High-Performance Polymer Materials Prepared By Continuous Photopolymerization

Known as new generation of green technology, UV curing technology has no solvent evaporation, short curing time, low temperature polymerization and other advantages over conventional curing technology, widely used in the fields of coatings, inks, adhesives, printing plates, electronic, micro-machining, rapid prototyping and so on. UV curing technology and solution polymerization techniques have been combined into a mutually complementary technology trend and fully developed. The production process gradually changes from the traditional static system to the dynamic system. The dynamic system has many advantages, such as fast heat dissipation, uniform illumination, complete reaction, and it will be an important trend in the field of UV curing technology in the future. However, the present dynamic UV curing technology can not satisfy the mass industial requirements for preparation of the solvent controlled and qualitative polymers.To solve the problem, based on the combination of photopolymerization and traditional polymerization, a continuous UV technology has been creatively posed to make the molecular weight and the particle size controlable.1. Preparation of molecular weight controlled polymer by continuous photopolymerization. At first, it's confirmed that the homopolymers of alkyl acrylate can be prepared by the continuous polymerization by infrared spectrum analysis; Next, by orthogonal experiments, the four factors:initiator concentration, solvent ratio, flow rate, monomer molecular weight have been studied, and the results showed that the initiator concentration is the most significant factor affecting the polymer molecular weight; Then, based on the results of the orthogonal experiment, we found that with the initiator concentration increasing, the molecular weight decreased, but the results of the ratio of good solvent reversed. According to the law of the single factor experiments and the similar structure with similar performance, the molecular weight of alkyl acrylate can be controlled around 3000 and 5000 respectively. Meanwhile, the feasibility to synthesize MA-co-AA and MA-co-HEA by continuous potopolymerization has also been confirmed by infrared spectrum analysis. Finally, from the dynamic analysis of static photopolymerization, we can find that with increase of illumination time, the molecular weight of PMA decreased. Comparison with the static photopolymerization, the dynamic one showed the superiority.2. Preparation of cross-linked PMMA particles by continuous photopolymerization. At first, it's confirmed that the cross-linked PMMA particles can be prepared by the continuous polymerization by SEM. Next, initiator concentration, the ratio of good solvent, monomer content, cross-linker concentration, and degree of cross-linker have been studied. The results showed that with the increase of initiator concentration, the particle size increased, both coefficient of variation(CV) and specific surface(S.P.Area) decreased, and the minimum size is 1.32μm; with the increase of ratio of good solvent, the particle size and CV increased, but S.P.Area decreased; with the increase of monomer content, the particle size increased gradually, both CV and S.P.Area decreased; and when the cross-linker concentration and degree of cross-linker increased, the particle size decreased, and the particle size of TM3 is the minimum,0.56μm. Finally, the circulation experiment and the SEM analysis confirmed the microspheres'nucleation and growth mechenism.