Fiber-forming properties

It polymerizes into a white powder, melting at about 140° and having film and fiber forming properties. 

Since 1935, when Carothers discovered the fiber-forming properties of polyamides, many chemists in the world have studied the synthesis of the raw materials for various polyamides, aliphatic diamines, aliphatic dibasic acids, caprolactam, and the w-amino fatty acids. The known synthetic routes to polyamides from w-amino fatty acids are as follows ... 

The polyanhydrides synthesized by melt condensation have fiber-forming properties in the molten state. They hydrolyze when exposed to air and this degradation is mainly controlled by the composition of the polymer. Homopolymers of aromatic monomers, such as CPH, degrade at a rate that is several orders of magnitude lower than that of homopolymers of aliphatic monomers. 

High-molecular-weight poly (thiol esters) show fiber-forming properties. This section covers the available data concerning melting points, crystallinity, solubility, and stability of this class of esters, and compares them with polyesters and polyamides. Information about spectra is also reviewed. 

The polarity of the ester linkage produces sufficient interchain forces to allow these polymers to develop good fiber-forming properties with number average molecular weights in the 15 to 25 thousand range. 

Three reasons underlie the widespread interest in macromolecules, in spite of the synthetic difficulties that exist. First, the entanglement of long-chain macromolecules provides physical properties (strength, toughness, elasticity, fiber-forming properties, etc.) that cannot be obtained with small-molecule systems. Second, because polymers have a low volatility they can be used as engineering materials. Third, the onedimensional character of linear polymers is of considerable interest from the viewpoints of anisotropic physical properties, electrical phenomena, and information storage at the molecular level. 

The linear structure of chitosan is mainly responsible for the fiber forming property. Chitosan fibers are produced by wet spinning method. In general, chitosan is dissolved in acetic acid to give a solution of 3% w/v and then extruded through the spinneret into... 

At DuPont corporation in the 1950s, as it became clear that control of nylon 6,6 production and sale would inevitably be out of the corporation s control, a polymer was synthesized, nylon 1, which was designed to allow DuPont to control another nylon-forming fiber that was of possible commercial importance. Anionic polymerization of alkyl isocyanates yields a polymer (R)NCO with stiff fiber-forming properties. However, hopes were dashed when the ceiling temperature of the polyisocyanate (nylon 1) was discovered to be near the boiling point of water. 

In the 1930 s, Carothers prepared a series of aliphatic poly(anhydride)s for potential use as fibers in the textile industry (1). However, the hydrolytic stability of these materials was very poor. By the mid-1950 s, Conix was able to synthesize aromatic poly(anhydride)s with improved film and fiber forming properties (2). Despite these properties, the polyanhydrides poor thermal and hydrolytic stability resulted in their limited use, and no conunercial applications were found. By the late 1960 s, however, hydrolytic instability became an important factor for polymers utilized in the manufacture of medical devices such as absorbable sutures and drug delivery systems. 

---