spectra and characteristic frequencies of inorganic ions. The thermal decomposition, i.e., pyrolysis, of inorganic/organometallic polymers (preceramic polymers) in an oxygen-free atmosphere is a chemical process which is implemented to prepare the so-called Polymer-Derived Ceramics (PDCs). The preparation of boron nitride porous ceramics by nanocasting mesoporous CMK-3 carbon with a molecular boron nitride precuror was discussed. The microtexture of the fibers was featureless as glassy-like materials when fibers were exposed at temperatures below 1400°C. Initial stages of degradation were accompanied by liberation of ammonia in addition to the expected aniline or methylamine; this was most pronounced for the methyl borazine. Furthermore, the BN illustrates superior oxidation resistance with weight increase lower than 0.3% below 900°C in air. This ceramic is predominantly / 24 / produced via powder-metallurgical process. The chief limitation at present is the practical necessity of working with powders, which makes it difficult to put the spectra on a quantitative basis. Boron nitride (BN) fibers were efficiently prepared from a B-aminoborazine-based polymer according to the Polymer-Derived Ceramic (PDC) route via melt-spinning and heat-treatments up to 1800°C in a controlled atmosphere. The latter offers an unusual combination of properties that cannot be found in any other ceramics. Boron nitride (BN) fibers were efficiently prepared from a B-aminoborazine-based polymer according to the Polymer-Derived Ceramic (PDC) route via melt-spinning and heat-treatments up to 1800°C in a controlled atmosphere. The precursor was obtained as an intermediate material by the reaction of KBH4 and NH4Cl at 120 °C for 48 h. h-BN was obtained by heating the intermediate material at 1250 °C for 10 h. The sample obtained was characterized by X-ray powder diffraction (XRD), Fourier transformation infrared spectroscopy (FT-IR), thermogravimetry (TG/DTA) and environment scanning electron microscopy (ESEM), which matched with h-BN. Concerning the former, Sneddon and co-/ 35 / workers [5] have studied the conversion process of / 36 / polyborazylene into boron nitride ceramic and shown / 37 / that a spinnable oligomer can be obtained by linking / 38 / dipentylamino groups to the polymer backbone. However, promising results were also obtained with borylborazines. Preceramic polymers offer the possibility of using versatile plastic shaping technologies as well as advanced laminated object manufacturing techniques. The polymers display direct B–N bonds between borazinic B3N3 rings and, in addition, a proportion of –N(CH3)– bridges for 5 and 6, as clearly underlined by 13C NMR spectroscopy. The polysilazanes studied are viscous liquids that can be converted to ceramic material with a yield of, Novel precursors polymerized from (alkylamino)borazines (AAB) were synthesized and transformation of processable poly-AAB to boron nitride (BN) was researched. (1) and (2) [16]. I. Mechanistic studies of borazine pyrolyses, Boron Nitride Fibers Prepared from Symmetric and Asymmetric Alkylaminoborazine, Boron nitride preceramics based on B,B,B-triaminoborazine, High-Performance Boron Nitride Fibers from Poly(borazme) Preceramics, Design, Processing, Properties and Surface Modification of Polymer-Derived Silicon-containing Non-Oxide Ceramic Hollow Fibers for Membrane Application, Synthesis of Photocatalytic Porous Boron or Silicon-Containing Nitride and Oxynitride Nanocomposites, New class of funCtionAl silicon caRBOnitride-based ceramic FIBErs from oRganometal compound-modified polySilazanes. The mechanical properties for 4-derived fibers could not be measured because of their brittleness, whereas measurements on 5- and 6-derived fibers gave tensile strength σR = 0.51 GPa, Young’s modulus E = 67 GPa, and σR = 0.69 GPa, E = 170 GPa, respectively. Also unlike PB, the DPA-PB polymers become fluid, without weight loss, in the range 75−95 °C. Such pendent groups allowed of controlling both melt-viscoelastic properties and thermal reactivity, and then to produce high quality fine-diameter endless green fibers via a stable melt-spinning process. The results indicated that crystalline h-BN with B/N ratio of 1:1.01 is main in the residue pyrolyzed at 1500°C. All products desorb with the same temperature profile, and the major desorbing species are NHâ and Nâ (polymer decomposition products) and HCl (side reaction products). The formation and composition of these gases and liquids is directly related to the composition of the original biomass feedstock, but the exact chemistry is not well understood. Techniques and analytical methods like Thermo-Gravimetrical Analysis (TGA) and Pyrolysis Gas Chromatography-Mass Spectroscopy (Py-GC-MS) were use for the study of the thermal decomposition of biomass and the speciation of the product yield during pyrolysis respectively.