偏高岭石-磷酸基矿物键合材料的制备与结构特征

在室温条件下，通过偏高岭石与磷酸水溶液中低聚[PO4]n^3n-四面体基团的缩合,制备了脱水铝硅酸盐-磷酸基矿物键合材料，该反应产物具有二维Si-O-Al-O-P结构。采用X射线衍射分析（x-ray diffraction，XRD）、Fourier红外吸收光谱、29^Si和27^Al魔角旋转核磁共振（nudear magnetic resonance，NMR）对反应产物进行了结构和反应机理分析。结果表明：反应产物中的Al^3＋具有3种化学环境特征。29^Si NMR的化学位移只在-110处出现，预示着[SiO4]四面体以层状结构方式存在。反应产物的红外光谱中偏高岭石的表征Al-O层结构特征的800Cm^-1共振吸收峰消失。反应产物的XRD谱具有非晶结构特征。据此，对键合反应机理模型进行了推测。

SYNTHESIS AND STRUCTURE CHARACTERIZATION OF GEOPOLYMERIC MATERIAL BASED ON METAKAOLINITE AND PHOSPHORIC ACID

A geopolymer material based on dehydrolyed aluminosilicate and phosphoric acid was synthesized from metakaolinite condensed with low-polymeric ~(3n-)_n tetrahedral units in phosphoric acid aqueous solution at room temperature.The product of the geopolymerization has a polymeric Si-O-Al-O-P three-dimensional structure.The material structure and geopolymerization mechanism of the products were investigated using X-ray diffraction(XRD),Fourier transform infrared(FTIR) spectroscopy,and()~(29)Si and()~(27)Al magic angle spinning nuclear magnetic resonance(NMR).The results show that there are three chemical environments for Al~(3+) in the geopolymer.The NMR chemical shift of()~(29)Si in the product is presented only at110,which demonstrates that the linking amongtetrahedral units keeps the layer structure in the geopolymers.In the infrared spectrum of the geopolymer,the resonance absorbance peak of 800 cm~(-1) of the Al-O layer of metakaolinite disappeared.The XRD pattern of the obtained polymers is essentially amorphous.A model of the geopolymerization mechanism was proposed to explain the experimental results.