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Phenyl-modified natural rubber was prepared in latex stage by bromination of deproteinized natural rubber followed by Suzuki-Miyaura cross-coupling reaction (SMC). First, the bromination of natural rubber was carried out by using N-bromosuccinimide (NBS) in latex stage. the brominine atom content increased as amount of NBA increased. Second, the allylic bromine atom was replaced to phenyl group with phenyl boronic acid in the presence of palladium catalyst, according to SMC reaction in latex stage. The resulting products were characterized by NMR spectroscopy. Signal at 7.13 ppm was assigned to the phenyl group of the product, while signals at 3.98, 4.14 and 4.44 ppm were assigned to the remaining allylic brominated cis-1,4-isoprene units. The phenyl group content and the conversion of SMC reaction were estimated to be 1.32 and 23.7 mol%, respectively. The glass transition temperature (Tg) of deproteneized natural rubber incerased from -62 °C to -46.7 °C, when the phenyl group was introduced into the rubber, Phenyl-modified natural rubber was prepared in latex stage by bromination of deproteinized natural rubber followed by Suzuki-Miyaura cross-coupling reaction (SMC). First, the bromination of natural rubber was carried out by using N-bromosuccinimide (NBS) in latex stage. the brominine atom content increased as amount of NBA increased. Second, the allylic bromine atom was replaced to phenyl group with phenyl boronic acid in the presence of palladium catalyst, according to SMC reaction in latex stage. The resulting products were characterized by NMR spectroscopy. Signal at 7.13 ppm was assigned to the phenyl group of the product, while signals at 3.98, 4.14 and 4.44 ppm were assigned to the remaining allylic brominated cis-1,4-isoprene units. The phenyl group content and the conversion of SMC reaction were estimated to be 1.32 and 23.7 mol%, respectively. The glass transition temperature (Tg) of deproteneized natural rubber incerased from -62 °C to -46.7 °C, when the phenyl group was introduced into the rubber

Brominated natural rubber (BrDPNR) was prepared by bromination of deproteinized natural rubber (DPNR) with N-bromosuccinimide (NBS) in a dichloromethane solution. The BrDPNR was characterized by 1D and 2D-NMR spectroscopy. The bromine atom content of the BrDPNR was dependent on the amount of NBS; that is, higher the amount of NBS, the higher the bromine atom content of the BrDPNR. The glass transition temperature of BrDPNR increased from -68°C to -16°C as amount of bromine atom increased. Cis-trans isomerization of isoprene units during the bromination was found by NMR measurements., Brominated natural rubber (BrDPNR) was prepared by bromination of deproteinized natural rubber (DPNR) with N-bromosuccinimide (NBS) in a dichloromethane solution. The BrDPNR was characterized by 1D and 2D-NMR spectroscopy. The bromine atom content of the BrDPNR was dependent on the amount of NBS; that is, higher the amount of NBS, the higher the bromine atom content of the BrDPNR. The glass transition temperature of BrDPNR increased from -68°C to -16°C as amount of bromine atom increased. Cis-trans isomerization of isoprene units during the bromination was found by NMR measurements.