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Table 18-2   Property Chart for Basic Polymers for Gearing
  Water Absorp.
24hrs.		 Mold Shrinkage Tensile
Strength
* Yield
·Break		 Flexural Modulus Izod Impact Strength Notched Deflect.
Temp.
@264psi		 Coeff. of Linear Thermal
Expan.		 Specific Gravity
Units % in./in. psi psi ft.lb/in. ºF 10-5 ºF  
ASTM D570 D955 D638 D790 D256 D648 D696 D792
1. Nylon 6/6 1.5 .015/.030 *11,200 175,000 2.1 220 4.5 varies 1.13/1.15
2. Nylon 6 1.6 .013/.025 *11,800 395,000 1.1 150 4.6 1.13
3. Acetal 0.2 .016/.030 *10,000 410,000 1.4/2.3 255 5.8 1.42
4.Polycarbonate
  30% G/F,
  15%PTFE		 0.06 .0035 *17,500 1,200,000 2 290 1.50 1.55
5. Polyester
 (thermoplastic)		 0.08 .020 *8,000
·12,000		 340,000 1.2 130 5.3 1.3
6.Polyphenylene
   sulfide
   30% G/F
   15%PTFE		 0.03 .002 *19,000 1,300,000 1.10 500 1.50 1.69
7. Polyester
   elastomer		 0.3 .012 *3,780
·5,500		 - - 122 10.00 1.25
8. Phenolic
   (molded)		 0.45 .007 ·7,000 340,000 .29 270 3.75 1.42
* These are average values for comparison purpose only.
Source: Clifford E. Adams, Plastic Gearing, Marcel Dekker Inc., N.Y. 1986. Reference 1.

Table 18-3   Physical Properties of DELRIN Acetal Resin and ZYTEL Nylon Resin
Properties-Units ASTM "DELRIN"
500            100		 "ZYTEL" 101
.2% Moisture 2.5% Moisture
Yield Strength, psi D638* 10,000 11,800 8,500
Shear Strength, psi D732* 9,510 9,600  
Impact Strength (lzod) D256* 1.4          2.3 0.9 2.0
Elongation at Yield,% D638* 15             75 5 25
Modulus of Elasticity, psi D790* 410,000 410,000 175,000
Hardness, Rockwell D785* M 94, R 120 M79     R118 M 94, R 120, etc.
Coefficient of Linear Thermal
Expansion, in./in.ºF		  
D696		  
4.5 x 10-5		  
4.5 x 10-5		  
Water Absorption
         24 hrs. %
         Saturation, %  		 
D570
D570		  
0.25
0.9		  
1.5
8.0		  
Specific Gravity D792 1.425 1.14 1.14
* Test conducted at 73ºF
Reprinted with the permission of E.l. DuPont de Nemours and Co.; see Reference 5.

              Resistant to: Common Solvents, Hydrocarbons, Esters, Ketones, Alkalis, Diluted Acids
              Not Resistant to: Phenol, Formic Acid, Concentrated Mineral Acid
              Reprinted with the permission of The Polymer Corp.; see Reference 14.

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