The Effect of Chitosan into Mechanical and Optical Properties of

Paper

Muryeti

, Faraqh Eka Pratiwi, and Risqi Tri Yuniastuti

Politeknik Negeri Jakarta, Prof. Siwabessy Street. Kampus Baru Universitas Indonesia, Depok, Indonesia

Keywords: Chitosan, Water Absorptiveness, Tensile Strength, Brightness, Papermaking

Abstract: Chitosan is one of a biomaterial non-toxic, biodegradable, and biocompatibility material. Chitosan has been

studied as an additive in papermaking to enhance the properties of paper such as mechanical and optical

properties. The aim of this research was to investigate the effect of chitosan on the properties of recycled

paper. In process of papermaking, four different concentrations of chitosan (0.5%; 1%; 1.5%, and 2%) were

added in 1% acetic acid. The efficiencies of chitosan in papermaking was examined by measuring and

analyzing the properties of paper, in particular mechanical and optical properties. The results showed that

with the increasing dosage of chitosan, the mechanical properties of paper, such as tensile strength increased

while the water absorption of paper decreased. It also found that the brightness of paper was not affected by

the addition of chitosan. The tensile index value of HVS paper was more significant than the newspaper. The

optimum/peak concentration of chitosan in papermaking was obtained at concentration of 1.5%. Furthermore

the water absorptiveness of HVS paper was lower than the newspaper. The application of chitosan

concentrations from 0.5% to 2%, cannot trigger the increasing of brightness of paper, which remained constant

with further increase of chitosan concentration. This research shows that chitosan is useful as an additive in

the recycled papermaking to improve the mechanical properties of paper.

1 INTRODUCTION

Paper is one of the printed materials that is very

needed in the printing and packaging industry. Paper

is the printing component that will determine

runnability and print quality. The properties of paper

and papermaking will affect the print quality that will

be produced. Paper is the required printing material.

With the increasing world population and the higher

consumption of paper usage, paper waste will also

increase. Increased paper production will result in

increasing raw materials for making wood paper from

plants needed. Nowadays, with the increasing

awareness of humans on the environment, recycled

paper becomes essential in life, which has a positive

impact on the environment, including saving natural

resources. Recycling papermaking can be reduced

excessive deforestation as raw material, reducing the

level of pollution due to paper waste and paper

processing and making processes are cheaper than

making and processing paper from virgin pulp.

Paper is made from cellulose fibers that are added

with additives such as fillers and sizing to improve

the properties of paper it produces. The filler used to

increase brightness, the opacity of paper, with fill the

pores of the paper. Fillers consist of white pigment as

inorganic compounds, such as calcium carbonate,

china clay, titanium dioxide, and others. A number of

these synthetic additives are non-biodegradable and

and may cause negative effects to environment.

Printing material should be non-toxic, eco-friendly,

and biodegradable. The development and

improvement of biodegradable materials has attracted

increasing research interest.

Chitosan is increasingly used and applied in a

wide variety of industries. Chitosan is a natural

heteropolymer containing glucosamine and acetyl

glucosamine. Chitosan has a unique characteristic

that is cation, biodegradable, biocompatible, non-

toxic, and has antimicrobial activity (Crini, 2008 and

Patale, 2011). Chitosan has anti-termite activity,

which can cause the paper to be stored for an extended

period (Muryeti, 2018). Chitosan can absorb heavy

metals such as Cu, Zn, Pb, Cd, and other heavy

metals. Chitosan active sites either in the form of NH

or in the protonated state of NH

can adsorb heavy

metals through the formation of chelates or ion

exchangers (

Mourya, 2010).

Muryeti, ., Pratiwi, F. and Yuniastuti, R.

The Effect of Chitosan into Mechanical and Optical Properties of Paper.

DOI: 10.5220/0009884200002905

In Proceedings of the 8th Annual Southeast Asian International Seminar (ASAIS 2019), pages 78-82

ISBN: 978-989-758-468-8

Chitosan also has the ability as an adsorbent to

dye such as mono azo dye, methyl orange, because

chitosan a protonated state, the amine group in

chitosan can bind to the sulfonate group of dyes

(

Chiou, 2006 and Zulkarnain, 2009).

