described below seems to provide optimum properties when used in a relatively balanced bi component blend of polymers it is preferred that at least one of the polymers is crystalline and more preferably that both polymers are crystalline generally crystalline polymers exhibit superior mechanical properties over non crystalline polymers table 1 sets forth typical structures of some polymers useful in the present invention table 1______________________________________polymer structure______________________________________polystyrenes amorphouspolycarbonates amorphouspolyetherimides amorphouspolyolefins amorphous or crystallinepolysulphones amorphouspolyethersulphones amorphouspolyacetals crystallinepolyamides crystallinepolyesters amorphous semi crystalline or crystallinepolyphenylene sulphides semi crystallinepolyphenylene oxides amorphouspolyetheretherketones crystalline______________________________________ the polymers may be blended in any suitable manner which will be evident to those of ordinary skill in the art for example the polymers may be in the form of powders or more preferably pellets the polymers may be blended by static or screw auger type mixing for example preferably the polymers are combined in a twin screw compounding extruder such as are commercially available from werner pfleiderer or a buss kneader from buss america inc of elk grove village ill the present polymeric composition is a combination of the polymer blend discussed above and at least one toughening elastomer typical elastomers suitable for use in the present invention have glass transition temperatures less than about 20 u00b0 c and preferably less than about 20 u00b0 c as used herein the term 34 elastomer 34 is defined to mean an amorphous polymer having a low glass transition temperature and high mobility of the polymer chain preferably the elastomer has a tensile modulus less than about 50 000 p s i alternatively or additionally it is preferred that the elastomer be functionalized to graft with at least.