ABSTRACT Specialty natural rubber (SpNR) latex, namely, deproteinized natural rubber (DPNR) latex and epoxidized natural rubber (ENR) latex, has been produced to meet specific product's requirements. However, SpNR is normally used in the form of block rubber to manufacture dry rubber products such as tires and automotive parts. The applications of SpNR latex into latex foam products will be diversified. Findings indicate that foamability of SpNR latex is lower compared to normal latex (LATZ) but shows longer stability time after foamed. Findings also indicate that foam collapse and foam coagulate are two main challenges in the fabrication process of SpNR latex foam. Despite these challenges, SpNR latex foam can be fabricated at different density levels. During the foaming process, additional foaming agent is required to fabricate a SpNR latex foam, which is different from fabricating a normal NR latex foam, especially at low latex foam density. Consequently, a higher level of sodium silicofluoride, used as the gelling agent, is required to set the cell structure of the foam. Findings also indicate that foam density influenced the gelling time and volume shrinkage of the SpNR latex foam. An ideal compounding, foaming, and gelling formulation to fabricate SpNR latex foam via Dunlop batch foaming process has been developed. Morphological study showed that all latex foams are open-cell structure, with lower density foam exhibiting higher porosity and mean pore size. Comparison on hysteresis behavior between DPNR and ENR latex foam indicated that ENR latex foam exhibits higher hysteresis loss ratio compared to DPNR latex foam.

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特种天然橡胶乳胶泡沫：发泡性研究和制造工艺

摘要 特种天然橡胶（SpNR）胶乳，即脱蛋白天然橡胶（DPNR）胶乳和环氧化天然橡胶（ENR）胶乳，已经生产以满足特定产品的要求。然而，SpNR 通常以块状橡胶的形式用于制造干橡胶制品，例如轮胎和汽车零件。SpNR胶乳在胶乳泡沫制品中的应用将会多样化。结果表明，SpNR 胶乳的起泡性低于普通胶乳 (LATZ)，但在起泡后表现出较长的稳定时间。研究结果还表明，泡沫破裂和泡沫凝结是 SpNR 乳胶泡沫制造过程中的两个主要挑战。尽管存在这些挑战，SpNR 乳胶泡沫仍可以以不同的密度水平制造。在发泡过程中，制造 SpNR 乳胶泡沫需要额外的发泡剂，这与制造普通 NR 乳胶泡沫不同，尤其是在低乳胶泡沫密度的情况下。因此，需要较高含量的硅氟化钠作为胶凝剂来设定泡沫的泡孔结构。研究结果还表明，泡沫密度影响 SpNR 乳胶泡沫的胶凝时间和体积收缩率。已开发出一种理想的复合、发泡和胶凝配方，可通过邓禄普批量发泡工艺制造 SpNR 乳胶泡沫。形态学研究表明，所有乳胶泡沫都是开孔结构，密度较低的泡沫表现出较高的孔隙率和平均孔径。DPNR 和 ENR 乳胶泡沫之间的滞后行为比较表明，与 DPNR 乳胶泡沫相比，ENR 乳胶泡沫表现出更高的滞后损失率。