Annealing temperature, poly

Annealing temperature, poly(vinyl alcohol) hydrogel property effect, 228-241 Arg-Gly-Asp-Ser, ftinction, 221 Arg-Gly-Asp-Ser-cairying microspheres, leukocyte activation, 220-227... 

Poly(arylene ether ketone) and poly(arylene ether sulfone) were also tried to be incorporated into the hybrids with silica gel by means of the sol-gel procedure [19, 20], For example, triethoxysilyl-terminated organic polymer was subjected to co-hydrolysis with tetraethoxysilane. A systematic change in mechanical and physical properties of the hybrid glass has been found with the content of organic polymer and the annealing temperatures. 

The effect of annealing temperatures (65 - 250 °C) and blend composition of Nafion 117, solution-cast Nafion , poly(vinyl alcohol) (PVA) and Nafion /PVAblend membranes for application to the direct methanol fuel cell is reported in [148], These authors have found that a Nafion /PVAblend membrane at 5 wt% PVA (annealed at 230 °C) show a similar proton conductivity of that found to Nafion 117, but with a three times lower methanol permeability compared to Nafion 117. They also found that for Nafion /PVA (50 wt% PVA) blend membranes, the methanol permeability decreases by approximately one order of magnitude, whilst the proton conductivity remained relatively constant, with increasing annealing temperature. The Nafion /PVA blend membrane at 5 wt% PVA and 230 °C annealing temperature had a similar proton conductivity, but three times lower methanol permeability compared to unannealed Nafion 117 (benchmark in PEM fuel cells). 

In a kinetic sense, the system is a better solvent than HFIP alone. We postulate that MeCl2 swells the amorphous regions of PET thereby providing HFIP with an easy access to the crystalline regions. This swelling action does not occur with HFIP alone, and the dissolution process takes much longer. At room temperature, amorphous PET is Instantaneously solubilized by this solvent system. PET that has been annealed for >24 hr at 220 C to yield maximum crystallinity dissolves in <4 hr at room temperature. PET annealed in this manner does not dissolve in pure HFIP after 14 days at room temperature. Poly(butylene terephthalate) and aliphatic polyamides are soluble in this solvent system. Polystyrene is also soluble, which permits conventional calibration and the use of the universal calibration approach. We have determined the Mark-Houwlnk relationships for PET and polystyrene in 70/30 MeCl2/HFIP to be... 

Similar results have been submitted on solutions of PMMA and poly(styrene-co-acrylonitrile) (SAN) in toluene [96], The components are miscible when the AN content in SAN ranges from 9.4 up to 34.4 wt% (window of miscibility). Only immiscible pairs were studied. An example of structure evolution in blend solutions, comprising copolymers of different AN content, in the course of annealing time at constant annealing temperature is shown in Fig. 15. The results can be summarized as follows ... 

The crystallized fraction, which was defined as the ratio of the dark area to the total area in the optical micrographs, is shown in Fig. 12.7 as a function of the tx for different annealing temperatures T (from 500 to 530°C). The tx necessary to form a continuous poly-Si layer (i.e., to reach a crystallized fraction of 100%) becomes shorter with increasing annealing temperature. For example, at 530°C a continuous poly-Si film was formed after 19 min. Whereas, it took 90 min to form a continuous poly-Si film at 500°C. The time necessary to finalize the ALILE process can be separated into the above... 

Fig. 12.10. Preferential (100) orientation R(ioo) of a poly-Si surface versus annealing temperature (Ta) for two types of samples (the definition of R(ioo) is based on a 20° tilt with respect to the perfect (100) orientation). The permeable membrane was formed either by exposure to air for about 2 h at room temperature (solid circles) or in a furnace by exposure to an oxygen atmosphere for 2h at 560°C (open circles). (from [46])...

Erb T, Zhokhavets U, Hoppe H, Gobsch G, Al-lbrahim M, Ambacher O (2006) Absorption and crystallinity of poly(3-hex)dthiophene)/fullerene blends in dependence on annealing temperature. Thin Sohd Films 511-512 483... 

The quantitative measurement of the effect of annealing of poly(vinyl chloride) near the glass transition temperature was described by Foltz and McKinney (160). The method is based on the use of a quenched sample of the polymer as the reference material the DSC curve so obtained is then the difference in heat energy between the sample and the annealed material. By this technique it is possible to measure small energy differences which in the usual procedure appear as minor inflections on the slope of the Tg curve or as irregularities prior to the start of the glass transition. 

Takahashi Y (1983) Packing disorder in form II of poly(vinylidene fluoride) influence of elongation and annealing temperature. Polymer J. 15 733... 

Also poly(chloro-/7-xylylene) (parylene-C) has been used as a gate dielectric material for transistors [42]. The devices exhibit positive bias shifts with negative DC gate-source voltages. No hysteresis was observed in the transfer characteristics for the devices. This tendency was enhanced with increasing annealing temperatures. 

Androsch R, Wunderlich B (1999) A Study of the Annealing of Poly(ethylene-co-octaie)s by Temperature-modulated and Standard Differential Scanning Calorimetry. Macromolecules 32 7238-7247. 

Crystallinity of poly(ethylene terephthalate) as a function of annealing temperature determined using X-ray diffractometry, IR spectroscopy and DSC... 

Figure 5.23 presents the calculated crystallinity of poly(ethylene terephthalate) as a function of annealing temperature using DSC and X-ray and IR spectroscopy data. It can seen that the estimates of vary greatly. DSC is clearly the least sensitive to the effect of annealing on the sample crystallmity. 

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