the following description illustrates the manner in which the principles of the present invention are applied , but is not to be construed as in any sense limiting the scope of the invention . in the preferred method of practicing this invention , about one hundred parts by weight of high - density polyethylene resin is blended with between about 0 . 1 and about 0 . 3 parts by weight of a polyvinyloctadecyl ether . the mixture of polyethylene and polyether is heated to a temperature between about 140 ° c . and about 350 ° c . in an extruder , thereby forming a melt adapted for extrusion . the melt is then extended into a fused extrudate of any desired form or shape . more preferably , the mixture is heated to a temperature between about 200 ° c . and about 300 ° c . in the extruder . the polyvinyloctadecyl ether used in the present invention as a process modifier is characterized as having a number - average molecular weight of between about 1 , 000 and about 10 , 000 , and more preferably between about 3 , 000 and about 5 , 000 . a polyvinyloctadecyl ether suitable for practicing this invention is manufactured and sold by the american hoechst corporation , mountainside , new jersey , under the tradename &# 34 ; wax v .&# 34 ; the present invention will now be further illustrated by means of the following examples , which are not to be interpreted as in any sense limiting the scope of the invention . a sample of high - density polyethylene resin was multiply - extruded into pellets on a three - quarter - inch 24 : 1 screw ratio thermoplastic extruder with a temperature profile for zones 1 through 4 of 170 °, 185 °, 190 °, and 190 ° c . respectively , at fifty revolutions per minute ( rpm ). the pellets obtained thereby were then blown into film on a one - inch laboratory extruder with a one - inch annular die and a die gap of 0 . 025 inches , at a screw speed of sixty rpm , and a temperature profile for zones 1 and 2 , and gate and die zones 1 and 2 of 193 °, 196 °, 198 °, and 198 ° c ., respectively . conventional high - density polyethylene film and rheological tests were made to characterize the extruded film . in example 1 , no processing modifier was added to the polyethylene . in example 2 , 0 . 2 weight percent zinc stearate , a known processing modifier , was added . in examples 3 and 4 , 0 . 2 weight percent of a polyvinyloctadecyl ether was added , said ether characterized as having a number - average molecular weight of about 4 , 000 . the test results obtained are listed in table i , below . table i______________________________________ tensile percentageexample yield strength elongation tearing impactno . strength at break at break resist . resist . ______________________________________1 3304 5248 570 46 7742 2565 5411 656 67 16213 2956 6836 683 202 21474 3070 6818 688 183 2060______________________________________ the data displayed in table i above clearly show the results of adding a polyvinyloctadecyl ether to high - density polyethylene as a processing modifier during extrusion . with the exception of yield strength , the properties listed therein were significantly improved by the use of the polyether modifier according to the present invention . by way of comparison , the use of zinc stearate in example 2 led to values of these properties which were intermediate between the resin extruded with no processing modifier added , in example 1 , and the resins extruded with the addition of 0 . 2 percent polyvinyloctadecyl ether , in examples 3 and 4 . in addition , the surfaces of the films blown in examples 3 and 4 were considerably smoother than the surface of the film blown in example 1 , and substantially smoother than the surface of the film blown in example 2 . while certain representative embodiments and details have been shown for the purpose of illustrating the present invention , it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention .