CMC与金属离子螯合及其产物用作纸张阻燃助剂的研究

Study on the Reaction of CMC with Metal Ions and Application of Their Products in Flame Retardant Materials

关键词:  CMC  金属离子  螯合  阻燃

Key Words:CMC  metal ions  chelate  flame ratardant

摘要:将羧甲基纤维素钠（CMC）与Cu²⁺、Ca²⁺进行螯合反应，用紫外可见分光光度仪测定其吸收光谱，探讨螯合物最佳螯合比及其热稳定性，并将其浸渍到定性滤纸中研究其阻燃性能。结果表明，Cu²⁺与CMC螯合物在205 nm处有最大吸收峰，且为单吸收峰，—COO^-反应活性强于—OH，可判定CMC与Cu²⁺螯合反应中，—COO^-参与和Cu²⁺的螯合，—OH未参与反应，推测出最佳螯合比为1；CMC与Ca²⁺螯合时，当螯合比c(Ca²⁺)/c(—COO^-)小于1时，螯合物表现为双吸收峰，最大吸收波长分别为192、228 nm，表明—COO^-与—OH均参与到螯合反应中，当螯合比大于1时，螯合物表现为单吸收峰，最大吸收波长为192 nm，仅有—COO^-参与和Ca²⁺的螯合反应，并推测出最佳螯合比为2。热重分析表明，螯合物质量残留百分比均高于10%，定性滤纸质量残留百分比仅为2.87%，螯合物相较定性滤纸具有更好的热稳定性。将CMC、CMC-Cu、CMC-Ca浸渍定性滤纸，能赋予滤纸阻燃性，且经CMC-Ca处理后的定性滤纸阻燃效果最优，其极限氧指数值可达24.9%，炭化长度仅为68 mm。

Abstract:The CMC was mixed with Cu²⁺ and Ca²⁺ to carry out chelation reaction, and using the UV spectrophotometer to determine the absorbance of the products, the best chelation ratio was found. The results showed that the λ_max of the chelate created by Cu²⁺ and CMC was at 205 nm. Because of the reactivity of —COO^- was stronger than —OH, —COO^- participated the reaction with Cu²⁺ , but —OH did not. It was speculated that the best chelation ratio was 1. When c(—COO^-)/c(Ca²⁺) was less than 1, the chelate had double absorption peaks. λ_max were at 192 nm and 228 nm. It also showed that —COO^- and —OH were both involved in the chelating reaction. When c(—COO^-)/c(Ca²⁺) was more than 1, the chelate had a single absorption peak, and λ_max was at 192 nm. It was speculated that the best chelating ratio was 2. Using the TG to test the stability of the chelates, its flame retardant mechanism was discussed. The qualitative filter paper immersed with the chelating solution was subjected to vertical burning test, and the limiting oxygen index was measured. The results showed that the percentage of residual mass in thermogravimetric analysis of chelates was higher than 10%, but the percentage of residual mass in qualitative filter paper was only 2.87%. It indicated that the chelates had better thermal stability than qualitative filter paper. Adding the chelates to qualitative filter paper, the paper was difficult to burn. And the qualitative filter paper treated by CMC-Ca had the best flame retardant property. Its limit oxygen index could reach 24.9% and the carbonization length was only 68 mm.