This paper describes the utilisation of urea as a single chemical agent to obtain deproteinised high ammoniated natural rubber latex (HA-NRL). The role of urea in HA-NRL deproteinisation was further investigated by employing two different concentrations of urea solution which are low (0.01–0.05%) and high (1.0–5.0%) concentrations. The study assessed the potential usage of urea as a single denaturing agent in the presence of neither stabilising agent nor additives during the deproteinisation process. The effect of different urea concentrations on properties of deproteinised NRL was further scrutinised by using sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE), nitrogen content analysis, extractable protein (EP) content, Zeta potential, attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy and physical strength. The presence of residual urea is pertinent as the concentration of urea increases while contributing to the increase of total nitrogen content in the resultant film. Leaching the film with hot water is sufficient to remove the residual urea as supported by an ATR-FTIR analysis. Initial exploratory data analysis of low and high urea concentrations on the effect of nitrogen content, EP, surface charge properties of latex and green strength of the deproteinised NRL were evaluated and their relation to each factor was further discussed. Based on the initial findings, urea was observed to be less effective as a single denaturant. Nonetheless, the properties of the deproteinised HA-NRL treated with urea were revealed to be markedly influenced by the urea concentration.

中文翻译：

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尿素作为天然橡胶胶乳脱蛋白中的单一变性剂

本文描述了利用尿素作为单一化学试剂来获得脱蛋白的高氨化天然橡胶胶乳（HA-NRL）。尿素在HA-NRL脱蛋白中的作用通过使用两种不同浓度的尿素溶液（低浓度（0.01–0.05％）和高浓度（1.0–5.0％））进一步研究。该研究评估了脱蛋白过程中在既没有稳定剂也没有添加剂的情况下尿素作为单一变性剂的潜在用途。通过使用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE），氮含量分析，可提取蛋白（EP）含量，Zeta电位，进一步研究了不同尿素浓度对脱蛋白NRL性质的影响。衰减全反射傅里叶变换红外（ATR-FTIR）光谱和物理强度。残留尿素的存在与尿素浓度的增加有关，同时有助于所得膜中总氮含量的增加。用ATR-FTIR分析表明，用热水浸出薄膜足以去除残留的尿素。初步探索性数据分析了低尿素浓度和高尿素浓度对氮含量，EP，乳胶的表面电荷性质和脱蛋白NRL的生胶强度的影响，并进一步讨论了它们与各个因素的关系。基于最初的发现，观察到尿素作为单一变性剂效果较差。尽管如此，