Methyl methacrylate grafting cellulose nitrate

Gel permeation chromatography (GPC) of poly(methyl methacrylate) and cellulose nitrate showed elution volume peaks at 62.5 ml for PMMA and at 87.5 for cellulose nitrate (Figure 5), due to their difference in molecular weight. A mixture of poly(methyl methacrylate) and cellulose nitrate of the same ratio as that of the graft copolymer was recorded and two peaks in elution volume at almost identical positions were observed. This shows that the constituent homopolymers retain their identity in a physical mixture. The isolated graft copolymer showed a single peak in elution volume at 80.0 ml. The second peak in elution volume is absent in spite of poly(methyl methacrylate) attached to cellulose nitrate as revealed by infrared spectrum. Hence, these results indicate that GPC can be used as a technique to differentiate between homopolymer, physical mixture, and graft copolymer. 

Figure 6. Effect of grafting time on the graft copolymerization of methyl methacrylate onto cellulose nitrate with ceric ammonium nitrate as initiator. (Reprinted, with permission, from Ref. 19. Copyright 1979, Wiley.)...

Figure 10. Effect of initiator concentration on the graft copolymerization of methyl methacrylate onto cellulose nitrate initiated by a, benzoyl peroxide and b, azobisisobutyronitrile. Key O, grafting efficiency 9, percent grafting.

Figure 13. Probable mechanism of grafting of methyl methacrylate onto cellulose nitrate. Key Enol, enolization In, initiator M, monomer.

Benzoyl Peroxide and Azobisisobutyronitrile-Initiated Graft Copolymerization. Cellulose nitrate (CN) (10 g) was dissolved in methyl isobutyl ketone (90 ml) in a three-necked flask and to this solution methyl methacrylate (10 ml) and benzoyl... 

The nuclear magnetic resonance spectra of cellulose nitrate and of cellulose-g-poly(methyl methacrylate) after separation from cellulose nitrate and poly(methyl methacrylate), are shown in Figures 3 and 4, respectively. The graft copolymer shows the presence of C1CH3 proton at 1.06, indicating the presence of poly(methyl methacrylate) chains attached to cellulose nitrate. 

Figure 5. GPC curves of 1, cellulose nitrate 2, polyf methyl methacrylate) 3, physical mixture of cellulose nitrate and polyf methyl methacrylate) and 4, graft copolymer of cellulose nitrate-g-poly-(methyl methacrylate). (Reprinted, with permission, from Ref. 21. 

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