聚乙烯醇和聚丙烯酸钠复合纳米纤维膜吸湿材料研究

本文通过纳米纺丝法制备了一类新型聚乙烯醇(PVA)与聚丙烯酸钠(PAAS)的复合纳米纤维膜吸湿材料(NFMs),并对该类材料进行性能测试和吸附模型验证,与通过溶液蒸发法制备的普通膜(SCMs)进行性能对比。结果表明:在25℃、相对湿度为80%下,PAAS质量分数为20%的PVA-PAAS复合纳米纤维膜最大吸附量为0.3 kg/kg,相比纯PVA纳米纤维膜吸附剂提高78%。在复合纳米纤维膜中,约90%的水蒸气吸附在5 min内完成,仅需15 min就能达到最大平衡吸附量。PVA-PAAS纳米纤维膜具有较快的脱附速率,在15 min内达到最大脱附量平衡点,是PVA-PAAS普通膜达到平衡所需时间的1/200。当再生空气状态为45℃、4 MPa和50℃、6 MPa时,吸附的水蒸气量脱除比率均高于80%。由此可见,PVA-PAAS纳米纤维膜能够在低温条件下较好地实现再生,可以利用太阳能等低品位能源。10次循环后,纳米纤维膜的吸附与脱附量、吸附与脱附速率均未发生变化,具有较好的稳定性。

Study on Desiccant Nanofibrous Membranes based on Composite Polyvinyl Alcohol/Sodium Polyacrylate

A new type of composite polyvinyl alcohol/sodium polyacrylate (PVA-PAAS) nanofibrous membranes (NFMs) was prepared using the electrospinning method. The adsorption and desorption performance of these materials was compared with the PVA-PAAS solution-casted membranes (SCMs) experimentally. The test results show that the PVA-PAAS NFMs with 20% mass fraction of PAAS could adsorb 0.3 kg/kg of water vapor at 25 ?C and 80%RH, whose adsorption capacity is 78% larger than that of pure PVA NFMs under the same state. Approximately 90% of the adsorbed water vapor could be removed within 5 min, and adsorption equilibrium could be achieved in 15 min by the PVA-PAAS NFMs. Similarly, the PVA-PAAS NFMs exhibited a fast desorption rate and took only 15 min to reach desorption equilibrium, which is 1/200 of the required time for the PVA-PAAS SCMs to reach the same. When the regeneration air conditions were at 45 ?C, 4000 kPa and 50 ?C, 6000 kPa, both the desorption rates of water vapor in the PVA-PAAS NFMs were higher than 80%. Thus, the PVA-PAAS NFMs can be regenerated under low-temperature conditions, which make their utilization in low-grade energy possible. After 10 cycle tests, the capacity and rates of adsorption and desorption of the PVA-PAAS NFMs did not change, which indicates that this type of desiccants possesses good stability.