A sodium hypophosphite (SHP) modified polycarboxylatesuperplasticizer (P-PCE) was synthesized successfully and the synthesis parameters were optimized through orthogonal experiment. Gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS), ³¹P magic spinning nuclear magnetic resonance (³¹P MAS NMR) spectroscopy and elemental analysis measurements were used to characterize the molecular structure of P-PCE. Effects of P-PCE on the dispersing performance of cement paste were systematically investigated via mini slump test. The results showed that P-PCE exhibited superior dispersing performance, more retarding hydration effect and better sulfate and clay tolerance than conventional PCE (C-PCE). Results showed that the maximum flow of cement paste could reach up to 305 mm, while that of the C-PCE was 285 mm.The maximum variation of adsorption of P-PCE was 9% and 15% in the presence of sulfate and clay, whereas that of C-PCE was 15% and 25%, respectively, leading to better sulfate and clay tolerance. These significant advantages could be ascribed to the high anion density and high calcium complexing capacity induced by introducingphosphinate group and phosphonate group into the molecular structure of P-PCE. The as-synthesized P-PCE can be used as a kind of high performance superplasticizer in concrete engineering.

中文翻译：

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次磷酸钠改性聚羧酸减水剂的合成与表征

成功合成了次磷酸钠（SHP）改性聚羧酸减水剂（P-PCE），并通过正交试验优化了合成参数。凝胶渗透色谱（GPC）、X射线光电子能谱（XPS）、³¹ P魔旋核磁共振（³¹P MAS NMR) 光谱和元素分析测量用于表征 P-PCE 的分子结构。通过小型坍落度试验系统研究了P-PCE对水泥浆体分散性能的影响。结果表明，与传统的PCE（C-PCE）相比，P-PCE具有更好的分散性能、更强的延缓水化作用以及更好的硫酸盐和粘土耐受性。结果表明，水泥浆的最大流量可达305 mm，而C-PCE的最大流量为285 mm。在硫酸盐和粘土存在下，P-PCE的最大吸附变化分别为9%和15%，而 C-PCE 分别为 15% 和 25%，导致更好的硫酸盐和粘土耐受性。这些显着优势可归因于通过在P-PCE的分子结构中引入次膦酸盐基团和膦酸盐基团诱导的高阴离子密度和高钙络合能力。合成后的P-PCE可作为一种高性能减水剂用于混凝土工程。