199 teaches the preparation of metallocene catalysts non metallocene single site catalysts containing heteroatomic ligands e g boraaryl pyrrolyl azaborolinyl or quinolinyl are also well known in the art the hdpe can also be multimodal by u201c multimodal u201d it is meant that the polymer comprises at least two components one of which has a relatively low molecular weight the other a relatively high molecular weight the multimodal polyethylene can be produced by polymerization using conditions that create a multimodal polymer product this can be accomplished by using a catalyst system with two or more different catalytic sites or by using two or multi stage polymerization processes with different process conditions in the different stages e g different temperatures pressures polymerization media hydrogen partial pressures etc multimodal hdpe may be produced by a multistage ethylene polymerization using a series of reactors with comonomer addition in only one of the reactors a preferred modified starch component is hydroxypropylated amylose starch other substituents may be hydroxyethyl or hydroxybutyl to form hydroxyether substitutions or anhydrides such as maleic phthalic or octenyl succinic anhydride can be used to produce ester derivatives the degree of substitution the average number of hydroxyl groups in a unit that are substituted is preferably 0 05 to.