nted by, for example, the constitutional formula ##STR1## wherein R is an aliphatic or aromatic group, organic acid, anhydride thereof and acid amide such as methylnadic anhydride, dichloromaleic anhydride; maleic amide; itaconic acid; and itaconic anhydride, natural fat and oil such as soybean oil; tung oil; castor oil; linseed oil; hempseed oil; cotton seed oil; sesame oil; rapeseed oil; peanut