Study On The Polymerization Of Cationic Acrylate Emulsion

The cationic polyacrylate emulsion is characterized by good weather resistance, acid and alkali resistance, aging resistance, stain resistance, film forming, non-toxic, and good adhesion with negatively charged material because of its positive charge, thus it has been widely used in the paint, pressure-sensitive adhesives, fabric treatment, antistatic agent, paper making and so on. However, due to the higher requirement of emulsifier, initiator system and cationic comonomer, the cationic polyacrylate emulsion developed slowly, so explore how to synthesis the cationic polyacrylate emulsion with ordinary system is very important for the development of cationic emulsion. In this paper, the cationic polyacrylate emulsion has been obtained by using cationic emulsifier system without cationic comonomer.The effect of different polymerization processes on emulsion polymerization and properties was explored, compared with the emulsion obtained through seeds semi-continuous emulsion polymerization, the cationic polyacrylate emulsion prepared by the batch emulsion polymerization owns higher solid content and conversion rate, small particle diameter with 83.05nm and narrow particle size distribution, the PDI is 0.232, and the centrifugal stability, acid alkali stability, stability and storage stability of the performance test of emulsion exhibited good stability.Conductivity method was used to test the ordinary single-chain cationic emulsifier:cetyl trimethyl ammonium bromide (CTAB), cetyl trimethyl ammonium chloride (1631), and the system mixed with nonionic emulsifier (Aliphatic alcohol polyoxyethylene ethers:AEO9,AEO20), the critical micelle concentration (cmc) of each system was got by extrapolate method. The result showed that:the cmc value of the system CTAB/AEO9/AEO20=2/1/1 was significantly lower than other systems, which illustrated that the mixture has greater synergy. The emulsion adding the protective colloid Polyving akohol (PVA) performs better appearance and properties than the system without PVA-124 or PVA1750±50, The optimum amount of PVA-124 is 1% of total monomer. The comprehensive analysis on the systematic researches about the effect of mixture ratio and content on the properties of the emulsifier prepared by using different emulsifier systems showed that the emulsion exhibits performances better when CTAB/AEO9/AEO20=2/1/1 and the emulsifier content is 4.38%.The effect of different initiator systems on emulsion properities was also investigated. The results showed that the emulsion prepared by ammonium persulphate (APS) performs lower solid content and conversion ratio than of 2, 2’-azobis[2-methylpropionamidine] dihydrochloride (AIBA), because of the generation of gel lead to lower solid content and conversion ratio as well as the poor stability of the emulsion. For redox initiator system, the emulsion employed tert-butyl hydroperoxide-Ferrous sulfate (TBHP-FeSO4) initiator exhibits better performance comparably. By comprehensive comparison can obtain better emulsion with high convertion of 99.9%, the optimum initiator is AIBA with a content of 0.3%.The different kinds of functional monomer had great impact on the emulsion. The emulsion obtained by adding Hydroxypropyl acrylate (HPA) with APS as initiator, exhibited a decrease in particle diameter and the responding stability is also significantly improved than that of other functional monomers; the emulsion obtained by adding HPA with AIBA as initiator exhibited better performance. Futher more, the different dropping methods of functional monomer have been explored. The experimental results showed that the emulsion obtained by after adding method exhibits superior properties than the emulsion by the direct adding into the seed emulsion.The influencing factors of emulsion polymerization mechanism and part of polymerization kinetics have been discussed, the results showed that the polymerization of the emulsion obtained by using the emulsifier system of 1631+AEO9+AEO20 follows micellar nucleation mechanism and homogeneous nucleation mechanism, while being with CTAB+AEO9+AEO20 or Gemini+AEO9+AEO20 as emulsifier (the Gemini emulsifier is polyoxyethylene alkyl vinyl double ammonium), the micellar nucleation mechanism worked. In the reaction with PVA-124, the emulsion was obtained by micellar nucleation mechanism, while the emulsion without PVA-124 was synthesised via micellar nucleation mechanism and homogeneous nucleation mechanism. The emulsion with APS or AIBA as the initiator both followed the micellar nucleation mechanism. The effects of polymerization process, emulsifier and initiator on the instantaneous conversion of emulsion have been discussed.