Engineering topics
Publications and source records attributed to Parker, J. A..
Fire retardant properties of low density polymer foam are increased. Foam has pendant nitrile groups which form thermally-stable heterocyclic structures at temperature below degradation temperature of urethane linkages.
A passenger compartment surrounded by a fire-retardant shell, to protect the occupants long enough for the fire to burn out or for fire-fighting equipment to reach the aircraft and extinguish it, is proposed as a new concept for saving lives in crash fires. This concept is made possible by the recent development of two new fire-retardant materials: a very lightweight foam plastic, called polyisocyanurate foam, and an intumescent paint. Exposed to heat, the intumescent paint expands to many times its original thickness and insulates the surface underneath it. Demonstration tests are illustrated, described and discussed. However, some problems, such as preventing fuselage rupture and protecting windows, must be solved before such a system can be used.
Three statistical methods of general validity are valuable for characterizing any polymer which results from chain polymerization of multifunctional branching monomers linked through bifunctional monomers.
The thermal protection of flammable structures with intumescent protective coatings is discussed. Various materials which have demonstrated an ability to provide protection through intumecence are described. Materials tests for intumescent coatings are presented and physical properties of various materials are included.
Description of a statistical method for characterizing the structure of an average phenolic-novolak prepolymer molecule in terms of the total number of phenolic nuclei that compose the molecule and the number of these nuclei that are pendent. It is only necessary to resort to experimental pyrolysis to evaluate the thermokinetic parameters for pyrolysis for the ablator. In addition, the fraction of phenolic involved in the major pyrolysis reactions can be estimated in terms of the parameters previously evaluated. It is shown that the overlapping reactions which occur during pyrolysis of a phenolic-novolak can be resolved by pyrolyzing samples with different extents of cure. It is then possible to determine the kinetic parameters for pyrolysis for the major reactions by well-known methods which often fail when reactions are not well resolved.
Modification of polyurethanes with alkyl halide resins, inorganic salts, and encapsulated volatile and reactive halogen for fuel fire control
The development of fire-retardant coatings to protect surfaces which may be exposed to fire or extreme heat is a subject of intense interest to many industries. A fire-retardant paint has been developed which represents a new chemical approach for preparing intumescent coatings, and potentially, is very important to fire-prevention authorities. The requirements for a superior coating include ease of application, suitability to a wide variety of surfaces and finishes, and stability over an extended period of time within a broad range of ambient temperature and humidity conditions. These innovative coatings, when activated by the heat of a fire, react to form a thick, low-density, polymeric coating or char layer. Water vapor and sulphur dioxide are released during the intumescent reaction. Two fire-protection mechanisms thus become available: (1) the char layer retards the flow of heat, due to the extremely low thermal conductivity; and (2) water vapor and sulfur dioxide are released, providing fire quenching properties. Still another mechanism functions in cases where the char, by virtue of its high oxidation resistance and low thermal conductivity, reaches a sufficiently high temperature to re-radiate much of the incident heat load. The coatings consist of dispersions of selective salts of a nitro-amino-arornatic compound. Specifically, para-nitroaniline bisulfate and the ammonium salt of para-nitroaniline-ortho sulphuric acid (2-amino-5-nitrobenzenesulphuric acid) are used. Suitable vehicles are cellulose nitrate of lacquer grade, a nitrite-phenolic modified rubber, or epoxy-polysulfide copolymer. Three separate formulations have been developed. A solvent is usually employed, such as methylethyl ketone, butyl acetate, or toluene, which renders the coatings suitably thin and which evaporates after the coatings are applied. Generally, the intumescent material is treated as insoluble in the vehicle, and is ground and dispersed in the vehicle and solvent like an ordinary coating pigment. The char found on intumescence is better in terms of yield and physical properties than chars obtained from many previously known intumescent materials. Prior to intumescence, the coating has a density of 85 pounds per cubic foot. After intumescence, the density is approximately 0.3 pounds per cubic loot. The linear expansion of the coatings ranges from 70 to 200 times the applied coating thickness.
Fire-retardant paint, when activated by the heat of fire, reacts to form a thick, low-density, polymeric coating or char layer. Water vapor and sulphur dioxide are released during the intumescent reaction.
Kinetic model for acid catalyzed Delrin decomposition, testing for Delrin-citric acid system and predicting thermograms with nonlinear regression analysis
Low density polybenzimidazole composites as ablative heat shields, discussing arc-heated wind tunnel tests of linear and crosslinked structures
Polyurethane foam composites for low heating rate thermal protection, noting astroquartz fiber additive effect on performance
Low density polyurethane foam with and without honeycomb as ablative material for reentry vehicles, discussing oxidation resistance
Ablative materials thermal protection characteristics at low heating rates evaluated by convective heating tests, stressing polyurethane foam composite
Ablative materials for thermal protection at low convective heating rates, comparing foam and state-of-art materials performance
Ablation products and high temperature boundary layer chemistry of polytetrafluoroethylene /Teflon/ in arc jet streams using mass spectrometer
Polymer structure and cross-link density effects on thermal analysis of phenol-formaldehyde polymers pyrolysis products
Heat insulating polyurethane foam retards and suppresses fuel fires. Uniformly dispersed in the foam is a halogenated polymer capable of splitting off hydrogen halide upon heating and charring of the polyurethane.