Polyolefins, analysis

In this review, we will focus on the new and most recent technological developments in automation, infi ared detection, and its applications in polyolefin analysis. 

Monrabal B, Sancho-Tello J, Montesinos J, Tarin R, Ortin A, del Hierro P, Bas M (2012) High temperature gel permeation chromatograph (GPC/SEC) with integrated IR5 MCT detector for polyolefin analysis a breakthrough in sensitivity and automation. In The applications book, July 2012. LCGC Europe, Chester... 

SEC-LS has been used at temperatures of 145°C, for example, for polyolefin analysis. It has also been used with aqueous mobile phases. In the latter case... 

High-temperature GPC, TREF and Crystaf are used almost exclusively to analyze polyolefins. Other more general polymer analytical techniques are also commonly used for polyolefin analysis. Because they are less specific to polyolefins, they will be described only very briefly in the remaining part of this section. 

When properly used, DSC can generate detailed information that is complementary to Crystaf and TREF. Although very interesting, this subject is beyond the scope of this chapter and the reader is referred to the literature in the field for more details [9-11 ]. NMR is also very important in polyolefin analysis [ 12 ]. 

Wild L, Blatz C (1993) Development of high performance tref for polyolefin analysis. In Chung TC (ed) New advances in polyolefins. Plenum, New York, pp 147-157 Soares JBP, Hamielec AE (1995) Polymer 36 1639... 

Abstract The synthesis and characterization of polyolefins continues to be one of the most important areas for academic and industrial research. One consequence of the development of new tailor-made polyolefins is the need for new and improved analytical techniques for the analysis of polyolefins with respect to molar mass, molecular topology and chemical composition distribution. This review presents different new and relevant techniques for polyolefin analysis. The analysis of copolymers by combining high-temperature SEC and FTIR spectroscopy yields information on chemical composition and molecular topology as a function of molar mass. Crystallization based fractionation techniques are powerful methods for the analysis of short-chain branching in LLDPE and the analysis of polyolefin blends. These methods include temperature-rising elution fractionation, crystallization analysis fractionation and the recently developed crystaUization-elution fractionation. 

Keywords Crystallization analysis fractionation Field Flow Fractionation High performance liquid chromatography Hyphenated techniques Liquid chromatography Polyolefin analysis SEC-NMR coupling Size exclusion chromatography Temperature rising elution fractionation Two-dimensional liquid chromatography... 

Recently a fascinating new development in crystallization based techniques for CCD analysis of semicrystalline polyolefins has been published. This new technique is called CEF. As demonstrated by Monrabal and Heirro [75] the use of only TREE or CRYSTAF for polyolefin analysis might lead to equivocal results and the use of both techniques for unequivocal results was recommended. CEF is an important step forward in this direction and it combines the separation power of TREE and CRYSTAF in one single fast run. 

As described in the previous sections, there are a number of fractionation techniques that are used very successfully in polyolefin analysis, including HT-SEC, CRYSTAF and TREE. For copolymers, CRYSTAF and TREF provide information about the chemical composition distribution. The drawbacks of these methods are that (1) they are very time-consuming and (2) they work only for crystallizable polyolefins. The latest development in this field, CEF, is able to obtain similar results to TREF in less than 1 h and is, therefore, a significant improvement. Still, CEF is based on crystallization and can only address the crystallizable part of a polyolefin sample. 

Polyolefins are one of the most important synthetic polymeric materials in all spheres of human activities ranging from packaging and construction to computer science and medicine. Similar to other polymeric materials, polyolefins are distributed in their molecular properties and in-depth analysis of these properties is required using the most sophisticated analytical methods. This helps to establish structure-property relationships and broadens the application of polyolefins in science and technology. In this review we have discussed recent developments in different analytical techniques for polyolefin analysis. 

To summarize, all techniques used for polyolefin characterization have advantages and disadvantages. Some information can be obtained more reliably from one technique and some other fi om other techniques. One really has to decide on the problems to be addressed using a given technique. Nevertheless, 2D-HT-HPLC seems to be one major technique to be used for polyolefin analysis in the future due to its ability to provide MMD as a function of CCD of the sample which is not possible by other approaches. 

Development of high performance analytical TREF for polyolefin analysis has recently been reported by Wild and Blatz [124]. Their goal was to develop TREF to the point where it is economical, fast, and easy to carry out, making it approach analytical SEC in convenience. These authors ... 

L Wild, C Blatz. Development of high performance TREF for polyolefin analysis. In TC Chung, ed. New Advances in Polyolefins, New York Plenum 1993, pp 147-157. 

The method describes procedures for the determination of trace amounts of titanium, aluminium and iron in polyolefins. Analysis of a 5 g sample oiables aluminium, iron and titanium to be determined in amounts down to 1 ppm with an accuracy of 1 ppm. 

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