4669-59-4Relevant articles and documents
Incorporating a silicon unit into a polyether backbone - an effective approach to enhance polyether solubility in CO2
Zhang, Yongfei,Zhu, Zewen,Bai, Zhenguo,Jiang, Wei,Liu, Fengqi,Tang, Jun
, p. 16616 - 16622 (2017)
A series of poly(silyl ether)s were prepared by condensation polymerization and hydrosilation polymerization through incorporating a silicon unit into a polyether backbone. The phase behavior of poly(silyl ether)s in CO2 was measured in terms of concentration, molecular weight and temperature. Through incorporating the silicon unit, the poly(silyl ether)s exhibited high solubility in CO2 compared to the precursors of polyether. For example, the cloud point pressure decreased from 24.6 MPa for poly(1,2-propene glycol) (PPG) to 16.5 MPa for poly(dimethylsiloxane-alt-propene glycol) (PSPG) with a concentration of 0.6 wt% at 30 °C. Moreover, the molecular weight dependence of solubility for PSPG and PSDPG in CO2 compared with PPG was weakened. The key factor to enhance the solubility of poly(silyl ether)s in CO2 was systematically researched via surface tension and glass transition temperature. The results demonstrated that higher solubility of synthesized poly(silyl ether)s in CO2 compared to PPG was mainly attributed to lower polymer-polymer interactions.
Insertion of phenyl isocyanate into monoand diaminosilanes
Kraushaar, Konstantin,Herbig, Marcus,Schmidt, Dana,Wagler, J?rg,B?hme, Uwe,Kroke, Edwin
, p. 909 - 921 (2018/01/19)
The aminosilanes MenSi(NRR')4-n (n = 2,3) with NRR' = ethylamino (NHEt), n-propylamino (NHnPr), sec-butylamino (NHsBu), n-octylamino (NHnOct), n-dodecylamino (NHnDodec), allylamino (NHAll), tert-butylamino (NHtBu), diethylamino (NEt2), and anilino (NHPh) were synthesized and their reactions with phenyl isocyanate were studied. In all cases of these silanes Me3SiNRR' and Me2Si(NRR')2 formal insertion of the -NCO group into their Si-N bonds was observed, i.e. formation of products with Si-N (rather than Si-O) bonds was found. In some cases, the products could be crystallized and their molecular structures have been elucidated with single-crystal X-ray diffraction analyses.
From CO2 to polysiloxanes: Di(carbamoyloxy)silanes Me 2Si[(OCO)NRR′]2 as precursors for PDMS
Kraushaar, Konstantin,Wiltzsch, Conny,Wagler, Joerg,Boehme, Uwe,Schwarzer, Anke,Roewer, Gerhard,Kroke, Edwin
experimental part, p. 4779 - 4785 (2012/10/07)
Double insertion of carbon dioxide into the Si-N bonds of diaminosilanes of the type Me2Si(NRR′)2 gives di(carbamoyloxy)silanes Me2Si[(OCO)NRR′]2. The reactions proceed exothermically and quantitatively in most cases. A comprehensive analysis of the CO2-insertion products including single-crystal X-ray structure analyses was carried out. Quantum chemical calculations indicate an activation energy of about 124 kJ/mol for both the first and the second insertion and support the exothermal nature of the reaction. Investigation of the thermal decomposition of the di(carbamoyloxy)silanes Me2Si[(OCO)NRR′] 2 reveals the formation of oligo- and polysiloxanes. Depending on the thermolysis parameters, isocyanates, amines, and/or ureas are formed in addition to the siloxanes. Various methods were applied to study the decomposition process and to identify and quantify the products, including thermal analyses, mass spectrometry, and FTIR and NMR (solution and solid-state) spectroscopy. The overall reaction scheme provides a novel route to polysiloxanes which uses carbon dioxide as an oxygen source.