Chapter 26, Problem 26.70P

Interpretation Introduction

(a)

Interpretation:

A polymer closely related to PET is PBT, which is made from terephthalic acid and $\text{butane-1, 4-diol}$. A structure for PBT is to be proposed and the condensed formula for the structure is to be written.

Concept introduction:

The PBT stands for poly(butylene terephthalate) and PET for poly(ethyl terephthalate), so both are the examples of polyesters. In PBT, butylene glycol is used instead of ethylene glycol. Increasing the length of the alkyl chain in the polymer will allow easier mobility of the polymer molecule results in the lowering of the melting point. Thus the mobility of the polymer molecule due to longer flexible alkyl chain the polymer molecule easily moves into a crystal lattice more quickly. The polyester can be synthesized from corresponding carboxylic acid and alcohol through the Fischer esterification reaction.

Interpretation Introduction

(b)

Interpretation:

A polymer closely related to PET is PBT, which is made from terephthalic acid and $\text{butane-1, 4-diol}$. It is to be stated the long-form of PBT and from the trivial name of PBT what should be expected.

Concept introduction:

The PBT stands for poly(butylene terephthalate) and PET for poly(ethyl terephthalate) so both are the examples of polyesters. In PBT, butylene glycol is used instead of ethylene glycol. Increasing the length of the alkyl chain in the polymer will allow easier mobility of the polymer molecule results in the lowering of the melting point. Thus the mobility of the polymer molecule due to longer flexible alkyl chain the polymer molecule easily moves into a crystal lattice more quickly.

Interpretation Introduction

(c)

Interpretation:

The PBT has a higher or lower melting point than the PET is to be explained.

Concept introduction:

The PBT stands for poly(butylene terephthalate) and PET for poly(ethyl terephthalate) so both are the examples of polyesters. In PBT, butylene glycol is used instead of ethylene glycol. Increasing the length of the alkyl chain in the polymer will allow easier mobility of the polymer molecule results in the lowering of the melting point. Thus the mobility of the polymer molecule due to longer flexible alkyl chain the polymer molecule easily moves into a crystal lattice more quickly.

Interpretation Introduction

(d)

Interpretation:

It is to be explained why PBT crystalizes more quickly than PET.

Concept introduction:

The PBT stands for poly(butylene terephthalate) and PET for poly(ethyl terephthalate) so both are the examples of polyesters. In PBT, butylene glycol is used instead of ethylene glycol. Increasing the length of the alkyl chain in the polymer will allow easier mobility of the polymer molecule results in the lowering of the melting point. Thus the mobility of the polymer molecule due to longer flexible alkyl chain the polymer molecule easily moves into a crystal lattice more quickly.