Based On Study Of Peo-b-pdms-b-peo The Fpeo-b-pdms-b-fpeo Waterborne Polyurethane Synthesis, Characterization And Performance

Aqueous polyurethane dispersion(PUD) materials not only have good performances,but also have more important merits such as non-pollution and transportation safety,which is a new but flourishing field and getting more and more attention.However,introduction of hydrophilic segments into PUD weakens the water resistance,and also,affects negatively chemical resistance and surface property for cured film of PUD.In order to expend its applications,PUD need to be improved further.Siloxane-modified polyurethane dispersion(Si-PUD),as a specie of novel macromolecule functional material,owing to the introduction of hydrophobic and non-polar siloxane,has very lowest surface energy,excellent resistance to water and oils.Therefore,FPU have supplied original PU gap in the above mentioned shortages. In this dissertation,as intermediates of Si-PUD,a kind of new polysiloxane diols, polyether blocked polysiloxane(PEO-b-PDMS-b-PEO) were synthesized,and the molecular weight of PEO-b-PDMS-b-PEO can be controlled easily.Compared with traditional polysiloxane diols,PEO-b-PDMS-b-PEO shows good storage stability and reactivity.PEO-b-PDMS-b-PEO with different molecular weight using as soft segments,a series of Si-PUDs were prepared and their structures and properties were investigated.It was found that the enrichment of siloxane onto surface was deficient. Taking into account the deficient enrichment,as well as inadequate chemical resistance of Si-PUD,we prepared a novel fluorinated polysiolxane diols (FPEO-b-PDMS-b-FPEO) based on PEO-b-PDMS-b-PEO.FPEO-b-PDMS-b-FPEO still has good reactivity.F-Si-PUD with FPEO-b-PDMS-b-FPEO as soft segment was then prepared and the its structure and properties of both bulk and surface were investigated,and the relation between the structures and properties were discussed preliminarily.1.A series of novel PEO-b-PDMS-b-PEO was synthesized by hydrosilation reaction of MAPEO with HPDMS that obtained via acid-catalyzed ring-opening equilibration reaction of D₄ with TMS.The molecular weight of PEO-b-PDMS-b-PEO could be controlled easily by varying the molecular weight of HPDMS.FTIR and ¹H-NMR spectroscopy confirmed the structure of PEO-b-PDMS-b-PEO and HPDMS.The conversion of Si-H bond to Si-C bond was affected by the catalyst amount,reaction time and temperature.The measurement of OH-value at different temperature showed that PEO-b-PDMS-b-PEO had good storage stability.Urethane reaction of OH and NCO group indicated that PEO-b-PDMS-b-PEO was more reactive towards to diisocyanates such as MDI,IPDI and TDI thanα,ω-bishydroxylbutyl terminated PDMS.2.Si-PUD with different molecular weight PEO-b-PDMS-b-PEO as intermediates(P-PUD) were synthesized.Studying on surface property of P-PUD showed that water contact angle(WCA) of film increased as the increase of temperature,indicating that the enrichment of siloxane onto surface was insufficient due to the competition of enriching tendence and interaction of polymeric molecules. Compared with genneral Si-PUD,P-PUD has better mechanical properties.Thermal analyse indicated that the introduction of polyether chains on the Si-PUD affected the thermal stability slightly.3.Fluorinated hydroxypolyether blocked polydimethylsiloxane (FPEO-b-PDMS-b-FPEO) were prepared by free radical grafting of HFP onto hydroxypolyether blocked polydimethylsiloxane initiated by ten-butyl peroxypivalate.It is found that tert-butyi peroxypivalate is a felicitous initiator used.in the synthesis of FPEO-b-PDMS-b-FPEO,which gives a moderate reactive temperature.FTIR and ¹H NMR spectroscopy confirmed the structure of formed products,meanwhile,the analysis of gel permeation chromatography indicated that molecular chains of both raw material PEO-b-PDMS-b-PEO and product FPEO-b-PDMS-b-FPEO were stable in grafting reaction process.4.F-Si-PUD based on FPEO-b-PDMS-b-FPEO was prepared and the its structure and properties of both bulk and surface were discussed preliminarily. Through FTIR analysis of the F-Si-PUD,it was found that the introduction of fluoridehad increased the interrelation of hard and soft segments of F-Si-PUD due to a new hydrogen bond(C-F···H-N) between hard and soft segments being engendered.The surface compositions of the FPU films were measured and analyzed by XPS.The experimental results indicated that both of fluorine and silicon enriched on the surface of polymer,and introduction of fluorine enhanced the enrichment of silcon.Further investigation indicated that F-Si-PUD had high chemical resistance and good mechanical properties because of introduction of fluorine.