Applications in Polymers, Paints, and Coatings

Micro-Scan Servies, Inc. offers a wide range of microscopic infrared analyses which previously have been either impossible or extremely difficult and time-consuming for the infrared spectroscopist to carry out. One can think of analysis by micro-FTIR spectroscopy as the organic and polymer chemist's analogue of electron-beam microprobe analysis. We can provide a full infrared spectrum of materials down to 10 microns in size.

APPLICATIONS

POLYMER FILM CONTAMINANTS

We can identify particulate or fibrous contaminants to 10 microns in diameter in extruded, cast, or blown films. Microtomy down to 1 micron thickness across gel slugs can provide samples that permit analysis of core materials. This can lead to the identification of incompatible polymers, additives, or thermally degraded material as sources of the gel mass. The resulting infrared spectra can be compared to our unique computer data-base of thermally degraded polymers and additives for positive identification. Multi-layer extrusions or coated polymers can be examined in straight or oblique sections to provide analysis of layers down to fractions of a micron in thickness. In some cases, tie layers and adhesives can be analyzed by using low-angle oblique sections and spectral subtractions. As in the case of single-layer films, we can identify particulate contaminants in any of the multilayer products.

EXTRUDED AND MOLDED PARTS

As in the case of films, defects in optically clear parts can be analyzed anywhere in the part. This is especially important for parts used in critical applications, such as medical, aerospace, or in particular, the optical recording materials industry. In the case of opaque or filled polymers, the same microsampling techniques can be applied to obvious surface defects such as streaks, delaminations, off-color areas, and black specks. We can provide depth-profile environmentally aged or abused parts to show penetration of damage or to provide a record of additive concentrations as a function of depth with 1 micron resolution. Examination of defects in the region of mechanical failures can help identify particulate stress concentrators which led to crack initiation.

FIBERS

Single fibers down to 5 microns in diameter are suitable for analysis if provided in a form appropriate for handling. Fibers of this size are typically flattened with an apparatus developed in our laboratory and can provide "textbook" spectra. In some cases, fibers are cast in a mounting medium and prepared by microtomy to provide an end-on analysis of the core of the material. Fiber coatings and dyescan, in some cases, be identified, as can external contaminants of fabrics. All fiber spectra are compared to our data-base of fibers, based of an NBS collection, for more certain identification of source.

PAINTS AND COATINGS

The applications here are in the determination of the sources of specks, spots, fisheyes, and adhesion problems. Analysis of particulate or fibrous contaminants in raw materials or formulated products can be carried out on particles isolated directly from a material or those found on process or test filters. As in the case of molded plastics, we can provide information on the penetration of environmental damage to the coating or show concentration gradients of additives resulting from that damaage or from material diffusion. We can examine adhesion problems using some of our microsampling techniques; or alternatively, on metal surfaces using pseudo-reflectance spectroscopy with a spot size down to 1 mm.

POLYMER DEFORMULATION

The combination of micro-FTIR with chromatographic, thermal, and microchemical techniques allows us to offer deformulation of unknown polymer compositions, even when challenged with very small samples.

Copyright © 2001 Micro-Scan Services, Inc.