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Author Thomas, V. ♦ Jayabalan, M.
Source Sree Chitra Tirunal Institute for Medical Sciences & Technology
Content type Text
Publisher Biomaterials
File Format PDF
Language English
Subject Domain (in DDC) Technology ♦ Medicine & health
Subject Domain (in MeSH) Biomedical and Dental Materials ♦ Chemicals and Drugs
Subject Keyword Biomaterials
Abstract In vitro oxidative degradation and lipid sorption of aliphatic, low elastic modulus and virtually cross-linked poly(urethane urea)s based on 4,4' methylene bis(cyclohexyl isocyanate), hydroxy terminated poly butadiene and hexamethylene diamine were evaluated. The aged samples revealed no weight loss in the oxidation medium. The IR spectral analyses revealed the stability of unsaturated double bonds at 964 cm(-1) (characteristic for polybutadiene soft segment) with no change in peak intensity. The poly(tetramethylene glycol) (PTMG)-added poly(ether urethane urea) polymer also revealed no disappearance of IR peaks for ether and unsaturated double bonds in samples aged in vitro oxidation medium. All the polymers have shown increase in weight due to lipid up take in lipid-rich medium (palm oil) but it was rather low in Dulbecco's modified eagle medium (DMEM) cholesterol. The slight change in mechanical properties of the present polymers in oxidation and DMEM is due to the rearrangement of molecular structure with virtual cross links of hydrogen bonding (physical cross linking) without degradation and plasticization effect of lipid. The influence of these media on the rearrangement of virtual cross links has been observed. Higher the virtual cross-link density, lesser is the loss of tensile properties of poly(urethane urea)s in the oxidation medium and vice versa. On the other hand, higher the virtual cross-link density of poly(urethane urea), higher is the loss of ultimate tensile strength and stress at 100% strain and vice versa in DMEM medium. (C) 2001 Elsevier Science Ltd. All rights reserved.
Education Level UG and PG
Learning Resource Type Article
Educational Framework Medical Council of India (MCI)
Volume Number 23
Issue Number 1
Page Count 10
Starting Page 273
Ending Page 282