Functional Integration Of Mechanically Adjustable Polyurethane Composite Films

Composite emulsion combines the characteristics of two or more substances and it is synthesized by physical blending or chemical copolymerization.Composite film is then prepared from the emulsion by the traditional solvent evaporation method.Polyurethane(PU)has excellent low-temperature performance,wear resistance,and corrosion resistance.However,PU contains hydrophilic groups in its molecular chain,which reduces the water resistance of the film and limits the application of PU materials.On the other hand,acrylate polymer(PA)has excellent mechanical properties,but its low-temperature performance,flexibility,wear resistance and chemical corrosion resistance need to be improved.Polyurethane-acrylate(PUA)composite emulsion is a kind of polymer with the advantages of both PU and PA.At the same time,the performance of the polymer film prepared from PUA will be significantly improved.However,the water resistance,heat resistance and tensile properties of the unmodified PUA film are poor,which limits its application range.Therefore,PUA must be modified to improve its comprehensive performance and broaden its application field.The significance of this research is that the comprehensive properties of the modified composite emulsion and polymer film were improved,and the application range of the modified film and coating is expanded.In this paper,siloxane-containing compounds were used to modify PUA to improve its comprehensive properties,which is conducive to expanding the application field of PUA composites.In this paper,three kinds of PUA modified emulsions were synthesized by free radical polymerization.The first is the synthesis of HSi-PUA composite emulsion modified by hydroxyl-terminated polydimethylsiloxane(HP-PDMS)monomer.The effect of HP-PDMS dosage on the properties of HSi-PUA emulsion and its polymer film was systematically investigated.The second is the preparation of MSi-PUA composite emulsion modified by 3-(trimethoxysilane)propyl acrylate(MPTS).The effect of MPTS content on the properties of MSi-PUA composite emulsion and its polymer film was studied.The third is the preparation of FSi-PUA composite emulsion modified by poly(methyl-3,3,5-trifluoropropylsiloxane)(PMTFPS).The effect of the amount of PMTFPS on the properties of FSi-PUA composite emulsion and its polymer film was studied.1.In HSi-PUA,siloxane was found to effectively improve the comprehensive performance of the HSi-PUA polymer film.Under the condition that the content of each component in the preparation process of HSi-PUA was unchanged when the mass fraction of HP-PDMS is 10 %,the composite PUA emulsion and its polymer film have excellent comprehensive performance.2.MPTS was modified as a low molecular coupling agent.The content of MPTS had a great influence on the properties of MSi-PUA emulsion and polymer film.The MSi-PUA film has excellent optical transmittance.When the content of the silane coupling agent reaches 10 %,the optical transmittance reaches 79.40 %.The water resistance test of the prepared film shows that the water contact angle is improved and the water absorption rate is reduced,which proves the excellent hydrophobic properties of the film material.Due to the excellent optical transparency of the film,it opens up opportunities for potential applications in optical devices,anti-fouling glasses,and touch protection screens.3.The modification of PMTFPS effectively improves the comprehensive properties of FSi-PUA polymer film and coating.When the content of PMTFPS reaches 15 %,the stability of the emulsion is poor and precipitation occurs.Due to the introduction of fluorosiloxane,the hydrophobicity of the polymer film was effectively improved,and the self-cleaning and antifouling properties of the coating were tested.With the increase of fluoropolysiloxane content in the emulsion,the film forming performance of FSi-PUA becames worse,the degree of microphase separation of the film increased,and the hydrophobicity of the film did not change significantly.Due to the introduction of fluorine-containing polysiloxane,the hydrophobic properties of the polymer film were effectively improved,and the self-cleaning and antifouling properties of the coating were tested.Due to the chemical inertia of fluorinecontaining polysiloxane,the coating surface also has good corrosion resistance.Therefore,fluoropolysiloxane modified composite emulsion has certain development prospects in the fields of antifouling coatings and leather finishing.