Recobrimento de substratos rigidos com hidrogel para utilização como superficie articular

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

Problems concerning the repair of damaged synovial joints are very ftequent and traumatic to a great number of people. In those cases where the damage extent is very high, the articular surface is usually an ultra high molecular weight polyethylene (UHMWPE), even though it under goes severe wear when used as the cartilage counterpart in artificial joints, which sometimes leads to prostheses failure. On the other hand, when the damage of the articular cartilage does not require its complete replacement, only the repair of local defects is sought by using either a metallic or a porous ceramic substrate coated with a hydrogel. Aming at reducing the wear to which the artificial joints are submitted, and in order to develop a device capable ofbeing used in osteochondral defects, defects which affect both the articular cartilage and the subchondral bone, this work studied the coating of solid porous substrates of UHMWPE and ceramic composite between hydroxyapatite (HA) and (3-tricalcium phosphate «(3- TCP) with a poly(2-hydroxyethyl methacrylate), polymer hydrogel (pREMA), a material widely investigated as a substitute for natural articular cartilage. This work also aimed at improving the mechanical properties of the hydrogel through the syntheses of sIPN-type blends between pREMA and cellulose acetate butyrate (CAB), pREMA and hydroxyethyl cellulose (HEC), and pHEMA and polyethyl methacrylate (pEM). The substrates were characterized by Scanning Electron Microscopy (SEM), Dynamical Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC) and Optical Microscopy (OM). Also, the coating materiaIs had their wear behavior evaluates in a TRI-PIN-ON-DISK equipment. The pHEMA coating was completely destroyed at the first wear cycles, white those coatings prepared with pHEMA - CAB and pREMA - PEM showed only slight signs of both abrasive and adhesive wear, after the complete experiment. The results thus obtained strongly suggest the possibility of improving the mechanical properties of the hydrogel by the syntheses of sIPN-type blends using linear reinforcing polymers CAB and PEM

ASSUNTO(S)

mistura (quimica) fricção hidroxiapatita tribologia coloides

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