arifur paper 02

Article Designation: Scholarly JTATM

Volume 7, Issue 2, Fall 2011 1

Volume 7, Issue 2, Fall 2011

Study on Modified Pineapple Leaf Fiber

Md. Arifur Rahman

Department of Applied Chemistry and Chemical Technology

Islamic University

Kushtia, Bangladesh

[email protected]

ABSTRACT

On the analysis of TG, DTG and DTA curves for untreated and treated PALF, we have

got the thermal stability of different modified fiber. Thermal stability of raw fiber is high

but acrylonitrile (AN) enhanced the stability in case of bleached PALF. Thermal stability

of acid & 25% NaOH treated fiber is low & high respectively from raw fiber. Thermal

stability is increased by increasing the concentration of sodium hydroxide.

Keywords: PALF (Pineapple Leaf Fiber), Acrylonitrile (AN), Thermal analysis, TG,

DTG, DTA

1. INTRODUCTION

Agriculture is an important sector in

Bangladeshi economy. Traditionally,

agricultural materials have been shipped

away for processing, or disposed of

postharvest. Diversification of the industry

is crucial in encouraging economic stability

and growth. Value-added processing would

helps in agricultural diversification.

Pineapple Leaf Fiber (PALF), the subject of

the present study, is thermal effect on

pineapple leaf fiber.

Picture 1. Pineapple (Ananas comosus)

Plant

A polymer is a versatile material. In the

present era of science is the most promising

and comprehensive field. Development of

polymer is a continuous process for

achieving polymer in a specific application

under certain environmental condition [1]

.

The bombardment of the invention of

different polymer field is increased day by

day. The natural polymer is biodegradable,

abundantly available, and easily

decomposable in the environment and eco-

friendly [2]

.The polymer materials that are

biodegradable are now enjoying

considerable popularity, especially from the

standpoint of environmental protection [3]

.

2. EXPERIMENTAL PROCEDURE

2.1 Raw Materials

Picture 1 shows Ananas Comosus plant and

from which the fiber is collected. These

mailto:[email protected]



fibers are comprised of vascular systems, the

cells are small and bound together by

pectin’s and for that reason this fibers have

widespread uses. The leaves are cut at the

base, rolled and keep under water for some

days to scrape away other mushy tissues

from the fibers. The fibers are then washed

with a lot of clean water and then dried in

the closed place. This gives fibers which are

subjected for investigation.

Local Name: Pineapple

Scientific Name: Ananas Comosus

Family: Bromeliaceae

3. THERMAL ANALYSIS

3.1 Differential Thermal Analysis (DTA)

The technique of DTA is an important tool

to study the structural and phase changes

occurring both in solid and in liquid

materials during heat treatment. These

changes may be due to dehydration,

transition from one crystalline from to

another, destruction of crystalline structure,

melting, oxidation, decomposition,

degradation temperatures, etc, DTA is a

process of accurately measuring the

difference in the temperature between a

thermocouple embedded to a sample and a

thermocouple in a standard inert material

such as aluminum oxide while both are

being heated at a uniform rate [4]

.The

principal of DTA consists of measuring heat

changes associated with the physical or

chemical changes occurring when any

substance is gradually heated. The

thermocouple (platinum-platinum rhodium

13%) for DTA is incorporated at the end of

each of the balance beam ceramic tubes, and

the temperature difference between the

holder on the sample side and the holder on

the references side is detected. This signal is

amplified and becomes the temperature

difference signal used to measure the

thermal change of the sample. These

differences of temperatures appear because

of the phase transitions or chemical

reactions in the sample involving the

evolution of heat and are known as

exothermic reaction or absorption of heat

known as endothermic reaction. The

exothermic and endothermic reactions are

generally shown in the DTA traces as

positive and negative deviations respectively

from a base line. So DTA offers a

continuous thermal record of reactions in a

sample. The areas under the bands or peaks

of DTA spectra are proportional to the

amount of heat absorbs or evolved from the

sample under investigation, where

temperature and sample dependent thermal

resistance are the proportionality factors.

Thus DTA is needed primarily for the

measurement of transition temperature.

Figure 1. Schematic diagrams showing

different part of a DTA

apparatus

3.2 Differential Thermo Gravimetry

(DTG)

DTG stands for Differential Thermo

Gravimetry. If not the weight itself rather

the first derivative of the sample weight with

respect to time at constant temperature or

with respect to temperature at constant value

of heating is determined then this procedure

is termed as DTG.

