Final answer:
Poly(but-1-ene) and poly(but-2-ene) have different glass transition temperatures due to the different branching structures resulting from their isomeric forms, which affects chain packing and overall polymer properties.
Step-by-step explanation:
The reason why poly(but-1-ene) has a different glass transition temperature (Tg) than poly(but-2-ene) is due to the different branching structures of their polymer chains. The compound 1-butene will produce a polymer with a more linear structure, whereas 2-butene will result in a polymer with more branching due to the position of the double bond. These structural differences affect how closely the polymer chains can pack together, resulting in variations in their glass transition temperatures.
When it comes to polymers, attributes such as chain length, molecular weight, and the polymerization process can influence the physical properties. However, in the case of these two polymers, the key difference lies in the isomeric structure of the monomers, which are isomers with the same molecular formula but different arrangements of atoms and therefore different physical and chemical properties.