The use of chitosan in various fields of modern

industry is quite a lot including in the pharmaceutical,

cosmetic, food, paper, textile, agriculture, membrane,

and health industries (Shigemasa, 1995).

Chitosan is produced from the deacetylation of

chitin and has the same chemical structure as chitin,

consisting of long molecular chains and high

molecular weight. The difference between chitin and

chitosan is that each chitin ring is present in the acetyl

group (-CH

-CO) in the second carbon atom, whereas

in chitosan there is an amine group (NH

). Chitosan

can be produced from chitin through a process of

acetylation using reacting using high concentrations

of alkali with a relatively long time and high

temperatures.

Chitosan has relatively more amino groups

compared to chitin, so it is more nucleophilic and

basic. The crystallinity of chitosan caused by

intermolecular and intramolecular hydrogen bonds. It

is lower than that of chitin, making it easier to apply

in several reagents. Chitosan is a biopolymer with

abundance after cellulose. Chitosan is similar to

cellulose in chemical structure but the C-2-hydroxyl

group of cellulose is replaced by an amino group

(Dutta, 2002). In previous studies, chitosan can be

used as an additive to improve wet strength in

papermaking and surface properties of paper for

offset printing (Li Q, 1992). The biopolymers such as

cellulose, chitosan, and chitosan-cellulose composite

were either crosslinked or uncrosslinked, and they

were added in a series of concentrations from 0.1% to

1.5% (Lertsutthiwong, 2002).

The study of the effect of chitosan additives on the

properties of recycled paper such as news print has

never been done. Based on this description, this

research aimed to identify/investigate/assess the

effect/impact of chitosan on the mechanical and

optical properties of recycled paper.

2 MATERIAL AND METHOD

2.1 Materials

The materials used in this experiment were chitosan,

acetic acid 1%, aquadest, and waste paper (newspaper

and HVS). The instruments required and used for this

research were laboratory glassware, analytical scale,

blender, screen, Elrepho, tensile tester, Cobb tester,

and oven.

2.2 Experimental Method

2.2.1 Preparation of Chitosan Solution

0.5 g, 1 g, 1.5 g, and 2.0 g of chitosan were weighed

using an analytical balance. Then the chitosan is

dissolved with 1% acetic acid. The mixture is stirred

for 2 hours, so it is homogeneous.

2.2.2 Handsheet Production

Paper samples (HVS and newspaper) weighed as

much as 50 g, then soaked in 10 L aquadest for 6

hours. After that, it is crushed using a blender. Pulp

slurry by adding water with pulp and chitosan with

various variations. Furthermore, a sheet of paper is

made using screens, so that a wet sheet of paper is

formed. Then the sheet of paper is dried in the oven.

Moreover, prepared for further paper testing.

2.2.4 Characteristic of Paper

Properties of paper have been tested including the

mechanical properties such as tensile strength and

water absorption and the optical properties such as

paper brightness. The capacity of water absorption of

paper sheet was measured by using Cobb's test,

according TAPPI T441 om-09 standard. The value of

water absorption can be obtained from the equation

below

Water absorption (cobb)x = 100 (a-b) (1)

Where

a = weight of the sample paper after testing (gram)

b = weight of the sample paper before testing (gram)

Tensile strength was determined using tensile tester

TAPPI T-494. The tensile strength test was conducted

three times. Paper brightness was measured by using

Elrepho test, according to TAPPI- 452 standard

method. Brightness value shows the percentage

reflectance of blue light at wavelength of 457 nm

reflected from the surface of paper.

3 RESULT AND DISCUSSION

The Cobb test determines the amount of water that is

taken up by a defined area of paper through one sided

contact with water. Table 1 shows the test result of

The Effect of Chitosan into Mechanical and Optical Properties of Paper

water absorption of paper with various chitosan

concentrations.