3.3 Thermo Gravimetric Analysis (TGA)

The TGA is a special branch of thermal

analysis, which examines the mass change

of a sample as a function of temperature in

the scanning mode or as a function of time

in the isothermal mode. Not all thermal

events bring about a change in the mass of

the sample (for example melting,

crystallization or glass transition), but there

are some very important exceptions which



include absorption, sublimation,

vaporization, oxidation, reduction and

decomposition. The TGA is used to

characterize the decomposition and thermal

stability of materials under a variety of

conditions, and to examine the kinetics of

the physico-chemical process occurring in

the sample. Sample weight changes are

measured as described in figure.

Figure shows the sample balance beam and

reference balance beam are independently

supported by a driving coil/pivot. When a

weight change occurs at the beam end, the

movement is conveyed to the opposite end

of the beam via the driving coil/pivot, when

optical position sensors detect changes in the

position of a slit. The signal from the optical

position sensor is sent to the balance circuit.

The balance circuit supplies sufficient

feedback current to the driving coil so that

the slit returns to the balance position. The

current running to the driving coils to the

sample side and the current running to the

driving coil on the reference side is detected

and converted into weight signals.

Figure 2. Principal of TGA measure

Figure 3. TG, DTA and DTG curves of raw pineapple leaf fiber

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

10.00

8.00

6.00

4.00

2.00

0.00

79.2Cel-7.6uV

77.4Cel0.13mg/min

358.7Cel1.78mg/min

301.7Cel0.45mg/min

358.2Cel-18.0uV

147.7Cel94.6%

5.2%321.2Cel93.1%

356.8Cel40.8%

373.8Cel15.9%

347.0Cel54.5%

77.1%



4. RESULTS & DISCUSSION

4.1 TG, DTA & DTG curves of raw

pineapple leaf fiber

Figure 3 shows that TG, DTA and DTG of

raw PALF. The TG curve shows that

initially 5.2% loss corresponded to moisture

content. Then the mass is decreased initially

as slow rate and finally the rate increased.

Light substances have removed first than the

heavy one.

Two endothermic DTA peaks at 79.20C,

358.20 C are obtained. The 1

st peak at 79.2

0

C due to the removal of moisture & 2nd

peak

for degradation of fiber.

Three DTG peaks are also found at 77.40

C,

301.70C and 358.7

0C correspond to light &

heavy material.

DTG curve of raw PALF depicts that the

maximum degradation occurs at the

temperature 358.70 C with the rate of 1.78

mg/min.

Figure 4. TG, DTA and DTG curves of scoured pineapple leaf fiber

4.2 TG, DTA and DTG curves of

scoured pineapple leaf fiber

Fig.4 shows that TG, DTA and DTG of

scoured PALF. The TG curve shows an

initial 6% loss corresponds moisture content.

The mass is losing initially at slower rate

than it ended. Light substances have

removed first than the heavy material.

Four endothermic DTA peaks 70.90C,

2390C, 309.4

0C and 352.9

0C are obtained.

The 1st peak at 70.9

0C is due to removal of

moisture. 4th peak is for degradation.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

5.000

4.000

3.000

2.000

1.000

0.000 76.8Cel0.118mg/min

70.9Cel-2.8uV

309.4Cel29.0uV 352.9Cel

21.4uV

349.9Cel1.209mg/min

239.0Cel29.3uV

283.3Cel0.254mg/min

138.1Cel93.7%

6.0%314.3Cel93.0%

349.5Cel47.2%

367.9Cel23.4%

340.5Cel58.2%

69.6%




C,

283.30C and 349.9

0C that corresponded to

light & heavy material. DTG curve of

scoured PALF depicts that the maximum

degradation has occurred at the temperature

349.90 C with the rate of 1.209 mg/min.

Figure 5. TG, DTA and DTG curves of a grafted pineapple leaf fiber

4.3 TG, DTA and DTG curves of AN

grafted pineapple leaf fiber

Fig.5 shows that TG, DTA and DTG of a

grafted PALF. The TG curve shows an

initial 3.6% loss for moisture content. The

mass is losing initially at slower rate than it

ended. Light substances have removed

initially than heavy material.

