Effects of different kinds of stabilizers on thermal stability, biocompatibility ‎and blood compatibility of PVC film sterilized by ethylene oxide for blood ‎bag

Background and objectives: The main purpose of this research was to find a proper Poly Vinyl Chloride (PVC) stabilizer system for medical purpose. It was sterilized by ethylene oxide gas, constant ratio of metallic soap stabilizers (calcium-zinc stearate) as well as stabilizers based on organotin (octyle sn-mercaptide, which is commercially known as 17mok901) and soybean oil were studied.
Methods: PVC S-6058 with value=60 from Iran Petrochemical Commercial Company, di-2 ethyl hexil phethalate plasticizer from Iran Azarshimi Company, epoxide soya bean oil (from South Africa’s MBT Company), calcium-zinc stearate (from India’s Shital Company), octyl tin mercaptide, commercially known as 17^® MOK 901, (from India’s Shital Company) and BHT (2,6-di-tert-butyl-4-methyl phenol) anti-oxidant (commercially known as Lanxess from Germany’s Volkanux Company) were provided and utilized during the research. PVC mixtures prepared by the aforementioned stabilizers were tested under mechanical testing, thermal gravimetric analysis (weight measurement under heating) (TGA) and Fourier transform infra-red (FTIR) (determination of functional groups in the stabilized PVC) before and after sterilization by ethylene oxide gas.
Results: Assessment of blood compatibility of samples was done by Hemolysis test, according to ISO 10993 standard part 4. Results of the tensile test demonstrated that calcium-zinc stearate was the best PVC stabilizer. In order to improve its tensile properties, with 2.67 strain rate, sterilization improved its mechanical properties while preserving strength.
Conclusion: The results from Fourier transform infra-red (FTIR) on chemical structures of samples suggested that sterilization by ethylene oxide gas had no negative effect on the structure of the stabilized PVC. Furthermore, the mixture made from PVC had stabilized on organotin and was of higher thermal stability as well as had better blood-compatibility properties with respect to other stabilizers. This confirms acceptable efficiency of stabilizers utilized for hygienic and medical purposes.