Acrylic and polyester, produced from synthetic materials, are made to maintain their shape even after washing many times. It is also due to these synthetic properties that they can be put in the dryer. However, these materials do not perform well at high temperatures. So, when you load your knitted acrylic items in the dryer, make sure to use a low-temperature cycle as too high a temperature can cause permanent wrinkles or, worse, shrink or melt these fabrics. And you would not want that to happen to your knitted acrylic blanket that you poured weeks or months on.