Construction And Property Of Polysilsesquioxane Nano Hybrid On Superhydrophobic Leather Coating

Recently,bionic superhydrophobic leathers due to its water-and oilrepellency,self-cleaning and easy care properties,which were widely used in garment,furniture decoration and artwork ornaments,etc.Therefore,it has an important theoretical and practical significance on preparing and appling a sort of leather superhydrophobic materials with environmental,high-performance and multi-functional haractristics.Organic-inorganic nanohybrids own the unique structure and are always the hot topic in the suerphydrophobic research fields.As a kind of novel organic-inorganic hybrids with excellent properties,on one hand,PSQ with favorable thermal,chemical stabilities and mechanical strength;on the other hand,enormous R organic groups embraced in PSQ can also greatly imporve the compatibility with other organic polymers,in particular,the modified polysiloxane with low surface free energy.As a result of the“Si-O-Si” moity contained in both parts,organic bonding between the above two sectors can be easily formed to synthesize the PSQ-based polymer hybrids with novel structure and even the composites with molecular level.Herein,PSQ nanospheres and modified polysiloxane were chemically bonded to synthesize two sorts of PSQ-based polysiloxane hybrids in this context.Next,superhydrophobic leather surfaces with dry rubbing resistance and breathable property were fabricated on basis of low surface free energy and crosslinked film-forming characteristics of organsilicone.The main research contents are listed as following:(1)Preparation of long-chain alkyl modified amino silicone hybrid(PGMSQ)latex and fabrication of superhydrophobic leather from itA series of monodispersed polyepoxymethylsilsesquioxane(PGMSQ)nanospheres were first fabricated via the hydrolysis-condensation method inaqueous solution and ammonium hydroxide was used as catalyst,?-(2,3-epoxypropoxy)propytrimethoxysilane(KH-560)and methyl triethoxysilane(MTES)as silicon sources,sodium dodecyl sulfonate(SDS)/fatty alcohol-polyoxyethylene ether(AEO-3)as mixed emulsifiers.Then,the crosslinked long-chain alkyl and aminosilicone(JRASO)was synthesized by the alkaline equilibration reaction with the pendant silicon hydroxyl,dodecyl and N-(?,?-dimethyl ammonium propyl)-?-propyl.Next,a sort of long-chain alkyl modified amino silicone hybrid(PGMSQ-JRASO)was prepared via cycloaddition reaction between JRASO and PGMSQ and then emulsified by nonionic mixed emulsifiers to acquire the cationic PGMSO-JRASO latex.Finally,superhydrophobic leather was obtained via the spraying method with dry rubbing resistance,environmental and breathable characteristics based on optimization of the preparation and application process.FT-IR,1H/29Si-NMR,and XPS were utilized to characterize the intermediates and the outcomes.Average particle sizes of the PGMSQ and PGMSQ-JRASO latexes,their micro-morphology and thermal stabilities were representatied by DLS,FESEM,AFM and TGA.Water vapor transmittance tester,water contact angle detector,and friction fastness instrument were applied to determine hydrophobicity,moisture permeability and rub resistance of the PGMSQ-JRASO treated nubuck leather.Results indicated that a series of PGMSQ nanospheres could be manufactured with regularly spherical particle and its average size of 50~230nm when the mole ratios of KH560 to MTES and oils to water were 0.1~0.4 and 0.03~0.14,respectively and the compound emulsifiers dose was 0.8~1.2%.While the dose of the crosslinking monomer MTES was 0.8%,the JRASO viscosity was 2869 m Pa?s,the ammonia value and the alkyl value were 0.3 and 0.9mmol/g,respectively,hydrophobicity of the as-prepared JRASO was optimal with the biggest WCA of142.8°.While the average diameter of the PGMSQ was 149.3nm,the PGMSQ content in PGMSQ-JRASO was 15%,and the dose of the mixed AEO-3/AEO-9emulsifiers was 25%,the appropriate PGMSQ-JRASO was obtained to spray the nubuck leather with 0.9% solid content.Then,it was dried under 80? and the excellent nubuck leather was acquired with WCA of 162.5°.Moreover,when the treated leather was dry rubbed 25 times,WCA could still maintain156.9° and water vapor transmittance was 2024.49g/(m2?day).FESEM observa-tion revealed that the PGMSQ nanospheres were coated on the leather fibers as monolayers and it will render the treated nubuck leather with micro/nano dual-scaled roughness and construction of superhydrophobic nubuck leather.Furthermore,breathability of the treated leather was not influenced at all.(2)Synthesis of the cross-linked PAMSQ/polysiloxane emulsion and construction of superhydrophobic leather from itA series of polyaminomethylsilsesquioxane(PAMSQ)nanospheres composites were first fabricated via the emulsion polymerization method and sodium hydroxide was used as catalyst,?-aminopropytriethoxysilane(KH-550)and methyl triethoxysilane(MTES)as precursors,sodium dodecyl sulfonate(SDS)/fatty alcohol-polyoxyethylene ether(AEO-9)as mixed emulsifiers.Then,the silicon hydroxyl-terminated polysiloxane intermediate with pendant vinyl groups was synthesized by alkaline equilibration reaction amongst octamethylcyclotetrasiloxane(D4),2,4,6,8-Tetramethyl-2,4,6,8-tetravinyl-cyclotetrasiloxane(D4Vi),MTES.Next,a sort of hydrophobic polysiloxanes(JPDMS)with crosslinked structures were prepared via hydrosilylation of polymethylhydrosiloxane(PHMS)and the above intermediate and then a series of cationic PAMSQ-JPDMS hybrid latexes were divided into in-situ condensation reaction from PAMSQ and JPDMS,and emulsified by nonionic mixed emulsifiers.Finally,superhydrophobic goat leather was obtained via the spraying method with dry rubbing resistance and breathable characteristic.FT-IR and 1H/29Si-NM-R analyses demonstrated that the as-prepared JPDMS and PAMSQ had the due structures.DLS,TEM,SEM and AFM measurements revealed that a series of PAMSQ nanospheres could be manufactured with regularly spherical particle and its average size of 50~200nm via orderly dripping monomers when the mass ratio of MTES to KH550 was 0.25~0.43,the compound emulsifiers dose was0.85~0.95% and the Na OH concentration was 4.5~20.0mmol/L.Application experiments results indicated that hydrophobicity of the as-prepared JRASO was optimal with the biggest WCA of 141.6°,while the dose of the crosslinking monomer was 0.3%,the vinyl value were 0.12mmmol/g,viscosity and Si-H content of the PHMS were 1982 m Pa?s and 0.15%,respectively.While the average diameter of the PAMSQ was 128.7nm,the PAMSQ content in PAMSQJPDMS was 15%,the appropriate PAMSQ-JPDMS was obtained to spray thegoat leather with 1.2% solid content.Then,the excellent goat leather was acquired with WCA of 163.8°.Moreover,when the treated leather was dry rubbed 100 times,WCA could still maintain 156.6° and water vapor transmittance was 3074.01g/(m2?day).FESEM observation revealed that the dense PAMSQ-JPDMS coating was covered on the goat leather surface and it will render the PAMSQ nanospheres uniformly distributed on the leather fibers surface.This particular micromorphology constitutes one of the primary reasons for construction of superhydrophobic surface.