Which type of poly(ethene) would be expected to have a lower density?

Low density poly(ethene) is expected to have a lower density because of its molecular structure and how the polymer chains are arranged. In low density poly(ethene), the polymer chains are more branched, which leads to a less compact arrangement. These branches prevent the molecules from packing closely together, resulting in lower density.

This structure also contributes to other properties such as increased flexibility and lower tensile strength compared to high density poly(ethene), which has a more linear structure that allows for closer packing of the chains and thus a higher density. On the other hand, high density poly(ethene) gathers its density from the tightly packed arrangement of its linear polymer chains, leading to a more rigid form.

Furthermore, the medium density poly(ethene) and ultra-high molecular weight poly(ethene) do not generally fall under the category of having greatly reduced density compared to low density poly(ethene). Medium density poly(ethene) features a combination of characteristics from both high and low density variations but does not provide the same level of decreased density as the low density variant. Ultra-high molecular weight poly(ethene) is known for its exceptional strength and robustness, resulting from long-chain structures, but still retains higher density compared