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Nanobiocomposites PLA/OMMT have been compounded in the Minilab microextruder and in the internal batch mixer with varying processing conditions. To check the degree of dispersion in processed nanocomposites, the rheological properties have been investigated systematically. Processed PLA/OMMT samples showed percolation in the melt, detected as a step increase in low-frequency elastic moduli compared to pure PLA. The melt elasticity of the nanocomposites increases progressively with mixing energy, which we associate with a progress of dispersion of clay agglomerates and confirm it directly by TEM results. An attempt was made to characterize the progress of dispersion by melt rheology coupled with light attenuation. The light attenuation coefficient decreases by a factor of 5, low-frequency loss tangent decreases by a factor of 6 with the progress of dispersion, and both characteristics reach saturation, which may be attributed to the maximum level of dispersion achieved in the present experimental conditions. The combination of low-frequency loss tangent and light attenuation coefficient provides a potentially sensitive method for the characterization of the degree of clay dispersion. The direct correlation between light attenuation coefficient and loss tangent follows linear dependence and may open an approach for the rapid inline analysis of the degree of dispersion in melt-processed nanocomposites. Our further studies will explore how general linear correlation is. TEM results showed directly that the internal batch mixer gave a much better level of dispersion of the nanoclay in the PLA matrix compared to the Minilab miniextruder. This good level of dispersion translates to the rheological, optical, and further on to the enhanced mechanical properties of PLA nanocomposites. The main reason for the poor dispersion level in the miniextruder and consequent loss in the mechanical properties is the thermal impact of the Minilab on the biodegradable PLA. The results presented in this study do not allow resolving the whole complexity of the nanocomposite structures; neither do they answer many fundamental questions of the phenomena behind polymer nanocomposites. However, an attempt is made to correlate rheological measurements related to the degree of dispersion with optical characterization, allowing inline process control. Inline characterization with optical probes is underway and will allow direct correlation between dispersion and thermomechanical history, and eventually better fundamental understanding of the dispersing process of clay agglomerates within a polymer matrix. The still open question of the relative importance of shear rate, shear stress, and mixing time in the dispersion process could be addressed in a more quantitative way.