Thermal analysis blends

Thermal analysis of homopolymer samples are simpler than those of blends. Separate thermal analysis of individual polymer components are made before doing the same for a blend in order to get more accurate and proper information on thermal characteristics. 

This second group of tests is designed to measure the mechanical response of a substance to applied vibrational loads or strains. Both temperature and frequency can be varied, and thus contribute to the information that these tests can provide. There are a number of such tests, of which the major ones are probably the torsion pendulum and dynamic mechanical thermal analysis (DMTA). The underlying principles of these dynamic tests have been covered earlier. Such tests are used as relatively rapid methods of characterisation and evaluation of viscoelastic polymers, including the measurement of T, the study of the curing characteristics of thermosets, and the study of polymer blends and their compatibility. They can be used in essentially non-destructive modes and, unlike the majority of measurements made in non-dynamic tests, they yield data on continuous properties of polymeric materials, rather than discontinuous ones, as are any of the types of strength which are measured routinely. 

Cheng, Y.-Y., Brillhart, M., Cebe, P. and Capel, M., X-ray scattering and thermal analysis study of the effects of molecular weight on phase structure in blends of polybutylene terephthalate with polycarbonate, J. Poly. Sci., Polym. Phys., 34, 2953-2965 (1996). 

In this research, commercially available PHB/PET copolyester LCP, PEN and PET were mechanically blended to form the LC phase of the blends. The critical composition of PHB in the PEN and PET forming an LC ternary blend was investigated, and the miscibility and thermal behavior were studied using thermal analysis. The PHB content in the ternary blend was controlled by the amount of PHB/PET copolyester, as a high-molecular-weight PHB homopolyester does... 

Richard B. Graver of Interez Inc., formerly Celanese Specialty Resins Division, Celanese Corporation. Both K-353 and the dicyanate monomers were used as received. All the blends were prepared by dissolving completely the components in methylene chloride, and the solvent was subsequently removed by slow evaporation with mild heating. The solid blends were then dried in vacuo at 65-75°C overnight before being subjected to thermal analysis. 

As a preliminary study, three 1 1 molar mixtures, BCB/THIOCy, BCB/METHYLCy, and BCB/BADCy, were prepared. The suggested catalytic system [10] was not Included In the blends since we wanted to minimize the competitive cyclotrlmerlzatlon of the dlcyanate monomers. The samples, along with pure dlcyanate samples, were then subjected to thermal analysis by DSC and TGA. 

The styrene content affects the crystallinity of ESI (131) for >50% styrene the copolymers are amorphous. As the styrene content is increased from 50 to 70% styrene the Tg increases from -15 °C to 20 °C. Low density foams were made (8) from a blend of 50% of various ESI polymers, 33% of EVA and 17% of azodicarbonamide blowing agent. Thermal analysis showed that the blends, with an ESI having approximately 70% styrene, had a Tg in the range 22 to 30 °C. Dynamic mechanical thermal analysis (DMTA) traces (see Section 5.1) show that these blends... 

The glass transition (Ta) and melting (Tm) temperature of the pure component polymers and their blends were determined on a Perkin-Elmer (DSC-4) differential scanning calorimeter and Thermal Analysis Data Station (TADS). All materials were analyzed at a heating and cooling rate of 20°C min-1 under a purge of dry nitrogen. Dynamic mechanical properties were determined with a Polymer Laboratories, Inc. dynamic mechanical thermal analyzer interfaced to a Hewlett-Packard microcomputer. The... 

Mijovic et al. analyzed the annealed blends from melts using dynamic mechanical thermal analysis and achieved similar results after an adjustment for shifting factors, AT s, as shown in Figure 7.3. The results were extended to include blends having a PVDF concentration greater than 80 wt %. It can be observed that the glass transition temperatures of the annealed blends reduce rapidly when the PVDF concentrations are above 80 wt %. 

