Is grafting from approach at all possible? What is the limit of the molecular weight in grafting onto approach?
A recent paper published on Carbon may be helpful for you to graft the PA6 on filler .（Lim, M.-Y.; Kim, H. J.; Baek, S. J.; Kim, K. Y.; Lee, S.-S.; Lee, J.-C. Improved strength and toughness of polyketone composites using extremely small amount of polyamide 6 grafted graphene oxides. Carbon 2014, 77, 366-378.）
interesting! Thank you so much. but I guess cellulose nanowhiskers will degrade extremely at 250 C, 5 hr even under nitrogen atmosphere
Then your best bet is to find a suitable thermal regulator or go with cellulose nano crystals instead.
@ Akwasi
To my best understanding cellulose nanowhiskers are the same as cellulose nanocrystals. what do you mean by cellulose nano crystals and thermal regulator?
@ Catherine
A typical example of what inconsistencies in definitions can cause. I will borrow your clause 'to the best of my knowledge' cellulose nano whiskers are the shortest spaghetti-like fibrils of cellulose which may come in smaller bundles of diameter ~5-30 nm, length ~ 150-500 nm and aspect ratio (L/d) ~ 30-150. A fibril comprises both crystalline cellulose I and amorphous phases. Cellulose nanocrystals are fine rod-like crystalline cellulose I phases of diameter ~2-20 nm, length >100-600 nm, and aspect ratio (L/d) ~10-100. Cellulose nano crystals comprises only crystalline cellulose I phase. Cellulose nano crystals are more thermally resistant and stable that cellulose nano whiskers.
Thermo regulator could be any medium that can take and regulate heat from the reacting medium, thereby allowing the reactions to proceed as they normally would while preserving the integrity of cellulose.
@ Ajwasi
According to that definition I am working with 'cellulose nano crystals" then! Do you think they would withstand that severe condition (250 C, for 5 hr)? any suggestion are welcome
At 250C some degree of depolymerization will occur, but it is to a good degree protected or safe at this temperature. Above 330C cellulose chains degrade. If you can keep your temperature at exactly 250C ± 2 using highly crystalline (highly thermally resistant) cellulose nano crystals as is often found in flax or hemp-sourced cellulose nano crystals, you should be able to retain some cellulose nano crystal integrity.
For grafting to approach, you may want to prepare masterbatch of lower melting temperature PA materials such as PA11 by Arkema which melts at 180. (Dont expect too much from this approach ).
recently group of Prof. Kamal did some interesting works on dispersion of NCC with/without surface modification, see for example:
- http://pubs.acs.org/doi/abs/10.1021/bm400784j
- http://www.sciencedirect.com/science/article/pii/S0032591014003222
- http://pubs.acs.org/doi/abs/10.1021/am500577e
For grafting to approach you can use nitroxide-mediated radical polymerization as nitroxides are quite stable even in water (which is the best for dispersion of NCC). Group pf Prof. Milan Maric in Mcgill have done some interesting works on this approach but as far as I know they haven't published it yet, you may want to follow his publications. The main drawback of this method is that there is a considerable chance that you affect the crystallinity of NCC which deteriorates its properties.
Good luck
- Badges
- Science topic