Compressibility of natural and synthetic high polymers at high pressures

Abstract

Co mpressio n da ta (-t. V IVo) are repor ted between 1,000 a nd 10,000 atmos pheres for the foll owing materi a ls : dry cellulose, polyvinylidene chloride (Saran), polyeth ylene, poly-rn onochlorotrifluoroeth ylene (K elF) , polytetrafluoro ethy le ne (T efion), a polyester (Seleetron 5003), and raw r ubbers, H ycar OR25, H ycar ORIS, Neoprene, a nd Thiokol ST. All compression curves are smooth excep t that for polytetrafiuoroethylene, which shows a transition at 5,500 a t mospheres, resulting in a change in volume (t. V I Vo) of approximatel y 2 percent. Coefficients of t he cubic eq uat ions,-t. V I Vo= a(P-2000) + b (P-2000)2 +C (P-2000)3 fi tted to t he data are as follows: Cellulose: a = 9.26 X 10-6 , b=-3.25 X 10-1O, c= 2.93 X 10-'s; polyvinyJidene chloride (Saran) : a = 2.17 X 10-s, b=-1. 90 X IO-9, c= 8. 73 X lO-l4 ; poly-ethylene: a = 1.89 X IO-s, b=-1.45 X IO-9, c = 6.lO X lO-14 ; polymonochlorotrifjuoro-ethylene (Kel-F): a = 9.89 X lO-6, b=-4. 74 X lO-1O , c= 8.29 X lO-' 5 ; pol yester (Selectroll 5003) : a = 1.76 X lO-s, b=-1.23 X 10-9, c= 4.82 X lO-14 ; H ycar OR25: a = 2.26 X IO-5, b=-2.03 X lO-9, c= 9. 09 X IO-I4 ; H ycar OR15: a = 2.17 X 10-5, b=-2.03 X lO-9, c = 9.42 X IO-I4; Neoprene: a = 2.04 X IO-s, b=-1.75 X 10-9 , c= 7.66 X 10-14 ; Thiokol ST : a = 1.92 X 10-5, b=-1.41 X 10-9, c= 6.07 X 10-14 • Co mprcssibilities calculated from these eq uations s how fictitious minima cir ca 10,000 atmosphere, although t he eq uations represen t the data satis-facto ril y to 10,000 atmospheres. The data given co mpare favorably with those obtaine d 0 11 similar materials by previou workers.