure conditions are present. 

This material is a cationic substantive amide softener designed for use on both synthetic and cellulosic fabric to supply excellent softness, sewability and some antistatic properties. This softener exhibits good resistance to yellowing and is compatible with a variety of textile finishing formulas. 

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