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Nylon 6.6 (Polyamide PA6.6) is the most common form of nylon, followed by Nylon 6 (PA6). Other commercial products include Nylon 4.6; nylon 6.12; nylon 11; and nylon 12. Nylons can be reinforced with graphite and glass fibers for added strength. In addition, graphite fiber adds electrical conductivity and static dissipation properties to nylon. Minerals and flame retardants form another group of additives added to nylon. Nylons tend to absorb moisture, which can degrade the properties of the polymer being processed if not allowed to dry prior to processing. However, some types of nylon are less prone to moisture absorption than others.
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| Different types of nylons have a wide range of properties. |
| Properties |
PA12 |
PA11 |
PA6.12 |
PA6.6 |
PA6 |
PA4.6 |
| Elastic modulus, MPa |
1100 |
1100 |
1800 |
1700 |
1100 |
1100 |
| Notched impact strength at 23 ° C, Charpy, kJ / m2 |
7 |
fourteen |
6 |
12 |
twenty |
45 |
| Notched impact strength at 30 ° C, Charpy, kJ / m2 |
6 |
eleven |
6 |
4 |
3 |
12 |
| Melting point, ° C |
178 |
189 |
218 |
260 |
222 |
295 |
| Temperature of admissible deformation HDT-B (0.45 MPa), ° C |
115 |
145 |
180 |
225 |
170 |
280 |
| Moisture absorption at 23 ° C and 50% rel. ow.,% |
0.80 |
0.80 |
1.30 |
2.50 |
3.00 |
3.70 |
| Density of dry material, gm / cc |
1.01 |
1.03 |
1.06 |
1.14 |
1.14 |
1.18 |
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Nylon 6.6 has a good balance of strength, stiffness, heat resistance, hydrocarbon resistance, lubricity and wear resistance. Nylon 6 has better creep resistance, but it has a lower modulus of elasticity compared to nylon 6.6; it is machined at nearly 27 ° C lower than nylon 6.6 and with less injection shrinkage. Nylon 6 gives a glossy finish, which is very useful where appearance matters. At the same time, nylon 6 has higher moisture absorption parameters than nylon 6.6.
Nylon 4.6 has the highest impact resistance of any nylon brand, but has a lower modulus than nylon 6.6. Nylon 4.6 has excellent wear and abrasion resistance and outstanding flow properties that make it easy to process. At the same time, material 4,6 has higher moisture absorption rates.
Compared to other nylons, nylon 12 has a relatively low concentration of amide groups in the polymer chain, which gives it the lowest water adsorption rate of any commercial nylon. It also has good to excellent resistance to oils, hydraulic fluids, solvents and salt. The material is also resistant to stress cracking and abrasion.
Nylon 6,12 also has fairly low moisture absorption and has many of the same properties as nylon 12. However, compared to nylon 12, polymer 6,12 has higher thermal flexural strength, tensile strength and static strength. bend.
Nylon 11 also has relatively low moisture absorption rates. It has a high degree of resistance to chemicals and a good ability to absorb large dosages of aggregates. However, compared to other types of nylon, nylon 11 is more expensive and less heat resistant.
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