This work presents a comprehensive study on the influence of processing variables (temperature, agitation speed) and type of diisocyanate crosslinker on the rheological properties of liquid and gel-like polyurethane formulations based on lignin and castor oil. With this aim, a green and facile one-step preparation protocol which avoids the use of any harmful catalyst or solvent was proposed. Different processing temperatures (25, 45, 70 °C), stirring speeds (23, 70, 140 rpm) and kinds of diisocyanates (hexamethylene diisocyanate, and toluene diisocyanate) were selected to process the different bio-sourced polyurethane samples. These processing variables have proven to be crucial to modulate and control the rheological (viscous and viscoelastic) properties, and curing kinetics after processing, due to the different chemical structures achieved that were elucidated by means of Fourier-transform infrared spectroscopy and differential scanning calorimetry. In general, a low processing temperature and low stirring speed favour the achievement of gel-like characteristics and/or the formation of highly viscous polyurethanes, as a consequence of a higher number of total hydrogen-bonded carbonyl groups, urethane/urea ratio and ratio of hydrogen-bonded/non-bonded urethane and urea linkages. Besides, the selected one-step process, in comparison with the reported two-step process, provides polyurethanes with similar rheological characteristics by significantly reducing the isocyanate content. Finally, lignin was demonstrated to act as an effective filler agent increasing the values of the viscoelastic moduli.

这项工作对工艺变量（温度，搅拌速度）和二异氰酸酯交联剂的类型对基于木质素和蓖麻油的液体和凝胶状聚氨酯配方的流变性质的影响进行了全面的研究。为此目的，提出了一种绿色且简便的一步制备方案，该方案避免了使用任何有害的催化剂或溶剂。选择不同的处理温度（25、45、70℃），搅拌速度（23、70、140 rpm）和二异氰酸酯的种类（六亚甲基二异氰酸酯和甲苯二异氰酸酯）来处理不同的生物来源聚氨酯样品。事实证明，这些加工变量对于调节和控制流变（粘和粘弹性）特性以及加工后的固化动力学至关重要，由于通过傅立叶变换红外光谱法和差示扫描量热法已阐明了所获得的不同化学结构。通常，低的加工温度和低的搅拌速度有利于获得凝胶状特性和/或形成高粘度的聚氨酯，这是由于总氢键合的羰基，氨基甲酸酯/脲的比例和比例较高的结果。氢键/非键氨基甲酸酯和脲键的连接 此外，与报道的两步法相比，选择的一步法可通过显着降低异氰酸酯含量为聚氨酯提供类似的流变特性。最后，木质素被证明是一种有效的填充剂，可增加粘弹性模量。