Vamell, D. F., Runt, J. P., Coleman, M. M. FT-IR and Thermal Analysis Studies of Blends of Poly(Caprolactone) and Homo- and Copolymers of Poly(vinylidene chloride). Preprint submitted to CARBON... 

Figure II. Records of differential thermal analysis of Mar-tinsburg anthraxolite in nitrogen atmosphere. Trace I. single nodule freshly pulverized. Trace II, aged, blended sample.

Elucidation of the morphology of the two stage latex particles, which had complete second stage monomer association, was carried out by a comparison with the corresponding copolymer and mechanical blend systems using electron microscopy and thermal analysis techniques. 

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. 

Like PU TPE, blends of thermoplastic polyurethanes and polyamide-12 (PA-12) have been studied by Polosmak and co-workers [61]. They have mixed two types of thermoplastic polyurethane (TPU) based on oligoether (polytetramethylene oxide, molecular weight, 1000) and oligoester (polyethylene butylene glycol adipate, molecular weight, 2000) and PA 12 were characterised by IR spectra and thermal analysis. IR spectra of TPU, PA-12 and their blends show that in amide one (Al) carbonyl absorbancy is seen to split [55] into two main bands with maxima at 1705 and 1730 cm 1. At 1730 cm 1,... 

Md Ali, A.R. and Dimick, P.S. (1994) Thermal analysis of palm mid fraction, cocoa butter and milk fraction blends by differential scanning calorimetry. J. Am. Oil Chem. Soc., 71(3), 299-302. 

The method used to provide contrast in transmission electron microscopy was successful in demonstrating the presence of a two-phase structure in homopolymer blends of BR and IR (Figure 2a). The opposite situation, i.e., a clear absence of any phase separation in the block copolymers, also is demonstrated, but much less convincingly by the comparison of Figures 2b and 2c. It is necessary to consider the evidence from all of the mechanical and thermal analysis experiments, along with the evidence from microscopy. 

Fig. 15. DiiTerential thermal analysis traces of a blend of chlorinated polyethylene with poly(methyl methacrylate) obtained by heating at a rate of 10 °C/min. The blend was kept at the quoted temperatures for 10 min. and was quenched prior to scanning. The appearance of two T s after treatment at 190 C is indicative of phase separation at this temperature...

Differential Scanning Calorimetry. Thermal analysis of PVME/PS blends and IPNs by DSC indicates only one glass transition temperature, which is located between the homopolymer T s. The position of Tg is dependent upon composition although it does not follow the prediction of the Fox equation (21), Table II. The breadth of the transition also increases significantly with increased PS content for the blends and IPNs. The broad transition might result from either the clustering of like mers near... 

The sensitivity of poly(methyl methacrylate), PMMA, to x-rays is enhanced by the addition of poly(epichlorohydrin). The two polymers are miscible as shown by thermal analysis and by optical clarity of blends. 

As well as inorganic complexes, thermal analysis is applicable to a wide range of substances, e.g. polymers, drugs, soils and coals. It can also be applied to mixtures of, for example, polymer blends. 

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). 

Metin, S., and R.W. Hartel, Thermal Analysis of Isothermal Crystallization Kinetics in Blends of Cocoa Butter with Milk Fat or Milk Fat Fractions, Ibid. 75 1617-1624 (1990). 

Figure 10.7 DSC curves of polyethylene terephthalate)-poly(acrylonitrile-butaliene-styrene) (PET-ABS) blends (a) conventional DSC first and second heating curves with heating and cooling rate of lOKmin-1 and (b) temperature modulated DSC (TMDSC) first heating curves with /3=2Kmin 1, p = 60s and 5= 1K. Tg, glass transition temperature. (Reproduced with permission from T. Hatakeyama and F.X. Quinn, Thermal Analysis Fundamentals and Applications to Polymer Science, 2nd ed., John Wiley Sons Ltd, Chichester. 1999 John Wiley Sons Ltd.)...

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