Whitepapers
NuSil Technology's commitment to silicone education is manifested in part by our investment in
Whitepapers. Although many of the documents are in true Whitepaper format, we provide additional
resources like a Terms & Definitions document and an Adhesive / Primer study. While some papers are
broad in scope, others are industry specific. Papers are typically added monthly. Registering with
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For further reading, please see our Technical Resources section.
2004 Archive
Nov 4, 2004
Optical Silicones for use in Harsh Operating Environments
The optics industry widely uses silicones for various fiber optic cable potting applications and light emitting diode protection. Optics manufacturers know traditional silicone elastomers, gels, thixotropic gels, and fluids not only perform extremely well in high temperature applications, but also offer refractive index matching so that silicones can transmit light...
The optics industry widely uses silicones for various fiber optic cable potting applications and light emitting diode protection. Optics manufacturers know traditional silicone elastomers, gels, thixotropic gels, and fluids not only perform extremely well in high temperature applications, but also offer refractive index matching so that silicones can transmit light with admirable efficiency. However, because environmental conditions may affect a material’s performance over time, one must also consider the conditions the device operates in to ensure long-term reliability. External environments may include exposure to a combination of UV light and temperature, while other environments may expose devices to hydrocarbon based fuels. This paper will delve into the chemistry of silicones and functional groups that lend themselves to properties such as temperature, fuel, and radiation resistance to show why silicone is the material of choice for optic applications under normally harmful forms of exposure. Data will be presented to examine silicone’s performance in these environments.
Jul 1, 2004
Choosing a Silicone Adhesive & Treatment System
As devices become smaller and bonds more critical, choosing the right adhesive system may be essential to the success of the device.This article investigates some adhesives and primers used to adhere difficult substrates.
As devices become smaller and bonds more critical, choosing the right adhesive system may be essential to the success of the device.This article investigates some adhesives and primers used to adhere difficult substrates.
Jun 25, 2004
Drug Delivery Market Summary
Silicones have been cited as materials regularly used in drug delivery devices. These drug delivery devices incorporating silicones primarily fall into three major categories:
- Implanted delivery devices
- Mucosal delivery devices
- Transdermal delivery devices
Implanted drug delivery devices include spinal treatment devices, ocular treatment devices and contraceptive devices. These delivery configurations typical utilize silicone...
Silicones have been cited as materials regularly used in drug delivery devices. These drug delivery devices incorporating silicones primarily fall into three major categories:
- Implanted delivery devices
- Mucosal delivery devices
- Transdermal delivery devices
Implanted drug delivery devices include spinal treatment devices, ocular treatment devices and contraceptive devices. These delivery configurations typical utilize silicone tubing or molded configurations. The silicone is used to either hold or precisely deliver the drug to a specific location. Liquid silicone rubbers or high consistency silicone rubbers can be molded into precise configurations required by these applications. Transmucosal drug delivery devices can include silicone elastomer systems with the drug incorporated into the silicone matrix. After the device is placed in contact with the mucosal membrane, the drug elutes from the device at a controlled rate. A non-medicated sheath is cited (References 12,11,7) as a means to control the initial burst of drug from the device. Drugs can be incorporated into liquid silicone rubbers and molded into various configurations. Transdermal delivery devices are primarily skin patches in configuration. The drug may be incorporated directly into the adhesive of the patch or may exist as a separate layer. Silicone pressure sensitive adhesives have been used in these applications because of the low skin sensitization, oxygen and drug permeability properties they offer. Silicone materials used in medical device configurations can also be treated with drug infused coatings.
Jun 24, 2004
Choosing a Silicone Primer
Silane primers are used to promote adhesion between two non-bonding surfaces. Although designed for use with silicone adhesives, they can also be used with other adhesives, such as epoxies. The primers usually consist of one or more reactive silanes, a condensation catalyst and some type of solvent carrier. The reactive...
Silane primers are used to promote adhesion between two non-bonding surfaces. Although designed for use with silicone adhesives, they can also be used with other adhesives, such as epoxies. The primers usually consist of one or more reactive silanes, a condensation catalyst and some type of solvent carrier. The reactive silanes typically have two different reactive groups: one compatible with the substrate and the other with the adhesive.
