Abstract: Herein we describe purified boron nitride nanotube compositions substantially free from hexagonal boron nitride. The compositions have a mass ratio of boron nitride nanotubes to hexagonal boron nitride of at least 100. Methods are provided for producing said purified boron nitride nanotube compositions wherein impure compositions are subjected to heating with a C5 to C11 hydrocarbon solvent under specified conditions.

Abstract: The heat of fusion is used as a measure of the brittleness of a semicrystalline polyamide part. Parts made of or which include semicrystalline polyamides can be replaced or be identified for replacement when they are or will become brittle based on periodic heat of fusion measurements.

Abstract: The heat of fusion is used as a measure of the brittleness of a semicrystalline polyamide part. Parts made of or which include semicrystalline polyamides can be replaced or be identified for replacement when they are or will become brittle based on periodic heat of fusion measurements.

Abstract: Graphene oxide/polyamide compositions are provided, as are methods for making and using the compositions. The graphene oxide component of the compositions has a C:O ratio of between 3 and 20, and comprises 0.01% to 5.0% by weight of the composition. Typical polyamide components include specialty nylons such as PA-11 and PA-12. The compositions have reduced water absorption and enhanced durability relative to otherwise identical polyamide compositions lacking the graphene oxide component. The compositions are particularly useful, for example, in flexible pipes and tubes used for transporting oil and gas.

Abstract: A method involving the use and creation of pre-aged witness coupons which characterizes and monitors the rate and extent of chemical and physical aging of the polymer in the structure during use in the field is described.

Abstract: A method involving the use and creation of pre-aged witness coupons which characterizes and monitors the rate and extent of chemical and physical aging of the polymer in the structure during use in the field is described.

Abstract: Polyamide liners used in sub sea and over ground transport operations, such as nylon (11), are handled in a way which increases the rate of chain recombination relative to the competing process of chain scission. This enhances and increased the useable life of the polyamide liner by effectively reducing its rate of aging. The can be accomplished by incorporating a chain extender or desiccant into the polyamide liner, incorporating hydrophobic moieties or hydrophobic polymers into the polyamide liner, or by providing a sheath which is less permeable to water at the inner surface of the polyamide liner. Rejuvenation of the polyamide liner can also be achieved by heat treatment of the polyamide liner by hot air, hot oil or gas, or other hot liquids that are at a temperature above 1000° C. Rejuvenation may be enhanced by including a chain extender or desiccant to a hot oil, gas, or other liquid that is exposed to the polyamide liner.

Abstract: The molecular weight of NYLON 11.RTM. (a polyamide made from aminoundecanoic acid) has been found to be a reliable indicator of the mechanical properties and remaining useful life of parts made therefrom. By periodically monitoring the molecular weight, and comparing the measured molecular weight to a standard curve or table, the expected useful life remaining, rate of deterioration, time of part replacement, and mechanical properties of a part can be determined. The molecular weight may advantageously be determined using witness coupons placed in close proximity to the part such that they are exposed to the same processing and environmental conditions as the part. These witness coupons can advantageously be retrieved at the required time period using a spooled piece of pipe or the like. Alternatively, the molecular weight may advantageously be determined from core samples taken from the part being monitored, during use in the field, on a periodic basis.

Abstract: A dosimeter with reproducible changes in .epsilon.', .epsilon.'', or their equivalent two parameter circuit representations, under a given treatment regime that correlate directly with changes in physical attributes of a material or fluid, such as strength, modulus or viscosity, is used to monitor the deterioration of the physical attributes of the material or fluid.

Abstract: An L-C circuit (tank circuit) is located in close proximity to polymer impregnated composite material layers during the fabrication process. Applicant has determined that the resonant frequency of the tank circuit and the shape of the frequency absorption curve vary as a function of the fiber density of polymer impregnated composite material. The frequency of the input to the tank circuit is periodically swept through a range of frequencies, and the tank circuit impedance is measured to determine the resonant frequency and shape of the frequency absorption curve.

Abstract: A dielectric probe for use with conventional frequency and time domain impedance analyzers comprises two chemically resistant electrodes deposited in an interdigitated pectinate configuration on particular non-conductive substrates, the spaces between the digits thereof being no greater than about 0.01 inch; methods and apparatus for monitoring and/or controlling chemical reactions, particularly polymerization reactions, in contact therewith, wherein the complex permittivity may be calculated over a wide range of frequencies and temperatures.

Abstract: A dielectric probe for use with conventional frequency and time domain impedance analyzers comprises two chemically resistant electrodes deposited in an interdigitated pectinate configuration on particular non-conductive substrates, the spaces between the digits thereof being no greater than about 0.01 inch; methods and apparatus for monitoring and/or controlling chemical reactions, particularly polymerization reactions, in contact therewith, wherein the complex permittivity may be calculated over a wide range of frequencies and temperatures.