Effect of MAPP Addition on Impact Strength, Water Absorption, and Filler Volume Fraction of the Waste Polypropylene Modified Coconut Wood Flour Glass Fiber Hybrid Composite

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Journal of Polymer Materials : An International

Journal

ISSN: 0973-8622

e-ISSN: 0976-3449

Subject: Chemistry

Periodicity: Quarterly

Month(s) of Publication: Mar., Jun., Sept. & Dec.

Current Volume: 33 (2016)

Chief Editor



Prof. Sukumar Maiti , Subarnarekha, J-23 Bidhannagar, Midnapore 721101,

West Bengal

Editor



Prof. S. K. Dolui, Department of Chemical Sciences, Tezpur University,

Tezpur

Co-Editor



Dr. Dibyendu S. Bag, Polymer Science Division, DMSRDE, Kanpur

Editorial Board



Charles E. Carraher, Florida Atlantic University, USA



Ben Zhong Tang, Hongkong University of Science & Technology



Tamaki Nakano, Hokkaido University, Japan

Advisory Board



A. Kumar, Tezpur University



A. K. Saxena, DMSRDE, Kanpur



Akhil Sen, BIT, Mesra



Amitabha De, SINP , Kolkata



Asim K. Ghosh, BARC, Mumbai



C. P . Reghunandhan Nair , VSSC, Thruvanthapuram



C.V. Avadhani, NCL, Pune



Cedric Gaillard, NIAR, France

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

Dilip Kumar Kakati, Gauhati University



H. B. Bohidar, JNU, New Delhi



Jude O. Iroh, University of Chincinnati, USA



K. C. Gupta, IIT Roorkee



L. Lapcik, T omas Bata University, Czech Republic



Manoranjan Patri, NMRL, Ambernath



Mariatti Jaafar, Universiti Sains Malaysia



P. H. Parsania, Saurastra University , Rajkot



P. P. Wadgaonkar NCL Pune



Pradip Kumar Dutta, MNNIT, Allahabad



Pranesh Chowdhury, Visva Bharati University

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Sabu Thomas, Mahatma Gandhi University, Kottayam



Susanta Banerjee, IIT Kharagpur



V . K. Gupta, Reliance Industries Ltd, Mumbai

List of Content

Volume 33 (2016) Issue 4 , (October-2016 to December-2016)

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Tribological Behavior of Phenolic Nanocomposites Reinforced by 2D Atomic

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JUN CHEN, YUPING TAI, JICHUN LIU, YONGZHEN ZHANG AND QINGSHAN NIU

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Experimental Investigation on Bearing Response of Carbon Reinforced

Aluminium laminates - Influence of natural fibre and specimen geometry

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Curing Characteristics and Tear Properties of Calcium Carbonate/Bentonite

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Isothermal Crystallization Kinetics of Polylactic Acid Toughened with an

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Effect of Hybrid Fillers in PP/EPDM Nanocomposites for Electrical Insulator

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Recycled Polypropylene/Peanut Shell Powder Composites: Effect of Filler

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ISMAIL

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Properties of Recycled Natural Latex Gloves Filled NBR: Effects of Sawdust

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Polyvinyl chloride Compounds (MALAYSIA)

by ARJULIZAN RUSLI, MOHAMMAD

ZAKWAN MOHAMAD AND AZURA ABDUL RASHID

Page: 657-665

Effect of MAPP Addition on Impact Strength, Water Absorption, and Filler

Volume Fraction of

the Waste Polypropylene/Modified Coconut Wood Flour/Glass Fiber Hybrid

Composite (INDONESIA)

by HALIMATUDDAHLIANA NASUTION, SILVIA, CASTIQLIANA AND NUIM HAYAT

Page: 667-676

The Potential of Donax Grandis Hypodermal Fiber as a reinforcement in

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YUSOFF, SITTI FATIMAH MHD RAMLE, IRSHAD UL HAQ BHAT, ABD HAMID

MAR IMAN, AND MOHD HASMIZAM RAZALI

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Preparation of Cross-linked and Fluorine-silicon Modified Acrylate Emulsion

by Using Mixed Green Surfactants (CHINA)

by XIUMING WANG, ZHONGBIN

BAO, AND LIJUN CHEN

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J. Polym. Mater. Vol. 33, No. 4, 2016, 667-676 © Prints Publications Pvt. Ltd.

