DEVELOPMENT OF O-RING BY USING PER-OXIDE CURING

Made by,

Mohammad Sameer Ghazi PP-005

Muhammad Anwer PP-011

Ahad Aslam Ghulam Hussain PP-029

S.M. Jasir Ahsan PP-036

Objective of Project

To develop a product via peroxide curing of specialty elastomer and achieve a material having low compression set

and high heat resistance.

Special Purpose Elastomers

Those elastomers that poses superior properties compared to general purpose elastomers, we call them specialty elastomer.

Some examples are:

• Silicon Rubber (inert, high service temperature)

• EPDM (air permeabiltiy, resistance to heat, ozone

resistance)

• HNBR (oil resistance, low compression set, high heat

resistance)

Choosing HNBR

HNBR derived from NBR showed better performance than NBR due to its high saturation.

Comparison of HNBR, NBR & Fluoroelastomer

PROPERTIES FLOUOROCARBONRUBBER

NITRILERUBBER

HNBRRUBBER

Mechanical strength Excellent Good Good to Excellent

Oil resistance Excellent Good Good

Compression set Excellent Fair Good to Excellent

Cost Expensive Fair Fair

Low Temperature Flexibility

Excellent Good Good to Excellent

Processing Hard Moderate Moderate

Purpose behind implementing Peroxide

Curing for HNBR

Static Application

HNBR being Highly Saturated Rubber

Good Compression Set especially at elevated

temperature

High Temperature Resistance

Low Flexibility

What is Peroxide Curing

• Direct carbon crosslinks are formed between saturated elastomer molecule.

ROOR 2 RO·RO· + H-P ROH + P·P· + P· P-P

Factors of Selection of Peroxide Curing Agent

Processing Temperature (160◦C)

Participation of active oxygen in cross-linking

function (Efficiency).

Here Di-cumyl peroxide suits best as a curing

agent.

Why Di-Cumyl Peroxide?

Serve as high temperature catalyst

Less sensitive to environment

Better performance

Sample Preparation

MATERIALS CODE A-1 B-1 C-1 D-1 E-1 F-1 G-1

HNBR (PHR)   100 100 100 100 100 100 100

C. BLACK (N220)

505 56 56 56 60 52 60 52

SILICA 007 - -     12   12

Zn OXIDE 538 5 5 5 5 5 5 5

Anti Ox./Oz. 280 1 1 1 1 1 1 1

TOTAL PHR   162 162 162 166 170 166 170

DCP (PHR)   5 5 5 5 5 5 5

EDMA(PHR)   0 7.5 9.5 6 6 6 6

TOTAL PHR   171.5 179 181 181.5 185.5 181.5 185.5

Preparation of Master Batch

Preparation of Finish

Characterization of Sample

TimeTemperatur

e

15 Min160 ˚C

15 Min160 ˚C

15 Min160 ˚C

15 Min160 ˚C

15 Min160 ˚C

15 Min160 ˚C

15 Min160 ˚C

100 % modulus

18.63 24.55 24.3 27.18 22.32 - 23.23

Tensile (Psi) 32.5 30.57 32.24 27.18 32.28 24.41 28.73

Elongation (%)

144 121 128 103 133.3 93 118

Tear Resistance

28.4 27 32 26.3 32.7 - -

Hardness 75 78 77 75 77 76 79

Tensile (Psi) 32.5 30.57 32.24 27.18 32.28 24.41 28.73

Compression set (%)

24 27 27 16 19 21 16

Comparing Samples

A-1 B-1 C-1 D-1 E-1 F-1 G-10

5

10

15

20

25

30

35

Tensile Strength Psi

Elongation %

A-1 B-1 C-1 D-1 E-1 F-1 G-10

20

40

60

80

100

120

140

160

Comparing Samples

A-1 B-1 C-1 D-1 E-1 L-1 M-10.000

5.000

10.000

15.000

20.000

25.000

30.000Compression Set %

A-1 B-1 C-1 D-1 E-1 F-1 G-173

74

75

76

77

78

79

80Hardness Shore A

Future Work

FKM can be used as a substitute of HNBR with

better service temperature above 200ºC.

Different particle sizes of carbon black can be

used to improve compression set (%) and oil swell

properties.

Towards the End….

D1 showed optimum results but has less hardness and elongation compared to E1.

E1 showed best required properties, therefore considered to be our final product.

Finally making our product cost effective.