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and confirms that the experimentally obtained PMMA was pol-ymerized via a free radical mechanism.

The existence of two TGA peaks for radically polymerizedPMMA can be explained via studying the degradation mechanismwithin the polymer backbone. Previous studies have concluded

that irregular structures (such as head-head coupling and unsatu-rated end groups) present in radically prepared PMMA may cause

PMMA to degrade in two steps, which is observed in Plots 1-4.(Kashiwagi et al., Holland et al.) Thermal degradation may in-volve backbone unzipping to form MMA monomer and a te r-

tiary radical, shown in Scheme X (adapted from Wilkie). Itshould be emphasized that this mechanism applies for thermaldegradation of PMMA in inert atmospheres. For radically pol-

ymerized PMMA samples that thermal degradation in oxygen, afour step degradation mechanism has been proposed.

Hirata et al. also postulated that PMMA will form a primary radi-cal in the presence of metal halides, such as complexed CuBr,which is shown in Scheme X+1 (adapted from Wilkie). PMMA

degradation via this mechanism will either terminate the radical orremove the radical from the polymer backbone, thereby hinderingfurther degradation of the polymer. This will result in prolongedPMMA degradation, which will increase the temperature range

required to degrade the PMMA sample and lead to a wider tem-perature curve.

Conclusion

AGET ATRP was successfully performed on all four samples. Itwas found by 1HNMR that molecular weight control depended

heavily on monomer to initiator concentration. There was no ap-parent effect on molecular weight from the amount of reducingagent. Additionally no correlation between molecular weight ofthe samples and Tg could be drawn. Sample 1 had the highest Tgwhich could be due to the difference in samples physical proper-

ties or possibly poor initiation. TGA data showed that samples 2,

3, and 4 had a residual anisole peak at 100-200 C whereas sam-ple 1 did not. The two-step degradation of PMMA was found tobe present in all samples of radically polymerized PMMA.

ASSOCIATED CONTENT

ACKNOWLEDGMENT

We thank Emily Hoff for her help with polymer synthesis and1HNMR, Austin Baranek for his help with thermal analysis, andDr. Derek Patton for his help throughout.

REFERENCES

1.Meng, Qinghua, Heng Liu, Sen Cheng, Chengxi Cao, JicunRen, and BV ELSEVIER SCIENCE. "A Novel MolecularProbe Sensing Polynuclear Hydrolyzed Aluminum by Chela-tion-enhanced Fluorescence."TALANTA, 99 (2012): 464-470.

2.Jimrna S. Zugazagitia, Mauricio Maya, Carlos Damian-Zea,Pedro Navarro, Hiram I. Beltran, Jorge Peon. Excited-Sate Dy-

namics and two-Photon Absorption Cross Sections of Fluores-cent Diphenyl-Tin(IV) Derivatives with Schiff Bases: A com-

parative Study of the Effect of Chelation from the Ultrafast to

the Steady-State Time Scale.Journal of Physical Chemistry.114 (2010): 704-714.

3.MORISIGE, K, and BV ELSEVIER SCIENCE. "Metal-complexes of Aromatic Schiff-base Compounds .1. Fluores-cence Properties of Aluminum and Gallium Complexes of Ar-

omatic Schiff-bases and Their Use in Fluorimetry." AnalyticaChimica Acta, 72.2 (1974): 295-305.

Scheme

Scheme

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