Plasma Surface Modification of Medical Expanded PTFE Membrane Facilitates Adhesion

2022-05-24   Pageview:15

Expanded polytetrafluoroethylene (ePTFE) membrane is a new type of medical polymer material, which is made of dispersed polytetrafluoroethylene resin through special processes such as expansion and stretching. , Low density, full of elasticity and toughness, can be bent arbitrarily. Expanded polytetrafluoroethylene (ePTFE) has stable and good chemical properties, good biocompatibility, anti-biological aging, and hardly causes rejection by the body, so it is widely used in artificial blood vessels, cardiac patches and other biomedical fields. However, like other PTFE materials, expanded polytetrafluoroethylene (ePTFE) also has the problem of difficult bonding. Not only does it have requirements for glue, but also surface treatment before bonding is essential. Today we will learn about it. Plasma surface modification process to improve the adhesive properties of medical ePTFE membranes.

Reasons why medical expanded polytetrafluoroethylene (ePTFE) membranes need to be bonded

Expanded polytetrafluoroethylene (ePTFE) membrane with special microporous structure is usually formed by high temperature stretching and setting to produce a microporous structure, which can process membrane materials below 1mm, while medical expanded polytetrafluoroethylene (ePTFE) ) The thickness of the film is usually between 4 and 12mm, so the method of superimposed bonding is generally used to bond into a sheet of a certain thickness. In addition, the expanded polytetrafluoroethylene (ePTFE) film can also be bonded with other medical materials to meet the needs of different uses.

Technological difficulties in bonding medical expanded polytetrafluoroethylene (ePTFE) membranes before plasma surface modification

The bonding of medical expanded polytetrafluoroethylene (ePTFE) film is affected by material characteristics, adhesive composition, temperature and other factors, so the following technical difficulties will be faced in the actual bonding process:

1) The bonding between expanded polytetrafluoroethylene (ePTFE) membranes is very difficult, PTFE dispersion medical grade and the adhesive with complex chemical composition may affect the quality of the product.

2) Since the expanded polytetrafluoroethylene (ePTFE) membrane is stretched under heating to produce a microporous structure, when heated to a certain temperature, it will shrink back and the micropores will disappear.

3) The ineffective components in the chemical binder may be removed with high temperature, and there is still a lack of a bonding method that can effectively solve the above difficult problems in the current technology.

PTFE Wax Aqueous Dispersion PTFE-1003 (PFOA Free) Chemical Composition: PTFE wax Model: PTFE-1003

Characteristics of Plasma Surface Modification of Medical Expanded Polytetrafluoroethylene (ePTFE) Membrane

Plasma surface modification is generally carried out at low temperature or room temperature, using ions generated by non-reactive gases such as He, Ar, N2, H2, and material surfaces to carry out physical and chemical reactions to form new nano-scale molecular structures, which can not only improve Adhesion to the surface of the material, maintaining the original characteristics of the material, and there will be no residual contamination on the surface.

Plasma surface modification treatment of expanded polytetrafluoroethylene (ePTFE) membranes, whether for tubular or sheet membranes, is a premium process. It can greatly improve the adhesion performance, avoid the shrinkage or disappearance of the micropores of the film due to excessive temperature, and will not produce by-products and so on. The degree of improvement of the bonding effect of the expanded polytetrafluoroethylene (ePTFE) film by the plasma surface modification process can be preliminarily verified by means of the dyne pen or the water contact angle. The change in the surface energy of the material can be reflected by the change in the contact angle of the sintered expanded polytetrafluoroethylene (ePTFE) membrane shown in the figure below.

1) The water drop angle of the sintered expanded polytetrafluoroethylene (ePTFE) membrane before plasma modification is 120 degrees

2) The water drop angle after plasma modification of the sintered expanded polytetrafluoroethylene (ePTFE) membrane is 73 degrees

Unsintered expanded polytetrafluoroethylene (ePTFE) membranes are very soft, and sintered expanded polytetrafluoroethylene (ePTFE) membranes are slightly harder. But in general, since the membrane material is very soft and easy to deform, the plasma surface modification equipment used should fully consider the material handling method and the convenience of picking and placing.

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