Experimental Investigation of AGET ATRP of MMA in Two-Step Emulsion System Kishor N. Up. Regmi, Ramdhane Dhib, Mehrab Mehrvar Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada Reactor System NSERC and Department of Chemical Engineering, Ryerson University for financial support. Introduction Results Objectives Concluding Remarks Synthetic Procedure Atom transfer radical polymerization (ATRP) is one of the most popular method of CRP. Currently there is exponential growth in the research of ATRP as it allows the production of polymers having controlled features (low MWD, high chain end functionality) with relative ease. Polymers synthesized by ATRP can be used as lubricants, surfactants, adhesives, inks, gels, dispersants, additives, thermoplastic elastomers, as well as for biomedical applications like drug delivery and artificial bones. ATRP in aqueous dispersed media has several advantages as compared to bulk and solution polymerization like: use of environmentally friendly and economical dispersant, very efficient heat transfer and less viscous reaction medium allowing high conversion. The literature on ATRPin aqueous dispersed media (emulsion ATRP) though not extensive is growing rapidly. The polymer chemistry and other kinetic/mechanistic aspects of ATRP in emulsion are still not well understood • Conduct the single-step and two-step emulsion AGET ATRP of MMA in a stirred tank reactor using commercially available chemicals: CuBr 2 , dNbpy, EBiB, AA and Brij 98. • Investigate the effect of single-step and two-step emulsion system on the stability of latex, conversion of the monomer and molecular weight distribution (MWD) of the polymer. • Generate a source of reliable experimental data (based on the statistical analysis) which will help in the better understanding of the system. − + / . + − +1 / Experimental Condition Acknowledgement • Experimental results indicate that it is possible to conduct ATRP in single–step and two-step emulsion system with limited presence of air. However it is very hard to get stable latex system without aggregation/coagulation, especially at higher conversion for both systems. • Control of polymerization is comparatively good in two-step emulsion than in single-step emulsion, as indicated by low PDI even at low conversion and low number average molecular weight. • Statistical analysis shows that: Temperature has the profound effect on all responses (conversion, Mn and PDI). EBiB is the important factor for Mn but not for other two effects. Catalyst complex has medium effect on all responses. Brij 98 is an important factor for conversion and PDI but not for Mn. Ascorbic acid has an important effect on PDI, however its effect on other two responses is not much important. Mechanism Single-step emulsion Two-step emulsion From preliminary investigation it was found that, livingness (narrow PDI and targeted molecular weight) is preserved better in two-step emulsion system than that in single- step emulsion system, thus DOE was prepared based on two-step emulsion system. Design specification: Five factor two-level fractional factorial experimental design with resolution 5 (2 v 5-1 ) having 5 center points Independent variable Level and range of independent variable Actual Variable Coded variable -1 0 1 Temp ( o C) X1 50 55 60 Brij 98 (g) X2 15.0000 16.5000 18.000 0 Ascorbic Acid (g) X3 0.0600 0.0660 0.0720 EBiB (g) X4 0.3987 0.4486 0.4984 CuBr 2 /dNBp y (g/g) X5 0.0838/0 .3065 0.0922/ 0.3372 0.1006/ 0.3678 Following condition is kept constant for all the runs (Two-step emulsions) N 2 purging Only for microemulsion (10 times with full release of pressure) Motor Speed 250 rpm Pressure 20 psi MMA I (g) 14.0400 MMA II (g) 42.1200 MMA total (g) 56.1600 Water (g) 348.9500 Main effects plot for conversion Main effects plot for PDI Main effects plot for Mn Variations of experimental number-average molar mass and polydispersity index (PDI) versus MMA conversions in single-step emulsion (Expt. 4). 1.7 1.8 1.9 2 2.1 2.2 2.3 1000 6000 11000 16000 21000 35.0 40.0 45.0 50.0 55.0 60.0 65.0 PDI Mn (g/mol) Conv (%) Mn, th Mn, GPC PDI Aggregation/Coagulation in Single- Step emulsion. Aggregation/Coagulation in Two-Step emulsion.