Soluble starch-g-poly(AM-co-C16DMAAC)高吸水性树脂的合成及性能

Synthesis and properties of Soluble starch-g-poly(AM-co-C16DMAAC) Super Absorbent Resin

摘要:

在可溶性淀粉（Soluble starch）和丙烯酰胺（AM）聚合体系中，引入了十六烷基二甲基烯丙基氯化铵（C16DMAAC），采用水溶液接枝共聚法和执行氢氧化钠水解步骤，单因素优化Soluble starch-g-poly(AM-co-C16DMAAC)高吸水性树脂的合成条件；通过红外光谱仪和扫描电镜进行表征测试，并对其吸水膨胀机理进行了分析。结果表明，树脂产品的合成最佳条件：在固含量为20%的50g聚合体系中，可溶性淀粉加量为40%，C(AM)/C(C16DMAAC)=99.2/0.80，V(APS，5000mg/L)=4 mL，m(MBA)=0.02 g，水解度DH=80%；该条件下制得的树脂产品在去离水和0.9 wt.% NaCl溶液中的吸水倍率为1964.96 g/g和76.77 g/g；实施氢氧化钠高温水解步骤，能提高产品的吸水倍率；单体C16DMAAC能显著提高丙烯酰胺基可溶性淀粉复合树脂的吸水性能；Soluble starch-g-poly(AM-co-C16DMAAC)树脂的吸水膨胀过程符合Fickian扩散模型。

Abstract:

Under the synthesis of super absorbent resin(SAR), hexadecyl dimethyl allyl ammonium chloride (C16DMAAC) was introduced to graft copolymerization of soluble starch and acrylamide onto the preparation of Soluble starch-g-poly(AM-co-C16DMAAC). The hydrolysis by adding sodium hydroxide (NaOH) under airtight and high temperature environment was also performed. Meanwhile, the best synthesis conditions were optimized by a series of single factor experiments. The structure was investigated by FTIR and SEM, and the water absorption and expansion mechanism were analyzed by the model. The experimental results showed that the most effective preparation conditions of Soluble starch-g-poly(AM-co-C16DMAAC) were determined, the weight of soluble starch was 40% of 10g solid content in 50g polymerization system, the molar ration of AM to C16DMAAC was 99.2/0.8, the volume of ammonium persulfate(APS, 5000 mg/L) was 4mL, the amount of N,N-methylene bisacrylamide(MBA) was 0.02g, lastly the degree of hydrolysis(DH) was 80%. Under this experimental conditions, the maximum water absorbency of Soluble starch-g-poly(AM-co-C16DMAAC) was 1964.96g/g in distilled water and 76.77g/g in 0.9 wt.% NaCl solution, respectively.By simply mixing the polymerized intermediate products with NaOH under airtight conditions at 90℃, sodium hydroxide can participate in a nucleophilic addition elimination reaction with -CONH2 on polymer chains. In this reaction, the transformation of -CONH2 into -COONa is accompanied by the release of ammonia. In addition, the water absorbency of resin can greatly enhanced by introducing C16DMAAC into soluble starch and AM system. Finally, the swelling process of Soluble starch-g-poly(AM-co-C16DMAAC) showed good fittings of water absorbency data to Fickian diffusion model.