Trioxane, crystalline, polymerisation

It is marketed as a 35-40 per cent, solution in water (formalin). The rpactions of formaldehyde are partly typical of aldehydes and partly peculiar to itself. By evaporating an aqueous solution paraformaldehyde or paraform (CH O), an amorphous white solid is produced it is insoluble in most solvents. When formaldehyde is distilled from a 60 ptr cent, solution containing 2 per cent, of sulphuric acid, it polymerises to a crystalline trimeride, trioxane, which can be extracted with methylene chloride this is crystalline (m.p. 62°, b.p. 115°), readily soluble in water, alcohol and ether, and devoid of aldehydic properties ... 

The techniques of opticaP and electron microscopy have been applied to solid state reactions, but it is difficult to obtain more than semi-quantitative results. Wagenblast et have studied the formation and growth of carbon precipitation in iron by electron microscopy. The polymerisation of crystalline trioxane... 

There are two different methods for producing polyacetals. Anionic polymerisation of formaldehyde produces homopolymers that crystallize particularly well and therefore have high stiffness and strength. The other method is cationic polymerisation of trioxane. Here the addition of small amounts of comonomers lowers the crystallinity to increase toughness. The stiffness and strength are however somewhat lower than for homopolymers. 

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See also in sourсe #XX -- [ , ]

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