聚(AM-co-C16DMAAC)/可溶性淀粉高吸水树脂的制备及溶胀动力学

Synthesis and swelling kinetics of soluble starch-g-poly(AM-co-C16DMAAC)super absorbent resin

为了提高传统丙烯酰胺(AM)基可溶性淀粉树脂的吸水性能,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Na OH水解,单因素优化制得AM-co-C16DMAAC高吸水性树脂。通过红外光谱仪和扫描电镜进行表征,并对其吸水膨胀机理进行了分析。结果表明,树脂产品的最佳合成条件为:在固体单体含量为20%的50g聚合体系中,可溶性淀粉加量为40%(以可溶性淀粉、AM和C16DMAAC总质量为基准,下同),n(AM)∶n(C16DMAAC)=99.2∶0.8,过硫酸铵(APS,5000 mg/L)4 mL,N,N-亚甲基双丙烯酰胺(MBA)0.02g,水解度DH=80%;该条件下制得的树脂产品在去离子水和生理盐水中的吸水倍率分别为1964.96和76.77g/g,较未添加C16DMAAC树脂分别提高61.53%和28.35%;氢氧化钠高温水解步骤和引入单体C16DMAAC能显著提高AM基可溶性淀粉复合树脂的吸水性能;AM-co-C16DMAAC树脂的吸水膨胀过程符合Fickian扩散模型,驱动力为树脂内外水渗透压差和Na+浓度差异。

In order to improve the water absorbency of traditional acrylamide(AM)based soluble starch resin,hexadecyl dimethyl allyl ammonium chloride(C16 DMAAC)was introduced to prepare a super absorbent resin,soluble starch-g-poly(AM-co-C16 DMAAC)by aqueous solution grafting copolymerization and sodium hydroxide hydrolysis.The synthesis conditions of soluble starch-g-poly(AM-co-C16 DMAAC)were optimized by a series of single factor experiments.The sample was characterized by FTIR and SEM.The mechanisms of water absorption and expansion of the resin were also analyzed.The results showed that the optimal conditions for synthesis of soluble starch-g-poly(AM-co-C16 DMAAC)were obtained as follows:mass of polymerization system 50 g,solid content of monomers 20%,content of soluble starch 40%(based on the total mass of soluble starch,AM and C16 DMAAC,the same below),n(AM)∶n(C16 DMAAC)=99.2∶0.8,dosage of ammonium persulfate(APS,5000 mg/L)4 m L,dosage of N,N-methylene bisacrylamide(MBA)0.02 g,and degree of hydrolysis(DH)of 80%.Under these conditions,the maximum water absorbency of soluble starch-g-poly(AM-co-C16 DMAAC)was 1964.96 g/g in distilled water and 76.77 g/g in saline solution,respectively,which was 61.53%and 28.35%higher than that resin without C16 DMAAC.Sodium hydroxide hydrolysis at high temperature and the introduction of C16 DMAAC monomer can significantly improve the water absorbency of AM based soluble starch resin.The swelling process of the resin was fitted to Fickian diffusion model,and the driving force was the difference of water osmotic pressure inside and outside of the resin and the difference of Na+concentration.