Microwave absorbing materials, soluble

As an extension of our earlier work we have studied soluble conductive polymers (sulfonic acids doped polyaniline (4), poly(3-alkyl thiophenes) (5)) for the design of a new generation of microwave absorbing materials (6). These studies have own that microwave properties were very dependent on minor changes in e q)erimental procedures. Therefore it was necessary to determine how synthetic conditions effects influence structural parameters of polymers, and how these structural parameters influence electrical, optical properties and stability over time. In the case of poly(a]kylthiophene)s, solubility of polymers permits a complete structural characterization and then a better understanding of links between... 

Soluble conducting polymers are very attractive materials in order to realize microwave absorbing materials. However, structural parameters of the polymer and details of preparation techniques have to be severely controlled in order to get reproducible and expected values. More specifically, DBSA doped polyaniline based materials are promising materials if two major problems are fixed homogeneity of properties after extrusion and stability over time. Work is in progress now in order to increase properties stability of the polymer. 

Figure 3, Elution profile of water-soluble material from microwave oven treated (200°C for 2 min) milled spruce chips after SEC using Superdex 75 and 200 columns, Rl-detection (solid line) and absorbance at 280 nm (hatched line) is shown (AU Absorbance units). The applied sample volume was 100 pd. The arrows mark the elution volumes from fractions of AcGGM analyzed with MALDI-MS (Mp 8500, 3900 and 1700). Monomeric sugars eluted at 39-40 ml. The elution volumes using dextran standards of molecular weights 70 000,...

---