Studies On Self-organized Polyurethanes

Gradient polymer blend materials through self-organization have attracted increasing attention of many investigators recently.Due to one component in blends having special functional groups,this component could self-organize to the surface of blend films during film-formation process or annealing process,and accordingly a film surface with special properties is obtained.Silicon-based polyurethanes have much lower surface free energy than easter-based polyurethanes,so self-organization will happen during the film-formation under effects of surface free energy.Finally,a silicon polymer material is obtained.In this material,one surface side exhibits special surface properties,such as anti-aging,long-life,self-cleaning properties, solvent-resistance and water-resistance,whereas,the other surface side shows good properties of polyurethanes.The creative achievements of this thesis are as follows.(1)It has been studied silicon-based polyurethane and easter-based polyurethane and 2,4-tolyleme diisocyanate reacted to self-organization film.(3)It has been comprehensively discussed that heat-treatment conditions could facilitate structure formation of blend of silicon-based polyurethane and easter-based polyurethane.The main research contents and conclusions are divided into the following parts. Using ethyl iodide and iodine as catalysts,1,3-bis(4-hydroxybutyl)tetramethyldi—siloxane(BHBTMDS) was directly synthesized from dimethyldichlorosilane, tetrahydrofuran and magnesium powder.And we studied the effects of the synthesis process on rate of production.The results showed that the rate of production of one-step synthesis was higher than two-step synthesis,and we added 18mL H₂O and 0.4mL HCl on the hydrolysis process,α,ω-Bis(4-hydroxybutyl) polydimethylsiloxane(HB-PDMS)with different molecular weight could be prepared through the reaction of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane and dimethoxydimethylsilane in the presence of a stoichiometric amount of water and hydrochloric acid.We studied the effects of the synthesis condition.The results showed that the reaction was carried at 80℃,and the compound of methanol and water removed the low molecular product.The number molecular weight of these hydroxybutyl-terminated polydimethylsiloxanes could be determined fairly by end group titration method.The number-average molecular weight of an HB-PDMS obtained is higher than the targeted molecular weight.Structures of BHBTMDS and HB-PDMS were characterized by Fourier transform infrared spectroscopy(FT-IR) and high-resolution ¹H NMRPoly(ethylene-glycol-adipate)diols was directly synthesized from adipic acid and ethanediol.We probed the relation of tension and molecular weight and temperture of HB-PDMS and poly(ethylene-glycol-adipate)diols.The results showed that the tension of HB-PDMS and poly(ethylene-glycol-adipate)diols increase as molecular weight increase.The tensiaon of HB-PDMS and poly(ethylene-glycol-adipate)diols decrease as temperature increase,and they are linear.Silicon-based polyurethane,based on HB-PDMS,2,4-tolylene diisocyanate, 1,4-butanediol as a chain extender and dibutyltin dilaurate as a catalyzer were synthesized using solution polymerization procedure.Easter-based polyurethane based on poly(ethylene-glycol-adipate)diols,2,4-tolylene diisocyanate(2,4-TDI), 1,4-butanediol as a chain extender and dibutyltin dilaurate as a catalyzer were synthesized using solution polymerization procedure.We studied the different properties between PDMS-based polyurethane and easter-based polyurethane.A complex micro-phase separation of soft segment from the hard segment was demonstrated by DSC.The decomposition of polyurethanes had two steps.The dynamic water contact angles of the sample from the Wilhelmy method indicated that the sample containing polydimethylsiloxane could not be wetted by water.It was suggested that the low surface energy characteristic of PDMS promoted migration to the air-polymer interface to form a predominately PDMS enriched surface.PDMS-based polyurethane based on poly(ethylene-glycol-adipate)diols and HB-PDMS,2,4-tolylene diisocyanate,1,4-butanediol as a chain extender and dibutyltin dilaurate as a catalyzer was synthesized using solution polymerization procedure,and we studied the effects of annealing process on self-organization.The results showed that under annealing process films could self-organize to material. When teflon was film-formation matix and when the ration of HB-PDMS to poly(ethylene-glycol-adipate)diols was 1:3,the surface free energy in film-teflon in terface of films decreased with enhancing heat-treating 6h at 120℃.The results of XPS showed silicon could move to surface.In this thesis,the relationship between film-formation conditions and the structure of silicon based-polyurethanes through self-organization has been clarified.The results provide the scientific foundation.The progress of blending in system belongs to green technology.It is worth noting that researchers and ultilizing of renewable resources are compliant with the national objective and sustainable development.