Study On Synthesis And Analysis Of Polysiloxane

Organic-silicon compounds have a lot of unique properties,such as high and low temperature resistance,weatherablity,anti-aging property,electrical insulation property, ozone-resistant performance,hydrophobic property,fireproof property,physiological inert and so on.Organic-silicon compound cannot be replaced by other organic polymer materials because of these excellent capabilities.They have been widely applied in aerospace, electronic and electrical,light industry,textile,machinery,construction,traffic and transportation,medical care,health,agriculture,people's daily life,etc.They have been become an important and indispensable new polymer materials to the national economy.The variety of breeds and the complexity of ingredients add difficulty to analysis of organic-silicon compounds.In fact,these products are always mixtures when they are in applied.There is no need to do separation and purification work.There are no good analytical methods for polysiloxanes at present.On the other hands,there must be some relationships between the properties of products and the kinds,contents of them.The qualitative and quantitative analysis of polysiloxanes is good for synthesis technology.High hydrogen-containing polysiloxane and aminoalkylpolysiloxane were analyzed qualitatively and quantitatively in this thesis.High hydrogen-containing polysiloxane are basic raw materials of organic-silicon industry.There are very much outgrowth during the production of it.Different high hydrogen-containing polysiloxane can be produced by different methods.The boiling point of high hydrogen-containing polysiloxane with low molecular weight is not very high,so it can be analyzed by GC-MS and GC.It is found that high hydrogen-containing polysiloxane is commonly by hydrosis and equilibrium of organic hydrochlorosilanes and organic chlorosilanes during the study process.The production consists of several types of polymethylhydrosiloxanes,and every type consists of many homologs of different polymerization degree.Hereby,the ingredients in polysiloxane are very complex.The molecule-ion in mass spectra of polymethylhydrosiloxanes gained from electron ionization(EI)is obvious commonly, except the cyclohydrosiloxanes of low molecular-weight.The major ions of all types of polymethylhydrosiloxanes are same and only the intensity of major ions has some difference.The difference becomes smaller with the molecular-weight increasing,so that they cannot be distinguished only by their mass spectra.However,The ingredients with semblable structure in polymethylhydrosiloxanes product exert some speciality in aspect of retention time of gas chromatography and distribution of content.The ingredients with low molecular weight and early retention time are analyzed by GC/MS and their structure is made sure.Then confirm the structure of ingredients with large molecular weight and late retention time with the speciality mentioned above.Then,they are analysed quantificationally by gas chromatography.Two types of high hydrogen-containing polysiloxanes were studied in the thesis.One is named Jiayi polysiloxane for short,and the other is Guangdong polysiloxane.The results indicate that,there are four types of homologs in the sample Jiayi polysiloxane and every type of homolog consist of high hydrogen-containing polysiloxane of different polymerization degree.All the polysiloxane have the same structure units—(CH₃)HSiO—and different ending groups.There are 38 components which were analyzed qualitatively by GC-MS and their relative contents are 88.4%.There are there types of homologs in the sample Guangdong polysiloxane and every type of homolog consist of high hydrogen-containing polysiloxane of different polymerization degree.All the polysiloxane have the same structure units—(CH₃)HSiO—and different ending groups.There are 43 components which were analyzed qualitatively by GC-MS and their relative contents are 90.9%.Then their retention indexes were calculated by comparison with alkanes in the same condition.At last,the molecular distribution was also studied.Aminoalkylpolysiloxane is more active than other common polysiloxane due to the aminoalkyl.As a result,it can be widely used in many fields.The sample 'Aminopropylpolysiloxane' was analyzed by GC-MS.However,many components cannot be evaporated in the inlet due to their high boiling point and molecular weight.As a result, these components cannot be seen in the TIC.In order to study the sample 'Aminopropylpolysiloxane' well,the LC-MS(ESI)was adopted,and the molecular weight scanning range was enlarged to 2000.Then it can be easily found that almost all the components of the sample have normal distribution in the mass spectrogram.The molecular weight of two adjacent components differs 74,which is the relative weight of structure unit, that is—(CH₃)₂SiO—.Both the GC-MS and LC-MS were used and this method raised the accuracy of qualitative analysis.27 components were analyzed qualitatively in all.On the basis of relative abundance of every peak in the ESI mass spectrograph,relative contents were approximately calculated by normalization method.All the qualitative components account for 62.5%roughly.Chromatography retention index is a very important qualitative analysis method. Retention indexes of some components of the sample 'Aminopropylpolysiloxane' were calculated in this paper according to the n-alkanes.The results provide a qualitative reference for researchers and analysis workers afterward.In a word,the synthetic and analysis methods in this paper are simple,easy and efficient. What is better,the research results are also satisfactory.The study idea in the paper can be widely applied in other types of organic-silicon compounds.It has good theoretical meaning and practical applied value.3.The originality in this thesis:(1)Analysing the large molecular-weight ingredients in hydrosilicon oil qualitatively, based on the qualitative results of low molecular-weight ingredients with character of mass spectra and retention behavior on chromatography.(2)Aminopropylpolysiloxane whose molecular-weights are larger than 1000 can not be analyzed qualitatively by GC-MS.Besides,it can not be analyzed only by LC-MS(ESI). Low-molecular weight components were analyzed qualitatively by GC-MS in this thesis, then on the basis of regularity of every peak in the ESI mass spectrograph and characteristics of molecular fragments,high-molecular weight components were analyzed qualitatively.The result was satisfactory and the method can be extended.