Preparation And Application Of Polynuclear Low-density Polymer Microspheres

Due to its uniquet structural characteristics,and can be adjusted to control the structure and functional design by controlling the preparation conditions,the core-shell polymer microspheres offers more superior advantages than conventional polymeric microspheres and are widely used in medicine,cosmetic,electronic information,film,paint,paper surface processing,plastic additives,acid mist suppression and other fields.In this paper,firstly,we used the existing laboratory technology to prepare small-diameter low-density polymer microspheres which particle size less than 500.0?m,and were used as the core material;Then preparing multi-core low-density polymer microspheres by the bulk-suspension polymerization method.That is to say,first,the prepolymer with a certain viscosity prepared by the bulk polymerization method,then the core material was mixed into the prepolymer,next,the prepolymer with cores was transferred to the suspension polymerization system to disperse into microspheres and aged,finally,a kind of multi-core low-density polymer microspheres were prepared.In addition,the physico-chemical modification of multicore microspheres was investigated by changing the type of cores embedded and modifying the wall materials by grafting,copolymerization,and cross-linking.And the multi-core polymer microspheres were used for the experimental study of acid mist suppression.The main conclusions of this paper are as follows:1.The prepolymer viscosity has an important influence on being microspheres formation,morpHology structure,particle size,flotation rate,and reaction system stability of multi-core low-density polymer microspheres.To meet the requirements of acid mist suppression used the polymer microspheres,the study determined to preparate the multi-core low-density polymer microspheres with characteristics of the preparation of multicore polymer microspheres:the reaction system is stable,the core is completely embedded,the spherical particles are regular,the density is less than1g/cm~3,and the particle size is between 0.5~2.0mm.The experimental results show that the preparation conditions for preparing the optimum viscosity prepolymer corresponding to the requirements of the multi-core polymer microspheres are as follows:the bulk polymerization time is 70~80 min,the initiator dosage is2.0%~3.0%,and the bulk polymerization temperature is 75?.2.There are important influences that suspension polymerization temperature,stirring speed,water-oil ratio,type and dosage of dispersant,low-density core polymer microspheres on the structure,particle size,flotation rate,density,stability of the reaction system and so on of multi-core low-density polymer microspheres.The experimental results show that the optimal conditions for preparating multi-core low-density polymer microspheres with particle diameters of about 2.00mm are as follows:Suspension polymerization temperature is 75?,water-oil ratio is 5:1,stirring speed is 800~1000rpm,dispersant PVA1788 and its dosage is 2.0%,the dosage of low density core polymer microspheres is 10.0%,and its diameter is40~120 mesh.3.This experiment method can not only embed small-sized and low-density polymer microspheres,but also embed many types of inorganic powder particles(metals,metal oxides,inorganic non-metals,inorganic non-metal oxides,phospHors etc.).In addition,cross-linking,copolymerization,and graft modification of the wall material of the multi-core low-density microspheres can also be performed.The experimental results show that the optimal conditions for the stable preparation of multi-core polymer microspheres modified chemically are as follows:the dosage of crosslinker DVB is less than 40%,the molar ratio of St:BA is higher than 1:1,and the best hydropHilic modifier is AA.4.The application research of multi-core polymer microspheres in acid mist suppression found that,acids are corrosive to multi-core polymer microspheres.However,multi-core polymer microspheres with a certain degree of cross-linking have good acid corrosion polymer resistance,even though the degree of crosslinking can be as low as 5%;There is good hydropHilicity for methacrylate multi-core polymer microspheres modified by acrylic acid and hydroxyethyl,in which the multi-core polymer microspheres modified by the acrylic have the best hydropHilicity.As for multi-core polymer microspheres,the better hydropHilicity,the worse agglomeration or the wall-hanging performance in acid liquid.In addition,the covering method of microspheres can inhibit effectively both static and dynamic acid mist,and the covering method of multi-core polymer microspheres modified by AA can inhibit energy efficiency better.