| The bio-vinyl acetate disproportionate rosin composite emulsion was prepared by miniemulsion method with poval (17-88) as protective colloid, disproportionate rosin (DR) as modified substance, lauryl sodium sulfate (SDS) as emulsifier, and ammonium persulfate (APS) as initiator. The preparation conditions for composite emulsion were optimized by single factor and orthogonal test method. The structure and properties of composite emulsion were characterized, and were compared with those of the PVAc emulsion and blend latex. The ploymerization kinetics model was established and then, the model parameters were fitted. The main contents are as follows:In the preparation of composite emulsion, the effects of the amount of the protective colloid, the amount of emulsifier, initiator, the amount of disproportionated rosin and reaction temperature on emulsion polymerization influenced the dry tensile strength and adhesive film absorption rate were investigated by single factor. The process of the preparation of composite emulsion was optimized via the method of orthogonal experimental. The optimum conditions from the single factor method show that were protective colloid 4.0 wt%(the proportion of monomers and water, the same as below), emulsifier 1.0 wt%, initiator 0.5 wt%, disproportionated rosin 2.0 wt%, polymerization reaction temperature 75 ℃. The order of five factors on composite emulsion the dry tensile strength was protective colloid> disproportionated rosin> temperature polymerization> initiator> emulsifier according to analysis of variance; the order of five factors on the rate of water absorption of composite emulsion was protective colloid> emulsifier> disproportionated rosin> initiator> polymerization temperature.In addition, PVAc emulsion, composite emulsion and blend latex were analysised and compared through FT-IR, DLS, TEM, DSC, TG and SEM. The result shows that disproportionated rosin doesn’t copolymer with vinyl acetate mononer, but we can adhesive the composite emulsion with narrower particle size distribution and smaller average particle size compared with PVAc emulsion, which is agreed with the electron microscope analysis. PVAc emulsion particle average size is 361.2 nm, PDI is 0.21. The composite emulsion particle average size is only 136.6 nm, PDI is 0.214. The blend latex particle average size distribution has two peaks, one is 690.3 nm, and the other is 2226 nm. The glass transition temperature tested of PVAc emulsion is 21.3 ℃, and the composite emulsion is only 12.3 ℃. While blend latex appeares two glass transition temperature is 36.81 ℃ and 19.6 ℃ respectively. The decomposition temperature range and size of PVAc emulsion, composite emulsion and blend latex are different. The thermal decomposition temperature and amount of residual of the composite emulsion are the largest. The film of composite emulsion is smooth under the scanning electron microscopy. The dry tensile strength of PVAc emulsion, composite emulsion and blend latex are 7.5 MPa, 11.8MPa and 9.6MPa.The efffects of the amount of emulsifier, intiator, monomer, disproportionat-ed rosin and the reaction temperature on conversion rate were investigated by weight method. The results showed that the rate of polymerization was increased with amoumt of emulsifier, initiator concentration and monomer concentration and reduced with amoumt of modified insoluble disproportionated rosin. The changes of polymerization rate with the time were investigated via the online tracking method, and the chemical ractivation energy and activation factor were calculated. The apparent activation energy of polymerization was 27.52 kJ/mol and the pre-exponential factor was 30.48 based on the Arrhenius formulae. The kinetic equation of composite emulsion was Rp=30.48e-27.52/RT J[SDS]0.373[APS]0.218[Bio-VAc]0.362[DR]-0.149. |
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