1, the melting point of propylene is related to the molecular weight of organic matter. The molecular weight of polypropylene is larger than that of polyethylene, so the melting point of propylene is higher.
2. The molecular weight of propylene is higher than that of ethylene, so the density and boiling point of propylene are higher than that of ethylene, the boiling point is slightly lower than that of propane, and the volatility is slightly stronger than that of propane, so the melting point is lower than that of ethylene.