Amino starches

Starch is the most widely used dry strength additive and is normally made in a cationic form by introducing a reactive monomeric or polymeric tertiary amine or quaternary ammonium derivative into the molecule. The most commonly used reagent for tertiary amino starch is 2-chloroethyldiethylammonium chloride, and for quaternary starch is 2,3-epoxypropyltrimethylammonium chloride (Figure 7.10). 

The reaction proceeded through nucleophilic displacement of chloride and a starch ether was formed. The ether derivative was quaternized and made cationic by addition of a mineral acid. Teriary amino starches so made are used predominantly at acidic pH where the charge remains maximum. As neutral pH is approached, the charge is diminished until at weakly alkaline pH the charge is lost. 

Cationic starch is a frequently-utilized retention aid, especially when paper strength improvement is a second objective.141,142 Low pH activates tertiary amino starch, but at pH 6 an amphoteric starch, and at pH above 7 a quartenary ammonium starch, will be needed. 

Most of the amino starches described in the literature contain amino groups in the side chains. They can be introduced either directly or indirectly. The latter case is illustrated by the reaction of starch with 4-nitrobenzoy 1 chloride, followed by reduction of the 4-nitrobenzoylated starch with aqueous sodium hydrogensulfite2417 or thiourea dioxide2418 to give (4-aminobenzoyl)starch.2417... 

Studies performed on the etherification of potato amylose and amylopectin with (diethylamino)ethyl chloride showed that amylose in the starch granule was more reactive than amylopectin.2429 However, the relative reactivity of both starch components could be changed by physical pretreatment of the granules, for instance, by milling, heat-moisture treatment, freeze-thawing, and chemisorption. The physicochemical properties of amino starches depend on the starch variety reacted 2430 Among potato, sweet potato, rice, wheat, and tapioca starch studied, the last reacted most readily. 

Lassaigne s test is obviously a test also for carbon in the presence of nitrogen. It can be used therefore to detect nitrogen in carbon-free inorganic compounds, e.g., complex nitrites, amino-sulphonic acid derivatives, etc., but such compounds must before fusion with sodium be mixed with some non-volatile nitrogen-free organic compound such as starch... 

Polymers. AH nitro alcohols are sources of formaldehyde for cross-linking in polymers of urea, melamine, phenols, resorcinol, etc (see Amino RESINS AND PLASTICS). Nitrodiols and 2-hydroxymethyl-2-nitro-l,3-propanediol can be used as polyols to form polyester or polyurethane products (see Polyesters Urethane polymers). 2-Methyl-2-nitro-l-propanol is used in tires to promote the adhesion of mbber to tire cord (qv). Nitro alcohols are used as hardening agents in photographic processes, and 2-hydroxymethyl-2-nitro-l,3-propanediol is a cross-linking agent for starch adhesives, polyamides, urea resins, or wool, and in tanning operations (17—25). Wrinkle-resistant fabric with reduced free formaldehyde content is obtained by treatment with... 

STMP reacts with other nucleophiles such as aqueous ammonia to yield amidophosphates, which contains a P—N bond. STMP is used for the modification of the physical properties of starch and proteins by reaction with the amino and hydroxyl groups. 

Some commercial durable antistatic finishes have been Hsted in Table 3 (98). Early patents suggest that amino resins (qv) can impart both antisHp and antistatic properties to nylon, acryUc, and polyester fabrics. CycHc polyurethanes, water-soluble amine salts cross-linked with styrene, and water-soluble amine salts of sulfonated polystyrene have been claimed to confer durable antistatic protection. Later patents included dibydroxyethyl sulfone [2580-77-0] hydroxyalkylated cellulose or starch, poly(vinyl alcohol) [9002-86-2] cross-linked with dimethylolethylene urea, chlorotria2ine derivatives, and epoxy-based products. Other patents claim the use of various acryUc polymers and copolymers. Essentially, durable antistats are polyelectrolytes, and the majority of usehil products involve variations of cross-linked polyamines containing polyethoxy segments (92,99—101). 

Cationic Starches. Commercial cationic starches are starch ethers that contain a tertiary amino or quaternary ammonium group, eg, the diethylaminoethyl ether of starch or the 2-hydroxy-3-(trimethylammonio)propyl ether of starch [9063-45-0], sold as its chloride salt [56780-58-6]. 

Recently, Li et al. [30], Yu et al. [31] reinvestigated the mechanism of graft copolymerization of vinyl monomers onto carbohydrates such as starch and cellulose initiated by the Ce(IV) ion with some new results as mentioned in Section II. Furthermore, they investigated the mechanism of model graft copolymerization of vinyl monomers onto chitosan [51]. They chose the compounds containing adjacent hydroxyl-amine structures, such as D-glucosamine, /mn5-2-amino-cyclohexanol, 2-... 

One of the commercial methods for production of lysine consists of a two-stage process using two species of bacteria. The carbon sources for production of amino acids are corn, potato starch, molasses, and whey. If starch is used, it must be hydrolysed to glucose to achieve higher yield. Escherichia coli is grown in a medium consisting of glycerol, corn-steep liquor and di-ammonium phosphate under aerobic conditions, with temperature and pH controlled. 

Glutamates can be produced by fermentation of starches or sugars, but also by breaking the bonds between amino acids in proteins, leaving free amino acids. This process is done by heat or by enzymes it is called hydrolyzing, because the bonds are broken by adding water. 

Seven diets were constructed from purified natural ingredients obtained from either C3 (beet sugar, rice starch, cottonseed oil, wood cellulose, Australian Cohuna brand casein, soy protein or wheat gluten for protein) or C4 foodwebs (cane sugar, corn starch, com oil, processed corn bran for fiber, Kenya casein for protein) supplemented with appropriate amounts of vitamins and minerals (Ambrose and Norr 1993 Table 3a). The amino acid compositions of wheat gluten and soy protein differ significantly from that of casein (Ambrose and Norr 1993). 

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