Four endothermic DTA peaks 75.60C,

2370C, 320.1

0C and 372.1

0C are obtained.

The 1st peak at 75.6

0 due to removal of

moisture. 4th peak for degradation.


C,

303.30C and 352.5

0C which corresponded to

light and heavy material. DTG curve of

scoured PALF depicts that the maximum

degradation occurred at the temperature

352.50 C with the rate of 0.739 mg/min.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

5.000

4.000

3.000

2.000

1.000

0.000

75.6Cel10.7uV

74.3Cel0.056mg/min

352.5Cel0.739mg/min

303.3Cel0.230mg/min

237.8Cel36.7uV

320.1Cel35.7uV 372.1Cel

23.6uV

141.8Cel95.9%

3.6%313.2Cel94.6%

350.7Cel62.5%

377.1Cel39.9%

345.0Cel67.2%

54.7%

351.5Cel33.1uV



Figure 6. TG, DTA and DTG curves of bleached pineapple leaf fiber.

4.4 TG, DTA and DTG curves of

bleached pineapple leaf fiber


bleached PALF. The TG curve shows an

initial 6.1% loss corresponds moisture

content. The mass is losing initially at

slower rate than it ended. Light substances

have removed initially than heavy material.

Three endothermic DTA peaks 76.70C,

239.10C and 352.1

0C are obtained. The 1

st

peak at 76.70C due to removal of moisture.

3rd

peak is for degradation.

Two DTG peaks are also found at 76.70

C

and 347.40C which are corresponds to light

and heavy material respectively. DTG curve

of scoured PALF depicts that the maximum

degradation at the temperature 347.40 C with

the rate of 1.55 mg/min.

4.5 Comparison (DTA & DTG) of Raw,

Bleached, Scoured & AN grafted

fiber

From above curves it may conclude that the

degrade temperature for Raw, Bleached,

Scoured and AN grafted PALF are

respectively 358.70C, 347.4

0C, 349.9

0C and

352.50C where maximum temperature of

raw fiber is 358.70C.Here we may found that

maximum degraded temperature of raw fiber

is the highest and the lowest for bleached

fiber. Due to bleach most of the lignin,

pectic matters, waxes etc have loosed so

thermal stability reduced. In case of grafted

fiber the temperature of maximum

degradation more than raw fiber because of

Acrylonitrile enhanced the thermal stability

of bleached PALF.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

10.00

8.00

6.00

4.00

2.00

0.00

76.7Cel-7.7uV

76.7Cel0.12mg/min

352.1Cel-11.9uV

347.4Cel1.55mg/min

239.1Cel23.7uV

169.6Cel93.6%

6.1%306.7Cel92.8%

346.9Cel37.4%

368.9Cel7.1%

337.6Cel50.0%

85.7%



Figure 7. TG, DTA and DTG curves of 5% CH3COOH treated fiber

4.6 TG, DTA and DTG curves of 5%

CH3COOH treated fiber

Fig.7 shows that TG, DTA and DTG of 5%

CH3COOH treated PALF. The TG curve

shows an initial 5.1% loss corresponds to

moisture content. Then the mass is losing

initial slower rate and ending is the faster

rate. Light substances have removed initially

and then heavier material removed. Two

endothermic DTA peaks 690C, 347.5

0 C are

obtained. The 1st peak at 69

0 C is due to

removal of moisture. 2nd

peak is for

degradation. Three DTG peaks are also

found at 68.40

C, 279.40C and 346.4

0 C

which are corresponds to light and heavy

material respectively. DTG curve of 5%

CH3COOH treated PALF depicts that the

maximum degradation occurs at the


mg/min.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in5.000

4.500

4.000

3.500

3.000

2.500

2.000

1.500

1.000

0.500

0.000

-0.500

68.4Cel0.068mg/min

69.0Cel9.6uV

279.4Cel0.160mg/min

346.4Cel1.245mg/min

347.5Cel13.5uV

173.8Cel94.6%

5.1%316.3Cel93.6%

344.8Cel45.0%

359.5Cel20.0%

337.7Cel56.9%

73.7%








shows an initial 2.6% loss corresponds

moisture content. Then the mass is

continuous losing having initial slower rate

and ending faster rate. Light substances have

removed initially and then heavier material

removed. Two endothermic DTA peaks

89.70C, 350.8

0 C are obtained. The 1

st peak

at 89.70 C is due to removal of moisture. 2

nd

peak is for degradation.


