Solution compatibility PVAC

ESR has been useful in studying the influence of dissolved gases on polymer mobility [801]. Stable nitroxyl radicals, such as 2,2,6,6-tetramethylpipe-ridin-l-oxyl (TEMPO) are widely employed as spectroscopic probes for observing binding sites and molecular motion of macromolecules [802]. ESR spectra of the TEMPO free radical in PC film at various temperature and in solution were reported [795]. The TEMPO spin probe method was also used to study diisooctylphthalate (DIOP) plasticiser diffusion in suspension polymerised PVC particles [803]. Similarly, the compatibility Umit of PVAc and di-nonylphthalate (DNP) was studied by means of 2,2-di-n-nonyl-5,5-dimethyl-3-oxazolidinyloxy spin probe ESR measurements and DSC [804] DNP is an effective plasticiser for PVAc for concentrations not exceeding 17 wt.%. According to ESR evidence BBP in PVC forms radicals more easily than DOP [805]. 

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