Thermoplastic elastomers analysis

Witsiepe, W.K., Segmented polyester thermoplastic elastomers, Adv. Chem. Ser., 129, 39, 1973. Srichatrapimuk V.W. and Cooper S.L., Infrared thermal analysis of pol3furethane block polymers, J. Macromol. Set Phys. B, 15, 267, 1978. 

Borgaonkar H. and Ramani K., Stability analysis in single screw extrusion of thermoplastic elastomers using simple design of experiments, Adv. Polym. Technol., 17, 115, 1998. 

Dufton P.W., Thermoplastic Elastomers, Rapra Industry Analysis Report, 2001. 

Dufton P (2001) Thermoplastic elastomers - a Rapra industry analysis report. Rapra Technology, Shawbury, UK... 

The physical interactions in TPE can be characterised by IR spectroscopy. A few examples of such studies are discussed here. Examples of PE based thermoplastic elastomers are NR/PE blends [50, 52]. TPE [49] based on 50/50 NR/LDPE, forms co-continuous morphological structure of both NR and LDPE. Thermal analysis shows that the blend is immiscible and from IR spectra of the 50/50 NR/LDPE blends [53], it is observed, the peaks of NR and PE exist almost in the same positions in the blend with a very little shift (Figure 5.12). The absorption band at 833 cm"1 for cis >C = C in NR (Figure 5.12) is shifted to 836 cm 1. Similarly the peak at 1370 cm"1 (C-H stretching of CH3 group) shifts to 1373 cm"1, while the peak for C=C double bond shifts from 1660 cm"1 to 1658 cm"1, and the band at 1467 cm"1 for -CH2 in LDPE (Figure 5.12) is shifted to 1462 cm 1. The spectra thus confirm that there exist only physical interactions in NR-PE blend. 

The above thermal analysis studies demonstrated the enhanced thermal stability of POSS materials, and suggested that there is potential to improve the flammability properties of polymers when compounded with these macromers. In a typical example of their application as flame retardants, a U.S. patent39 described the use of preceramic materials, namely, polycarbosilanes (PCS), polysilanes (PS), polysilsesquioxane (PSS) resins, and POSS (structures are shown in Figure 8.6) to improve the flammability properties of thermoplastic polymers such as, polypropylene and thermoplastic elastomers such as Kraton (polystyrene-polybutadiene-polystyrene, SBS) and Pebax (polyether block-polyamide copolymer). 

After following the microhardness behaviour during the stress-induced polymorphic transition of homo-PBT and its multiblock copolymers attention is now focused on the deformation behaviour of a blend of PBT and a PEE thermoplastic elastomer, the latter being a copolymer of PBT and PEO. This system is attractive not only because the two polymers have the same crystallizable component but also because the copolymer, being an elastomer, strongly affects the mechanical properties of the blend. It should be mentioned that these blends have been well characterized by differential scanning calorimetry, SAXS, dynamic mechanical thermal analysis and static mechanical measurements (Apostolov et al, 1994). 

Defined diblocks, triblock or multiblock copolymers find important applications in the areas of thermoplastic elastomers, data storage technology [126], and as compatibilizers (e.g. in polymer blends). In thin films these polymers may display different morphologies than in the bulk, which necessitates an accurate analysis. 

For instance, crystalline lamellae in an amorphous matrix (semicrystalline polymer materials), hard domains in a soft matrix (thermoplastic elastomers) several sharp peaks of colloidal crystals are observed in the SAXS, the unit cell can be determined. In this case peak profile analysis can be carried out using the methods discussed in Sect. 8.2.5... 

Rubberlike polymers include the thermoplastic elastomers (TPE) already mentioned in Chapter 1. They are mostly two-phase systems consisting of an elastic soft phase and a thermoplastic hard phase. The possible number of combinations is almost unlimited, which complicates their identification and nearly always necessitates expensive instrumental methods of analysis. In many cases the materials are block copolymers and, less frequently, blends. The following scheme provides an overview of the most important TPE types and can also be used as a guide for their qualitative analysis ... 

The environment in which the sport is taking place can also pose some constraints for example, the development of sensors for wet sports, impact sports or sports taking place in extreme temperature requires additional consideration for the system s robustness and stability. Further, local temperature, humidity and pH levels also change during physical exercise and can affect some sensors. For example, Cochrane et al. (2007) demonstrated how the electrical performance of their sensor material, a thermoplastic elastomer composite, was affected by high humidity. After 50% relative humidity, resistance increases rapidly with humidity. They attributed it to the carbon black nanoparticles of the composite, which are sensitive to water. At high humidity, temperature also had a small effect on resistance. Munro et al. (2008) also found that while their strain sensors were able to provide valid and reliable data compared to a video-based motion analysis system, the consistency of the feedback was affected by enviromnental conditions. 

The properties of the linear material 7.27 and the network copolymer 7.28 have been studied by dynamic mechanical analysis, DSC, and transmission electron microscopy. Evidence was obtained for the formation of highly ordered micro-phase-separated superstructures in the solid state from the materials 7.27. The Cu(bipy)2 moieties appear to form ordered stacks, and this leads to thermoplastic elastomer properties. In contrast, the network structure of 7.28 prevents significant microphase separation [51-53]. By means of related approaches, dinuclear Cu helical complexes have also been used to create block copolymers by functioning as cores [54], and polymer networks have also been formed by using diiron(II) triple helicates as cores for the formation of copolymers with methyl methacrylate [55]. 

Appel WPJ, Portale G, Wisse E, Dankers PYW, Meijer EW (2011) Aggregation of uieido-pyrimidmone supramolecular thermoplastic elastomers into nanofibers a kinetic analysis. Macromolecules 44(17) 6776-6784... 

Erdogan and co-workers [11] report a MS analysis of the gases evolved during the pyrolysis of NR, butadiene rubber (BR), SBR, styrene-butadiene-styrene (SBS) and styrene-isoprene-styrene thermoplastic elastomers and PS in the low (0-150 amu) mass range, using a quadrupole mass spectrometer. The results are interpreted using the variations in ion ratio as a function of temperature. 

Nanocomposite technology using small amounts of silicate layers can lead to improved properties of thermoplastic elastomers with or without conventional fillers such as carbon black, talc, etc. Mallick et al. [305] investigated the effect of EPR-g-M A, nanoclay and a combination of the two on phase morphology and the properties of (70/30w/w) nylon 6/EPR blends prepared by the melt-processing technique. They found that the number average domain diameter (Dn) of the dispersed EPR phase in the blend decreased in the presence of EPR-g-MA and clay. This observation indicated that nanoclay could be used as an effective compatibilizer in nylon 6/EPR blend. X-ray diffraction study and TEM analysis of the blend/clay nanocomposites revealed the delaminated clay morphology and preferential location of the exfoliated clay platelets in nylon 6 phase. 

This chapter is a perspective of the science and technology of elastomers and does not include a market analysis. Nevertheless, we must mention that the global market for these materials is large (Fig. 4.1). Global vulcanizable (conventional, vulcanizable) rubber consumption was about 20 million metric tons in 2004, whereas thermoplastic elastomer (TPE) consumption was about 1.5 million metric tons. The consumption of conventional rubbers is growing at a rate of about 3 to 4 percent, whereas the growth of TPE consumption is growing at about twice that rate. 

Market Analysis of Thermoplastics Elastomers, Robert Eller Associates, Inc., September 2000. 

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