Morphology polyphosphazene

Similarly, Table 7 shows the morphology characteristics of selected polyphosphazenes. 

Morphological features for POPs can range from low-temperature elastomers (when aliphatic alkoxy substituents of different length are attached to the polyphosphazene skeleton), to crystalline, film- and fibre-forming materials... 

As far as the morphology of these materials is concerned, we can distinguish at least two different cases depending on the type of fluorinated alcohol(s) attached to the phosphorus atoms of the polyphosphazene skeleton ... 

Allcock, H. R., Gebura, M., Kwon, S., and Neenan, T. X., Amphiphilic polyphosphazenes as membrane materials Influence of side group on radiation crosslinking, semipermeability, and surface morphology. Biomaterials. 19. 500, 1988. 

The morphology of the semicrystalline polyphosphazenes is complex. Table I provides examples of phosphazenes with two first order transitions denoted by T(l) and Tm. The T(l) is an intermediate transition to a partially ordered state. Between T(l)... 

JThe effect of the substituent on the properties of the polyphosphazenes is not fully understood. For instance, [NP(OCH ) ]n and [NP C CH. homopolymers are elastomers (8,29). Synthesis using lithium, in contrast to sodium, salts is claimed to produce rubber-like fluoroalkoxyphosphazene polymers (30). The presence of unreacted chlorine or low molecular weight oligomers can affect the bulk properties (31,32). Studies with phosphazene copolymers both in solution and in the bulk state (29,33-38) indicate a rather complex structure, which points out the need for additional work on the chain structure and morphology of these polymers. 

Polyphosphazenes. Single crystals of N P Cl. were grown on a variety of alkali halide crystals. The resuitant morphology of the trimer and polymer was identical and of 2 distinct types pyramidal or square shaped crystals, and rodlike crystals. All crystals were oriented in the substrate s <110> directions independent of method of crystallization. Representative films from vapor and solution depositions are shown in figures 2 and 3. 

Magill JH, Petermann J, Rieck U (1986) Morphology of polyphosphazenes oriented and unoriented. Colloid and Polymer Sci., 264 570... 

FIGURE 11.9 (a) Polyphosphazene nanofibrous scaffolds (b) SEM image illustrating the morphologies of cell-seeded 3D biomimetic scaffolds after... 

Herrero and Acosta (80) investigated the microstmcture of poly(ethylene oxide)-poly[(octafluoropentoxy)(trifluoroethoxy)phosphazene] blends. Limited miscibility of both components was inferred, based on the observed shift of the components glass-transition temperatures. Wycisk and co-workers (81) prepared membranes from blends of sulfonated poly[bis(3-methylphenoxy)phosphazene] with polyimides, polyacrylonitrile, and Kynar FLEX PVDF. Morphology, electrochemical performance, and methanol permeabilities of the membranes were then evaluated as part of a program to investigate such blends in direct methanol fuel cells. The polymers were immiscible and a domain-type structure was observed. The best compatibility resulted when the tetrabutylammonium or sodium salt of the polyphosphazene was used (82). 

The design of amphiphilic polyphosphazenes with self assembled morphologies for thermosensitive and micelle forming materials is another topic of current interest... 

Bose, S., Pramanik, N., Das, C.K., Ranjan, A., and Saxena, A.K. (2010) Synthesis and effect of polyphosphazenes on the thermal, mechanical and morphological properties of poly(etherimide)/ thermotropic liquid crystalline polymer blend. Mater. Des., 31,1148-1155. 

The morphology of the crystalline phase and the mesophase is correlated. They are both a function of the method of preparation of the samples, their past thermal history, and the defectiveness of the structure of the macromolecule [65]. Crystalline films of polyphosphazenes, polybistrifluoroethoxyphosphazene in particular, prepared from solution have a spherulitic structure which is preserved after melting of the crystalline phase to a total isotropic transition [41,53,57,62, 66]. On the contrary, optically anisotropic mesomorphic regions in the shape of rods in the microscope, which produce the beginning of crystals of the same... 

Tang, H., Pintauro, P.N. (2001) Polyphosphazene membranes. IV. Polymer morphology and proton conductivity in sulfonated poly[bis(3-methylphenoxy)phosphazene] films. Journal of Applied Polymer Science, 79, 49-59. 

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