Polyurethane elastomers analysis

Other reported TG-MS applications concern polybutadiene [153], styrene-butadiene rubbers [153], gums [14], polyisoprenes [52], polyurethanes [144, 146, 147, 166], ABS [144], chlorosulphonated polyethylene elastomer [169, 170] and elastomer blends (NBR/SBR/ BR) [13]. Table 1.5 summarises the use of advanced TG-MS systems in elastomer analysis. 

Najafi-Mohajeri, N. Jayakody, C Nelson, G.L. Cone calorimetric analysis of modified polyurethane elastomers and foams with flame-retardant additives. In Fire and Polymers. Materials and Solutions for Hazard Prevention, Nelson, G.L., Wilkie, C.A., Eds. ACS Symposium Series 797 American Chemical Society Washington, 2001 pp. 79-89. 

Nuclear Magnetic Resonance Spectroscopy. Like IR spectroscopy, NMR spectroscopy requires little sample preparation, and provides extremely detailed information on the composition of many resins. The only limitation is that the sample must be soluble in a deuterated solvent (e.g., deuterated chloroform, tetrahydro-furan, dimethylformamide). Commercial pulse Fourier transform NMR spectrometers with superconducting magnets (field strength 4-14 Tesla) allow routine measurement of high-resolution H- and C-NMR spectra. Two-dimensional NMR techniques and other multipulse techniques (e.g., distortionless enhancement of polarization transfer, DEPT) can also be used [10.16]. These methods are employed to analyze complicated structures. C-NMR spectroscopy is particularly suitable for the qualitative analysis of individual resins in binders, quantiative evaluations are more readily obtained by H-NMR spectroscopy. Comprehensive information on NMR measurements and the assignment of the resonance lines are given in the literature, e.g., for branched polyesters [10.17], alkyd resins [10.18], polyacrylates [10.19], polyurethane elastomers [10.20], fatty acids [10.21], cycloaliphatic diisocyanates [10.22], and epoxy resins [10.23]. 

Dallas, Tx., Spring 1998, p.24. 012 ANALYSIS OF A POLYURETHANE ELASTOMER USING THERMAL 2D FT-IR... 

DMA is an analysis technique used to determine the dynamic properties of the elastomers [13, 14]. Dynamic properties of the elastomeric materials are important because they influence the performance of certain parts such as wheels and tyres. This method determines the storage modulus G (elastic behaviour), loss modulus G (energy dissipation), tan 8, loss compliance ]" and glass transition temperature (Tg) values. The Tg of the soft segment can determine the low temperature behaviour of polyurethane elastomers. This is not only influenced by the nature of the soft... 

Our own work was motivated by the hope that more detailed information on the postcure process of polyurethane elastomers could be obtained by combining the quantitative measurements like the enhancement in the mechanical properties in time with various dynamic processes which take place concomitantly, similarly as performed by Toffey et al in the case of cellulose crosslinking by urethane groups when the dynamic mechanical thermal analysis (DMTA) was used [341],... 

Fig. 5.11. Dynamic mechanical thermal analysis (DMTA) properties of PPDI and CHDI polyurethane elastomers.

An Additional Rapid Infrared Method for the Quantitative Analysis of NCO Present in a Polyurethane Elastomer... 

It is possible to use differential thermal analysis (DTA) and thermogravi-metric analysis (TGA) to evaluate the thermal properties of several types of polyurethane elastomers. For example, a typical elastomer prepared from MDI, a polyether and an aliphatic diamine extender will show from DTA two very small endothermic changes, one at 150°C and one at 205°C that is identical with the softening temperature. The polymer is found to melt at 2WC and exhibit weight loss in two steps, respectively, beginning at 280°C and 325X. 

GENERAL ANALYSIS OF MISCELLANEOUS ELEMENTS IN A POLYURETHANE ELASTOMER... 

Bagdi, K. Molnar, K. Pukanszky, B. Jr. Pukanszky, B. Thermal analysis of the structure of segmented polyurethane elastomers. Journal of Thermal Analysis and Calorimetry, 2009, 98, 825-832. 

The CL analysis applied on the degradation of hydroxyl-terminated polybutadiene based polyurethane elastomers illustrates the effect of previous energetic treatment to which samples were subjected. The increase in the initial CL intensity and the shift of maximum CL intensity upon the shorter time are the effects of the initiation of oxidation by molecular scissions and, respectively, the reactions of free radicals with oxygen that leads to decrease in the material durability (Fig. 61) [06C1]. Another proof for the beginning of degradation by prior processing is the increased CL-emission at the start of the CL measurements. (Fig. 62). 

Haken and co-workers [161] described an analytical procedure for the rapid qualitative analysis of polyurethane elastomers, based on polycaprolactonediols (CAPA). These thermoplastic polyurethanes are a complex reaction product of an... 

Leung, L., M., Koberstein, J. X. (1985), Small-angle scattering analysis of hard-microdomains structure and microphase mixing in polyurethane elastomers, J. Polym. ScL, Polym. Phys. Ed., 23,1883-913. 

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