science

Artificial LeathersArtificial Leathers

Researchers

Master. Pornwasu Pongtheerawan

Miss. Arada Sungkanit

Miss. Tanpitcha Phongchaipaiboon

from from Acetobacter Xylinum

Intel ISEF 2009 -- 10-16 May, 2009

IntroductionIntroduction

SShadow puppets are cultural products used in

shadow plays in the Southern parts of Thailand.

shadow plays

Plastic-based artificial leathers have increasingly been used for manufacture of shadow puppet .Therefore the local produce for tourist souvenir

shadow puppets

Introduction: Current problemsIntroduction: Current problems

Low quality

Plastic based artificial leathers

- shot lifetime usage

- brittle

- hard to degrad

We therefore inspired to produce alternative cellulose- based artificial leathers to be used in shadow puppets production to replace the high cost genuine leathers or plastic-based artificial leathers.

Introduction : interesting IdeaIntroduction : interesting Idea

The search for new alternative source of artificial leathers began from our observation that a type of bacteria can produce “coconut gel” from coconut juice and that “coconut gel” looked like artificial leather when it is dry.

Introduction: Introduction: CharacteristicsCharacteristicsProperties of cellulose gel

- cellulose gel has 0.01 micron fibrils.

- crosslink

- absorb more water than cellulose from plants

Figure 1: : Cellulose gel fibrils

Ref: http://en.wikipedia.org/wiki/Microbial_cellulose

Coconut juiceCoconut juice

we found that cellulose gel cultured in coconut juice was too brittle due to the presence of air bubbles in the gel

MethodsMethods

Experiment 1Experiment 1 1A. Finding an optimal formula of culture media and optimal time for media sterilization.

since it gives the thickest cellulose gel with smooth texture without air bubbles.

This liquid medium contains high levels of glucose and fructose and has the pH in the range of 4.0-5.0 which are suitable conditions for cellulose production.

1B.1B. To find the optimal time for culture medium sterilization

Experiment 2Experiment 2 Finding optimal time for biological production of cellulose from A. xylinum

This formula could produce a 2.45 centimeters-thick cellulose gel, which was 41% than those used the traditional coconut juice medium after 7-days of cultivation.

Measure the thickness of the cellulose gels

Finding 2Finding 2 We found that cellulose could be fully produced in 7 days.

Time of culturing A. xylinum

0 0 0

0.50.7

1.6

2.5 2.5 2.5 2.5

0

0.5

1

1.5

2

2.5

3

1 2 3 4 5 6 7 8 9 10

day

thic

knes

s (m

m)

thickness(mm)

Figure 2 : Thickness of cellulose gel produced by A.xylinum at various days of cultivation

Sugar level ,pH Meter and Cell number

Number of A. xylinum cell in culture

0

500,000

1,000,000

1,500,000

0 6 7 10

D ay

Cel

l nu

mb

er(c

ell/

ml) Number of

A. xylinumcell inculture

pH Meter and R efrac tometer

0

5

1015

20

25

1 2 3 4

F ormula

pH a

nd S

ugar

le

vel(

o Bri

x)

Sugar level

pH

Experiment 3Experiment 3: Finding the optimal method and time for drying the cellulose parchments and to study characteristics of dry cellulose parchments (thickness of the dry parchments and the resistant strength)

Heat at 80 °C Heat at 90 °C

Heat at 100 °C Dry in sun light

However, the strength of such cellulose parchments was still not enough for artificial leathers applications.

Balance scale

Clip

Cellulose parchment

Sand

Plastic glass

Tissue paper

Figure 3 : test tensile strength

Experiment 4Experiment 4:: Evaluation of the quality of the cellulose parchments cross-linked with rambutan husk extracts compared with that of those uncross-linked parchments (Tensile strength and water absorption)

Figure 4 : Rambuton husk extractRef: www.thethaifruit.com/content/photos/scaled/9.JPG

Tanning with rambutan husk extract was found to increase tensile strength and reduce water absorption of the cellulose parchments because the tanning process cross-linked cellulose fibrils together.

We found that the tanned parchments’ strength was comparable to that of genuine leathers.

tensile modulus

398.12

329.18

188.12 169.26

050

100150200250300350400450

tanned (cross-linked) w ithout

soaking in w ater

tanned w ithsoaking in w ater

un-tannedw ithout soaking

in w ater

un-tanned w ithsoaking in w ater

Cellulose parchment

ten

sile

mo

du

lus

(MP

a)

Strength testing of cellulose parchment

0102030405060

tanned(cross-linked)w ithout

soaking inw ater

tannedw ith

soaking inw ater

un-tannedw ithout

soaking inw ater

un-tannedw ith

soaking inw ater

cellulose parchment

tensile strength (Mpa)

break strain (%)

tear resistance (N/mm)

Experiment 5Experiment 5:: Comparison of tensile strengths and price of the cellulose-based artificial leathers with those of commercialized leathers

the cost of our parchments was approximately 70% cheaper than that of the leathers

Tensile strength

57.77

49.69

44

46

48

50

52

54

56

58

60

Genuine leather cellulose-based leather

Materials

Ten

sile

t st

ren

gth

(M

Pa)

Figure 5: tensile stength of the cellulose-based artificial leather compared to that of genuine

In addition to shadow puppets, the cellulose-based leathers can also be used in many other applications such as hats or bags,

Experiment 6Experiment 6: Production of shadow puppets, hats, handbags, and other products from the dried, cross-linked cellulose

We found mostly people like products of cellulose-based artificial leathers.

Example of questionnaire regarding user satisfactory of the products

75%

80%

85%

90%

95%

100%

105%

Color Smell Durability Design Price

Shadow puppets

Hats

Bags

Figure 6 : satisfaction levels f customers regarding various characteristic of products made from cellulose-based artificial

leather

Product from cellulose-based artificial leathers

Conclusion

Production of environmental artificial leathers from agricultural wastes

Coconut juice Pineapple husk

1:1

Liquid culture A.xylinum Boiling for 30 min.

+ +

7 days cultivation

Heat at 80 °C For 30 hours.

Soaking with rambutan husks

Cellulose gel

Production of cellulose-based artificial leathersProduction of cellulose-based artificial leathers

Utilize agricultural wastes (coconut juice wastes, pineapple husks, rambutan husks )

Obtain artificial leathers which are

- Inexpensive

- Free of harmful chemicals or animal products

- Biodegradable

- Possible to be further developed into hats, bags, disposable products, and others.

Conserve natural environments

Reducing of wastes to natural

Animal feedstuff

science

Business

cellulose production

cellulose fibrils

alternative cellulose

cellulose gels

thickness of cellulose

thickest cellulose gel

w ater tanned w ith

cellulose gel fibrils