C,

283.90C and 350.8

0 C which are corresponds

to light and heavy material respectively.

DTG curve of 10% CH3COOH treated

PALF depicts that the maximum

degradation occurs at the temperature 350.80

C with the rate of 0.662 mg/min.

Temp Cel500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

TG

%

100.0

80.0

60.0

40.0

20.0

0.0

-20.0

-40.0

-60.0

-80.0

-100.0

-120.0

-140.0

DT

G m

g/m

in2.000

1.800

1.600

1.400

1.200

1.000

0.800

0.600

0.400

0.200

0.000

-0.200

-0.400

350.8Cel15.9uV

89.7Cel25.2uV

283.9Cel0.114mg/min

350.8Cel0.662mg/min

76.8Cel0.021mg/min

142.7Cel97.2%

2.6% 319.1Cel96.1%

349.1Cel48.2%

368.0Cel18.2%

343.4Cel57.2%

77.9%










initial slower rate and ending is the faster



endothermic DTA peaks 82.30C, 350.8

0 C

are obtained. The 1st peak at 82.3

0 C is

due to removal of moisture. 2nd

peak is for

degradation.


C,

277.10C and 349.3

0 C which are corresponds

to light and heavy materials respectively.

DTG curve of 5% CH3COOH treated PALF

depicts that the maximum degradation

occurs at the temperature 349.30 C with the

rate of 0.995 mg/min.

Temp Cel500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

5.000

4.500

4.000

3.500

3.000

2.500

2.000

1.500

1.000

0.500

0.000

-0.500

350.8Cel4.8uV

82.3Cel19.5uV

349.3Cel0.995mg/min

66.8Cel0.043mg/min

127.8Cel96.3%

3.7% 317.5Cel95.4%

346.8Cel46.3%

365.4Cel14.9%

341.5Cel55.1%

80.5%

277.1Cel0.142mg/min







20% CH3COOH treated PALF. The TG

curve shows an initial 3.6% loss corresponds


initially at slower rate and ending is the

faster rate. Light substances have removed

initially and then heavier material removed.

Two endothermic DTA peaks 70.80C, 351.9

0

C are obtained. The 1st peak at 70.8

0 C is


peak is for

degradation.


C,

283.80C and 351.9

0 C which are correspond

to light and heavy material. DTG curve of

20% CH3COOH treated PALF depicts that

the maximum degradation occurs at the


mg/min.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

5.000

4.000

3.000

2.000

1.000

0.000 70.3Cel0.066mg/min

283.8Cel0.219mg/min

351.9Cel1.292mg/min

351.9Cel-4.1uV

70.8Cel10.4uV

124.4Cel96.0%

3.6%318.7Cel94.6%

350.0Cel44.4%

368.0Cel15.5%

343.2Cel55.1%

79.1%



Figure 11. TG, DTA and DTG curves of 5% NaOH treated fiber


NaOH treated fiber


NaOH treated PALF. The TG curve shows

an initial 4.3% loss corresponds to moisture

content. Then the mass is losing initially

slower rate and ending is the faster rate.

Light substances have removed initially and

then heavier material removed. Two


0 C are


0 C is due to


peak is for

degradation.

Three DTG peaks were also found at 79.10 C

and 360.20C which are corresponds to light

and heavy materials respectively. DTG

curve of 5% NaOH treated PALF depicts

that the maximum degradation occurs at the


mg/min.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

5.000

4.000

3.000

2.000

1.000

0.000

360.2Cel7.8uV

360.2Cel1.378mg/min

78.0Cel8.7uV

79.1Cel0.069mg/min

140.4Cel95.1%

4.3%327.6Cel93.8%

358.3Cel44.0%

374.5Cel17.9%

350.8Cel55.9%

75.9%





NaOH treated fiber


10% NaOH treated PALF. The TG curve



initially slower rate and ending is the faster




0 C are


0 C is due to


peak is for

degradation.


C

and 330.80C which are correspond to light





mg/min.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

TG

%

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in5.000

4.000

3.000

2.000

1.000

0.000

79.0Cel6.3uV

316.8Cel41.6uV

80.2Cel0.071mg/min

330.8Cel1.124mg/min

163.9Cel95.7%

4.1%285.3Cel93.6%

330.4Cel50.8%

354.3Cel28.0%

319.4Cel60.9%

65.6%





NaOH treated fiber



shows an initial 4.4% loss corresponds to


initially slower rate and ending is the faster

rate. Lighter substances have removed

initially and then heavier material removed.

