The Synthesis And Characteristics Of New Amphiphilic Copolymer Retanning And Fatliquoring Agents

The amphiphilic acrylic retanning agents, which is usually composed ofhydrophobic and hydrophilic parts, has a wide application values in leather makingindustry. Because of hydrophilic and hydrophobic functionality, the amphiphilic acrylicsyntan combines the fatliquoring and retanning ability in a single product. Thesematerials could impart unique properties of softness and mechanical strength to leather,could be nearly100%taken up in the leather-making process, resulting in minimalimpact on the tannery waste water. In recent years, much attention has been paid to thepreparation and application of amphiphilic acrylic copolymer retanning agents in thedevelopment of the leather chemicals.In this paper, the synthesis and characteristics of3different kinds of amphiphilicacrylic copolymer retanning agents by emulsion polymerization is described. Thestructure of the prepared copolymers is characterized, and the correlation between thecomposition of the resulting retanning agents and its application properties has beeninvestigated. The results could provide some theories for the research of the synthesis,retanning mechanism of amphiphilic acrylic resin, and its application in leather makingindustry.The four parts of this paper:(1) LAT series amphiphilic acrylic copolymer of lauryl acrylate and acrylic acidhas been synthesized by emulsion polymerization, with AEO-9and SCO as emulsifiers,APS as initiator. The structure of the prepared copolymer was characterized by Fourierinfrared spectroscopy (FT-IR), and particle size was measured with dynamic lightscattering instrument (DLS). The correlation between the composition of the preparedcopolymer and its application properties has been investigated by measuring suchphysical/mechanical indexes of the retanned leather as tear strength, tensile strength,elongation at break and thickness increment. The retanning mechanism of the polymericsyntan was also explored by SEM, XRD and DMA. It has been found that theapplication properties of the product is strongly affected by the composition of theamphiphilic acrylic copolymer. The resulting product shows good fatliquoring andretanning functions for leather, and the tear strength, tensile strength, elongation atbreak and thickness increment of the retanned leather is promoted obviously.(2) Cellulose nanofibers TONCC has been prepared by the oxidation of kraft pulpwith TEMPO/NaBr/NaClO system, fllowed by ultrasonic treatment. The structure and properties of TONCC is characterized by AFM, XRD and conductimetric titration. ThenTONCC/LAT nanocomposites of TONCC and LAT amphiphilic acrylic copolymer hasbeen prepared by ultrasonic treatment, and its application properties is investigated. Theapplication results show that, the TONCC/LAT nano-composite has excellentfatliquoring performance, and the tensile strength of the retanned leather is promotedobviously.(3) CF serieas amphiphilic fluorinated acrylate copolymers of dodecafluoro-heptyl methacrylate (FA-1), dimethylaminoethyl methacrylate (DM), methacrylate (MA)and benzyl chloride has been synthesized by solution polymerization, with AIBN asinitiator. The structure of the resulting CF is characterized by FT-IR and1H-NMR, andits surface active properties have been investigated by measuring the surface tension ofthe CF solutions. It has been found that the surface active properties of the CFcopolymer are strongly affected by the composition of the resulting product. When themolar ratio of FA-1, DM and MA is5:5:1, the CF amphiphilic acrylate copolymershows excellent surface active performance.(4) FL series cationic fluorinated acrylate copolymer latex of fluorinated acrylateand alkyl acrylate monomers has been synthesized by emulsion polymerization, withV-50as initiator, and the structure of the resulting copolymer is characterized by FT-IRand DSC. The correlation between such polymerization conditions as amphiphilicfluorinated acrylate copolymer (CF), fluorinated acrylate monomers, alkyl acrylatemonomers with different long alkyl chains and the latex properties has been investigatedby contact angles. The results show that, the resulting product (FL15~18) synthesizedwith amphiphilic fluorinated acrylate copolymer (CF) as emulsifier shows higherhydrophobocity than that with low molecular surfactants as emulsifiers. When the doseof FL-17is10%(based on the weight of chromed leather), the dynamic waterpermeability times of the retanned leather reached up to2109.