Polyamide also

Mathiowitz [35 0] realizes reservoir-type delivery systems recurring to a photochemical control. Microcapsules, built up by interfacial polymerization of polyamide, also contain azobisisobutyronitrile, a substance that emanates nitrogen due to a photochemical action. Accordingly, after exposition to light, microcapsules internal pressure increases (as a result of nitrogen release) until membrane rupture and consequent contents release. 

Aliphatic polyamides, also known under the generic name nylon. Industrial nylons with the general structure [—RNHCO—] , such as PA-6, PA-11, and PA-12, are called monadic those with the general structure [ —NHR1NHCOR2CO —] are called dyadic (PA-4,6, PA-6,6, PA-6,9, PA-6,10, and PA-6,12). 

Studies of polyamides " also illustrate mechanisms involving MglOlD. Mg(OH)2 decomposes before the decomposition of PA-6 and after the decomposition of PA-66. The water formed by Mg(OH)2 before the decomposition of PA-6 gives a fire retardant effect. However, it is possible that the water thus formed may hasten the degradation of the polymer by hydrolyzing it. 

The oxidation process initiated in this way leads ultimately to the breakdown of the amide. The same mechanism was later shown to hold for polyamides also, and this is why polyamides with structure... 

Properties. The solid polyamide resins are alcohol soluble and if properly formulated can supply some degree of hydrocarbon compatibility. Thus, they can be applied from solvent solution. However, they also can be applied as hot melts or from water dispersions. Water-based forms known as suspensoids have been described (12). Solid polyamides also may be finely divided for use as powders. The films are characterized by resistance to moisture, moisture vapor transmission, grease, and oils. They are resistant to many solvents and chemicals including aliphatic hydrocarbons and mineral and vegetable oils. They do not resist lacquer-type solvents and alcohols. They have a high degree of flexibility and maintain their flexibility upon aging. Also, they are heat sealable at relatively low temperatures and adhere to an unusually wide variety of substrates. 

The fatty polyamides also demonstrate a high level of grease and oil resistance combined with a low order of irritation and toxicity... 

Thermoplastic - Thermoplastics are resin or plastic compounds which, after final processing, are capable of being repeatedly softened by heating and hardened by cooling by means of physical changes. There are a large number of thermoplastic polymers belonging to various classes such as polyolefins and polyamides. Also called thermoplastic resin. 

The resulting polyamides also have high molecular weight and the monomer reactants are carefully kept in stoichiometric amounts. 

Block polyester-polyamides also form through initiation of ring-opening polymerizations of... 

Newer polyamides also contain alicyclic groups. Of course, products derived from cyclohexane can occur in cis or trans configurations with very... 

Block polyester-polyamides also form through initiation of ring opening polymerizations of lactones by the terminal amine groups of the polyamides [428] ... 

Another class of membrane polymers are the polyamides. These polymers are characterised by the amide group (—CO — hlH —). Although aliphatic polyamides comprise a very largeelass of polymers, the aromatic polyamides are to be preferred as membrane materials because of their outstanding mechanical, thermal, chemical and hydrolytic stability, as well as their permselective properties, particularly in reverse osmosis. However, the aliphatic polyamides also show good chemical stability and may be used in microfiltration/ultrafildation applications. 

The amount of ammonia obtained in the destruction of polyamides also exceeds the number of terminal amino groups in the initial polymer. 

For example, polyacrylonitrile, which is theoretically 100% flexible, is actually stiff because of the steric hindrance of its large nitrile groups. Likewise, polyamides, also theoretically 100% flexible, are quite stiff because of hydrogen bonding between the chains. 

Recently, high-performance fibres have been developed based on aromatic polyamides, also known as aramids. These are tough enough to be used in rope and cable manufacture, or in protective clothing or body armour. An example of an aromatic polyamide used to make high-strength fibres is poly(p-phenylene terephthalamide), the trade name of which is Kevlar or Twaron ... 

Increasing temperature requirements under-the-bonnet has led to PPS replacing other plastics such as polyamide. Also, the share of diesel engines is increasing which is further encouraging growth in high temperature thermoplastics such as PPS at the expense of other plastics. 

The electrical electronics sector is the second most important market for polyamide accounting for 24% of total world demand in 2002. The use of PA in electrical applications has grown significantly in recent decades due to its excellent flame retardancy, and good balance of mechanical and thermal properties. Polyamide also permits better functionality and design at a lower cost than competing materials such as thermosets and metal. 

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