Bai Wenbo, Ji Bingyi, Fan Liren, Peng Qin, Liu Qi, Song Jiqing
Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Liaoning Province Modern Agricultural Production Base and Construction Engineering Center, Shenyang 110032, China.
Polymers (Basel). 2023 Feb 28;15(5):1233. doi: 10.3390/polym15051233.
To prepare a novel cassava starch-based phosphorus releasing super-absorbent polymer (CST-PRP-SAP), the single factor and orthogonal experiment were applied to analyze the effects of different reaction conditions on the absorption and phosphorus release capacities of CST-PRP-SAP samples. The structural and morphological characteristics of the cassava starch (CST), powdered rock phosphate (PRP), cassava starch-based super-absorbent polymer (CST-SAP) and CST-PRP-SAP samples were all compared with various technologies, such as the Fourier transform infrared spectroscopy and X-ray diffraction pattern, etc. The results showed that the CST-PRP-SAP samples had good performances of water retention and phosphorus release which were synthesized, such as the reaction temperature, starch content, PO content, crosslinking agent, initiator, neutralization degree, and acrylamide content, which were 60 °C, 20% /, 10% /, 0.02% /, 0.6% /, 70% /, and 15% /, respectively. The water absorbency of CST-PRP-SAP was almost larger than that of the CST-SAP sample with a PO content of 5.0% and 7.5%, and they all gradually decreased after three consecutive water absorption cycles. The CST-PRP-SAP sample could maintain about 50% of the initial water content after 24 h, even at the temperature of 40 °C. The swelling process of CST-PRP-SAP conformed to the non-Fickian diffusion, which was determined by the diffusion of water molecules and the relaxation process of polymer chain segments. The cumulative phosphorus release amount and release rate of the CST-PRP-SAP samples were increased with the increasing PRP content and the decreasing neutralization degree. After a 216 h immersion, the cumulative phosphorus release amount and release rate of the CST-PRP-SAP samples with different PRP contents were increased by 17.4 and 3.7 times, respectively. The rough surface of the CST-PRP-SAP sample after swelling was beneficial to the performance of water absorption and phosphorus release. The crystallization degree of PRP in the CST-PRP-SAP system was decreased and most of the PRP existed in the form of physical filling, and the available phosphorus content was increased to a certain extent. It was concluded that the CST-PRP-SAP synthesized in this study has excellent properties of continuous water absorption and retention with functions of promotion and the slow-release phosphorus.
为制备一种新型木薯淀粉基缓释磷高吸水性聚合物（CST-PRP-SAP），采用单因素试验和正交试验分析不同反应条件对CST-PRP-SAP样品吸水和释磷能力的影响。利用傅里叶变换红外光谱、X射线衍射图谱等多种技术对木薯淀粉（CST）、磷矿粉（PRP）、木薯淀粉基高吸水性聚合物（CST-SAP）和CST-PRP-SAP样品的结构和形态特征进行了比较。结果表明，所合成的CST-PRP-SAP样品具有良好的保水和释磷性能，其最佳反应条件为：反应温度60℃、淀粉含量20%、PO含量10%、交联剂0.02%、引发剂0.6%、中和度70%、丙烯酰胺含量15%。CST-PRP-SAP的吸水率几乎高于PO含量为5.0%和7.5%的CST-SAP样品，且在连续三次吸水循环后均逐渐降低。即使在40℃的温度下，CST-PRP-SAP样品在24小时后仍能保持约50%的初始含水量。CST-PRP-SAP的溶胀过程符合非菲克扩散，这是由水分子的扩散和聚合物链段的松弛过程决定的。CST-PRP-SAP样品的累积磷释放量和释放速率随PRP含量的增加和中和度的降低而增加。浸泡216小时后，不同PRP含量的CST-PRP-SAP样品的累积磷释放量和释放速率分别提高了17.4倍和3.7倍。溶胀后CST-PRP-SAP样品的粗糙表面有利于吸水和释磷性能。CST-PRP-SAP体系中PRP的结晶度降低，大部分PRP以物理填充的形式存在，有效磷含量有一定程度的提高。研究得出结论，本研究合成的CST-PRP-SAP具有优异的持续吸水保水性能以及促磷缓释功能。
