Solution blended

Adhesives. High concentration (>10%) solutions of poly(ethylene oxide) exhibit wet tack properties that are used in several adhesive appHcations. The tackiness disappears when the polymer dries and this property can be successfully utilized in appHcations that require adhesion only in moist conditions. PEO is also known to form solution complexes with several phenoHc and phenoxy resins. Solution blends of PEO and phenoxy resins are known to exhibit synergistic effects, leading to high adhesion strength on aluminum surfaces. Adhesive formulations are available from the manufacturers. 

One of the most important solution blend polymers is high-styrene resin, which is manufactured by several companies worldwide. This is a latex blend of high-styrene rubber and normal styrene butadiene rubber. The different high-styrene master batches are available in the world as ... 

Polysaccharides such as starch and cellulose have been used as reinforcing agents in natural rubber. Both solution blending and dry mixing methods have been employed for the development of biocomposites and the performance compared with the composites obtained using carbon black. Dry mixing method is more economically viable and environment friendly. 

Solution blending Polar as well as nonpolar solvents can be used in this method. The polymer is solubilized in a proper solvent and then mixed with the filler dispersion. In solution, the chains are well separated and easily enter the galleries or the layers of the fillers. After the clay gets dispersed and exfoliated, the solvent is evaporated usually under vacuum. High-density polyethylene [24], polyimide (PI) [25], and nematic hquid crystal [26] polymers have been synthesized by this method. The schematic presentation is given in Scheme 2.2. 

Jha and Bhowmick [51] have reported the development and properties of thermoplastic elastomeric blends from poly(ethylene terephthalate) and ACM by solution-blending technique. For the preparation of the blend the two components, i.e., poly(ethylene terephthalate) and ACM, were dried first in vacuum oven. The ACM was dissolved in nitrobenzene solvent at room temperature with occasional stirring for about three days to obtain homogeneous solution. PET was dissolved in nitrobenzene at 160°C for 30 min and the rubber solution was then added to it with constant stirring. The mixture was stirred continuously at 160°C for about 30 min. The blend was then drip precipitated from cold petroleum ether with stirring. The ratio of the petroleum ether/nitrobenzene was kept at 7 1. The precipitated polymer was then filtered, washed with petroleum ether to remove nitrobenzene, and then dried at 100°C in vacuum. 

The important yet unexpected result is that in NR-s-SBR (solution) blends, carbon black preferably locates in the interphase, especially when the rubber-filler interaction is similar for both polymers. In this case, the carbon black volume fraction is 0.6 for the interphase, 0.24 for s-SBR phase, and only 0.09 in the NR phase. The higher amount in SBR phase could be due to the presence of aromatic structure both in the black and the rubber. Further, carbon black is less compatible with NR-cE-1,4 BR blend than NR-s-SBR blend because of the crystallization tendency of the former blend. There is a preferential partition of carbon black in favor of cis-1,4 BR, a significant lower partition coefficient compared to NR-s-SBR. Further, it was observed that the partition coefficient decreases with increased filler loading. In the EPDM-BR blend, the partition coefficient is as large as 3 in favor of BR. 

Figures la and lb. Differential Scanning Calorimetry Results of the Second Cooling Runs for (a) Solution Blended and (b) Extrusion Blended PLA/EVAc Homopolymers and Copolymers.

Figure 2. Normalized Mass of Solution Blended / Uncatalyzed Samples During 330 Days of Incubation.

Pearce E, Kwei TK (1992) In Noda 1, Rubingh D (eds) Polymer solutions, blends and interfaces. Elsevier, Amsterdam, pp 133-149... 

Morphological structures and properties of a series of poly(ethyl acrylate)/clay nanocomposites prepared by the two distinctively different techniques of in situ ATRP and solution blending were studied by Datta et al. [79]. Tailor-made PNCs with predictable molecular weights and narrow polydispersity indices were prepared at different clay loadings. WAXD and studies revealed that the in situ approach is the better option because it provided an exfoliated morphology. By contrast, conventional solution blending led only to interlayer expansion of the clay gallery. 

Solution blends of 20-25% by weight were formed in DM Ac, with conventional dry spinning and film casting techniques used to produce blend fiber and film, respectively. Blend powders were prepared by precipitating the dope with a non-solvent (water). All materials were extensively washed in methanol or water to reduce residual solvent to less than 1 wt %. Neat resin tensile bars and plaques were compression molded from both powder and fiber. 

Figure 1 shows a typical PBI/polyimide solution blended phase diagram after solvent removal. It is clear that, in the absence of solvent, the single phase... 

PAr is soluble in similar polar organic solvents (e.g., NMP, DMAc, DMSO, etc.) which dissolve PBI. It was observed that miscible solution blends of PBI and PAr could be formed. For example, NMP dopes containing 10 wt % PBI and PAr are visually homogeneous and contain no insolubles as formed. After being kept at room temperature for a period of time (e.g., several days), a PBI-rich phase starts to form precipitate, but this polyphasic material can be easily redissolved into a single phase with a mild heating (i.e., 100 °C for 20 min). Based on the haze level, the stability of the PBI/PAr/NMP solutions appeared to increase with the increase of the relative PAr concentrations. 

Figure 8 illustrates the relationship between inherent viscosity (IV) and concentration for PBI/PAr/NMP solutions. It is interesting to note that the IV of all solution blends exhibited normal polymer solution characteristics. At a fixed concentration (0.5%), it was noted that the IV of the solution blends exceeded the rule of mixtures (see Fig. 9) suggesting that PBI and PAr exhibit specific interactions in a dilute solution, such that the resulting hydrodynamic sizes of the blends were greater than that of the calculated averages based on each component. 

Using dissolution techniques, it was observed that the 10 and 25% 6F-PAI (ODA-based) could be co-dissolved with PBI using DMAc. Solution blends with PBI-PAI ratios ranging from 20/80 to 80/20, in 20% increments, were visually homogeneous and contained no insoluble materials. At 15-20% solids concentration, these blends were processible and showed no sign of polymer precipitation for at least 24 h. Transparent, apparently miscible, blend films were cast from the solution blends of PBI and 10% 6F-PAI. 

All polyimide alloys were solution blended at a 50/50 weight ratio by codissolving the polymer pairs in a common solvent, such as methylene chloride (MeCl2) or a mixture of MeCl2 and hexafluoroisopropanol (HFIP), co-precipi-tating in methanol and then drying overnight under vacuum at 100 °C. 

Most of the work to date concerns the area with the greatest potential for commercial exploitation, the blending of LCPs with conventional polymers. While a few studies of solution blending with Kevlar do exist [57-61], most of the work has centered on melt blending thermotropic copolyesters (Vectra, Xydar) with engineering thermoplastics (PET, PC, PEI, etc.). For convenience, this work may be separated into three blend regions based on LCP content, namely ... 

As mentioned in Section 2.3,3, because SC IT is the most general theory for the ordering of block copolymers to date, a brief outline is given here. The simplest case of a diblock copolymer melt is considered, following Matsen and Schick (1994). The extension to other melts of other architectures, solutions, blends or semicrystalline copolymers is discussed in the appropriate chapter. 

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