338 The Philippine Journal of Science 



SUMMARY AND CONCLUSIONS 



The data in the literature on the mechanical properties of 

 coir are very deficient and often have been misinterpreted. 



Coconut fiber in the Philippines is extracted in small quantity, 

 entirely by the retting and beating process. 



The results show retted filaments to average 228 millimeters, 

 and machine-cleaned filaments, 245 millimeters, in length. Most 

 filaments taper and have elliptical cross sections, the dimensions 

 of which are given. The finest filaments have a circular cross 

 section. 



Tensile tests conducted on single filaments average 832 kilo- 

 grams per square centimeter for the retted, and 1,208 kilograms 

 per square centimeter for the machine-cleaned fiber. The dif- 

 ference in ultimate tensile strength is less marked when the 

 fibers are fabricated into rope. The strength of coir filaments 

 and coir cordage is very low, roughly, one-tenth that of single 

 abaca filaments (Government inspected grades "F" and "G") ; 

 the strength of coir rope is about one-fifth that of abaca rope 

 of the same size. 



Immersion in tap water for twenty-four hours decreases the 

 strength of coir rope from 14 to 26 per cent, whereas there 

 is little change in the strength of abaca rope. Long immersion 

 of the coir in fresh water produces little further change, but 

 additional impairment is produced by the action of salt water and 

 weather. 



Coir cordage and coir filaments are characterized by great 

 elongation, which in some cases attains 39 per cent. There* is 

 little difference between the ultimate elongation of the filaments 

 and that of the rope, though in the latter it is slightly greater. 

 Wetting increases the elongation of coir rope about 3 per cent. 



Abaca filaments (grades "F" and "G") give an average elonga- 

 tion of only 3.6 per cent, but the ropes made from filaments of 

 these grades give an elongation of from three to four times as 

 much. 



Coir has pronounced plastic properties and has no definite 

 modulus of elasticity. 



Due to the small elastic tensile resilience of coir its "shock- 

 absorbing" power is relatively small, whereas abaca is a highly 

 resilient fiber and is eminently suited to absorb shocks. 



The coir industry in the Philippines should be developed in 

 order to furnish a fiber for bristles, brushes, doormats, mat- 

 tresses, cushions, ship fenders, etc. 



