Pilling is a very complex phenomenon because it is affected by many technical factors that define the overall quality of textiles, let's see some of them here below:
Type of fiber used
There is a difference between synthetic pills and pills on natural fabrics. Synthetic pills are almost impossible to remove, while pills on natural fabrics are easily removable with simple tools. Synthetic pilling often erupts in loose threads when you try to remove them, and that’s a problem you won’t have with garments made of natural fibers.
Lenght of the fiber used
Short length fibers are prone to pill easier than longer fibers. This is because long fibers have greater resistance to friction and don’t pill easily.
Composition of the fabric used
When a fabric is made from a blend, where one fibre is strong and one is weak pilling will be more noticeable, because the weaker fibre wears and breaks, while the stronger fibre holds the pills to the cloth.
Type of yarn used
If the yarns are more compact (highly twisted), they will have a low level of pilling than a loose yarn (with low twist).
Structure of the fabric used
Knitted fabrics will pill easily, as they have a loose structure, while woven fabrics and fabrics made from tightly twisted yarns are less likely to pill, because the fibres are held tightly in the cloth. So, the closer the structure of a fabric, the lesser it is prone to produce fluff. The purpose of purchase is still very much important though.
Type of finishing used
Fabric finishing treatments exerts a large effect on the pilling properties. As the surface of the fabric changes hence the pilling properties also changes after finishing. For example, the ordinary compact fabrics with a flat surface are stronger and more capable of withstanding friction than a rough and brushed surface.
Can you prevent pilling to occur? Well, some degree of pilling is always possible, but there are some ways you can help slow down or prevent it.
When washing your garment, first check the care label to know what's the best setting to go for
Sort laundry properly before washing.
Washing delicate items in the same load as jeans or heavy garments will cause more abrasion and harm to the surface of fabrics.
Turn garments inside out while you wash them, so that the face side does not rub against other clothes
Don’t overload the washing machine, otherwise your clothes will rub together and cause more friction.
Choose short, gentle, cold water wash cycles or even hand wash your clothes
Skip harsh cleaners and damaging bleach which can weaken fibers causing them to break and pill.
Use the right amount of detergent, if it's much it's going to damage your garments
Consider using fabric softener to help protect clothing fibers
The ingredients in fabric softener coat the fibers of the fabric so that abrasion is lessened.