Two endothermic DTA peaks 78.30C, 361.8

0

C are obtained. The 1st peak at 78.3

0 C is


peak is for

degradation.


C






mg/min.

Temp Cel500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in5.000

4.500

4.000

3.500

3.000

2.500

2.000

1.500

1.000

0.500

0.000

-0.500

78.3Cel9.7uV

79.5Cel0.068mg/min

361.8Cel1.9uV

359.2Cel1.366mg/min

149.4Cel95.4%

4.4% 324.8Cel94.7%

356.9Cel45.5%

374.6Cel18.3%

349.5Cel56.6%

76.4%





NaOH treated fiber



shows an initial loss corresponds moisture

content. Then the mass is losing initially

slower rate and ending is the faster rate.

Light substances have removed initially and

then heavier material removed. Two

endothermic DTA peaks 81.70C, 356.5

0 C

are obtained. The 1st peak at 81.7

0 C is due

to removal of moisture. 2nd

peak is for

degradation.


C






mg/min.

4.14 Comparison (DTA& DTG) of Raw &


From above curves it may concluded that

the maximum degradation temperature of

different CH3COOH treated pineapple leaf

fiber is lower than the raw fiber. This may

due to the degradation of fiber by acid

treatment and its thermal stability decreases.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

10.00

8.00

6.00

4.00

2.00

0.00

81.7Cel-9.4uV

81.7Cel0.13mg/min

355.4Cel3.32mg/min

356.5Cel-50.2uV

332.4Cel94.4%

355.1Cel46.6%

369.9Cel15.4%

351.2Cel55.0%

79.0%



Fig.15 TG, DTA & DTG of raw & different CH3 COOH treated pineapple leaf fiber

Fig.15 shows that the thermal stability of

raw fiber is maximum & decreases by

treating acid. This may due to the action of

acid fiber is degraded.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

10.00

8.00

6.00

4.00

2.00

0.00

Black-Raw, Maroon-5%CH3COOH. Green-10%, Red-15%, Blue-20%CH3COOH



Fig.16 TG, DTA & DTG of raw & different NaOH treated pineapple leaf fiber

4.16 Comparison (DTA& DTG) of Raw

& different NaOH treated fiber:

Fig.16 shows that the thermal stability of

25% NaOH treated fiber is maximum &

wide range of TG curve. This may due to the

formation of Cell-ONa bond with the

cellulose of the raw fiber & increases its

thermal stability.

5. CONCLUSIONS

Thermal stability of raw fiber is high &

Acrylonitrile enhanced the thermal stability

of bleached PALF. Thermal stability of acid

& 25% NaOH treated fiber is low & high

respectively from raw fiber. Thermal

stability is increased by increasing the

concentration of sodium hydroxide. This

may due to the formation of Cell-ONa bond

with the cellulose of the raw fiber &

increases its thermal stability.

6. ACKNOWLEDGEMENTS

The authors are grateful to Polymer

Research Laboratory (Islamic University,

Kushtia) and BCSIR (Dhaka) authority for

providing them with the facilities for the

work.

7. REFERENCES

1). Uddin, M.K., Khan, M.A., Ali, K.M.I., J.

Apppl. Polym. Sc.; 60,887- 895, 1996.

2). Pickiclana; Mucha; Inter. Polym. Sci.

Tehnol; 26,24,1999.

3). Piekiena, J., Muchaa, M., Inter, Plym.

Science. Technol. 26(6), pp.97-101,

1999.

4). Keattch C. J. and Dollimore D., “An

Introduction to Thermogravimetry,”

Heyden and Son Ltd, Newyork, 1969.

Temp Cel

500.0400.0300.0200.0100.0

DT

A u

V

200.0

150.0

100.0

50.0

0.0

-50.0

-100.0

-150.0

-200.0

TG

%

100.0

50.0

0.0

-50.0

-100.0

-150.0

DT

G m

g/m

in

10.00

8.00

6.00

4.00

2.00

0.00

Black-raw, Green-5% NaoHLime-15%NaOH,Blue-25%NaOH

arifur paper 02

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