48 chromatography • spectroscopy
Fig. 1. High Temperature GPC/SEC System.
sulphides, excel other materials by their mechanical strength and their resistance to chemical and physical degradation. Tese favourable properties turn into hurdles when it comes to characterisation of these polymers. Tey are difficult to analyse because they are crystalline and often require elevated temperatures or special solvents for complete dissolution.
Gel permeation chromatography (GPC, also known as size exclusion chromatography, SEC) is an established technique used for the characterisation of polymers with regard to their molecular weight distribution. Te GPC analysis of engineering plastics at high temperatures requires specialised instruments and columns. Te high temperature is required throughout the whole experiment to avoid re- crystallisation and to ensure that the sample remains in solution.
Analysis of engineering plastics by gel permeation chromatography
Jens Reichenberger outlines new developments for efficient sample preparation and optimised separation conditions for the GPC analysis of various engineering plastics.
V
Fig. 2. System start-up and equillibration of temparature and RI tignal.
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arious types of engineering plastics showing superior
characteristics under high thermal or mechanical load have been developed recently. Tese materials are supposed to complementing traditional materials, such as wood, metals or ordinary plastics. As the applications of these high performance polymers increase, there is a need for methods to accurately and precisely characterise these materials. Some engineering plastics were analysed using a new GPC/ SEC system and a series of GPC column designed for high temperature GPC/SEC analysis.
Engineering plastics, such as ultra-high molecular weight polyolefins or polyphenylene
We investigated separation conditions for various polymers. For these experiments a new type of high temperature GPC/SEC system, the HLC-8321GPC/HT (HT EcoSEC System) was used (Fig. 1). Te system provides stable thermostatisation up to 220°C, autosampler, pumps, and as integrated standard detector an extremely stable refractive index detector with an independent temperature control. With regard
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