Table 8. Hardness and Moisture Absorption Tests of Plastics 



Materials 



NCEL 



Durometer Reading (model D) 



Moisture 



Absorption 



(%) 



No. 



Control (dry)I/ 



Exposed (wet) 



Delrin 



67 



80 



80 



0.29 



Nylon 



68 



71 



63 



0.54 



Phenolic laminate 



69 



89 



75 



1.82 



Polycarbonate 



70 



80 



80 



0.33 



Teflon 



71 



59 



55 



0.002 



Cellulose acetate 



73 



79 



71 



1.97 



Polyethylene 



74 



46 



44 



0.03 



Extruded acrylic 



75 



89 



80 



0.23 



Polystyrene 



76 



85 



82 



0.08 



Cast acrylic 



77 



90 



82 



0.51 



PVC pipe 



72 



82 



74 



0.30 



Vinyl tube 



66 



48 



3?> 



0.37 



Vinyl tube 



78 



-2/ 



_2/ 



0.59 



Vinyl tube 



79 



_2/ 



-V 



0.28 



Vinyl tube 



80 



57 



A7 



0.15 



Phenolic laminate 



S-5 



91 



77 



3.37 



Phenolic laminate 



S-7 



90 



80 



2.41 



Phenolic laminate 



S-8 



90 



77 



3.77 



Phenolic laminate 



S-9 



Lost 



Lost 



— 



Melamine laminate 



S-10 



95 



88 



0.44 



Epoxy laminate 



s-n 



Lost 



Lost 



— 



Rubber vacuum tube 



— 



— 



— 



1.31 



Jy Dried and tested in a room in which the relative humidity was kept at 20% 

 and the temperature was kept at 23°C. 



2/ Tested by a model A-2 durometer, NCEL No. 78 had a control reading of 

 74 and an exposed reading of 72; NCEL No. 79 had a control reading of 

 72 and an exposed reading of 72. 



37 



