7- Polysulfones:
Polysulfons are a family of polymers which have linkages in their backbones .
Polysulfones have excellent mechanical properties and chemical resis¬tance. One of the important polysulfones is poly( aryl sulfones) .
Some of the characteristics of polysulfones are:
(1) Heat resistant: Heat deflection temperature ( HDT) 174°C;
(2) Excellent hydrolytic stability to hot water and steam sterilization;
(3) Excellent chemical resistance to inorganic acids & bases;
(4) Food, water and medical contact compliance.
They are used as membranes for hemodialysis. Polysulfones have been used as orthopeadic biomaterials due to their excellent mechanical properties ( tensile modulus – 2. 4 GPa). To improve their bone-bonding properties, polysulfones were used to make composites with bioactive glass.
8- Poly( ether ether ketone):
The structure of Poly( ether ether ketone) (PEEK) :
PEEK is a crystalline polymer with a glass transition temperature of 145°C The most common form of PEEK is the one shown, derived from Bisphenol A, although limitless variations are possible, and a few are commercially pro¬duced. PEEK is a remarkable material, highly crystalline, thermally stable, resistant to many chemicals, and very tough. It can be melt-processed at very high temperatures ( >300°C), and is useful for special applications like pipes in oil refineries and chemical plants, and parts for scientific instruments, aero¬space and biomedical devices where high price is not a limitation.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
|