How do you condition nylon parts?
The most commonly used method of active condition- ing is to immerse the molded parts in either hot or cold water until the required moisture content has been reached. However, this conditioning process causes the moisture to be distributed unevenly with more moisture on the surface of the part and less in the core.
At what temperature does nylon become brittle?
In a so-called dry-as-molded nylon, the glass transition temperature is approximately 75Â°C. With sufficient moisture absorption, this transition temperature can decline to room temperature or even below. The effect of this can be observed in Figure 2.
How do you soften nylon plastic?
Place the brittle parts into a Ziploc® or other airtight, plastic bag and sprinkle them with water. Let them sit for as little as 12 hours and you’ll be surprised at how flexible and strong they become.
Why is dry nylon so brittle?
All nylons absorb moisture from their immediate environment and eventually reach a level equal with the relative humidity of the atmosphere. Moisture has a plasticizing effect on nylons that increases flexibility and impact resistance. Over-drying has the opposite effect, causing brittleness.
Does water degrade nylon?
Nylon is hygroscopic, meaning that it absorbs moisture right out of the air surrounding the material or directly from water if it is submersed. The higher the humidity, the faster it will absorb moisture. Under normal conditions, say 20-80% RH, nylon will reach saturation in about 24 hours.
Why does nylon absorb moisture?
Nylon resins absorb water due to the hydrophilicity inherent to the amide bonds in the resins. The equilibrium water contents vary according to the kind of polyamides and to the environmental conditions.
Which nylon is most hygroscopic?
Resins moved from storage to the molding machine often must be dried because of these properties. They must be processed quickly after drying. Nylon 6 is one of the more hygroscopic resins and is capable of containing as much as 9% of its weight in water.
What is brittleness temperature?
Brittleness temperature is the temperature at which 50% of the tested specimens exhibit brittle failure at specified impact conditions. It is utilized primarily for plastics and elastomers. Test Procedure: Brittle temperature is the temperature at which 50% of the specimens fail.
How do you revive nylon?
The simplest solution would be to find a dye that comes as close to the original color of the clothing or product that has faded nylon on it. Mix the dye according to the instructions that are on the box or bottle and put the solution in a spray bottle. Then spray the faded parts of the fabric and let dry.
Does water break down nylon?
At the molecular level, nylon contains hydrophilic amide groups. Therefore nylon is water-absorbent. Water absorption will result in dimensional change. Assuming ordinary atmospheric conditions (23°C/60%RH), the equilibrium water absorption is 3.5% for nylon 6, 2.5% for nylon 66, and 1.5% for nylon 610.
Can you over dry nylon?
Most nylon manufacturers will recommend drying nylon to below 0.2% moisture content. This will typically yield acceptable parts but reducing the moisture even further will improve the properties still more. A lot of people speak of “over drying” nylon but you cannot really dry it too much.
How is the moisture conditioning process for nylon done?
The moisture conditioning process takes many forms. Some simply pour a prescribed amount of water into molded parts contained in a moisture-proof package such as a polybag. Others prefer placing saturated paper towels into the package with the nylon parts and allowing the water to migrate out of the paper and into the nylon.
Why do nylon products need to be immersed in water?
After storage for a period of time, products made from this raw material will deform and expand due to absorption of moisture in the air, thus resulting in size change. Therefore, after a nylon product is molded, it should first be immersed in 100-120°C water or potassium acetate solution, to keep it isolated from the air.
What causes the dimensional stability of nylon to change?
But there are environmental factors that also cause parts to increase in size over time. The best example of this is the dimensional growth that occurs when parts molded in nylon absorb moisture from the atmosphere.
What is the transition temperature for Nylon 6 / 6?
Above the glass transition temperature, an unfilled nylon 6 or nylon 6/6 loses approximately 80% of its room-temperature stiffness and strength, but in the process becomes substantially tougher. In a so-called dry-as-molded nylon, the glass transition temperature is approximately 75Â°C.