Raman microscopy in lateral mapping of chemical and physical composition of paper coating

摘要

This paper shows how confocal Raman microscopy reveals the distribution of paper coating chemicals in the x-y plane.The use of two microscope objectives enabled bulk and surface analysis of styrene butadiene (SB) latex and calcium carbonate in coated papers.In the bulk coating analysis,spatial mapping of chemical distribution covered 0.15 mm~2 areas with a 10mum lateral resolution.We analyzed a 1 mm~2 area in shorter measurement time by using a coarser lateral resolution.The bulk compositional maps revealed the distribution of chemicals and gave information on the coating thickness.These measurements were possible to perform through magenta ink;information about ink density could be obtained at the same time.In the surface analysis,the analyzed layer was only about 2 mum thick.The surface measurements were obtained from a larger area (26 cm~2),but using fewer measurement points.That led to a shortened analysis time,while giving even more valid quantitative results on the variation of SB-latex content.