## 1 Introduction
Many investigations concentrated on LNR [14; 15; 16] and deproteinized LNR (LDNR) [17] via oxidatively degraded using H\({}_{2}\)O\({}_{2}\) and NaNO\({}_{2}\) reagents. The broken chains had different end groups depending on the pH of the reaction medium. [PERSON] et al. [14] studied the in situ epoxidation of natural rubber latex in chain-scissoring conditions. The epoxide ring underwent a ring-opening process at low pH and prolonged time, forming hydroxyl, carbonyl, and ether groups. [PERSON] et al. [15] investigated the degradation of NR using peroxide acid in the presence of NaNO\({}_{2}\). They found that NR depolymerized into LNR with an epoxyl and a hydroxyl group. The rate of degradation was affected by reaction temperature and time. [PERSON] et al. [16] proposed the degradation mechanisms were different as H\({}_{2}\)O\({}_{2}\) and NaNO\({}_{2}\) underwent different routes in acidic and alkaline media. The end groups of the LNR samples performed in acidic and alkaline media were found to be hydroxyl and carbonyl, respectively. [PERSON] et al. [18] studied LNR production and the effect of CoCl\({}_{2}\) catalyst and NaNO\({}_{2}\) levels on the molecular weight of LNR. They concluded that reaction time and NaNO\({}_{2}\) and CoCl\({}_{2}\) concentrations affected the molecular weight of the LNR produced. [PERSON] and [PERSON] [19] investigated the kinetics of degradation of NR using a combination of potassium persulfate (K\({}_{2}\)S\({}_{2}\)O\({}_{8}\)) as a radical initiator and propanal as a secondary reagent. They reported that the intrinsic viscosity [n] of the LNR obtained depended on the initiator concentration, amount of propanol, dry rubber content, reaction time, and temperature. The degradation rate exhibited a second-order rate law dependence on the cleavage of a single carbon-carbon bond of a polyisoprene chain. The activation energy of the degradation reaction was 76.56 kJ/mol. Many relevant investigations, including the effects of various chemicals and environmental conditions as well as the mechanism of NR degradation in acidic and basic environments, have been previously carried out. However, rarely have studies on the rate of NR degradation been reported. The objectives of this research were to prepare liquid natural rubber with oxidative degradation by using hydrogen peroxide (H\({}_{2}\)O\({}_{2}\)), formic acid (HCOOH), and sodium nitrite (NaNO\({}_{2}\)) as reagents. Intrinsic viscosity ([n]) was characterized by the dilution method using an Ubbelohde capillary viscometer at 30 \({}^{\circ}\)C when toluene has operated as a solvent. The number-average molecular weight of LNR was calculated by using Mark-Houwink equation [20]. The efficiency of the degradation of NR was determined by measuring its number-average molecular weight (M\({}_{\rm n}\)). The effects of reaction parameters such as H\({}_{2}\)O\({}_{2}\), HCOOH, and NaNO\({}_{2}\) concentrations, reaction temperature, and reaction time were investigated. The LNR was then characterized for its chemical structure using FTIR, while scanning electron microscopy (SEM) was used to observe the morphology of the latex particles. The degradative kinetics of the NR to form LNR based on molecular weight data have been evaluated. The thermal decomposition of the rubber samples was studied in terms of thermogravimetric analysis (TGA) and derivative thermogravimetric (DTG).