Deproteinization of Nonammonia and Ammonia Natural Rubber Latices by Ethylenediaminetetraacetic Acid

Table 1

Nitrogen content of FNR and deproteinized FNR (DPNR) by using EDTA-4Na at various concentrations.

Samples	Preservative	pH	EDTA-4Na (wt%)	Nitrogen content; (wt%)
FNR	—	6.5	—	0.638
FR-NH3	Ammonia	10	—	0.587
FR-SH	SH	10	—	0.551
FR-NH3	Ammonia	10	0.05	0.043
FR-NH3	Ammonia	10	0.10	0.009
FR-NH3	Ammonia	10	0.20	0.008
FR-SH	SH	10	0.05	0.012
FR-SH	SH	10	0.10	0.005
FR-SH	SH	10	0.20	0.005