SYNOPSIS
This article examines the partitioning of a poly(methy1 methacrylate) (PMMA) macromonomer in poly(n-butyl acrylate) (PBA) latexes synthesized via miniemulsion polymerization. 13C-NMR analysis using [HI Tlp and T2 measurements indicate that approximately 85% of the PMMA macromonomer partitions and is grafted to the surface of the latex particles. This observation was confirmed by soap titration measurements. The [HI T l p relaxation of the PMMA component in the P(BA-g-MMA macromonomer) latex is compared with the relaxation of the PMMA component in a poly(BA-co-MMA) latex. The PMMA contents in each of these latexes were 10% by weight. The [H]Tlp relaxation and T2 relaxation of the PMMA in the poly(BA-g-MMA macromonomer) latex have bi-exponential decays, while the PMMA component present in the poly(BA-co-MMA) latex is characterized by a single exponential decay. The bi-exponential decay is attributed to the existence of two non-contiguous phases of grafted PMMA in the former latex. It is also possible to calculate the thickness of the PMMA grafted region on the surface of the latex particles based on the fraction of the PMMA grafted at the particle surface and the radius of the latex particles. This value is in the range of 3-4 nm.