Study On A New Type Of Composite Hydrophilic Polyurethane Wound Dressing

A dressing is an indispensable cover of a wound in the surgical clinic. It can effectively prevent from infection, reduce the super-metabolism and super- volatilization of water, accelerate the growth of epithelial tissue, form microclimate with suitable temperature and humidity advantageous to a wound healing. A new wound dressing should not only have good biocompatibility, the mechanical properties, characteristic to germs isolation and waterproof, but also the high absorbability of water and good permeability. In order to meet the need of the surgical clinic for wound dressings, and to solve the problems of traditional dressing and current surgical dressings, a new type of dressing has been designed and developed. It consists of tow layers, the outer layer- permeable polyurethane (PU) membrane, and the inner layer-improved soft PU foam made from hydrophilic PU. Polyethylene glycol (PEG), instead of expensive special polyethers, is applied to preparing the hydrophilic PU performed-polymer. The PU preformed-polymer is used to preparing the hydrophilic PU foam. It results in increasing of absorbability of water and the strength. The effects of various factors on the processing and properties of PU foam have been studied, and the optimum processing conditions have been found. The PU preformed-polymer is also used to preparing PU membrane, and the processing conditions of the membrane have been improved It has been found that the PU membrane is porous by SEM observation, the compatibility of the soft segment and the hard segment is good by DSC analyses, and there is more PEG in the membrane surfaces than in their bulk by 17R and XPS analyses. All these result in improving permeability of PU membrane. The mechanism of the permeation of moisture of PU membrane has also been studied, and it has been found that the process of permeation of PU membrane is controlled by the hydrated reaction and diflion. By way of good design, the dressing has not only high absorbability of water and permeability, but also waterproof and isolation of germs. The dressing can be sterilized by steam of ethane epoxy. From the experimental results of biological safety of materials have shown that these two kind of synthesized biomedical materials are safe and biocompatible, which can meet the demands of surgical clinic. The result of preliminary clinic application test is good.