Correspondence author e-mail: h_dahliana@yahoo.com

Effect of MAPP Addition on Impact Strength, Water

Absorption, and Filler Volume Fraction of the Waste

Polypropylene/Modified Coconut Wood Flour/Glass

Fiber Hybrid Composite

HALIMATUDDAHLIANA NASUTION1_{, SILVIA}2_{, CASTIQLIANA}3_{AND NUIM HAYAT}4

Department of Chemical Engineering, Faculty of Engineering, University of Sumatera Utara, North Sumatra,

20155 Medan, Indonesia

ABSTRACT

In this study, hybrid composite materials were prepared from combination of modified coconut wood flour (MCWF) and glass fiber (GF) as fillers, and waste polypropylene (WPP) as matrix. The coconut wood flour (CWF) was modified by 18% sodium hydroxyde solution to reduce its hydroxyl group.The interfacial adhesion between the non-polar waste polypropylene matrix and the polar fillers could be enhanced by using maleic anhydride-g-polypropylene (MAPP) which was synthesized from the refluxed reaction of maleic anhydride, polypropylene, xylene and benzoyl peroxide at 135°C. MAPP and GF composition were made constant at 2 wt. % and 10 wt. %, respectively and MCWF composition was varied from 10 – 40 wt.%. Mixing process was carried out in an extruder at 180o_{C and the}

samples were then molded in a hot press machine. The impact strength, water absorption, and filler volume fraction analysis were investigated. The results showed that addition 30 wt.% of MCWF and 10 wt.% of MAPP can elevate the impact strength of the composite. The study also revealed that water absorption of the composite has reduced with the utilization of MAPP. As comparison, composite without MAPP, no fillers and using one type of filler were also prepared. These results were also supported by Fourier Transform Infra - Red (FTIR) and Scanning Electron Microscopy (SEM) analysis.

KEYWORDS: Coconut Wood Flour, Hybrid Composite, Waste Polypropylene.

INTRODUCTION

Hybrid composite is a system constituted by two different reinforcements incorporated into

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668 Nasution et al.

JJournal of Polymer Materials, December 2016

CWF is needed to reduce its polarity [6]_.

Compatabilizer, such as maleic anhydride-g-polypropylene (MAPP) could also be applied to improve the compatibility of the matrix with

the reinforcement [7]_{. In Indonesia, the}

production of plastic waste was second ranked as domestic waste producer at 5,4 million tons per annum (14% of total waste production in Indonesia). As a matrix, polypropylene has good physical, mechanical, and thermal properties at room temperature. Its stiffness, low density, high impact strength and lower cost make it widely use in many applications [8]_{. Lee et al.}[9]_have

studied hybrid composite polypropylene/wood flour/clay with MAPP with improved tensile strength and stiffness. In this study, the effect of MAPP addition on impact strength, water absorption and filler volume fraction of waste polypropylene (WPP) / Modified coconut wood flour (MCWF) / Glass Fiber (GF) Hybrid Composite were investigated. Fourier Transform Infra - Red (FTIR) characterization and Scanning Electron Microscopy (SEM) analysis were used to show the morphology of the fractured samples and structural changes after modification.

