Changes of composition and structure of various samples of polymethylsilsesquioxane (PMSQ) pyrolysed at different temperature under flowing nitrogen were investigated by means of FT-IR and X-ray photoelectron spectros...Changes of composition and structure of various samples of polymethylsilsesquioxane (PMSQ) pyrolysed at different temperature under flowing nitrogen were investigated by means of FT-IR and X-ray photoelectron spectroscopy. Two temperature domains correspond to important changes in the chemical composition of PMSQ. The former (Tp < 500oC) is related to the transition from regular structure to irregular structure and the latter (Tp > 500oC) is associated with the organic-inorgnic transition.展开更多
A new method for the preparation of a soluble ladderlike polymethylsilsesquioxane with high molecular weight ((?)=10~5—10~6) and low molecular weight distribution (D=Mw/Mn) in common solvents instead of the formerly ...A new method for the preparation of a soluble ladderlike polymethylsilsesquioxane with high molecular weight ((?)=10~5—10~6) and low molecular weight distribution (D=Mw/Mn) in common solvents instead of the formerly used toxic methylisobutylketone has been developed. The structure and macromolecular regularity were characterized by IR, X-ray diffraction, and ^(29)Si-NMR spectroscopy. The thermal property was studied by TGA and DSC.展开更多
A hydrophobic-hydrophilic gradient rod with a length of 40 mm and a diameter of 3 mm was prepared by heating a polymethylsilsesquioxane rod in a cylindrical stove with temperature gradient. The rod was thus pyrolyzed ...A hydrophobic-hydrophilic gradient rod with a length of 40 mm and a diameter of 3 mm was prepared by heating a polymethylsilsesquioxane rod in a cylindrical stove with temperature gradient. The rod was thus pyrolyzed under a temperature gradient condition. The organic end of the gradient rod appears hydrophobic with a contact angle of 109.9° while the other end is hydrophilic with a contact angle of 62.4°. The gradient chemical structure and the gradient microstructure along the rod were characterized by FTIR and SEM, respectively.展开更多
基金This project is supported by the National Natural Science Foundation of China(No.20074039)State Key Laboratory of Polymer Physics&Chemistry of lnstitute of Chemistry of Chinese Academy of Sciences(No.00-B-01).
文摘Changes of composition and structure of various samples of polymethylsilsesquioxane (PMSQ) pyrolysed at different temperature under flowing nitrogen were investigated by means of FT-IR and X-ray photoelectron spectroscopy. Two temperature domains correspond to important changes in the chemical composition of PMSQ. The former (Tp < 500oC) is related to the transition from regular structure to irregular structure and the latter (Tp > 500oC) is associated with the organic-inorgnic transition.
文摘A new method for the preparation of a soluble ladderlike polymethylsilsesquioxane with high molecular weight ((?)=10~5—10~6) and low molecular weight distribution (D=Mw/Mn) in common solvents instead of the formerly used toxic methylisobutylketone has been developed. The structure and macromolecular regularity were characterized by IR, X-ray diffraction, and ^(29)Si-NMR spectroscopy. The thermal property was studied by TGA and DSC.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 20074039) and National 863High-technology Project as well as the Science Foundation of PPLAS (No. 00-B-01).
文摘A hydrophobic-hydrophilic gradient rod with a length of 40 mm and a diameter of 3 mm was prepared by heating a polymethylsilsesquioxane rod in a cylindrical stove with temperature gradient. The rod was thus pyrolyzed under a temperature gradient condition. The organic end of the gradient rod appears hydrophobic with a contact angle of 109.9° while the other end is hydrophilic with a contact angle of 62.4°. The gradient chemical structure and the gradient microstructure along the rod were characterized by FTIR and SEM, respectively.
