Polymers sealants

K. L. Houghton and M. E. Moss "Chlorinated Paraffins as Plasticizers in Polymer Sealant Systems," A.SC Supplier Short Course Nashville, Term., May 14-17,1990. 

Components/ mechanism of action Light-activated polyethylene-glycol (PEG) polymer sealant for lung tissue. Monomeric (2-octyl cyanoacrylate) formulation tissue adhesive for skin closure. Bovine albumin cross-linked with gluteraldehyde tissue adhesive/sealant. 

The excellent adhesion of MS Polymer sealants to conventional construction substrates such as glass, metal, and plastics (e.g., PVC) is derived finm the widely used silane adhesion promoter V-(P-aminoethyl)-3-aminopropyltrimethoxysilane, DYNASYLAN DAMO-T. Another aspect of using a diaminosilane is the intrinsic change of pH that results in fast hydrolysis and condensation reactions of the MS Polymer . To guarantee a certain shelf life, MS Polymer sealants are generally formulated with vinyltrimethoxysilane, DYNASYLAN VTMO as a water scavenger. 

The goal of the research reported here was to determine the effects of non-sensitizing diaminosilane adhesion promoter DYNASYLAN 1146 on the mechanical properties and the adhesion of a standard MS Polymer sealant. DYNASYLAN DAMO-T is used as a reference. 

Summarized below are the effects of two diaminosilane adhesion promoters (DYNASYLAN DAMO-T and DYNASYLAN 1146) on MS Polymer sealant properties based on the above given formulation ... 

Stag Epoxide Resins. [Stag Polymers Sealants Ltd.] Liq. xides. 

Uses Mfg. of phenolic and thermosetting resins, furan polymers, urea-formaldehyde resins wetting agent foundry sand binders corrosion-resist, resins intermediate for esterification and etherification paints solvent, plasticizer for phenolic resins solvent for dyes and resins nonreactive epoxy resin diluent vise, reducer, cure promoter, and carrier in amine-cured epoxy resins gel retarder in casein/protein glues polymer sealants/cements synthetic flavoring agent in foods and pharmaceuticals cosmetics ingred. in food-pkg. adhesives... 

Tsai JH, Lin LW (2001) Micro-macro fluidic interconnectors with an integrated polymer sealant. J Micromech Microeng 11 577-581... 

Moisture Permeation of Polymer Sealants and Interface Modifying Films... 

The original intent of this project was to identify and/or perfect vendor-supplied, state-of-the-art hydro-phobic polymer sealants, such that the end product could meet military criteria for hermeticity in hybrid microelectronic devices. Solubility and diffusivity constants and permeabilities for several types of hydrophobic polymers were determined. Data from the laboratory and theory from literature both indicate that moisture impermeable polymers are not attainable, at least to meet military standards. The project objective was then redirected towards finding a means of passivating the surface of a microelectronic device against moisture. It was found that interface modification, i.e., passivation of the chemically reactive surface species, provides significant protection in high temperature and humidity environments. Plasma polymerization of hexamethyIdi-silazane (HMDS) afforded phenomenal protection to moisture sensitive thin film nichrome resistors even under the most severe test conditions. 

The original objective for the research presented here was to find a low cost, repairable seal for hybrid devices which would meet military requirements for hermeticity. Some polymer sealants were claimed to be "impermeable to water" or "hydrophobic". If this proved to be the case, and they were also easily removed for repair, then a low cost hybrid package might be constructed using polymer sealants. 

The foregoing moisture solubility data shows that the term "hydrophobic polymer" is really not applicable for the materials tested, except possibly the silastyrene. A brief review of some theoretical presentations by L.H. Lee and others (5,6) indicate that the initial objective of finding a hermetic polymer sealant may never be realized. Fig. 3 from a presentation by Lee (5) reveals the reason for this assumption. 

Thus, experimental and theoretical evidence supports the conclusion that hydrophobic polymer sealants for potential use in a military hybrid device do not exist at this time. ... 

The first part of this project verified the theoretical conclusion that no polymer can be truly hydrophobic (allowing no water penetration) by nature of dispersion forces which attract nonpolar polymer molecules and polar water molecules. These forces cannot be eliminated. All of the "hydrophobic" polymer sealants tested exhibited diffusivity and solubility constants. Thus, sealing a hybrid with such polymers would eventually allow moisture penetration to the interior of the hybrid which subsequently could not meet MIL-STD-883, Method 1018 requirements of a hermetic hybrid. 

Recommended for polymers sealants, hot melt solventborne adhesives ... 

Alternatively, a roll can be wound to fit a prismatic case as commonly found in lithium ion batteries. The roll is placed in a fitted conductive metal casing that has a Teflon or rubber gasket seal separating the outer can and top button contact. The cylindrical metal rod around which the film is wound becomes the internal contact. Contacts are ensured by soldering and then electrolyte is injected into the cell followed by a curable polymer sealant. The top of the casing is fitted with a vent, gasket layer, and top contact plate. To seal the device, the top of the can is mechanically crimped and the outer metal casing acts as the other contact and provides mechanical stability and rupture resistance. 

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