端羧基型超支化聚酰胺的结构特点及阻垢性能

采用熔融聚合法,以柠檬酸为反应单体,二乙醇胺为中心核,成功制备了端羧基型超支化聚酰胺。通过FTIR和1H-NMR对其结构进行了表征,并将其应用于工业循环用水的阻垢研究中,研究了阻垢剂的添加量、水样环境的p H和水样温度对其阻碳酸钙和硫酸钙的能力。结果表明,端羧基型超支化聚酰胺不仅具有良好的分散性能,而且对Ca CO3和Ca SO4均具有良好的阻垢性能。当阻垢剂的用量为15 mg/L时,其阻碳酸钙垢的阻垢效率能够达到93. 7%;当其用量为22 mg/L时,阻硫酸钙垢的阻垢效率达到92. 4%,且在较宽的温度范围及p H=6~9的范围内使用,阻垢效率一直呈现出较高水平。XRD分析表明,端羧基型超支化聚酰胺能够抑制钙垢晶体的生长,降低钙垢的结晶度,起到抑制钙垢的结垢能力。

Structural Characteristics and Scale Inhibition Properties of Carboxyl-Terminated Hyperbranched Polyamides

Carboxyl-terminated hyperbranched polyamide was successfully prepared by melt polymerization with citric acid as reaction monomer and diethanolamine as core.Its structure was characterized by FTIR and 1H-NMR.It was applied to scale inhibition of industrial circulating water.The effects of scale inhibitor dosage,pH of water environment and water temperature on calcium carbonate and calcium sulfate inhibition were discussed.The results showed that carboxyl-terminated hyperbranched polyamide not only had good dispersibility,but also had good scale inhibition properties for CaCO3 and CaSO4.When the dosage of scale inhibitor was 15 mg/L,the scale inhibition efficiency of calcium carbonate reached 93.7%.When the dosage was 22 mg/L,the scale inhibition efficiency of calcium sulfate reached 92.4%.Moreover,carboxyl-terminated hyperbranched polyamide had excellent inhibition efficiency under a wide range of temperature and pH=6~9.The XRD analysis showed that carboxyl-terminated hyperbranched polyamide could inhibit the growth of calcium scale crystals,reduce the crystallinity of calcium scale and inhibit the scaling ability.