EXPERIMENTAL CONDITION

Materials Preparation

Wasted Polypropylene (WPP) was collected from wasted mineral water plastic cup disposal. The WPP were cut into smaller pieces (±5 mm x 5 mm). Coconut wood flour (CWF) was supplied from furniture store waste. CWF was dried under the sunlight and milled in a ball mill into 100 mesh particles. Chopped strand E-type glass fibers (GF) were supplied by PT. Justus Kimiaraya (Medan, Indonesia). The GF were milled in a ball mill into 100 mesh particles. Commercial xylene supplied by CV. Rudang Jaya (Medan, Indonesia) was used as received.

constituents which would give convenience in balancing each of their superior and inferior properties. Introduction of extra reinforcement or matrix are conducted to overwhelm the weakness of the other reinforcement or matrix, and this will eventually lead to cost and performance balance through an appropriate material design. Using a hybrid composite that contains two or more types of different fibers, the advantages of one type of fiber could complement deficiencies in the

other [1,2]_{. Environmental issues which has}

become major concern is the main reason to develop replacement of synthetic fibers with natural fibers. However, the fact if the natural fibers reinforced composites provide lower mechanical properties and poorer water resistance when compared to synthetic fibers (such as glass fibers) cannot be neglected. Therefore, in order to overcome these weaknesses, glass fiber (GF) and natural fiber can be integrated in a matrix to formulate a hybrid composite that demonstrates best properties of its constituents, and thereby, an superior, economical and environment-friendly composite could be generated. Coconut wood flour (CWF) was selected as the natural fibers in this research due to its

abundant supply (397 thousand m3_per

annum all over the world) [3]_{. CWF is also}

inexpensive, has a low density [4]_,

biodegradable and is not abrasive during the

process [1,4]_{. CWF also have high content of}

cellulose (40,99%) which shows a good indication to be used in polymeric composites, as a material that has high content of cellulose

would exhibit stiff and strong material [5]_{. The}

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Effect of MAPP Addition on Impact Strength, Water Absorption, and Filler Volume Fraction of the Waste Polypropylene/Modified Coconut Wood Flour/Glass Fiber Hybrid Composite

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Journal of Polymer Materials, December 2016

To produce MAPP, isotactic polypropylene (melt flow index 14 g/10 min) supplied by Titan PP Polymers (TitanPro 6331 grade) (Johor, Malaysia), maleic anhydride, acetone and benzoyl peroxide (supplied by Merck Indonesia) were used as received.

The coconut wood flour was immersed in 18% solution of NaOH, heated at 90o_{C for half an hour. Followed by}

washing with distilled water to remove all traces of alkali until neutral, and then dried in tray dryer to diminish water absorption.

1 g of maleic anhydride, 10 g of polypropylene and 90 ml xylene were refluxed at 135 o_{C for 20 minutes. 0,1 g}

of benzoyl peroxide which had been dissolved in 10 ml xylene were added into the solution and reacted for 10 minutes. The product were immersed in acetone to precipitate the MAPP. The filtered MAPP were then rinsed with distilled water until neutral pH was obtained. Finally, the MAPP were dried in a tray dryer for 24 hours,

milled in a ball mill into 100 mesh particles and characterized by FTIR spectroscopy.

Sample Preparation

Composites were manufactured in a two-stage process. In the first stage, WPP, MCWF, GF and MAPP were premixed mechanically at certain formulations. The mixtures were then fed into a single-screwed extruder at a screw speed of 50 rpm and temperature profile of 180 o_{C. In the second stage, the stranded extrudates}

were granulated manually and cooled in a water bath. The procured granules of extrudates were then dried at 105 o_{C for 24 hours before being molded in a hot press}

machine at 180 o_{C. The hybrid composites were}

produced with various contents of MCWF from 10 to 40 wt.%. The GF loadings and MAPP addition were remained constant at 10 wt.% and 2% respectively. All formulations of the composite components and abbreviations used for the respective formulations were given based on the codes in Table 1.

TABLE 1. Formulation of hybrid composite constituent

Sample WPP MCWF GF MAPP

Code (%) (%) (%) (%)

Izod impact strength for the specimens was determined having dimensions 60 x10 x 3 mm as per ASTM D-4812 - 11, with ‘‘V’’ notch depth of 2,54 mm and notch angle of 45o_{, using Impact Testing Machine. The conventional V}

notched specimens were according to ASTM D-256.

