Abstract
Graft copolymerization of methacryloyl glycine (M-Gly) and methacryloyl glycine esters (M-Gly-OR) onto natural rubber was investigated using benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN) as radical initiators under various conditions. Several physic chemical properties of graft copolymers obtained were also examined.
Graft copolymerization of M-Gly : 1) As a polymerization solvent the mixture of toluene and dioxane with the composition of 1 : 1 to 2 : 1 by volume was suitable. 2) BPO was effective as an initiator and its optimum concentration was 3.125 x 10-3 mole/1. If AIBN was used, a homopolymer was obtained almost exclusively and graft polymerization hardly occurred. 3) With a higher rubber concentration and the use of 0.015 mol monomer against 0.01 mol rubber (polymerization temperature : 80 °C) good result was obtained in t he grafting. 4) The appropriate polymerization temperature was 60 to 80 °C, but a very long time was needed at 60 °C. Irradiation with light instead of heating was also effective. 5) As the degree of grafting increased, the polymer obtained became more easily swollen in water but hardly swollen in benzene and carbon tetrachloride.
Graft copolymerization of M-Gly-OR : 1) BPO was an effective initiator as in the case of M-Gly. 2) The optimum polymerization temperature was 100 °C, and if the temperature was lower, graft copolymerization hardly occurred. 3) The graft copolymer obtained became softer as the carbon number in ester groups of monomers increased.
