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The synthesis of polymers and polymer additives from renewable biosources is of increasing interest. Products based on biosources offer independence from the uncertainty and fluctuation in petrochemical markets and may offer clear advantages over petrochemical counterparts in terms of toxicity, biodegradability, and environmental impact. Isosorbide is a diether diol available from glucose which may be obtained from starch produced by a variety of seed crops. Isosorbide may be converted to a variety of bis-phosphorus esters (phosphinate, phosphonate, phosphate) using either direct phosphorylation or the Atherton-Todd procedure.

Phosphorus compounds derived from renewable biomaterials are of increasing interest as polymer additives. These compounds may have both a plasticizing and flameretarding effect on a polymer matrix into which they are incorporated. The thermal degradation of a series of phosphorus esters derived from a diol generated by the esterification of isosorbide (from starch) with 10-undecenoic acid (from castor oil) followed by thiol-ene reaction with 2-hydroxyethanethiol has been examined using thermogravimetry and infrared spectroscopy. All the esters undergo degradation over the temperature range of 250-310°C to generate a substantial residual char. Infrared analysis of samples undergoing degradation suggests that a prominent reaction is elimination of a phosphorus acid.

Compounds containing sulfur in various forms may be used as flame retardants or as adjuvants to promote the activity of other flame-retarding elements, most notably phosphorus. To gain a better understanding of the nature of the sulfur moiety in a flame retardant on performance, a series of phosphorus esters derived from isosorbide containing sulfur at various levels of oxygenation (sulfide, sulfoxide, sulfone) have been prepared and evaluated for flame-retardant impact in diglycidyl ether of bis-phenol A epoxy. In all cases, the presence of sulfur positively impacts flame retardancy. In general, the impact on flame retardancy increases as the level of oxygenation at sulfur increases (sulfone. sulfoxide. sulfide).