The effect of cellulose nanocrystals (CNCs) on the reinforcing, cross-linking, and solvent barrier properties of lightly cross-linked natural rubber (NR) latex films for dipped goods applications were investigated. Predispersed CNCs, activating, and curing agents were mixed with natural rubber latex and allowed to mature for 2 h. Films were then prepared from the matured latex via dipping and solvent casting processes. The incorporation of CNCs in the NR latex led to remarkable improvement in tensile strength and modulus with progressively thinner films. An increase in the cross-linking density of the rubber films were observed as a result of the incorporation of CNCs, which was observed from proton nuclear magnetic resonance analysis, and toluene swelling studies. This was likely attributed to an enhanced dispersion of the zinc oxide (ZnO) used as a cross-linking activator as observed from electron dispersive X-ray spectroscopy (EDX). A possible mechanism for the improved dispersion of ZnO in the latex in the presence of CNCs was the formation of Zn–CNC complexes. Higher cross-linking densities also led to lower water absorption over a prolonged time period. The nanocomposite thin films showed low permeability to a nonpolar solvent vapor, such as tetrahydrofuran (THF), but increased permeability to water vapor. A practical application of the observed barrier properties in dipped rubber goods could be in gloves, where permeation of perspiration from hands, is allowed while preventing the passage of nonpolar solvents.

中文翻译：

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纤维素纳米晶体与手套在橡胶胶乳中的协同交联和增强作用

研究了纤维素纳米晶体（CNC）对浸渍产品中轻度交联的天然橡胶（NR）乳胶薄膜的补强，交联和溶剂阻隔性能的影响。将预分散的CNCs，活化剂和固化剂与天然橡胶胶乳混合，使其熟化2小时。然后通过浸渍和溶剂流延法从成熟的胶乳制备膜。在NR乳胶中加入CNCs可以使薄膜的厚度逐渐减小，从而极大地提高了拉伸强度和模量。由于掺入了CNC，从而观察到橡胶膜的交联密度增加，这是从质子核磁共振分析和甲苯溶胀研究中观察到的。如从电子色散X射线光谱法（EDX）观察到的，这可能归因于用作交联活化剂的氧化锌（ZnO）的分散性增强。在存在CNC的情况下改善ZnO在胶乳中的分散的可能机制是Zn-CNC络合物的形成。较高的交联密度还导致延长的时间段内较低的吸水率。纳米复合薄膜对诸如四氢呋喃（THF）之类的非极性溶剂蒸气显示出低渗透性，但是对水蒸气的渗透性增加。在浸渍的橡胶制品中观察到的阻隔性能的实际应用可以是在手套中，在手套中允许从手渗透汗水，同时防止非极性溶剂通过。在存在CNC的情况下改善ZnO在胶乳中的分散的可能机制是Zn-CNC络合物的形成。较高的交联密度还导致延长的时间段内较低的吸水率。纳米复合薄膜对诸如四氢呋喃（THF）之类的非极性溶剂蒸气显示出低渗透性，但是对水蒸气的渗透性增加。在浸渍的橡胶制品中观察到的阻隔性能的实际应用可以是在手套中，在手套中允许从手渗透汗水，同时防止非极性溶剂通过。在存在CNC的情况下改善ZnO在胶乳中的分散的可能机制是Zn-CNC络合物的形成。较高的交联密度还导致延长的时间段内较低的吸水率。纳米复合薄膜对诸如四氢呋喃（THF）之类的非极性溶剂蒸气显示出低渗透性，但是对水蒸气的渗透性增加。在浸渍的橡胶制品中观察到的阻隔性能的实际应用可以是在手套中，在手套中允许从手渗透汗水，同时防止非极性溶剂通过。纳米复合薄膜显示出对非极性溶剂蒸气（例如四氢呋喃（THF））的低渗透性，但增加了对水蒸气的渗透性。在浸渍的橡胶制品中观察到的阻隔性能的实际应用可以是在手套中，该手套允许从手中排汗，同时防止非极性溶剂通过。纳米复合薄膜对诸如四氢呋喃（THF）之类的非极性溶剂蒸气显示出低渗透性，但是对水蒸气的渗透性增加。在浸渍的橡胶制品中观察到的阻隔性能的实际应用可以是在手套中，在手套中允许从手渗透汗水，同时防止非极性溶剂通过。