Fabrication of Polystyrene/Clay nanocomposites

by

Vivek Patil

(708042)

Nitin Purohit

(708044)

Under guidance of

Dr. R.K.Goyal

Objective

To fabricate polystyrene matrix composite by changing the weight percent of the nano sized clay particles for packaging and timing belt applications

To study effect of wt. % of clay on various properties of PS/ Clay nanocomposite

Introduction

Composite

1. Definition

2. Nano compositesPolystyrene

1. Structure

2. PropertiesClay

1. Types

2. Properties

Properties of polystyrene

Colorless substance

Thermoplastic polymer

Glass transition temp. – 85 to 125 ºC

Melting point – 240 ºC

Used in automobiles, consumer electronics, packaging.

Nano Clay particles

Inorganic material Types 1. Fireclay 2. Bentonite 3. Limonite 4. Kalonite Montmorillonite (MMT) 1. Sodium and Calcium MMT 2. High aspect ratio

Properties of Polystyrene and Clay

Sr.

No.Properties Polystyrene Clay

1 Density 1.05 g/cc 1.70 g/cc

2 Tensile strength 46–60 MPa 101 MPa

3Coefficient of Thermal

Expansion8× 10−5 /K 1.72×10-8/K

4 Dielectric constant 2.4- 2.7 1.8- 2.8

Experimental process

Clay/ Chloroform + Sonication Polystyrene

PS/ CLAY were mixed in chloroform using Magnetic stirrer with heating for 4 hrs .

Drying in oven at 65oC for 2 hrs.

Hot pressing at 200oC / 300 kg

Composite pellet of 5 mm thickness and 13 mm diameter

Characterization

Hot pressing of composite film

Temperature 200°C

Load 300 kg

Soaking Time 15 min.

Line diagram of hot compression

Pellet Dimensions t= 5 mm d= 13 mm

3 Samples with 0wt.%, 2wt.% and 5wt.% of Clay in PS were prepared

Density measurement

Volume fraction :

Vf = Wf / [Wf + (1-Wf).ρf / ρm ]

Theoretical density by Rule of Mixture :

ρTh = (ρm Vm + ρf Vf)

Experimental density by Archimedes method :

ρExp = [Wair / (Wair -Walcohol)]. ρalcohol

Density Vs Wt. % of Clay

Wt. % of Clay Experimental density Theoretical density

0 1.0042 1.05

2 1.0195 1.058

5 1.0265 1.071

Micro hardness measurement

Microhardness - resistance to indentation Using Vickers Microhardness tester (FM 700 Future

Tech.) Load - 100 gm Dwell time - 15 sec Vickers hardness(Hv) :

Hv = (1.8544×P)/ d2

Microhardness Vs Wt. % of Clay

SampleAverage

Reading (Hv)

Pure PS 16.35

2%

Clay/PS16.50

5%

Clay/PS16.85

Dielectric Constant measurement

Dielectric constant – measure of degree of slow down of electromagnetic waves travelling through insulating material

Using Precision Impedance Analyzer (Wayne Kerr 6500 B), Capacitance is measured

Dielectric constant : Ԑ = (c×t)/( Ԑ0×A)

Dielectric Constant Vs Wt. % of Clay(10 MHz)

Results

Nanocomposites of PS/ Clay of various compositions can be prepared by using hot pressing with proper loading.

The mass of sample depends on the weight percentage of filler. Density of nanocomposite increases as clay content increases Microhardness of nanocomposite increases as Wt. % of clay in

PS increases Dielectric constant of nanocomposite increases as clay content

increases

Future Scope

 

Study on effect of change in wt.% of clay in PS/Clay nanocomposite on

a) Melt flow index

b) Coefficient of thermal expansion

To study the dispersion of Clay in nanocomposites by XRD.

Acknowledgements

We are immensely thankful to HOD, Dr. M. J. Rathod for allowing us to carry the project out. Our sincere thanks to our guide Dr. R. K. Goyal who helped us in every way while doing the project work. All other professors and non-teaching staff of the department were also very helpful to us throughout the project. All the B.Tech students and Mr. Amol Kadam from M.Tech working in the same area helped us too.

References

1.R.K. Goyal , A.N. Tiwari , Y.S. Negi

Microhardness of PEEK/ceramic micro- and nanocomposites: Correlation with Halpin–Tsai model 

2.Tsung et al.

Preparation of exfoliated PS/Clay nanocomposites, advances materials 17 (2005) 1769-1773.

3. Yuaci Hu et al.”Nanoindentation study of Nylon 11/Clay

composites”, Polymer Testing 25 (2006) 492-497.

4.Santosh D. and I.P.Jog,”Polybutene/clay nanocomposites and its properties” Polymer science 41 (2003) 1021-1041.

Thank You.