superabsorbent polymers (SAPs) are famous for their excellent water absorption capability. In this work, poly (acrylic acid)-based superabsorbent polymer was developed via free radical polymerization by innovatively using 1,2,3,4-butane tetracarboxylic acid (BTA) as one unique physical cross-linker. Water-soluble BTA molecules contain four carboxyl groups that can interact with poly(acrylic acid) (PAA) polymeric chains through hydrogen bonds. Such force made the products swell but not dissolve in water, determining that BTA took a great role of cross-links. The effects of initiator, catalyzer, neutralizer and cross-linking agent on water-absorbing capacities of as-obtained PAA/BTA-SAP products were explored. The results revealed that swelling ratios of such PAA/BTA-SAP in distilled water was 4480 g/g, in 0.9 wt% NaCl solution was 55 g/g and in 5 wt% urea solution was 1890 g/g. Swelling kinetics indicated that polymer chains of the product in distilled water underwent relaxation and stretching in the swelling stage. The excellent water uptake was attributed to the formation of a well-structured three-dimensional network for SAPs via multiple hydrogen bonds between PAA polymer and BTA molecule. Therefore, the present work provides a new horizon to explore BTA as one unique cross-linker to prepare SAPs with the enhanced water uptake.

高吸水性聚合物（SAP）以其优异的吸水能力而闻名。在这项工作中，创新性地使用1,2,3,4-丁烷四甲酸（BTA）作为一种独特的物理交联剂，通过自由基聚合开发了聚（丙烯酸）基高吸水性聚合物。水溶性 BTA 分子含有四个羧基，可通过氢键与聚丙烯酸 (PAA) 聚合物链相互作用。这种力使产品在水中膨胀但不溶解，决定了BTA起到了很大的交联作用。探讨了引发剂、催化剂、中和剂和交联剂对所得PAA/BTA-SAP产品吸水能力的影响。结果表明，该PAA/BTA-SAP在蒸馏水中的溶胀比为4480g/g，在0.9wt％的NaCl溶液中的溶胀比为55g/g，在5wt％的尿素溶液中的溶胀比为1890g/g。溶胀动力学表明，产物在蒸馏水中的聚合物链在溶胀阶段经历了松弛和拉伸。优异的吸水率归因于通过 PAA 聚合物和 BTA 分子之间的多个氢键形成了结构良好的三维网络。因此，目前的工作为探索 BTA 作为一种独特的交联剂来制备具有增强吸水性的 SAP 提供了新的视野。