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In continuation to the previous work on copper (lignin/silica/fatty acids) (Cu-LSF) complex as a natural antioxidant/electrical conductivity agent for nitrile-butadiene rubber (NBR), this study aims to perform further investigations for NBR vulcanizates loaded with different concentrations of Cu-LSF complex, including swelling behavior and hardness properties, as well as evaluating their thermal stability via thermogravimetric analysis.

The behavior of Cu-LSF complex in NBR matrix was compared with that of the standard commercial antioxidants (2,2,4-trimethyl-1,2-dihydroquinoline/N-isopropyl-N′-phenyl-p-phenylenediamine [TMQ/IPPD]).

Results revealed that Cu-LSF complex can act as an effective reinforcing and hardening agent, with exhibiting fluid resistance, even when compared with the commercial antioxidants. In comparison with the previous studies on its Zn and Ca analogues and their behavior in different rubber matrixes, Cu-LSF complex showed higher values of hardness and less susceptibility for swelling, respectively. Moreover, Cu-LSF antioxidant activity becomes in accordance with the previous work.

The new Cu-LSF complex could be used as a green alternative to the commercial antioxidants (TMQ/IPPD) with introducing further advantages to the rubber matrix, such as hardening, fluid resistance and thermal stability.

The paper presents the results of measuring the diffusion processes in epoxy resins based on bisphenol A and bisphenol S hardened with aromatic polyamines. The effects acting on the diffusion of acids into the resins thus hardened are discussed. These involve mostly the diffusion processes of solutions connected with a chemical reaction affecting the chemical stability of material. The chemical resistance of epoxy resins is affected by the molecular weight and type of epoxy resin, the polyamine functionality, the polyamine concentration, and the kind of plasticizer. The measurements performed by a microscopic method gave the values of diffusion coefficients relating to the penetration of some inorganic and organic acids into the epoxy resin based copolymers.

Components such as propeller or helicopter rotor blades, wings, or structural members consist of an outer shell of thin metal, plastic or plywood, with an internal supporting filling of low density (about 4 lb./cu. ft.) and having a closed cellular structure formed by expanding a thermoplastic material such as polyrinyl chloride, incorporating a hardening agent such as phenol formaldehyde or urea resin or a paint‐hardening material. The manufacturing process is carried out in two stages, the mix for the internal filling being first placed in a mould similar in shape to, but smaller than, the outer shell, and then heated sufficiently to cause the mix to fill the mould, from which it is then removed and allowed to cool to a solid‐like mass having a similar shape to the outer shell. The cooled mass is then inserted in the shell and heating continued until the gases liberated expand the mass to fill the shell and apply internal pressure thereto, to impart the desired rigidity to the member.

It has been known for many years that lanolin films applied to iron and steel surfaces will give excellent protection against rusting. These lanolin coatings are usually regarded as ‘temporary’ coatings, in the sense that they are used primarily for the protection of bright steel parts during transport and storage, and often must be removed before the part is used. This conception of the temporary nature of lanolin coatings is perhaps a little unfortunate, since in certain circumstances they can give long‐term protection comparable with that obtained with much more expensive coatings. It is also often overlooked that lanolin coatings can give excellent protection against corrosive agents other than water, e.g. acids, alkalis and salts.

For the purposes of this article, adhesives, lutes and putties are excluded even though many of them have applications in the corrosion‐resistant field. Included are the pouring and mortar‐type cements based on bitumen or sulphur, sodium and potassium silicate solutions, silica sols, rubber or synthetic rubber latices, and synthetic resins. The author considers the composition and working properties of these cements and surveys present trends in their use in industry. Recent and possible future developments are covered.

Granol special concrete hardener is said to provide a quick and economical method of hardening concrete floors and preventing ‘dusting.’ It will give a much denser and harder surface to either new or old concrete. It is easy to apply and the manufacturers say that its ease of application and efficiency are a source of economy in labour costs and materials.

The purpose of this paper is to present three-dimensional (3D) printing of structures with a new method called selective laser baking (SLB) of Poly Dimethyl Siloxane (PDMS).

A 3D model is designed on the computer. PDMS Base is mixed with its hardener and poured into a container. Before it is hardened which normally occures after several hours, a CO₂ laser selectively exposes different areas on the surface of the PDMS mixture according to the pattern of a slice of a 3D model designed on the computer. Because of the thermal effect of the CO2 laser, once exposed, PDMS heats up and hardens, producing a cured layer of PDMS which is attached to a base. The base with the cured layer is lowered in the container for a short distance and a layer of new uncured PDMS is spread over the previous layer. The laser exposes new areas again and hardens them. This process is repeated until the whole structure is fabricated.

The parameters involved in the baking process are investigated and the relation between temperature, mixing portion and laser irradiance on the curing time and layer thickness are investigated.

This fabrication technique is a unique fabrication method that helps to 3D print with two base polymers which their polymerization can be boosted by heat. This 3D printing method has not been presented earlier.

THROUGHOUT the history of the advance of aviation the development of light alloys occurs and recurs as a silver thread, lightening the pattern. From the very first the possibility of aviation has been bound up with the design of the prime mover, and the remarkable strides made during the past two decades in the production of power from a minimum of weight are largely due to the alloys of aluminium, their strength and rigidity for a given weight, their thermal properties, and their capacity for prolonged, reliable service.

Aluminium stearate is a fine, bulky, odourless and colourless powder forming a plastic mass when heated, having the properties both of organic and inorganic matter. It embraces most of the characteristics of other metallic stearates and is regarded as the most important of these. Several studies of the material have already appeared in past years.

Guanidine stearate will function as a lubricant for melamine/formaldehyde resins (and guanamine/formaldehyde resins), and glyceryl monostearate can improve the mechanical properties of the former. Laurie acid can be applied to the production of high grade baking enemel resins in combination with melamine. Stearic acid can be used in the manufacture of melamine resins, e.g. by reaction with formaldehyde and butanol, to give resins for lacquers, and to yield moulding resins. Sodium myristate is usable as a chain transfer agent in the emulsion polymerisation of methyl methacrylate. Copolymerisation of methacrolein dibutyrate and methyl methacrylate has given resins that can be moulded or used in varnishes, and reaction products of stearic acid with methacrylic acid and neodymium oxide has given transparent optical resins. Cellulose laurate can produce extensibilities of nitrocellulose of the order of 100%, and cetyl acetate can act similarly in film, having little tendency to yellowing, but it has also little stability to exterior exposure. When ethylene glycol monmethyl ether acetyl ricinoleate is incorporated into nitrocellulose as a plasticizer, it gives films that are clear, tough and flexible. Stearic acid can act as a stabilizer for nitrocellulose. Lauryl phosphate has been applied as a catalyst in the modification of olefinic petroleum results, by reaction with acrylic resins, and distearyl pentaerythritol diphosphite can function as a heat stabilizer in petroleum resins.