Water Absorption Analysis

The specimens of dimension 25 x 25 mm (ASTM D 570) were tested. The samples were dried in an oven at 50± 5o_{C for 24 hour, cooled in desiccators for 24 hours.}

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were removed from water one at a time, all surface water was wiped off with a dry cloth, and they were immediately weighed to the nearest 0,01 g. The percentage of composite mass accretion during water absorption was determined. The water absorption of the test was determined with the following equation:

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where w is the composite mass after t immersion days, w_o is the composite mass before immersion.

Filler Volume Fraction

Consider a composite material that consists of fibers and matrix material. The volume of the composite material is equal to the sum of the volume of the fillers and the matrix.

Vc = Vf + Vm (2)

where Vc is the composite volume, Vf is the filler volume and Vm is the matrix volume.

The matrix volume fraction (Mvf) was measured with the formula:

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The filler volume fraction (Fvf) can be calculated by this equation:

Fvf = 1 – Mvf (4)

Fourier Transform Infra - Red (FTIR) characterization and Scanning Electron Microscopy (SEM) analysis were considered to identify to show structural changes and morphology of fractured samples, respectively.

RESULTS AND DISCUSSION

Fourier Transform Infra-Red (FTIR) Analysis

Figure 1. shows the FTIR spectra of the synthesized compatabilizer, maleic anhydride - g - polypropylene (MAPP). It revealed the presence of absorbance in the wavelength

number of 2955 cm-1 _{which indicated the}

existence of alkanes groups (C–H). Ketones groups (C=O) and C–O from anhydrides were

also observed at 1712 cm-1 _{and 1165 cm}-1

respectively. Moreover the appearance of C–

H from –CH₂ (methylene) and C–H from –CH₃

(methyl) were also determined in the peak

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Journal of Polymer Materials, December 2016

absorbance at 1454 cm-1_{and 1369 cm}-1_{. All of}

these peak absorbances numbers strongly supported the chemical structure of maleic

Fig. 3. FTIR Spectra of Hybrid Composite, Unmodified and Modified Coconut Wood Flour Fig. 2. Chemical structure of maleic anhydride-g-polypropylene (MAPP)

anhydride-g-polypropylene which was presented in Figure 2.

From Figure 3, it is observed that alkaly modification had successfully decreasing the polarity of MCWF by strongly reduced the

peak absorbance in the wavelength number of

3444 cm-1_{and 2357 cm}-1_{(for –OH) and 1593}

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JJournal of Polymer Materials, December 2016 of absorbance in the wavelength number of 2878

cm-1_{and 2357 cm}-1 _{which indicated the}

presence of –OH and N–H (the main functional group of cellulose) had been dispersed well into the matrix (WPP).

Impact Strength

Figure 4 shows the variation of impact properties

of the hybrid composites.The impact strength

is a parameter that shows the maximum number of pressure caused by the high speed could be received by a material before it undergoes cracking. Results of this testing

Fig. 4. Impact strength properties of hybrid composites as functions of the fiber loadings

indicate the toughness, it is strongly influenced by the strength of the bond interphase and the characteristic of the matrix and fillers [10].

From Figure 4, the drop of impact properties is occurred to composites without MAPP (sample code 4, 6, 8, 10). It might be due to poor interfacial adhesion between the matrix and the fillers, which is a general phenomenon in incompatible composites with different characteristics, such as non polar of the PP

and GF and the polar of CWF [6]_.

However, addition of GF gave a significant effect in raising the impact strength of the

composite, from 37.9 J/cm2_{to 40.5 J/cm}2_(for

sample codes 2 to 5). Abdul Khalil et al. [11]

also reported a similar trend. This result is

due to the high energy absorption capability of the glass fiber. Conversely, declining impact strength was observed when MCWF

was added into composite from 49.5 J/cm2

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673

Journal of Polymer Materials, December 2016 reduction was stimulated by the lower ability

to absorb energy.

