Release Rate Test Research Articles

An Intermediate‐Scale Calorimeter for building materials and assemblies

AbstractA new Intermediate Scale Heat Release Rate Test Method is being developed primarily for testing assemblies in the vertical mode. Using the oxygen consumption calorimetry methodology and exhaust collection systems that already exist in many laboratories in the US and around the world, the apparatus is very economical to install. The sample size lends itself to reptitive testing in a short period of time. Sample preparation is generally quick and easy. Further development of the method should progress now that the method has been introduced at ASTM and will be introduced formally into ISO in the near future. There has been a favorable response by several laboratories who are considering construction of the apparatus. Additional assemblies tests are already underway and additional data will be presented in the near future.

A Simple Constant Strain Energy Release Rate Loading Method for Double Cantilever Beam Specimens

Abstract A simple loading arrangement is proposed to permit nearly constant strain energy release rate testing of double cantilever beam specimens. The inexpensive arrangement may be well suited to long term and environmental exposure testing of these specimens. An added advantage of the technique is that it also provides an attractive method to measure debond length. The geometrically nonlinear loading device provides constant strain energy release rate loading under idealized conditions. Analysis of the technique for realistic conditions reveals the appropriate test window for the device, and allows design guidelines to be developed. Experimental evaluation confirms the analytical predictions.

The Peninsula Blister Test: A High and Constant Strain Energy Release Rate Fracture Specimen for Adhesives

Abstract An extension of the island blister developed by Allen and Senturia to a peninsula-like geometry produces a fracture test which retains the very high strain energy release rates which are possible with the island blister, and also results in a constant strain energy release rate test for adhesive bonds. Analytical solutions are provided for predicting the strain energy release rates for this peninsula blister specimen when the blister adherend may be considered a plate, a pre-stressed membrane, and a simple membrane. Preliminary experimental results for a PSA tape are also presented. The analytical results suggest that the specimen may be extended to a variety of practical adhesive systems.

The Constrained Blister—A Nearly Constant Strain Energy Release Rate Test for Adhesives

Abstract A modification of the blister test permits nearly constant strain energy release rate testing of adhesive bonds. By constraining the deformation of the blister, a promising device for automated evaluation of critical strain energy release rates can be obtained. The procedure is especially amenable to viscoelastic and environmentally-assisted debonding processes. Preliminary experimental evaluation of the time-dependent adhesive fracture toughness of a tape product is included.

A comparison of test methods for determining in vitro drug release from transdermal delivery dosage forms

Three test methods for determining in vitro drug release rate from transdermal delivery dosage forms were tested for equivalency of results, ease of implementation and precision. The ‘paddle-over-disk’ (POD) method is under consideration by the USP as a standarized method for release-rate testing of all transdermal delivery dosage forms. The ‘reciprocating disk’ (RD) and ‘diffusion cell’ (DC) methods are both commonly employed throughout the pharmaceutical industry. The three methods were demonstrated to be equivalent in terms of release rate profile (curve shape) and total drug released over the lifetime of the dosage form tested (Transderm-Scop). The precision for the RD method as measured by the mean relative standard deviation over all time points was 4.6%; the precision of the POD method was 5.4% and that for the DC method was 6.7%. Steady-state flux values derived from the POD and RD methods were equivalent (∼4 μg cm −2 h −1) but were ∼25% greater than the steady-state flux value derived from the DC method (∼3 μg cm −2 h −1). All three methods gave results which were within the specifications of the manufacturer (CIBA-GEIGY). The POD method was the easiest to use on a routine basis, required the least amount of specialized equipment and most resembled the current test methodology for dissolution testing of other dosage forms such as tablets or capsules.

Computer based hazard assessment using release rate test data

Two procedures for making a fire hazard assessment of a compartment are described. Both are based on release rate data from ASTM E906, a small-scale fire test for materials and products. Fire performance characteristics given by this test, i.e., ease of ignition, flame travel rate, rate and total release of heat and visible smoke, are obtained over a range of exposure conditions. By assuming or by calculating the exposure conditions to which individual items in the compartment are subjected, the course of a ‘real’ fire and the fire performance of the items and the total fire system can be predicted. A fire hazard assessment is then calculated from the fire performance of the system.

Use of Release Rate Tests To Evaluate Upholstery Systems

Release rate tests were made on upholstery systems at several radiant heat flux levels to determine the effect a fiberglass barrier has on their com bustibility. Four fabrics and two foams were used. From results of release rate tests on these typical upholstery systems, with and without the barrier, it was possible to determine the amount of combustible material (foam and batting) behind the barrier that is "burned" as a function of time and incident flux.