Materials such as polystyrene (PS), polycarbonate (PC), acrylics (PMMA), acrylonitrile-butadiene styrene (ABS) and polyvinyl chloride (PVC) are said to be amorphous thermoplastics. This signifies that in the solid state their molecular structure is random and disordered, the long chain molecules being all entangled rather like solidified spaghetti.