Callistemon
The trouble with acrylic is that it is a plastic and the fibres get washed down to the sea.
^And these tiny fibres — less than 5 millimeters in length, with diameters measured in micrometers (one-thousandth of a millimeter) — can eventually reach the ocean. There, they’re adding to the microplastic pollution that’s accumulating in the food chain and being ingested by all sorts of marine wildlife, and even us. Most of the plastic that’s in the ocean, in terms of number of pieces, is not in the form of whole products like cups or straws, but instead broken-down shreds of plastic.^
This is one of the reasons I don't buy it. I also find that although it is nowhere near as warm as natural fibres it can be sweaty to wear.
M&S used to be really good for jumpers. I still have an ancient aran sweater that belonged to my father (who died nearly 30 years ago). It has a St Michael label, and apart from a couple of mended moth bites, it is going strong.