Partial degradation of high ammonia natural rubber (HANR) in the latex stage was successfully carried out in the presence of periodic acid as a water-soluble degrading agent at ambient temperatures, i.e. 30 °C. The number average molecular weight (M_n), weight average of molecular weight (M_w), gel content and Mooney viscosity were decreased as the periodic acid concentrations increased. The polydispersity was slightly increased with increasing periodic acid concentrations. The relationship between M_w, gel content and Mooney viscosity was established. M_w in the range of 8.0 × 10⁵ g/mol to 1.2 × 10⁶ g/mol, and gel content between 30 and 45 wt% successfully achieved the Mooney viscosity of raw natural rubber ranging from 60 to 85 MU. To obtain such properties, periodic acid concentration between 17 and 19 phr was used to partially degrade the natural rubber in the latex stage. The structural characterisations determined by Fourier transform infra-red (FTIR) and nuclear magnetic resonance (NMR) spectroscopies confirmed the occurrence of chain scission to form carbonyl terminal groups as a result of partial degradation. In summary, the Mooney viscosity of raw natural rubber can be controlled by partial degradation of natural rubber in the latex stage, contributed by a controlled decrease in molecular weight and gel content. Hence, this work may be useful in altering the properties of raw natural rubber that are suitable for processing of dry rubber products.

在高碘酸作为水溶性降解剂的高碘酸存在下，在环境温度（即30°C）下成功地完成了高氨天然橡胶（HANR）在乳胶阶段的部分降解。随着高碘酸浓度的增加，数均分子量（M _n），分子量的重均分子量（M _w），凝胶含量和门尼粘度降低。随着高碘酸浓度的增加，多分散性略有增加。建立了M _w，凝胶含量与门尼粘度之间的关系。M _w在8.0×10 ⁵  g / mol至1.2×10 ^{6的范围内} 克/摩尔，凝胶含量在30至45 wt％之间，成功地使天然橡胶的门尼粘度达到60至85 MU。为了获得这样的性能，在乳胶阶段使用17到19 phr之间的高碘酸浓度来部分降解天然橡胶。通过傅里叶变换红外（FTIR）和核磁共振（NMR）光谱确定的结构特征证实了由于部分降解而发生断链形成羰基端基的现象。总之，可以通过在乳胶阶段中天然橡胶的部分降解来控制原料天然橡胶的门尼粘度，这归因于分子量和凝胶含量的受控降低。因此，