Acrylamide-starch graft copolymers

The use of an oxidized starch acetate 180, urea 20, and water 200 as a gummed tape adhesive has been patented. The formulation of an acrylamide starch graft polymer is also claimed hydrolyzed low viscosity acrylamide-starch graft copolymer 67, canary dextrin 20, animal glue 10, urea 10, petrolatum 0.25, and sodium hexametaphosphate 0.1, are heated for 30 minutes at 185-205 F (85-96 C). ... 

Acrylamide graft copolymers such as those with starch (qv)(131), dextran (132), and lignin (qv) (133), have been studied to try to reduce copolymer costs. A general disadvantage of acrylamide copolymers is greater cost compared to partially hydroly2ed polyacrylamides. 

Graft copolymer of starch, acrylamide, and polyvinyl alcohol [671]... 

The graft copolymers of acrylamide, acrylic acid, and cellulose or starch are used as water absorbents and in enhanced oil recovery systems. 

The ozonization method has been extended to the most varied polymer/monomer systems, such as polybutadiene-03 with acrylamide, methyl methacrylate or styrene, cellulose-03 with styrene or acrylonitrile (127), starch-03 with styrene (126). In this last case the formation of some homopolystyrene as side-product has been mentionned by the authors. The starch-styrene graft copolymers are claimed to be good emulsifiers for water-oil suspensions. 

Both starch-g-PAN and starch-g-polyacrylamide were prepared by cobalt-60 initiation, since acrylamide does not graft efficiently in the presence of ceric ammonium nitrate (16). Both graft copolymers were irradiated with ultrasound to give totally soluble products the ultrasonic treatment of starch-g-PAN was carried out in DMSO, while that of starch-g-polyacrylamide was run in water. 

A similar procedure was used to prepare starch-j -polyacrylamlde, and 15 g of acrylamide (97%, Polysciences) was used In the polymerization. After irradiation, the reaction mass was extracted several times with water to remove ungrafted polyacrylamide, and the graft copolymer was washed with ethanol and vacuum dried at 60°C. Weight percent polyacrylamide in the graft copolymer (% add-on) was 35%, based on the weight gain of starch. 

Sealing tape has 35 to 90 pounds per ream of kraft paper as a substrate, whereas, reinforced sealing tape is based on a bonded laminate of kraft paper, reinforcing fibers, and kraft paper. The adhesives applied to these substrates may be thin-boiling, waxy starches alone, or blended with a soluble dextrin (5). More recently, blends of a soluble dextrin with oxidized potato or a hydrox-ypropyl ether of an oxidized potato starch are being used (9). Also, the acetate or succinate of an oxidized waxy starch may be used (15) as well as specially produced waxy starch acrylamide graft copolymer products (16). 

There have been many studies of graft copolymer formation initiated by ionizing radiation, and methods have been discussed.88 Among the systems studied are styrene onto polyethylene,88 styrene onto polypropylene,100 styrene onto Nylon-6,101 styrene onto ethylene-vinyl acetate copolymers,102 styrene and MMA onto natural rubber,103 pentafluorostyrene onto Nylon and polyethylene,104 acrylamide onto Nylon-6,105 acrylamide onto starch,100 vinyl monomers... 

Solutions of starch-acrylamide, graft copolymers, were prepared by J. J. Meister and the solution viscosity was researched with the goal to prepare highly viscous solutions He was able to prove, that graft copolymers also age. However, the data have another feature not found in the viscosities of the PAAm-solutions. That is, that graft-copolymer solution viscosity increases between 24 and 48 hours. After this a typical viscosity decrease can be observed as was mentioned earlier. 

It may be of interest, that dextran-acrylamide, graft copolymers, prepared in a very similar way to starch-acrylamide, graft copolymers, donot show this aging effect, see page 28 in 3 in 6 ... 

Meister, J. J. Rheology of Starch-Acrylamide/Graft Copolymer Solutions. J. Rheol. 25(5) (1981) 487-506... 

Additional aging effects could be found for graft copolymers (starch-acrylamide copolymers [36], synthetic amylose [36],poly(acrylamide-co-methacryloxyethyl-N,N,N,-trimethylammoniumchloride) PAAm/M [30] and poly(acrylamide-co-sodium-2-sulfoethylmethacrylate) [37]. 

Graft CO- and ter-polymers of starch have been prepared by free-radical polymerizations of vinyl monomers onto y-irradiated starch in a prototype commercial process. Products with graft contents of up to 46% were obtained by grafting acrylamide and quaternary amine-containing esters of methacrylic acid onto starch. The graft copolymers possessed retention and drainage properties superior to commercial flocculants. 

Different types of floeculants can be prepared by aminomethylation the amino-methyl derivatives of polyacrylamide represent the most widely adopted class of compounds, which includes high-molecular-weight floeculants (502, 517 in Table 38, 562 in Table 40), and has been widely patented. The large amount of research on these pnxlucts is concerned, in particular, with is(x lcctric points, the content of functionalized co-units, the extent of amido groups hydrolysis, and the use of copolymcrs. -"- Applications of acrylamide copolymers grafted onto starch or other polysaccharides arc also considered. ... 

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