Poly formaldehyde properties

Properties of composites obtained by template poly condensation of urea and formaldehyde in the presence of poly(acrylic acid) were described by Papisov et al. Products of template polycondensation obtained for 1 1 ratio of template to monomers are typical glasses, but elastic deformation up to 50% at 90°C is quite remarkable. This behavior is quite different from composites polyacrylic acid-urea-formaldehyde polymer obtained by conventional methods. Introduction of polyacrylic acid to the reacting system of urea-formaldehyde, even in a very small quantity (2-5%) leads to fibrilization of the product structure. Materials obtained have a high compressive strength (30-100 kg/cm ). Further polycondensation of the excess of urea and formaldehyde results in fibrillar structure composites. Structure and properties of such composites can be widely varied by changes in initial composition and reaction conditions. 

While catalysts are also used in the production of other types of polymers, the properties of most of these materials are not particularly dependent on the type of catalyst employed. Many poly condensation reactions, e. g. the formation of polyesters, polyamides or urea-formaldehyde resins, are speeded up by addition of some Bronsted or Lewis acids. Since relevant properties of these polymer products, such as their average chain lengths, are controlled by equilibrium parameters, primarily by the reaction temperatures and molar ratios of the monomers employed, and since their linkage patterns are dictated by the functional groups involved, addition of a catalyst has little leverage on the properties of the resulting polymer materials. 

Several other polyamides are derived from natural poly(amino acids) that are subject to a subsequent synthetic treatment. Examples are casein, groundnut protein fiber, and zein, which after a treatment with formaldehyde led to new materials with better mechanical/solubility properties. For example, casein is a mixture of several proteins that forms 3% of milk (as casein calcium salt). Casein can be fractionated into simpler proteins designated as a, 3, y, and k [37]. The amino acid content of casein is similar to... 

Depending on their structure, the polymers containing heterocycles have various applications. For example, poly(furfuryl alcohol) is used in composite materials with fillers such as sand and concrete, in copolymers with formaldehyde, etc. Some of the polymers from this group have special properties such as good electrical conductivity (after appropriate doping). Among these polymers are poly(thiophene-2,5-diyl) and particularly polypyrrole, CAS 109-97-7, (usually in carbon black doped with an organic acid anion). The structure of this polymer is shown below ... 

Noxythiolin (N-hydroxy N-methylthiourea) is supplied as a dry powder and on aqueous reconstitution slowly releases formaldehyde and N-methylthiourea. The compound has extensive antibacterial and antifungal properties and is used both topically and in accessible body cavities as an irrigation solution and in the treatment of peritonitis. Polynoxylin (poly[methylenedi(hydroxymethyl) urea]) is a similar compound available in gel and lozenge formulations. 

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