Study Of The Preparation And Stability Of Oil In Water(O/W) Natural Rosin Emulsion

In this paper,the theory of rosin emulsion and the research progress of rosin emulsion at home and abroad are summarized.Oil in water(O/W)natural rosin emulsion was prepared from natural rosin.The characteristics of the emulsion are good water solubility,good stability and non-toxic and harmless.The emulsion can be used as an adhesive emulsion for waterborne adhesives and water-based coatings.The research contents of this paper include the following aspects.Firstly,the rosin emulsion was prepared by compound emulsifier,and the technological conditions affecting the stability of rosin emulsion were evaluated and optimized.The results showed that the optimum process conditions were as follows:emulsifier HLB value was 10,emulsifier dosage was 11.37%,emulsifying temperature was about 119?,oil water ratio was 10:31,stirring speed 800 rpm,the adding method of emulsifier is two phase method,and emulsifier content had the greatest influence on the stability of rosin emulsion.Under this condition,the O/W type natural rosin emulsion was milky white,dispersed uniformly and non stratified centrifugation,and stored at room temperature for 28 days.Secondly,based on the evaluation and optimization of the conditions for the stability of rosin emulsion,the stability of rosin emulsion was analyzed theoretically.Results: rosin emulsion stability have relationship with interfacial tension,interfacial film,electrostatic repulsion,steric factors,particle size and distribution,temperature and so on,and the selection and dosage of emulsifier is the key factor to determine the above factors.Thirdly,based on the results of theoretical analysis,through the optimization of emulsifier,the anionic ONIST APS-350 emulsifier was selected to prepare rosin emulsion,On the basis of investigating the influence of emulsifier content,emulsifying temperature,oil-water ratio and stirring speed on the particle size distribution of O/W natural rosin emulsion,response surface methodology(RSM)was used to simulate and optimize the process parameters.The results showed that the optimum parameters were determined as follows: emulsifier content 9.95%,temperature 112?,and the oil-water ratio 10:31,stirring speed 500 rpm.Under this condition the O/W type natural rosin emulsion has blue light,uniformly distributed,non stratified centrifugation.The average particle size of the emulsion was 131.1nm,which was in agreement with thepredicted value of 138.091 nm.The PDI value of the emulsion was 0.054,and the emulsion storage at room temperature for six months did not layered.Finally,using the rosin emulsion,which was prepared by the anionic ONIST APS-350 emulsifier in the optimum process conditions,investigated the morphological characteristics of rosin particles and the interaction of rosin and emulsifier by TEM.The results show that the particle size of the emulsion is uniform spherical distribution,the particle size distribution is about 130 nm,it is consistent with the experimental value.And it can be observed that the emulsifier interacted with rosin particles forms a dense interfacial film which is coated with the core shell structure and the interface between the core and the core of the oil phase is clearly visible.This structure leads that the rosin is dispersed in the aqueous phase in the form of small particles,thereby improving the stability of the rosin emulsion.