Table 1: Water absorption in various concentrations of

chitosan

Concentration of

Chitosan (%)

Water absorption (g/m

)

HVS Newspaper

0 69.78 98.52

0.5 72.69 92.35

1 63.61 85.78

1.5 52.97 72.54

2 47.36 70.92

HVS paper without chitosan had a Cobb value of

69.78 g/m

. The addition of 0.5% chitosan

concentration resulted in a Cobb value of 72.69 g/ m

At chitosan concentration of 1%, a Cobb value was

63.61 g/ m

. While paper with the chitosan

concentration of 1.5% had a Cobb value of 52.97

g/m

. Furthermore, with the addition of chitosan

concentration of 2%, Cobb value was 47.46 g/m

The newspaper sample untreated with chitosan

had a water absorption value of 98.52 g/m

. The

addition of chitosan at a concentration of 0.5%

resulted in water absorption value of 92.35 g/m

Water absorption value were 85.78 g/m

, 72.54 g/m

and 70.92 g/m

when treated with chitosan

concentrations of 1%, 1.5% and 2% respectively. The

data showed that the chitosan addition reduced the

water absorption of paper made from HVS paper and

waste newspaper, where the water absorption of

waste newspaper is higher than HVS paper.

Newspapers have more paper pores compared to

HVS, and this causes the newspaper water absorption

value is higher than the HVS. Both newspaper and

HVS paper that does not contain chitosan have a

higher absorption value than paper containing

chitosan, and this is due to chitosan as an additive

(sizing agent). This result was not consistent; chitosan

has many hydroxyl groups so that it can bind to water,

due to increasing the water absorption paper. In the

previous research, water absorption decreased by

increasing the concentration of chitosan. With the

formation of the structure of the film layer on the

surface of the fiber (Sarwar, 2009).

The tensile strength represents the maximum

force needed to break a strip of paper. Tensile

strength is one of the most important basic physical

properties of paper. Therefore, it is necessary to

increase paper quality by improving other factors,

such as fiber length. Tensile strength is a measure of

how resistant the paper is to a web break. The

strength, length and bonding of fiber, degree of fiber

refining, the direction of the fiber, and filler are the

main sources of the tensile strength of paper

(Khantayanuwong, 2017).

Table 2 shows the result of tensile strength

measurement on paper.

Table 2: Tensile index of paper that contain of chitosan

Cencentration

of chitosan

(%)

Tensile index

HVS

(Nm/g)

Newspaper

(Nm/g)

0 23.67 17.25

0.5 35.26 20.71

1 41.79 32.58

1.5 45.32 35.74

2 40.85 35.90

HVS paper that did not contain chitosan had tensile

index of 23.67 Nm/g, which exhibited lowest tensile

strength. The addition of chitosan at a concentration

of 0.5% resulted in a tensile index of 35.26 Nm/g. At

chitosan concentration of 1%, a tensile index was

41.79 Nm/g. HVS paper with the chitosan

concentration of 1.5% had tensile index of 45.32

Nm/g. Moreover, with the addition of chitosan

concentration of 2 %, tensile index was 40.85 Nm/g

and had no significant effect on tensile strength.

Furthermore this study showed that tensile index

of newspaper was 20.71 Nm/g when treated with

chitosan concentration of 0.5%. Tensile index were

32.58 Nm/g, 35.74 Nm/g, and 35.90 Nm/g when

treated with chitosan concentration of 1%, 1.5% and

2% respectively. Tensile strength of HVS paper is

higher than tensile strength of newsprint.

The tensile strength test showed that tensile index

of HVS paper and newspaper increased with

increasing of concentration of chitosan and this result

is consistent with the previous research (Ashori,

2006). The results showed that chitosan at

concentration of 1.5% can be identified as optimum

concentration. However chitosan concentration

addition of more than 0.5%, did not increase the

tensile index. One factor that affects tensile strength

is fiber length.

The chitosan's structure is resemble to cellulose.

It should be compatible with the cellulose, thus

making it possible to create strong bonding with

fibers and giving the strength of paper (Nada, 2006).

Chitosan, which has hydroxyl and amine groups,

can form hydrogen bonds with cellulose fibers,

cellulose fibers to form strong bonds, this affects the

tensile strength of the paper produced. Cellulose is

held by hydrogen bonding, and these bonds influence

the fiber cross-linking distance (

Mucha, 2000)

ASAIS 2019 - Annual Southeast Asian International Seminar

Tensile strength is indicative of the strength

derived from factors such as fiber strength, fiber

length, and bonding. The tensile index of HVS paper

is higher than the tensile index of newspaper, and this

is because cellulose fibers from newspapers are

secondary fibers from paper recycling. HVS paper

made from primary fibers has more long fibers.

