Research Fields
  Industrialized Techniques
  Polymeric Microsphere World
  Institute of Polymer Science & Engineering
  Department of Chemical Engineering
  Tsinghua University
  Our research interests include both theory and application in five aspects as follows.  
  1. Emulsion Polymerization  
  As one of the polymerization methods, emulsion polymerization has become more and more important because of its friendly environmentally advantage. However, since emulsion polymerization system is too complicated, many academic and technical problems remain unsolved. In this field, our researches are mostly focused on design and control of latex particle morphologies based on thermodynamic and kinetic factors, preparations and applications of functional polymer latexes with ambient self-crosslinked properties, relationship between the particle morphology and the properties of latex and its film. Monomers used included acrylics, styrene, silicone, isocyanides, vinyl acetate, etc. The polymerization can be performed in the presence/absence of emulsifiers. Some new kinds of latexes have been invented and industrialized in China for different applications.  
  2. Functional Polymeric Microspheres  

A wonderful trip in the Polymeric Microspheres' World

Functional polymeric microspheres are those particles with reactive and/or functional groups on their surface or inside them, or with special morphologies, and have many direct and potential applications in many aspects. The design, the control and the application of different kinds of functional polymeric microspheres are the first 3 important aspects in this area. Our research interests include micron-sized, submicron-sized and micron-sized functional polymer.

(a) Porous polymer latex particles.
Using different emulsion polymerization processes combined with different post-treatment methods, several kinds of submicron or micron sized porous latex particles with controllable particle size and hollow volume inside them have been prepared in the absence/presence of surfactants. These kinds of particles are expected to be used in special coatings (sound and vibration damping, for example), biochemical and biomedical fields, polymer pigment, paper manufacturing additive, water-maintaining materials, etc.

(b) Monodispersed polymer particles with surface active groups.
Monodispersed polymer particles with surface groups (such as -COOH, -OH, -SO3H etc.) have been synthesized by means of Dispersion Polymerization, Emulsion Polymerization, Microemulsion Polymerization, or Miniemulsion Polymerization in our Lab. The diameter can be controlled in the range from several dozen nanometers to several microns, and the distribution of active groups can be managed as well. The applications of these monodispersed polymer particles are under consideration.

(c) Polymer particles for bio-technique applications.
To meet the need of biochemical and biomedical application, specific polymer particles should be designed and prepared. We are interested in the bio-molecules immobilization, the target delivery, and controlled release of active. In this field, two kinds of submicron sized soap-free latexes particles have been synthesized and used as immobilizing carriers of enzyme and medicine in our Lab. The immobilizing method, the stability and the activity of the immobilized biomaterials, as well as the relationship between them have been investigated.
Diagnosis polymer particle is another interest of ours. Micron sized polymer particles with several microns in diameter and with surface functional groups have been synthesized, and their applications are being explored.

(d) Self-colored polymer latex particles.
To enhance the color stability of waterborne polymer system, novel unsaturated monomers with chromophore group were synthesized and used to copolymerize with other monomers, the polymerization and the relationship between colloidal properties and materials were investigated. The color stability of the latex films can be significantly improved.

(e) Polymer particles with different morphology.
Polymer particle morphology is so amusing and supernatural, and in common, we can control it! We have made several kinds of particles with different morphologies such as core/shell, strawberry-like, porosity, IPN and the like.

  3. Silicone Materials  
  Due to its Si-O-Si bonds and the side substitutes, silicone has many specific properties including outstanding thermal stability, good low temperature properties, good stability towards O2, O3 and corona discharge, excellent dielectric properties, low surface tension, and good biologic compatibility. In this field, our research interests include mainly performance enhancing of polymer materials by silicone modification (chemically introducing silicone into a polymer molecule), polyacrylics-polysiloxane latex particles with well-designed structures, such as core/shell, grafting, and interpenetrating networks, polymer supported hydrosilylation catalyst of high activity, selectivity and good reusability,and other silicone materials such as RTV silicone rubber, damping silicone rubber and silicone latex. Micron-sized polymer supported platinum complex catalyst beads have been used in the hydrosilylation of unsaturated monomers with Si-H-containing compounds to prepare specific silicones. Our damping silicone rubbers have been used as damping materials in helicopter, hand-lifting missile and cruise missile, and good application results were obtained.  
  4. Phase inverse technique of polymers  
  It is well known that free radical emulsion polymerization is a mainly important method to prepare waterborne polymer products from unsaturated monomers. However, some of conventional polymers such as alkyd and epoxy resin can not be synthesized by free radical polymerization mechanism, and phase inverse technique become only one method to prepare waterborne products of this kind of polymers. Unfortunately, some of theoretical and technical problems for phase inversion of polymers are not clarified till now. In this case, the phase inversion phenomena between polymer and water were investigated, and some waterborne polymer systems, such as alkyd, polyurethane and polyether were studied.  
  5. Water-borne coating, paint and adhesive  
  We are also interested in waterborne coating, paint and adhesives. Based on systematic researches, several kinds of waterborne film-forming resins such as modified polyacrylics, polysilioxane, polyurethane, polyether and alkyd resin have been prepared using emulsion polymerization or phase inverse techniques, and some of them have been used to produce water-borne coatings, paints and adhesives.