Final answer:
a) M_n = l / r The number-average molecular weight of a linear polyethylene can be calculated using the total chain molecule length divided by the average chain end-to-end distance formula.
Step-by-step explanation:
n
= l / r
In a linear polyethylene, the total chain molecule length (l) represents the total number of monomers in the chain. The average chain end-to-end distance (r) measures the average distance between the ends of the polymer chain. By dividing the total chain molecule length (l) by the average chain end-to-end distance (r), the number-average molecular weight (M
n
) of the linear polyethylene can be calculated.
When discussing polyethylene, which is formed from the polymerization of ethylene (ethene) monomers, it’s important to understand that the structural details like chain length and branching impact the polymer's properties significantly. For example, low-density polyethylene (LDPE) has a higher degree of branching than high-density polyethylene (HDPE), resulting in different physical characteristics.