Ether has very similar structure as alcohol. Why there is hydrogen bonding in alcohol but not in ether? Oxygen atoms have two lone pairs in both cases.

Ether has no H atoms directly bonded to electronegative O.

It is the H-O bond that produces the [CE]d[/CE]+ partial charge on the H that produces Hydrogen bonding.

Then I have a question about the intermolecular force in PET. Is there any hydrogen bonding between the PET chains?

For a good hydrogen bond, you need an attached H-O. In PET, there are plenty of Oxygens, but none of them have a hydrogen attached directly.

 

http://www.polymerprocessing.com/polymers/PET.html

here is an example of h bonds between acetone molecules. so in ether it might be there but unsignificantly weak. wikipedia also says about h bonds between acetone

http://books.google.com/books?id=be0T64ZWp9EC&pg=PA211&lpg=PA211&dq=manku,+hydrogen+bonding&source=bl&ots=5NxzqpHuhM&sig=BsxXqR1qOlqcH229JBJN8yw6sEI&hl=en&ei=w8J2S5GWK8qwrAf77qT1Dw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAcQ6AEwAA#v=onepage&q=&f=false

 

sorry o tried but cant upload the specific page tthis time but try page no-213