Graft polymerization of vinyl acetate onto starch. Saponification to starch-g-poly(vinyl alcohol). [. gamma. rays]

Journal Article · Mon Jan 01 00:00:00 EST 1979 · J. Appl. Polym. Sci.; (United States)

DOI:https://doi.org/10.1002/app.1979.070230121· OSTI ID:6213880

Fanta, G F; Burr, R C; Doane, W M; Russell, C R

Graft polymerizations of vinyl acetate onto granular cornstarch were initiated by cobalt-60 irradiation of starch-monomer-water mixtures, and ungrafted poly(vinyl acetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1.0 Mrad. Over half of the polymer was present as ungrafted poly(vinyl acetate) (grafting efficiency less than 50%), and the graft copolymer contained only 34% grafted synthetic polymer (34% add-on). Lower irradiation doses produced lower conversions of monomer to polymer and gave graft copolymers with lower % add-on. Addition of minor amounts of acrylamide, methyl acrylate, and methacrylic acid as comonomers produced only small increases in % add-on and grafting efficency. Grafting efficiency was increased to 70% when a monomer mixture containing about 10% methyl methacrylate was used. Grafting efficiency could be increased to over 90% if the graft polymerization of vinyl acetate--methyl methacrylate was carried out near 0/sup 0/C; although conversion of monomers to polymer was low and grafted polymer contained 40 to 50% poly(methyl methacrylate). Selected graft copolymers were treated with methanolic sodium hydroxide to convert starch-g-poly(vinyl acetate) to starch-g-poly(vinyl alcohol). The molecular weight of the poly(vinyl alcohol) moiety was about 30,000. The solubility of starch-g-poly(vinyl alcohol) in hot water was less than 50; however, solubility could be increased by substituting either acid-modified or hypochlorite-oxidized for unmodified starch in the graft polymerization reaction. Vinyl acetate was also graft polymerized onto acid-modified starch which had been dispersed and partially solubilized by heating in water. A total irradiation dose of either 1.0 or 0.5 Mrad gave starch-g-poly(vinyl acetate) with about 35% add-on, and a grafting efficiency of about 40% was obtained.alcohol).

• Research Organization: Dept. of Agriculture, Peoria, IL
• OSTI ID: 6213880
• Journal Information: J. Appl. Polym. Sci.; (United States), Vol. 23:1
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
ACETIC ACID ESTERS
CHEMICAL RADIATION EFFECTS
STARCH
VINYL MONOMERS
COPOLYMERIZATION
GAMMA RADIATION
GRAFT POLYMERS
SAPONIFICATION
CARBOHYDRATES
CARBOXYLIC ACID ESTERS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ESTERS
HYDROLYSIS
IONIZING RADIATIONS
LYSIS
MONOMERS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
POLYMERIZATION
POLYMERS
POLYSACCHARIDES
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
REAGENTS
SACCHARIDES
SOLVOLYSIS
400600* - Radiation Chemistry