Nanocrystalline cellulose is a kind of nanomaterial that has got tens of nanometers width and hundreads of nanometers length and produced with the method of acid hydrolysis of amporphous structures of cellulose for isolating crystalline domains. Flax, hemp, coconout, banana plants and processed materials like paper pulp and microcrystalline cellulose are the common sources for producing nanocrystalline cellulose.

Aspect ratio, is a unitless number that definites length/width ratio of nanocrystallites. Nanocrystalline cellulose can have aspect ratio values between 1-100 respect to their production source [1]. As that can be seen in Table 1, resources effects the final product directly. Also crystal sizes effects the mechanical behaviour of composites directly, too.

Table 1. Comparasion of length and width values of nanocrystalline celluloses from different sources [2]

 

In our works, lignocellulosic and cotton plant derived linter and paper pulp were used as resource of nanocrystalline cellulose production. In Table 2, crystalline sizes that produced from treatment of cellulosic raw materials with sulfuric acid are given.

 

Tablo 2. TEM Analysis linked crystalline sizes of the nanocrystalline cellulose specimens that are derived from different sources

			NCC from Linter		NCC from Long Cut Paper Pulp		NCC from Short Cut Paper Pulp
			Length [nm]	Diameter [nm]	Length [nm]	Diameter [nm]	Length [nm]	Diameter [nm]
			108,43	2,92	94,72	12,16	181,25	31,32
			160,74	2,97	104,41	13,21	193,56	44,44
			174,99	3,11	127,99	16,71	224,99	46,02
			188,75	3,23	173,12	17,23	318,8	54,41
			202,3	3,32	177,74	20,68	364,34	55,55
			205,75	6	188,79	25,07	386,73	66,32
			208,12	6,76	208,74		430,48	66,66
			214,78	7,88	326,1			66,66
			216,91	9,01	447,53			80,88
			232,09	16,33				87,64
			234,77	58,91				88,88
			240,93	61,45				88,88
			240,98	64,69				89,26
			251,91	64,69				111,1
			253,84	67,16
			253,93	71,44
			266,18	75,19
			269,45	75,73
			274,37	77,99
			278,84
Mean Values			223,903	35,72526	205,46	17,51	300,0214	69,85857
Length/Diameter Values
Smallest Length/Smallest Diameter			95,49315068		36,80345395		13,74457216
Smallest Length/Biggest Diameter			1,39030645		7,789473684		1,631413141
Biggest Length/Biggest Diameter			3,575330171		17,85121659		3,874707471
Biggest Length/Smallest Diameter			37,13356164		7,789473684		5,787037037
Mean Length/Mean Diameter			6,267357612		11,73386636		4,29469745

 

Compatibility between results of our works and related literature can be easily seen from Table 2. Aspect ratio values are also given in Table 2.

 

Table 3. Comparasion of mechanical properties of nanocrystalline cellulose and industrial fibers [1]

 

Composite materials are the major application area of nanocrystalline cellulose. Nanocrystalline cellulose is more strengthful material than steel with 145 GPa elasticity modulus and more stiffer than aluminium with 7,5 GPa tensile strength but also less dense material than others [1]. As it can be seen in Table 3, density values of nanocrystalline cellulose is close to the Kevlar fiber but nanocrystalline cellulose has got two times better mechanical properties. Nanocrystalline cellulose is much stregthful and less dense material compared to common fibers that are use in composites and also more renewable material than its closest rival “carbon nano tube”.

 

Table 4. Comparasion of mechanical behaviour of nanocrystalline cellulose reinforced composites [3]

Matrix	NCC-Source and Size [Dia., Len. [nm]]	%NCC [wt %]	Increase on Young  Modulus [%]	Increase onTensile  Strength [%]	Increase on Elongation  at Brake [%]
Polyethylene Oxide	Bacterial [11, 420]	0-0,4	139,9	72,3	-233,3
Polyacrylic Acid	Cotton	0-20	7633,9	5658,6	-99,9
Polyethylene Oxide	MCC [10, 112]	0-20	392,1	240,8	-37,5
	Cotton [5-10, 40-100]	0-20	190,5	377,5	-33,5
	Tunicate [20, 2000]	0-15	98,8	-	-
Polyvinyl alcohol	Ramie [3-10, 100-250]	0-15	270,9	-	-
Polycaprolactone	Ramie [3-10, 100-250]	0-7,5	64,3	37,2	49,0
Polystyrene	Paper [10-20, 200]	0-9	60	-	-
Polymethyl methacrylate	Bacterial [15-20, 300-8μm]	0-20	-	-	-
	Wood [17, 190-660]	0-41	17	30,2	-1,4
Polylactic acid	MCC [92, 124]	0-10	37	30,2	-1,4
EVOH	Bacterial [30 nm]	0-8	-	-	-
Polylactic acid	Cotton	0-12,5	-	161,9	-
Silk	Wood bark [25-40, 400-500]	0-4	300,3	208,0	-55,6

 

In Table 4 effects of different sources like cotton, ramie and MCC derived nanocrystalline cellulose reinforced matrixes like polyethylene oxide, polyacrylic acid and polyvinyl alcohol on mechanical properties has been monitored. As it can be seen on related table nanocrystalline cellulose gives advanced mechanical properties to reinforced material.

 

Nanocrystalline cellulose has got exiting and potential application areas like paper, painting, building, and aerospace materials, food and drug additives because of its advanced mechanical properties and biocompatible, biodegredable, renewable and chemically modifiedable structure.

1. Peresin, M.S., A mini-review on properties of nanocrystalline cellulose and its potential applications. Revista Investigaciones Aplicadas, 2013. 7(2): p. 58-73.
2. Habibi, Y., L.A. Lucia, and O.J. Rojas, Cellulose nanocrystals: chemistry, self-assembly, and applications. Chemical reviews, 2010. 110(6): p. 3479-3500.
3. Zhou, C. and Q. Wu, Recent development in applications of cellulose nanocrystals for advanced polymer-based nanocomposites by novel fabrication strategies. 2012: INTECH Open Access Publisher.

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