采用温敏性聚(N-异丙基丙烯酰胺)(PNIPAM)为凝固剂的新型胶态成型已应用于制备复杂形状的陶瓷器件。本文作者研究 PNIPAM 水溶液性能和添加 PNIPAM 的 ZnO 悬浮液的流变性能。结果表明，PNIPAM 表现出明显的温敏性且转变温度在32°C 左右。当温度高于40°C (Tc，温敏悬浮液的临界转变温度），添加8 mg/mL PNIPAM 的50% ZnO(体积分数)悬浮液的黏度急剧增加，温度为50°C 时黏度高达11.49 Pa·s 并表现出较强弹性。原因在于高温下 PNIPAM 分子的析出导致悬浮液的有效固相体积分数增加以及 ZnO 陶瓷颗粒之间的絮凝作用。此外，20°C 下悬浮液的最大固相体积分数明显高于40°C 下的，也可证明 PNIPAM 的相转变可诱导悬浮液的絮凝。
Novel colloidal processing using thermosensitive poly(N-isopropylacrylamide) (PNIPAM) as a coagulating agent has been developed to prepare complex-shaped ceramic components. In this work, the properties of PNIPAM aqueous solutions and the rheological behavior of ZnO suspensions with PNIPAM were investigated. The results show that the PNIPAM solutions exhibit obvious thermosensitivity and its transition temperature is around 32 °C. When the temperature is above 40 °C (Tc, the critical transition temperature of thermosensitive suspension), the 50% ZnO (volume fraction) suspension with 8 mg/mL PNIPAM has a sharp increase in viscosity and reaches up to 11.49 Pa·s at 50 °C, displaying strong elasticity. The main reasons are the increase of effective volume fraction attributed to precipitation of PNIPAM segments and the flocculation between ZnO powder particles. In addition, the maximum solid loading (volume fraction) at 20 °C is higher than that at 40 °C, which proves that the phase transition of PNIPAM can induce the flocculation of suspension.
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