Biopolymers: does PHB/PHBV have a hydrogen bond? (1 Viewer)

[fatassmcfat]

Ok so I'm trying to account for the high melting point and insolubility in water in PHB/PHBV and I said that it has a hydrogen bond, but now that I look at the picture I think the O is attached to the C.....so confused. I thought being insoluble in water would be because the water cant overcome the strength of PHBV's forces (thus it has a stronger hydrogen bond)- even though PHBV is polar so technically is should dissolve in water (like dissolves like)

Plaz help

Also, PHBV is a mix of PHB and PHV correct? Some of the info I find on PHB is the exact same i have for PHBV...

 

[strawberrye]

I don't think there is a hydrogen bond at all, to account for the high melting point, you could see that each repeating unit of a PHB polymer has a large number of molecules(higher molecular weight, greater the boiling point-because more intermolecular bonds),the large number of intermolecular bonds because of the large number of molecules means that it requires significant heat energy to break these bonds-mostly dipole-dipole and dispersion, hydrogen bonds usually involves a Hydrogen atom bonded to a highly electronegative atom such as Oxygen, fluorine or nitrogen, which is not evident in the polymer, and the insolubility in water-because it lacks hydrogen bonds, means can't have polar bonding-remember unlike repel, like attracts-hence because its forces are weaker and similar to water bondage, so difficult to dissolve in water

And yes, PHBV is a mixture of PHB and PHV from the best of my knowledge. And to account for why the similarity between PHB and PHBV is so similar is because the bacterium, Ralstonia eutrophus is used to produce a copolymer with PHB to form PHBV-so since the process of production and chemicals to produce it is similar, that might account for the similar information, and from my memory, PHBV was the official polymer marketed as biopol-hope this helps

 

[someth1ng]

There's no hydrogen bonds between PHB chains - polymers are usually insoluble in water because they are so large. This means a lot of intermolecular forces with other polymer chains. To dissolve, you need to completely remove it from the rest of the polymers and it would take a lot of energy, making it unfavourable and hence, insoluble.

 

[fatassmcfat]

THANK YOU SO MUCH!!!!!!!!!!!!! strawberryre and someth1ng would you guys also know what is the reason behind biodegradability in terms of structure?

 

[strawberrye]

Well, because biopolymers usually refers to polymers that are partially or totally made of once living things, in this case, the polymer is made from bacteria, this means that its segments can be broken down by natural decomposers-often under anaerobic conditions that can be found in rubbish dumps-because things made with bacteria have biological bonds... and just some extra information, when biopolymer are partially made from biological organisms such as bacteria, it means that decomposers can break these biological segments-which would also accelerate the disintegration of the non-biological parts-hope this helps

Or to clarify the concept further, imagine wood-it is made of cellulosic material and lignin, it can be broken down by rotting worms and stuff because it is biological material-biological organisms consumes biological material, they can't consume non-biological material without choking or death or causing severe injuries to their intestines-I know not exactly the same as biopolymers-but hopefully this makes my point slightly clearer