高吸水聚丙烯酸钠的表征

The Characterization of Superabsorbent Polyacrylates

对高吸水聚丙烯酸钠进行了FTIR、DSC、热稳定性、吸湿性能的分析 ,结果表明 :在16 2 9cm-1,15 6 2cm-1,145 7cm-1处出现—COONa的羰基伸缩振动峰 ,在 140 7cm-1出现了—COOH的羰基弯曲振动峰 ;残留水分对高吸水聚丙烯酸钠有很大的增塑作用 ,很难用DSC直接对其Tg 进行表征 ;高吸水聚丙烯酸钠具有良好的热稳定性和较高的吸湿性 .并发现水温在0 .5～ 99℃范围内对高吸水聚丙烯酸钠的吸水倍数影响不大 .聚丙烯酸钠水凝胶中的水有相变水和非冻结水两种存在形式 ,其中非冻结水含量为 2 .13g水 / g绝干树脂 ,该数值大大高于非离子型水凝胶 .

FTIR, DSC, heat stability and hygroscopility of superabsorbent polyacrylates were investigated. It was illustrated in FTIR spectra that superabsorbent polyacrylate had stretching vibration band of carboxyl group of —COONa in 1629 cm -1 , 1562 cm -1 , 1457 cm -1 and bend vibration band of carboxyl group of —COOH in 1407 cm -1 . It was rather difficult to determine the T g of crosslinked polyacrylate directly by DSC because even a small amount of water had significant plasticization to the polymer. Superabsorbent polyacrylate had good heat stability and high hygroscopility. In the range of 0.5 ℃ and 99 ℃, the effect of water temperature on water absorbency was rather small. There were crystallizable water and non_crystallizable water in polyacrylate hydrogel; the content of the non_crystallizable water was 2.13 g/g dry resin, much higher than that in non_ionic hydrogels.