An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Aaron M. Forster, Peter Krommenhoek, Li Piin Sung, Chris A. Michaels, Kurt Wood
Instrumented indentation was used to investigate the mechanical properties of coatings for automotive and architectural applications. First, the mechanical properties in the cross-section of a multi-layer acrylic-melamine automotive coating subjected to
A previous X-ray absorption study of tile adhesive mortars [1] identified a new phenomenon during drying, namely the movement of small cement particles from the interior of the specimen to its surface. An analysis based on Stokes equation indicated that
Un dispositif de conception assez simple a été développé pour mesurer directement le seuil de cisaillement de diverses suspensions concentrées. Il consiste en une plaque immergée verticalement dans le matériau étudié et sur laquelle on vient imposer un
Fluorinated and acrylic coatings are commonly used as binders for exterior coatings because of their excellent resistance to UV radiation and many corrosive chemical agents. It is known that the fluorinated component of the coating usually has a lower
Li Piin Sung, Xiaohong Gu, Derek L. Ho, Forrest A. Landis, D Nguyen
Fluoropolymer-based coatings have been greatly used as binders for exterior coatings because of their excellent resistance to UV radiation as well as to many corrosive chemical agents. It is also known that the fluorinated component usually has a lower
Aaron M. Forster, Stephanie S. Watson, Jonathan White
The elastic modulus of a polystyrene-butyl acrylate latex coating was measured using three different techniques: instrumented indentation, dynamic mechanical analysis, and tensile testing. The coating was formulated with 25 nm and 250 nm diameter TiO2
Quantification of the mechanical properties, such as the non-linear viscoelastic behavior, for a cured sealant is complicated by the presence of the Mullins Effect. The Mullins Effect, commonly observed in elastomers, refers to an observed increase in the
The uncontrolled aggregation of amorphous calcium phosphate (ACP) particulate fillers and their uneven distribution within polymer matrices can have adverse effects on the properties of ACP composites. In this paper we assessed the influence of non-ionic
The objective of this study was to elucidate the effect of chemical structure and composition of the polymer matrix on the degree of vinyl conversion (DC) of copolymers (unfilled resins) and their amorphous calcium phosphate (ACP) composites attained upon
Justin N. O'Donnell, Sarah Langhorst, Michael D. Fow, Joseph M. Antonucci, Drago Skrtic
This study explores how resin type affects selected physicochemical properties of complex methacrylate copolymers and their amorphous calcium phosphate (ACP)-filled and glass-filled composites. Two series of photo-polymerizable resin matrices were
Joannie W. Chin, Donald L. Hunston, Aaron M. Forster, Justin M. Ocel, Jean M. Hartmann, Paul Fuchs
Epoxies are increasingly used in construction for structural applications and properties such as creep are very important. For this reason, the thermo-viscoelastic properties and creep response of two commercial, ambient cure structural epoxy adhesives
Kar T. Tan, Christopher C. White, Cyril Clerici, Donald L. Hunston, Bryan D. Vogt, Sushil K. Satija, Joshua E. Goldman, Kristen L. Steffens
Studies have show that certain adhesive joints exhibit a dramatic loss of strength when exposed to humidities above a certain critical value. Although much is know about this effect, questions still exist. This study combines neutron reflectivity
Nicos Martys, Didier Lootens, William L. George, Steven G. Satterfield, Pascal Hebraud
Spatial-temporal correlations in the startup-up flow of colloidal suspensions composed of attractive spherical particles under static and shear conditions are studied by computer simulation. The evolution of particle organization with time is followed as
Didier Lootens, Nicos Martys, William L. George, Steven G. Satterfield, Pascal Hebraud
Results comparing experiments on a model system of mono-disperse silica-particles with the numerical simulation of highly concentrated suspension of spherical particles subject to a constant rate of strain are presented. Giant fluctuations of the shear
The system of programs described in this paper is concerned with estimating the damage ensuing from exposure of specimens in dry and humid atmospheres to UV and visible radiation covering the solar range. Damage is monitored quantitatively by changes in IR
Joannie W. Chin, Sylvain H. Petit, Amanda L. Forster, Kirk D. Rice, Michael A. Riley
During routine field use of soft body armor, the ballistic panels often become saturated with perspiration. This unsavory condition motivates the user to clean and/or deodorize the armor, and anecdotal evidence is given for various methods used to
Concrete is generally viewed as a durable and long-lasting construction material. However, the long-term performance of a concrete structure can be greatly compromised by early-age cracking. One recent informal estimate from the industry places this as a
Aaron M. Forster, Chris A. Michaels, Justin Lucas, Li Piin Sung
Thermoplastic olefins (TPO) have made significant inroads as polymeric materials for interior and exterior automotive parts. Spray applied chlorinated polyolefins (CPO) are often used to improve paint adhesion to the low surface energy TPO substrates. The
Donald L. Hunston, Kar T. Tan, Christopher C. White
Filled viscoelastic solids, have been used for the last 40 years as building sealants to separate indoor from outdoor environments. The most important property of the sealant is the ability to respond to imposed strain while maintaining the critical
Christopher C. White, Kar T. Tan, Donald L. Hunston
Fire resistive materials are exceptional at providing an effective thermal barrier to structural steel from the heat flux from a fire, provided it is in close proximity to the steel during the fire event. The adhesion of the fire resistive materials is
Gary E. Schumacher, Joseph M. Antonucci, Justin N. O'Donnell, Drago Skrtic
Bioactive, amorphous calcium phosphate (ACP)-filled polymeric composites in aqueous environments release significant amounts of Ca and PO4 ions leading to deposition of an apatitic mineral that is similar to that found in enamel. These materials are
Gale A. Holmes, R C. Peterson, Donald L. Hunston, Walter G. McDonough
In this paper, we examine the regions of debonding between the fibers and the matrix surrounding fiber breaks formed during single-fiber fragmentation tests. The materials used were E-glass fibers embedded in a matrix of diglycidyl ether of bisphenol-A
Chiara F. Ferraris, Roy Cooley, Joe Grein, Max A. Peltz, Michael Topputo, Steve Verdino
The goal of the tests reported here was to further determine the feasibility of using a concrete mixing truck as a rotational rheometer. This work is the continuation of preliminary tests [ , ] that seemed to indicated that the yield stress and the plastic