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为了探讨聚乙二醇(PEG)渗透材料在不同pH条件下的性能,用NaOH溶液和稀盐酸调节PEG渗透材料的pH值.采用核磁共振研究不同pH值条件对PEG结构的影响.研究表明:当pH值在2~8时,PEG渗透材料放置7d可以保持稳定的pH值;在酸性条件下,由于PEG中的O对酸中H+形成作用,削弱了O原子对与O间接相连的-CH2基团的引力,使该-CH2基团中的H原子的化学位移向低场偏移,但PEG的结构不变;在pH值大于8的条件下,氢键的形成导致线状的PEG发生立体扭结,从而产生沉淀.因此,在pH值为2~8的范围内,可以稳定使用PEG渗透材料.
In order to investigate the properties of polyethylene glycol (PEG) infiltration materials under different pH conditions, the pH value of PEG permeation materials was adjusted with NaOH solution and dilute hydrochloric acid.The effects of different pH conditions on the structure of PEG were studied by NMR.The results showed that: When the pH value is between 2 and 8, the PEG permeable material can be kept at a steady pH value for 7 days. Under acidic conditions, O in the PEG acts to weaken the H + in the acid and weakens the effect of the O atom on the -CH 2 The gravitation of the group causes the chemical shift of the H atom in the -CH2 group to shift to a low field, but the structure of the PEG does not change. At pH values above 8, the formation of hydrogen bonds leads to the occurrence of linear PEG Therefore, it is possible to stably use the PEG permeable material in the pH range of 2 to 8.