A, polyamide plastic 
 Polyamides, commonly known as "nylon", referred to as the PA for the largest general-purpose engineering plastic varieties. PA including types 
 , Concrete can be named as PAxy, where x represents the number of carbon atoms of the diamine, y, on behalf of the dicarboxylic acid number of carbon atoms. Plastics PA PA and a small amount of aromatic aliphatic with the PA. Specific varieties of PA6, PA66, PA610, of PA1010, PA11,, of PA12, PA9, PA612, PA46, PA1212, cast nylon (the MC5) and aromatic nylon and so on. PA6 which accounted for 47%, PA66 45%. 
 PA is currently the largest application for auto parts, the United States accounted for 30.7%, Western Europe accounted for 31.6%, Japan accounted for 34.5%. Other use of packaging films, electronic, mechanical parts, and other daily necessities. 
 1, the performance of the amide plastic 
 (1) the general performance of PA appearance of transparent or opaque, milky white or yellowish granules, apparent horny, hard and products surface gloss. PA water absorption is relatively large, the greater the proportion of amide groups, the higher the water absorption, in particular: 
 Of PA6> PA66> PA610> of PA1010 PA11,> of PA12> PA1212. PA is self-extinguishing plastics, when burned, charred wool or nails taste. PA in the medium plastic barrier, the barrier increases with the proportion of amide / methylene improved barrier effect of PA6 is best. PA6, O2 permeability from 25 to 40 cm 3? Mm / m? D? Mpa 
 CO2 permeability of 150 to 200 cm 3? Mm / m? D? Mpa 
 H2O permeability 150g? Mm / m? D? Mpa 
 (2) the mechanical properties of PA at room temperature tensile strength and impact strength are higher impact strength than the PC and POM high. With increasing temperature and humidity, the tensile strength of a sharp decline in the impact strength improved significantly. The glass fiber reinforced PA in intensity by the temperature and humidity less affected. 
 Better resistance to fatigue in the PA, second only to the POM, the the fiberglass enhancement can also be increased by about 50%. 
 Poor creep resistance of the PA, not suitable for the manufacture of sophisticated products can be improved, but the glass fiber reinforced. 
 PA rubbing resistance and abrasion resistance and excellent wear resistance of a commonly used plastic varieties. Among them, the different varieties of the friction factor less oil-free lubrication friction factor of only 0.1 to 0.3. Wear resistance to PA1010 best. PA added molybdenum disulfide, graphite, F4, and PE can further improve the friction and wear resistance. 
 (3) heat distortion temperature of the thermal properties of PA are not high, usually 50 ~ 75 ℃. Can improve glass fiber reinforced more than four times the thermal conductivity of up to 200 ℃ PA is very small, only 0.16 ~ 0.4W / M? K,. PA of the linear expansion coefficient, and increases with the degree of crystallinity. 
 (4) low temperature and low humidity conditions, the electrical properties of PA as an excellent insulating material, insulating properties with increasing temperature and humidity and the dramatic deterioration with amide ratio is most sensitive to the molecule, such as PA6 maximum PA12 minimum. 
 (5) environmental performance of PA resistance, chemical stability good, can be resistant to most organic solvents such as alcohols, aromatic hydrocarbons, esters and ketones, in particular, is outstanding oil resistance. PA acid, alkali, salt can lead to swelling, the most harmful inorganic salts of zinc chloride. PA can be dissolved in formic acid and phenolic compounds. 
 PA lightfastness is not good, strength in the sun soon decreased, and brittle, and therefore can not be used outdoors.