Cellulose and Chitin as Nanoscopic Biomaterials - The Nanoscience and Technology of Renewable Biomaterials - page 227

Table8.4 StoragemodulusvaluesforC-9celluloseesterreinforcedwithchitinandsurface
derivatizedchitinnanoparticles.Theparticlesareobservedtoprovidesimilarorbetter
reinforcementrelativetonanoclayfillers.

Weight fraction Storage modulus (MPa)

100 ◦ C 30 ◦ C 70 ◦ C −

0.00 1906 112 4

Unmodified chitin nanocrystals
0.05 2006 169 28

0.10 2096 190 32

0.15 2070 174 27

C6 esterified nanocrystals
0.05

1994 157 24

0.10 2260 217 33

0.15 2145 203 30

C9 esterified nanocrystals
0.05 2392 175 29

0.10 2325 180 34

0.15 2475 222 38

C18 esterified nanocrystals
0.05 1973 146 24

0.10 2440 168 31

0.15 2072 205 33

Nanoclay
0.05

1906 94 9

0.10 2240 150 13

0.15 2190 190 17

8.7 Conclusions

Cellulose and chitin nanoparticles were effectively isolated from bagasse, and shrimp
shells, respectively, both waste products of the food industry. Microscopic character-
ization of these materials has shown them to be nanoparticle and highly crystalline in
nature. The abundance of hydroxyl groups available on the surface of these materials
facilitated their topochemical modification. The confinement of the reactions to the par-
ticle surface, and the preservation of the crystal integrity were confirmed by XRD, and
FTIR techniques. Contact angle analysis has shown that the hydrophobicity of the chitin
particles was greatly enhanced after modification with medium- to long-chain aliphatic
esters. The nanoparticles were melt processed with a biodegradable co-polyester and
biobased cellulose ester matrix phase. Mechanical results indicate that these materials
impart substantial strength in composite applications. The data provided within this
chapter is a mere subset of the potential that nanoscopic biomaterials such as cellulose
and chitin possess in the field of composite materials. There are suggestions from sev-
eral laboratories that transcrystallization at the nanoparticle surface may contribute to
the increased modulus of nanocomposites. If so then facilitating interfacial crystalliza-
tion through surface modification may prove to be a robust route to the formation of