Abstract Renewable resource based cationic waterborne polyurethanes (cWPUs) have been prepared from hydroxyl telechelic natural rubber (HTNR) with a range of number average molecular weights (Mn) (2820, 1800, and 950 g mol−1), toluene-2,4-diisocyanate (TDI), N-methyl diethanolamine (NMDEA), and ethylene glycol (EG). The chemical structure of the cWPUs was confirmed by FT-IR and 1H NMR. Particle size and zeta potential of prepared cWPUs were also characterized by ZS nanosizer. By varying the levels of Mn of HTNR, the obtained cWPUs were stable with a milky blue appearance, forming yellowish films. The smallest particle sizes of 76.4 nm were achieved using Mn of HTNR of 2820 g mol−1 while zeta potential value ranges from 67 to 71 mV were observed with increasing Mn of HTNR. Lap shear testing of these WPUs indicates their potential in real cow leather adhesive applications, with the best adhesive result coming from cWPU based on an HTNR molecular weight of 1800 g mol−1. The results show the potential of natural rubber as a green adhesive material in suitable aqueous environments.

中文翻译：

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羟基遥爪天然橡胶分子量对新型阳离子水性聚氨酯的影响：皮革应用水性粘合剂的新方法

摘要 以可再生资源为基础的阳离子水性聚氨酯 (cWPUs) 由羟基遥爪天然橡胶 (HTNR) 制备而成，其数均分子量 (Mn) (2820、1800 和 950 g mol-1)、甲苯-2,4 -二异氰酸酯 (TDI)、N-甲基二乙醇胺 (NMDEA) 和乙二醇 (EG)。cWPU 的化学结构通过 FT-IR 和 1H NMR 证实。制备的 cWPU 的粒径和 zeta 电位也通过 ZS 纳米粒度仪表征。通过改变 HTNR 中 Mn 的含量，获得的 cWPUs 稳定，呈乳蓝色外观，形成淡黄色薄膜。使用 2820 g mol-1 的 HTNR Mn 实现了 76.4 nm 的最小粒径，而随着 HTNR Mn 的增加，zeta 电位值范围为 67 至 71 mV。这些 WPU 的搭接剪切测试表明它们在真牛皮粘合剂应用中的潜力，最好的粘合剂结果来自 cWPU，基于 1800 g mol−1 的 HTNR 分子量。结果显示了天然橡胶在合适的水性环境中作为绿色粘合剂材料的潜力。