Esterification Of Lignosulfonate And Preparation Of Its Acrylate Copolymer

As the by-product of pulp and paper industry,calcium lignosulfonate(LS)had complex structure.The phenolic hydroxyl group in LS could inhibit the free radical polymerization,which limited the high value utilization of LS.On the other hand,calcium lignosulfonate had excellent hydrophilicity and plenty of hydroxyl reaction sites.The soluble macromonomer which had high polymerization activity were obtained through the reaction between LS and esterification reagents.The reaction increased the grafting efficiency of LS.At the same time,the inhibition of phenolic hydroxyl group on free radical polymerization were weakened.The reaction was carried out between LS and two kinds of esterification agents included acryloyl chloride(AC)and undecyl chloride(UC).N,N-dimethylacetamide(DMAc)and triethylamine(TEA)were acted as solvent and catalyst respectively.The reaction solution was treated by filtration,precipitation,centrifugation,washing and drying.The optimized reaction conditions were obtained by orthogonal experiment with reaction time,reaction temperature and reactant ratio.The optimized reaction conditions of the esterification with AC was at the temperature of 60 ? for 8 hours and mass ratio of reactants(AC:LS and UC:LS)was 1.2:1.0.Structures of LS,AC-LS and UC-LS were characterized by fourier transform infrared spectrometer(FTIR),nuclear magnetic resonance spectrometer(NMR)and ultraviolet absorption spectrometer(UV).Contents of double bond and hydroxyl in LS,AC-LS and UC-LS were explored by titration and quantitative method of NMR.The polymerization of AC-LS and UC-LS were investigated by differential scanning calorimetry(DSC).Molecular weights of homopolymers were determined by gel permeation chromatography(GPC).Double bond in AC-LS and UC-LS were masked by the three-dimensional structure of LS.The collision ratio between esterification products and other molecules were declined.The electron cloud of double bond was dispersed because of aromatic ring.The influence of the three-dimensional structure and electron cloud on the polymerization was explored.As a small molecule,SG had similar structure to LS.SG was esterified by methacrylic anhydride(MA)in DMSO with TEA as catalyst.The reaction solution was treated by filtration,precipitation,centrifugation,washing and drying.The structures of SG and MA-SG were characterized by FTIR,NMR and UV.Calorific of the mixture of MA-SG and APS was measured by DSC.The molecular weight of PMA-SG was determined by GPC.Latex was prepared by emulsion polymerization with AC-LS and acrylate monomers.Homopolymer and the unreacted AC-LS in polymer were removed by extraction acetone and water in order.The effect of AC-LS dossage on polymerization were discussed.With the increase of AC-LS dossage,the particle size and polydispersity(PDI)of latex increased,the solid content,monomer conversion rate,grafting rate,and AC-LS conversion rate gradually decreased.The UV absorbability of acrylate latex,copolymer latex and the blending latex were measured respectively.And Tg of copolymers were measured by DSC.