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System and Method for High Throughput Screening of Plastics for Oxidative Stability

IP.com Disclosure Number: IPCOM000004366D
Publication Date: 2000-Oct-18
Document File: 2 page(s) / 21K

Publishing Venue

The IP.com Prior Art Database

Abstract

A novel system and method for rapid screening of plastic compositions for thermal stability is described. The system and method comprise a plate 100, which is constructed of metal or ceramic, and can be heated to temperatures as high as 300 degrees C for prolonged periods without change or decomposition. The plate contains a plurality of sample wells 120 on its top. The sample wells are circular with a diameter between one millimeters and two centimeters, and depth at their centers of 0.05 millimeters to one centimeter. The system and method further comprise an infrared sensor 160, which is capable of recording infrared emissions in a spatially resolved fashion from the surface of the plate.

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System and Method for High Throughput Screening of Plastics for Oxidative Stability

High throughput methods for screening are at the forefront of chemical and biological research. While it is often possible to make a high number of variations to a composition, it is often much more challenging to find a reliable yet rapid means to screen multiple compositions simultaneously or in rapid sequence. Without rapid means for screening, high throughput methods are of limited utility. Such has been the case for screening of plastic compositions having improved thermal stability. Although oxidative stability is an important property of plastics for many critical uses, including stadium furniture, artificial turf, interior and exterior car parts, under-hood automotive wiring, general wire and cable coatings, etc., and much research is conducted to identify plastic compositions having improved oxidative stability, high throughput screening methods are needed for this important application.

A novel system and method for rapid screening of plastic compositions for thermal stability is described. The system and method comprise a plate 100, which is constructed of metal or ceramic, and can be heated to temperatures as high as 300 degrees C for prolonged periods without change or decomposition. The plate contains a plurality of sample wells 120 on its top. The sample wells are circular with a diameter between one millimeters and two centimeters, and depth at their centers of 0.05 millimeters to one centimeter. The system and method further comprise an infrared sensor 160, which is capable of recording infrared emissions in a spatially resolved fashion from the surface of the plate.

Drawing 1 shows a top view of the plate. Drawing 2 shows a side view of the system, including the plate and the infrared sensor.

Drawing 1: Top view of Plate

Drawing 2: Side view of the system

The method entails placing samples of plastic compositions (analytes) within the wells and raising the plate temperature to an elevated temperature for a prolonged period of time. The system can be placed in a controlled atmosphere, such as pure oxygen to accelerate oxidation, or it can be used in air. When the samples begin to oxidize, the infrared sensor will detect the exothermic oxidation reactions. The rate of oxidation will thus be resolved in time and spatially with respect to position on the plate. Those samples that have highest oxidative stability will show the slowest onset and/or rate of exothermic oxidation.

Example: 36 individual polypropylene pellets, each representing a different composition, are placed in each of 36 sample wells on a plate, which is held within an atmosphere of 99.99% oxygen. The temperature is then raised from ambient to 210 degrees C and is maintained at 210 degrees C for 2 hours. The progress of the sample oxidations is monitored with the infrared sensor.