Nonexclusive examples of plasticizers that can be used include ethylene glycol, mono or disaccharides such as sucrose and sorbitol, urea, thiourea, mixtures of mono or disaccharides and urea, and amine oxides derived from natural fatty acids, which often have mixtures of products of different lengths of alkyl chains generally characterized by the formula ##STR1## where R1 is an alkyl group having