Browsing by Author "JAYABALAN, M"
Now showing 1 - 16 of 16
Results Per Page
Sort Options
Item ACCELERATED DEGRADATION OF POLY(ESTER URETHANE) BY ADENOSINE-TRIPHOSPHATE(JOURNAL OF APPLIED POLYMER SCIENCE, 1991) SREENIVASAN, K; JAYABALAN, M; RAO, KVCItem AGING OF RADIATION-STERILIZED POLYPROPYLENE - CHANGES IN SEMICRYSTALLINITY(BIOMATERIALS, 1989)Item INTERACTIONS OF ENZYMES AND FUNGI WITH CROSS-LINKED POLYURETHANES PREPARED FOR BIOMEDICAL APPLICATIONS(MEDICAL PROGRESS THROUGH TECHNOLOGY, 1994)Shelf life and long-term environmental stability of polyurethanes intended for percutaneous applications and various biomedical applications are largely depend on their resistance to fungal attack and growth. Two classes of aliphatic crosslinked polyurethanes based on hexamethylene diisocyanate (HDI) and bicyclo-hexyl-methane diisocyanate (SM DI) were subjected to cell-free enzymatic degradation using hydrolytic and oxidative enzymes and to fungal attack and fungal growth using Aspergillus niger and Penicillium Sp. The present crosslinked polyurethanes are not susceptible to degradation by hydrolytic enzymes. The marginal loss of tensile strength in buffered solution of papain is attributed to plasticization by the absorbed components of the enzyme solution. The PEG based crosslinked polyurethanes are marginally susceptible to degradation by lactic dehydrogenase solution. The present polyurethanes are resistant to fungal attack. The fungal growth was not observed with PTMG and PPG based Polyurethanes, however, a marginal growth was observed with PEG based polyurethanes.Item INVIVO BIOCOMPATIBILITY OF ALIPHATIC SEGMENTED POLYURETHANE IN RABBIT(JOURNAL OF BIOSCIENCES, 1989) JAYABALAN, M; RATHINAM, K; KUMARY, TV; MOHANTY, MItem INVIVO BIOCOMPATIBILITY OF AN ALIPHATIC CROSS-LINKED POLYURETHANE IN RABBIT(JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, 1991)A cage implantation technique has been adopted in a rabbit animal model to investigate the biocompatibility of an aliphatic crosslinked polyurethane based on hexamethylene diisocyanate (HDI). In this study, four cages are represented; the cage containing the candidate polyurethane material, biomedical grade polyurethane (Tecoflex), the commercial grade polyvinylchloride (PVC), and an empty cage which were implanted subcutaneously in rabbits. Exudates were aspirated from these cages at 4, 7, 14, and 21 days postimplantation. Exudates were analyzed for variations in proteins, cell counts, and extracellular enzymes. Results with the four types of cage implants showed that the candidate polyurethane caused an inflammatory response comparable to that caused by medical-grade Tecoflex and the empty cage control.Item MECHANICAL-PROPERTIES OF POLYURETHANE-POLY(ACRYLAMIDE) INTERPENETRATING NETWORKS(ACTA POLYMERICA, 1991) NAIR, PD; JAYABALAN, M; MURTHY, VNKItem MULTIPLE GAMMA-RADIATION STERILIZATION OF POLYESTER FIBERS(BIOMATERIALS, 1988)Item NEWTONIAN BEHAVIOR OF SHEARED AQUEOUS CARBOXYMETHYLCELLULOSE SOLUTION ON AGING(BRITISH POLYMER JOURNAL, 1989) JAYABALAN, MItem POLYURETHANE-POLYACRYLAMIDE IPNS .1. SYNTHESIS AND CHARACTERIZATION(JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 1990) NAIR, PD; JAYABALAN, M; KRISHNAMURTHY, VNItem STERILIZATION AND REPROCESSING OF MATERIALS AND MEDICAL DEVICES - REUSABILITY(JOURNAL OF BIOMATERIALS APPLICATIONS, 1995)Problems associated with reprocessing of disposable medical devices such as hemodialysers with resterilization for reuse and changes in material properties with resterilization of polymeric (PVC, polypropylene, polyester, polycarbonate) materials intended for development of disposable devices are reviewed. Reprocessing of hospital supplies, polystyrene microtiter plate and angiographic catheter for reuse is also discussed.Item STUDIES ON MIGRATION BEHAVIOR OF CHEMICALLY TREATED PLASTICIZED POLY(VINYL CHLORIDE) FOR BLOOD CONTACT APPLICATIONS(JOURNAL OF MATERIALS SCIENCE LETTERS, 1995)Item STUDIES ON THE EFFECT OF DEGREE OF HYDROPHILICITY ON TISSUE-RESPONSE OF POLYURETHANE INTERPENETRATING POLYMER NETWORKS(BIOMATERIALS, 1992)Interpenetrating polymer networks of polyurethane and vinyl monomers such as polyacrylamide, polyvinyl pyrrolidone, poly(hydroxyethyl methacrylate) and poly(methyl methacrylate) were implanted intramuscularly in rabbits. Attempts were made to correlate the morphological aspects of the interpenetrating polymer networks to their histological response. A relatively increased hydrophillicity of hydrophobicity of the interpenetrating polymer networks as in the case of polyurethane-polyvinyl pyrrolidone and polyurethane-poly(methyl methacrylate) interpenetrating polymer networks, respectively, could elicit an inert response whilst degradation of materials promoted reactivity.Item STUDIES ON THE EFFECT OF EXTRACTION OF ISOPHORONE DIISOCYANATE-BASED SEGMENTED POLYURETHANES(PROCEEDINGS OF THE INDIAN ACADEMY OF SCIENCES-CHEMICAL SCIENCES, 1989) KUMAR, NS; JAYABALAN, MItem STUDIES ON THE SORPTION OF LIPIDS IN SEGMENTED POLYURETHANES .2. EFFECT OF HARD-SEGMENT CONTENT(JOURNAL OF APPLIED POLYMER SCIENCE, 1992) SREENIVASAN, K; JAYABALAN, M; RAO, KVCDiffusion and absorption, of a few representative components found in blood, in segmented polyurethane are studied. The absorption of the components, confined to the soft segment, is found to be Fickian. Both diffusion coefficients and equilibrium absorption was found to decrease with % hard-segment content. An empirical equation has been proposed to visualize the absorption behavior with soft/hard-segment content.Item THE PRESSURE-INDUCED CALCIUM DEPOSITION ON CROSS-LINKED POLYURETHANES(ARTIFICIAL ORGANS, 1992)The pressure-induced calcium deposition in crosslinked polyurethane was studied. Two polyurethane systems, IPDI-PTMG/PPG-TMP and SMDI-PTMG/PPG-TMP were subjected to calcification under induced pressure. Calcium deposition in IPDI polymers was linear with the increase of soft segment (PTMG) content whereas in SMDI polymers the reverse trend was observed. Decreased phase mixing and hydrophilicity in the polymer (SMDI based) having increased soft segment content was attributed to the decreased calcification. The enhanced amount of calcium deposition under pressure indicates the possible influence of pressure on calcification.Item THERMAL-ANALYSIS OF USED AND RADIATION TREATED POLYCARBONATE (L-MW) BIOMATERIAL(BULLETIN OF MATERIALS SCIENCE, 1988) JAYABALAN, M; SREENIVASAN, K; NAIR, PD; JALAJAMANI, KN