Synthesis, Characterization, And Application Of Highly Branched Copolymer As Filling-Retanning Agent

Highly branched polymer has evolved based on"classical"hyperbranched polymer. The reduction of the degree of branching density has been explored by increasing linear chains to dilute the branching structure, according to application requirement. Currently, the definition between hyperbranched polymer and highly branched polymer have not explicit, generally referred to as hyperbranched polymers.Mono-glyceride trimaleate is prepared by esterification from glycerol with maleic anhydride (MA), which is employed as allyl branching monomer to copolymerize with acrylic acid to prepare highly branched copolymers (HBPMA) via aqueous free radical solution copolymerization. The optimization and characteristics of copolymers have been discussed, and which as retanning agent for leather-making.The influences of molar ratio between glycerol and maleic anhydride, temperature and time on esterification rate of MA are discussed during branching monomer synthesis, The characteristics of the branching monomers are determined by nuclear magnetic resonance spectroscopy (NMR). The double bond functionality (DBF) is determined by esterification rate of MA and NMR method.Series of HBPMA are synthesized by free radical polymerization. The influence of comonomer feed ratio, neutralization degree, the dosage of initiator and the type of branching comonomer on double bond conversion of branching monomer and aqueous solution viscosity are investigated. The results show that, MGT is employed as allyl branching monomer, which can reach high conversation when n(AA):n(MGT) is 6:1, neutralization degree is 0.4, the mass of initiator ammonium persulfate is 4%. The effect of comonomer feed ratio, the dosage of initiator and the type of branching comonomer on molar mass and intrinsic viscosity of copolymers are determined by size exclusion chromatography (SEC).The characteristics of HBPMA are determined by NMR and SEC. The branched structure is confirmed by the corresponding Mark-Houwinkαvalue and branching factors (g′). The properties of solution and thermal are determined by viscometer, differential scanning calorimetry (DSC), thermogravimetry (TG).HBPMA are applied in leather retanning as filling-retanning agent. According to the research of indexes such as filling quality and pliability are discussed. The results show that HBPMA perform well in filling and retanning leather and especially in the case of HBPMA-III. The results of scanning electron microscopic (SEM) show that HBPMA disperse well the leather fiber.