Jun 24, 2004
Silicone Adhesives and Primers on Low Surface Energy Plastics and High Strength Metals for Medical Devices
This paper will demonstrate the ability of silicone adhesives, with the aid of primers, flame treatment, or plasma treatment, to adhere to low surface energy plastics and to high strength metals. In general, some plastics are difficult to adhere to because of their low surface energy, available bond sites, and...
This paper will demonstrate the ability of silicone adhesives, with the aid of primers, flame treatment, or plasma treatment, to adhere to low surface energy plastics and to high strength metals. In general, some plastics are difficult to adhere to because of their low surface energy, available bond sites, and chemical interaction. Most plastic have a surface energy under 50 dynes/cm while aluminum, an easier substrate to adhere to, is closer to 825 dynes/cm. Surface energy is a thermodynamic effect of how a liquid will ‘wet out’ on a surface. Low surface energy materials, like plastics, do not allow a liquid, like an adhesive, to ‘wet out’ on its surface. Adhesion chemistry tells us that the better an adhesive can ‘wet out’ on a substrate, the more surface area it can cover and allow more reactive groups to bond, making a stronger bond. Several low surface energy plastics and high strength metals were tested with silicone adhesives and primers, as well as with plasma treatment, to achieve cohesive bond failure when performing lap-shear testing. This list of substrates evaluated include polycarbonate, polyetherimide, polyamide, polyurethane, polymethylmethacrylate, polysulphone, titanium, stainless steel, and aluminum.
Jun 16, 2004
Low Outgas Silicone Pressure Sensitive Adhesive for Aerospace Applications
The need for a low outgas, thermally stable, high performance adhesive has initiated the development of a new experimental silicone Pressure Sensitive Adhesive (PSA) able to pass ASTM E-595, low outgassing requirements of 1% or less Total Mass Loss (TML) and 0.1% or less Collectable Volatile Condensable Materials (CVCM). The...
The need for a low outgas, thermally stable, high performance adhesive has initiated the development of a new experimental silicone Pressure Sensitive Adhesive (PSA) able to pass ASTM E-595, low outgassing requirements of 1% or less Total Mass Loss (TML) and 0.1% or less Collectable Volatile Condensable Materials (CVCM). The performance goals were to maintain performance under load at temperatures above 175°C and have similar properties to other low outgassed silicone PSA’s as tested by peel, loop tack, shear, release force and Blunt probe tack.
Jun 14, 2004
Silicones as a Material of Choice for Drug Delivery Applications
This paper will investigate the benefits of using silicone in drug delivery applications. This investigation first provides an overview of how versatile of a material silicone can be to the drug delivery industry. An examination of the chemistry of silicone, the multiple material composition options and various cure chemistries demonstrates...
This paper will investigate the benefits of using silicone in drug delivery applications. This investigation first provides an overview of how versatile of a material silicone can be to the drug delivery industry. An examination of the chemistry of silicone, the multiple material composition options and various cure chemistries demonstrates how silicone can be tailored to fit specific drug delivery applications. Then, a general investigation of the way a silicone interacts with a drug, in regards to compatibility and potential interactions, exhibits silicone’s ability to deliver pharmaceutical agents. The paper will also review factors that have made silicones the materials of choice in the medical device industry, particularly for long-term implantable devices. Examples of applications demonstrate the reasons for choosing silicone over a different material. The paper will finish with real world examples of current drug delivery applications incorporating a silicone, such as hormone replacement therapies, to manifest the benefits of using silicone in drug delivery applications.
Jun 8, 2004
Adhering to Difficult Substrates
Adhesive echnology is equal parts chemistry and ‘black magic’. Because there are so many different substrates, each adhesive can not be actually tested before hand on each and everyone. However, by testing on some novel substrates, or difficult to adhere to, inferences can be made which can narrow the choices...
Adhesive echnology is equal parts chemistry and ‘black magic’. Because there are so many different substrates, each adhesive can not be actually tested before hand on each and everyone. However, by testing on some novel substrates, or difficult to adhere to, inferences can be made which can narrow the choices of adhesives. We can define adhesion as the chemical bonding of two substrates. Substrates that have reactive groups available for bonding like OH groups on glass and aluminum make this chemical bond easier. Substrates with nothing to react to make adhesion difficult; graphite and PTFE. Multiple other substrates fit somewhere in-between.