Secondary fibers have fewer long fibers; this causes a

higher tensile index for HVS compared to newspapers

Adding excessive chitosan will result in the

strength of the paper being compliant. This is due to

the paper pores filled by chitosan will reduce the braid

between the fibers, resulting in reduced mechanical

strength of the paper.

It also will cause the occurrence of dusting on the

paper. Chitosan that is not attached to the surface of

the paper will act on the image on the printing plate

so that it will ultimately affect the course of print

production and decrease the quality of printing.

When the surface-sized sheet is treated with

chitosan solution, a portion of the additive solution

penetrates with water into the fibrous structure.

Interaction between chitosan and fiber would

improve bonding strength and resistance of paper to

water, due to the formation of amide bonds during the

printing ink drying process. Interaction with amino

groups of chitosan with fiber the presence of water,

they can form ionic and amino bonds (Ashori, 2006).

The brightness of paper measures the amount of

reflectance of blue light at wavelength of 456 nm

reflected from the surface of paper. The results of the

paper brightness test can be shown in Table 3.

Table 3: The brightness of paper in various concentration

of chitosan

Concentration

Chitosan (%)

Brightness (%)

HVS Newspaper

0 81.19 67.25

0.5 81.68 67.34

1 82.85 68.12

1.5 84.47 68.85

2 80.94 67.94

HVS paper that did not contain chitosan had paper

brightness of 81.19%. The paper brightness were

81.68%, 82.85%, 84.47%, and 80.94% when treated

with chitosan concentration of 0.5%, 1%, 1.5% and

2% respectively. The application of chitosan

concentrations from 0.5% to 2%, cannot trigger the

increasing of brightness of paper, which remained

constant with further increase of chitosan

concentration.

The paper brightness of waste newspaper without

chitosan was 67.25%. The addition of 0.5% chitosan

concentration resulted in paper brightness of 67.34%.

The paper brightness were 68.12%, 68.85% and

67.94% when treated with chitosan concentration of

1%, 1.5% and 2% respectively.

The brightness value higher the number, the

whiter the paper. The paper brightness was influenced

by fillers, bleaching process, and OBA substances.

HVS paper brightness value is higher than the

brightness of the newspaper because the HVS paper

raw material, which has a higher brightness value

than the newspaper. The data obtained shows that

there is no effect of chitosan on the value of paper

brightness, both on HVS paper and newspaper. The

brightness of HVS paper is greater than the brightness

of the newspaper. Papers with large amounts of

residual lignin will have lower brightness. The

brightness of paper increased with an increasing of

filler. The decrease brightness of paper both of HVS

and newspaper was possibly due to the increase in

light absorption of the higher apparent density of

handsheet.

For further research, to increasing the mechanical

properties of paper, chitosan should be combination

with other such as carboxymethyl cellulose and starch

to enhance the strength properties of paper.

4 CONCLUSION

Chitosan is a biomaterial that used as an additive in

papermaking to improve paper properties. The

application of chitosan into the paper will affect the

properties of the paper produced, among others, the

paper's tensile resistance and water absorption. The

addition of chitosan does not affect the paper

brightness. With the increasing of chitosan

concentration, the tensile strength increased, but the

water absorption of paper decreased. The application

of chitosan concentrations from 0.5% to 2%, cannot

trigger the increasing of brightness of paper, which

remained constant with further increase of chitosan

concentration. This study showed that chitosan at

concentration of 1.5% can be identified as optimum

concentration. The tensile index of HVS paper is

greater than the tensile index of newspaper, whereas

water absorptiveness of HVS paper is lower than

water absorptiveness of newspaper. This research

shows that chitosan is useful and effective as an

additive in papermaking to improve the mechanical

properties of paper.

The Effect of Chitosan into Mechanical and Optical Properties of Paper

ACKNOWLTEDGEMENTS

The author would like to express sincere thanks to

Directorate General for Research and Technology,

Higher Education for providing financial support for

this research. The appreciation also goes to Politeknik

Negeri Jakarta for providing facilities and supporting

the research.

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ASAIS 2019 - Annual Southeast Asian International Seminar