MODIFICATION OF THE PROPERTIES OF NATURAL RUBBER BY COPOLYMERIZATION WITH A BIOPOLYMER FOR A CONTROLLED RELEASE OF UREA FERTILIZER - Fertilizers: Components, Uses in Agriculture and Environmental Impacts - page 251

Figure 30. The cumulative urea released (%) from the capsules coated with different polymer types.
Figure 31. Possible mechanism for encapsulation of the urea fertiliserfertilizer with NR-g-St.
3.7. NR-g-CPAM
Cationic polyacryamide (CPAM) was successfully grafted onto the NR molecule in its
latex form by introducing the initiator-KPS to the NR latex particles in addition to the CPAM
solution. ATR-FTIR spectroscopy revealed that the CPAM was chemically attached to the
NR particles, as observed by the bands at 3300~3500 cm -1 that refer to amine groups and at
1659 and 952 cm -1 and the amide quaternary and ammonium groups. In addition, the
chemical structure of NR-g-MCPAM was confirmed at 180 (carbonyl group) and 176 (ester
group) ppm by using solid state 13 C NMR. The thermal stability of the NR and CPAM was