Solid state chemical polymerization

This contribution gives a review of recent spectroscopic investigations concerning the photophysical and photochemical primary and secondary processes of the solid state polymerization reaction in diacetylene single crystals. It will be shown, that diacetylenes are an unique model system for the study of the reaction mechanism of a solid state chemical reaction which is characterized by a variety of reaction intermediates. The polymerization reaction in these crystals is of special importance, due to the resulting polymer single crystals, which exhibit extraordinary anisotropic physical properties. 

TXN undergoes solid-state polymerization by chemical-induced processes as well as by radiation. That TXN may undergo polymerization in the solid state was observed as early as in 1930 U1), but for a long time this observation was not used. In 1954 Mesrobian et al. published the first paper on the radiation-induced polymerization in the solid state (acrylamide polymerization) 1121 and the solid-state polymerization of TXN was rediscovered a few years later 113). Radiation-induced solid-state polymerization of TXN gained importance and it was believed that it could lead... 

Recent results suggest that carbon dioxide polymerization does not occur via intermediate states where molecules gradually distort as pressure increases, but is most likely caused by solid-state chemical reactions between CO2 molecules [59]. Such studies are important to gain better insight into transformations of light element-based molecules under high pressure and temperature and may open up new horizons in solid state chemistry under extreme conditions. 

Pilloton R, Mela J, Marradini L (1999) Screen printed electrochemical biosensors on ceramic and polymeric substrates. Advances in science and technology solid state chemical and biochemical sensors, vol. 26, pp. 501-507. 

Due to its high reactivity, DBF reacts even with oxygen contained in the air in the solid state and affords a copolymer consisting of DBF and -0-0- units (Fig. 4). Solid-state polymerization is an efficient method in controlling polymer structure. Several diyne and diene monomers undergo solid-state polymerization, leading to polymers with controlled chemical and stereostructures [64-70]. However, solid-state vinyl polymerization is rare ([71] and references therein [72-75]). 

With further understanding how molecular rotors interact with their environment and with application-specific chemical modifications, a more widespread use of molecular rotors in biological and chemical studies can be expected. Ratiometric dyes and lifetime imaging will enable accurate viscosity measurements in cells where concentration gradients exist. The examination of polymerization dynamics benefits from the use of molecular rotors because of their real-time response rates. Presently, the reaction may force the reporters into specific areas of the polymer matrix, for example, into water pockets, but targeted molecular rotors that integrate with the matrix could prevent this behavior. With their relationship to free volume, the field of fluid dynamics can benefit from molecular rotors, because the applicability of viscosity models (DSE, Gierer-Wirtz, free volume, and WLF models) can be elucidated. Lastly, an important field of development is the surface-immobilization of molecular rotors, which promises new solid-state sensors for microviscosity [145]. 

Physical and chemical changes may often be induced by raising or lowering the temperature of a substance. Typical examples are phase transitions, such as fusion, or chemical reactions, such as the solid state polymerization of sodium chloroacetate, which has an onset at 471 K [227] ... 

Chuah, H. H., Vinson, R. W. and Ulzelmeier, C. W., The Kinetics of Poly(Propylene Terephthalate) Solid-state Polymerization in Research Awareness Bulletin, Shell Chemical Company, July 1993, Houston, TX, pp. 101-103. 

FIGURE 37. Proposed polymer structures from THY obtained by solid-state polymerization at ambient temperature without irradiation. Reprinted with permission from Reference 53. Copyright (1994) American Chemical Society... 

In order to study the cure behavior of the PTEB system, 1JC NMR of uncured and cured PTEB in the solid state was performed using crosspolarization magic-angle spinning techniques. The results show the polymerization to be via aromatization. The extent of cure versus cure temperature was determined quantitatively. It was found that the material was almost completely cured after one hour at 215°C. As the cure goes to completion, the ability to react decreases due to the corresponding rapid increase in Tg. Chemical shifts of the resonances in the cured material are consistent with a highly crosslinked condensed aromatic network. 

Figure 10.6 Si solid-state CP-MAS NMR spectra for imprinted materials prepared by the chemical vapor deposition (CVD) and subsequent hydrolysis-polymerization of SifOCHs). (a)-(d) solid lines represent the imprinted materials on Rh monomer/Si02, and dotted lines correspond to the Si02 support (al)-(dl) difference spectra, which correspond to be surface Si02-matrix overlayers.

Nuclear magnetic resonance (NMR) spectroscopy is a most effective and significant method for observing the structure and dynamics of polymer chains both in solution and in the solid state [1]. Undoubtedly the widest application of NMR spectroscopy is in the field of structure determination. The identification of certain atoms or groups in a molecule as well as their position relative to each other can be obtained by one-, two-, and three-dimensional NMR. Of importance to polymerization of vinyl monomers is the orientation of each vinyl monomer unit to the growing chain tacticity. The time scale involved in NMR measurements makes it possible to study certain rate processes, including chemical reaction rates. Other applications are isomerism, internal relaxation, conformational analysis, and tautomerism. 

Most modern materials are formed empirically by solid-state methods. These methods generally involve more processing activity than chemical synthesis (for example, sintering of ceramic powders, modifying concrete by polymers, thermomechanical processing of alloys, layering polymeric membranes for... 

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