Otherwise, the improvement of impact properties is occurred to composites with MAPP (sample code 5, 7, 9) with the increased of MCWF loadings up to 30 wt.%. Further increment of MCWF resulted to weaker impact properties. The increased impact strength were caused by improved interfacial adhesion between the matrix and

the fibers [12]_{. However as the fiber loadings}

content were extended, fibers to fibers contact were increased and this eventually lead to lower ability of fibers to support stresses transferred from matrix. This observation was also in approval of previous study reported by Ashori et al. [13]_.

Water Absorption

The rate of water absorption depends on the internal material status, nature of reinforcements, fiber–matrix interface, as well as environmental factors such as temperature

and applied stress[12]_{. The material shrinks or}

swells when the incorporated wood is dried or absorbs water; this lack of dimensional stability

is a major drawback of such materials [14]_{. In}

this study, after the test period, the samples were removed from the water, dried with a cotton cloth, and reweighed.

Figure 5 shows the water absorption of hybrid composites. With the increased of MCWF loadings, the water absorption increased from 9.7% to 13.5% (sample codes 8 to 10). Sample code 2 (with formulation of 88/10/0/2)

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JJournal of Polymer Materials, December 2016 and sample code 5 (with formulation of 78/10/ 10/2) resulted the same amount of water absorption due to negligible water absorption

capacity of water impermeable glass fiber [12]_.

However, addition of MAPP had significantly reduced the water absorption by 11.3% (sample codes 10 to 11) since there is more compatibility and better adherence to the polymer matrix which covers more wood’s surface and reduces the direct contact wood-water. It also increases the ester linkages between the hydroxyl groups of MCWF and the anhydride part of MAPP. Therefore, the

amount of free OH– in the wood cellulose is reduced because some of them are interacting with succinic anhydride, so this change generates less water absorption, compared to

the composite without MAPP [14]_.

Fiber Volume Fraction

Table 2 shows that the fiber volume fraction increased with the increasing amount of fillers in the composite. The increasing amount of MCWF which has lower density than the WPP and GF, resulting in a lower density of the composite. It is also indicated that the

TABLE 2. Filler Volume Fraction of Hybrid Composite

Sample code Composite ratio (WP/MCWF/GF/MAPP) Filler Volume Filler Volume Fraction

1 100/0/0/0 0 0

2 88/10/0/2 12 0,125

3 88/0/10/2 12 0,126

4 80/10/10/0 20 0,224

5 78/10/10/2 22 0,203

6 70/20/10/0 30 0,318

7 68/20/10/2 32 0,303

8 60/30/10/0 40 0,421

9 58/30/10/2 42 0,413

10 50/40/10/0 50 0,522

11 48/40/10/2 52 0,502

composite with MAPP has lower fiber volume fraction. This was due to the improved interfacial adhesion between the matrix and the fillers that causes the composite to have less void and higher density.

Fracture Sample Analysis

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Journal of Polymer Materials, December 2016 composition is also presented. It was clearly

showed the uniform distribution of filler in WPP matrix. This was due to the improved interfacial adhesion created by the MAPP. Without MAPP, fillers pull-out was observed. It is caused by the weak interfacial adhesion that makes the stress transfer from the fillers to the matrix and consequently failed. Adding MAPP had significantly helped in enhance the interfacial adhesion of the composite.

CONCLUSION

The utilization of MAPP as compatibilizer improved the impact properties and reduced water absorption of the composite. The highest impact strength was achieved in WPP/MCWF/GF/MAPP ratio of 58/30/10/2. Moreover, SEM micrographs showed that MAPP had significantly enhanced the interfacial adhesion between the matrix and the fillers.

Acknowledgment

The authors would like to thank to University of Sumatera Utara.

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Received: 20-06-2016