A process for preparing an ultra-high molecular weight polymer via emulsion polymerization at room temperature

Abstract

The invention discloses a process for preparing an ultra-high molecular weight polymer via emulsion polymerization at the room temperature, belonging to the fields of polymer synthesis. Persulfate as initiator, water as medium, anionic surfactant as emulsifier, sodium bicarbonate as pH regulator, styrene, (meth) acrylate or vinyl acetate as monomer, is subjected to a free radical polymerization at room temperature and the normal pressure. The ultra-high molecular weight polymers were successfully obtained, which the weight average molecular weight of the polymers were larger than 100×104 g/mol. The monomer conversion can be above 85% after the reaction was proceeded about 1˜6 hours. The process for preparing an ultra-high molecular weight polymer is carried out under the conditions of conventional free radical emulsion polymerization at the room temperature and normal pressure without the addition of other assist initiators. There is no need to control temperature and pressure of the reaction, low energy consumption, short reaction time and high monomer conversion, ultra-high molecular weight and narrow molecular weight distribution of the polymers achieved, and the molecular weight and molecular weight distribution can be adjusted and controlled in a wider range. The polymerization is simple and stable, the commercial materials can be directly used in the reaction, which greatly reduce the cost, easy operation, mild conditions and the environmental friendly process. This process is highly suitable for synthesizing ultra-high molecular weight polymers from various monomers. These advantages of this process is of great significance for the research and application of ultra-high molecular weight polymers.

1 . A process for preparing an ultra-high molecular weight polymer via emulsion polymerization at room temperature comprising a persulfate as an initiator, water as a medium, an anionic surfactant as an emulsifier, sodium bicarbonate as a pH regulator, styrene, vinyl acetate or (meth) acrylate as a monomer to polymerize by free radical emulsion to obtain the ultra-high molecular weight polymer wherein the weight average molecular weight of the ultra-high molecular weight polymer is larger than 100×104 g/mol. 
     
     
         2 . A process for preparing an ultra-high molecular weight polymer via emulsion polymerization at room temperature as described in  claim 1 , wherein the initiator is potassium persulfate or ammonium persulfate. 
     
     
         3 . A process for preparing an ultra-high molecular weight polymer via emulsion polymerization at room temperature as described in  claim 1 , wherein the molar ratio of initiator and monomer is 1˜5:100. 
     
     
         4 . A process for preparing an ultra-high molecular weight polymer via emulsion polymerization at room temperature as described in  claim 1 , wherein the mass ratio of water and monomer is 2˜5:1. 
     
     
         5 . A process for preparing an ultra-high molecular weight polymer via emulsion polymerization at room temperature as described in  claim 1 , wherein the polymerization temperature is room temperature and the polymerization reaction time is controlled in a range of 1˜6 hours. 
     
     
         6 . A process for preparing an ultra-high molecular weight polymer via emulsion polymerization at room temperature as described in  claim 1 , wherein the surfactant is an anionic surfactant, sodium dodecyl benzene sulfonate, or sodium dodecyl sulfate. 
     
     
         7 . A process for preparing an ultra-high molecular weight polymer via emulsion polymerization at room temperature as described in  claim 1 , wherein the mass ratio of the surfactant and monomer is 4-6 wt %. 
     
     
         8 . A process for preparing an ultra-high molecular weight polymer via emulsion polymerization at room temperature as described in  claim 1 , wherein the mass ratio of the pH modifier sodium bicarbonate and monomer is 2˜4 wt % and the pH value is adjusted to 7˜8.