content_image/901049.jpg content_image/901052.jpg content_image/901051.jpg
<img src='content_image/901049.jpg'>

[0079] Examples of the monomer from which recurring units (a2) are derived are shown below, but not limited thereto. Herein RA and R$^{42 }$are as defined above. 

<img src='content_image/901052.jpg'>

<img src='content_image/901051.jpg'>

-continued 

