In vivo evaluation of polyurethanes based on novel macrodiols and MDI.
A series of novel polyurethane elastomers based on methylenediphenyl diisocyanate, 1,4-butanediol and the macrodiols, poly(hexamethylene oxide), poly(octamethylene oxide), and poly(decamethylene oxide) were implanted subcutaneously in sheep for periods of 3 and 6 months. The specimens that were subjected to 3 months of implantation were strained to 250% of their resting length, while those implanted for 6 months had no applied external strain. SEM examination of the explanted specimens revealed that the novel materials displayed resistance to environmental stress cracking. Proprietary materials, Pellethane 2363-80A, Biomer and Tecoflex EG-80A, which had been implanted under identical conditions, showed evidence of significant stress cracking. The extent of stress cracking in the 3-month strained experiment was similar to that from the 6-month unstrained experiment. Stress cracking was also observed in Pellethane 2363-55D, when implanted for 6 months (unstrained). Neither changes in molecular weight nor in tensile properties provided a clear indication of early susceptibility to degradation by environmental stress cracking.
Brandwood
A
A
Centre for Biomedical Engineering, University of New South Wales, Kensington, Australia.
Meijs
G F
GF
Gunatillake
P A
PA
Noble
K R
KR
Schindhelm
K
K
Rizzardo
E
E
D000818:Animals; D001672:Biocompatible Materials; D002072:Butylene Glycols; D004868:Equipment Failure; D005549:Foreign-Body Reaction; D006018:Glycols; D006244:Hardness; D008297:Male; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D019736:Prostheses and Implants; D012756:Sheep; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
D001672:Biocompatible Materials; D002072:Butylene Glycols; D006018:Glycols; D011108:Polymers; D011140:Polyurethanes; C059617:pellethane 2363-55D; C047554:polytetramethylene glycol; C090631:polyhexamethylene oxide; C090630:polydecamethylene oxide; C090632:polyoctamethylene oxide; C031892:biomer; C062725:Tecoflex; C039681:1,4-butanediol