丙硅乳液的核磁共振研究

THE NMR STUDY ON ORGANOSILINO ACRYLIC EMULSIONS

单介绍了2 9SiNMR实验技术 ;用2 9SiNMR测定了丙硅乳液原料羟基硅氧烷的平均聚合度、平均分子量、平均羟基含量 ;用1 3CNMR分析了丙硅乳液的结构组成 .

Organosilino acrylic emulsions have received attentions because of its industrial applications. The properties of the polymer depend upon the composition and structure. Dihydroxypolydimethylsiloxane is a kind of monomer to synthesze the emulsions, its everage hydroxyl value affects its reactivity, so analyzing its average hydroxyl value one can obtain the quality of dihydroxypolydimethylsiloxane. NMR is usually the preferred technique to study composition and structure of the polymer.\;The method of 29 Si NMR is discussed. The average degree of polymerization\$(\{DP\}),\$ the average molecular weight\$(\{M\}),\$ the average hydroxyl value of dihydroxylpolydimethylsiloxane fluid mixtrues were investigated by 29 Si NMR. To ensure that quantitative data were obtained, a small amount of chromium(Ⅲ) acetylacetonate was added as a relaxation reagent to shorten the 29 Si spin lattice relaxation times\$(T\-1)\$, and inverse \{\}\+1H gated decoupling was used to eliminate the negative nuclear Overhauser effect(NOE), and longer recycle delay was used. To eliminate the broad peak of silicon glass NMR tube, pluse program was changed, a delay was added before acquisition.\;The composition of organosilino acrylic emulsions were investigated by \{\}\+\{13\}C NMR. \;