Design and Study of Ricinoleates as processing aids and activators in rubbers…

What is RPA Any material used at relatively low dosage

levels, will improve processing characteristics without significantly affecting physical properties.

They also improve the physical properties such as,

Elasticity, Flex life, Low temp performance and, Aid in incorporation & dispersion of

pigments

RPA – main appc’s

RPA & its effects-

What is an Activator

- Increase the efficiency of cross-linking

- Help in dispersing the sulphur and accelerator

Driving- FACTOR

Conventional Processing aid, petroleum based Polycyclic Aromatic Hydrocarbons (PAH) has been banned in European countries at 2009.

Stearic acid (present as activator), is a saturated fatty acid obtained from animal fat.

Driving- FACTOR

Zn can be released into the environment from rubber during production, use, and recycling of rubber goods, particularly tyres.

Harmful effect of soluble Zn-compounds to aquatic organisms.

ZnO causes a mammalian reproductive toxinExposure to zinc oxide in the air, result in a nervous

malady called metal fume fever.ZnS deposited on the wall of the mold, causes mold

fouling.

Car photo

ZnO Reduction

AS FUTURE TECHNOLOGISTS, WE

OFFER YOU SOLUTIONS…

EXPERIMENT We have tried to reduce the ZnO by

using a combination of metal oxide (MgO & Ca(OH)2) of varying ratios, is mixed with CASTOR OIL under microwave heating at a set frequency (1.32GHz).

Composition of Castor OilAcid Name Average percentage Range

Ricinoleic acid 85 to 95%

Oleic acid 2 to 6%

Linoleic acid 1 to 5%

Linolenic acid 0.5 to 1%

Stearic acid 0.5 to 1%

Palmitic acid 0.5 to 1%

Dihydroxystearic acid 0.3 to 0.5%

Others 0.2 to 0.5%

Structure of Castor oilMono-unsaturated,

18 carbon fatty acid (esters of 12-

hydroxy-9-octadecenoicacid)

Contains Functional groups:

1.carboxylic group

2.unsaturation 3.hydroxy group

Why Castor Oil

Naturally obtained non-toxic Vegetable oilVegetable oil offers LubricityOther seed oils lack the HYDROXY GroupDue to this Hydroxy group- 1. Reactive 2. Offers xtra stability 3. High viscosity

Metal Oxide Varying ratiosCOMPOUND ZnO MgO Ca(OH)2

1 1 1 1

2 2 1 1

3 1 1 2

4 1 2 1

5 1 0 0

6 0 1 0

7 0 0 1

Blank Preparation

NRZnOstearic acidSulphurCBS

MATERIALS Parts by Weight

Natural Rubber 100

Zinc Oxide 3

Stearic Acid 2

Sulphur 2.5

Acc (CBS) 1

RX formulationMATERIALS Parts by Weight

Natural Rubber 100

Activator System 5

Sulphur 2.5

Acc (CBS) 1

Natural RubberActivatorSulphurAcc (CBS)

03.

756.

258.

75

11.2

5

13.7

50

102030405060708090

RHEOGRAPH

rxrx1rx2

Torq

ue

1600C for 20mins

1.75

5.25

8.75

12.2

5

15.7

5

19.2

50

1020304050607080

RHEOGRAPH

rx3rx4rx5

Torq

ue

1600C for 20mins

01.

755.

258.

75

12.2

5

15.7

5

19.2

50

5

10

15

20

25

30

35

RHEOGRAPH

rx6rx7

Torq

ue

Both RX6 and RX7 haven’t cured, so we neglected both the samples.

INFERENCE :

1600C for 20mins

COMPOUNDS Ts2 mins Tc90 mins

RX 1.04 4.15

RX1 1.27 2.45

RX2 1.44 2.70

RX3 2.06 3.11

RX4 1.52 2.58

RX5 1.54 2.69

RX6 0.00 0.00

RX7 0.47 0.47

Rheological Props (GUM cmpds)

INFERENCE : Scorch time is INCREASED, While Cure time is very much DECREASED

Tests for Gum cmpds :Hardness (ASTM D2240)Tensile Properties (ASTM D412)Tear Strength (ASTM D624)Aging properties (ASTM D573)

Hardness

0

10

20

30

40

50

60

Hardness

RX

RX1

RX2

RX3

RX4

RX5

COMPOUNDS HARDNESS (Shore A)

RX 58

RX1 18

RX2 25

RX3 16

RX4 16

RX5 32

INFERENCE : Hardness values found to decrease with our Activator compounds

COMPOUNDS TENSILE STRENGTH

MPa

RX 22.65

RX1 1.44

RX2 4.65

RX3 2.99

RX4 2.83

RX5 4.5

TENSILE STRENGTH

INFERENCE : T.S is very much lower

RXRX2

RX4

0

5

10

15

20

25

Column1

MAX Strain %

0

100

200

300

400

500

600

700

EB%

RX

RX1

RX2

RX3

RX4

RX5

COMPOUNDS Max Strain%

RX 436.5

RX1 558

RX2 587

RX3 573

RX4 615

RX5 489

INFERENCE : profound increase in STRAIN %

All our Activator Compounds exceeded above 600% elongation

COMPOUND 100% MOD 200% MOD 300% MOD

RX 1.97 3.71 15.97

RX1 0.84 1.24 3.24

RX2 0.44 0.74 1.04

RX3 0.57 0.76 1.14

RX4 0.58 0.78 1.07

RX5 1.53 2.38 5.12

MODULUS

MODULUS = Resistance to extension or stiffness

INFERENCE : Modulus was found to be low

Aging PropertiesCOMPOUND Tensile Strength MPa

R 15.4

RX1 0.3

RX2 2.8

RX3 1.1

RX4 1.02

RX5 2.6

Aging Condition- 700C for 7 days

Tear Strength (GUM cmpds)

COMPOUNDS TEAR STRENGTH (Kgf/mm)

RX 0.264

RX1 0.731

RX2 1.839

RX3 0.701

RX4 1.051

RX5 2.076

INFERENCE : Tear Strength usually higher for our Activator Cmpds

PC FormulationMATERIALS Parts by Weight

Nitrile Rubber, NBR

100

C-Black 50

Activator system 5

Sulphur 1.5

TMTD 1.5

CBS 1.5

Benchmarked with usual mixture,

ZnO - 3 phrSt Acid – 2 phr

Rheograph

1.75 3.5 5.25 7 8.75 10.50

20

40

60

80

100

120

140

PPC1PC2

Time (mins)

Torq

ue (

)lb

-in

)

1600C for 20mins

Rheograph

1.75 3.5 5.25 7 8.75 10.50

20

40

60

80

100

120

140

PC3PC4PC5

Time (mins)

Torq

ue (

)lb

-in

)1600C for 20mins

Rheological PropsCOMPOUNDS Ts2 mins Tc90 mins

P 1.03 11.00

PC1 1.15 1.54

PC2 1.21 2.33

PC3 3.07 6.05

PC4 1.13 3.13

PC5 1.37 3.34

INFERENCE : Scorch time is INCREASED, While Cure time is very much DECREASED

1600C for 20mins

Tests for C-B filled cmpds

HardnessTensile StrengthTear StrengthSwelling IndexCompression SetFlex Cracking Resistance

HardnessCOMPOUND HARDNESS (Shore A)

P 76

PC1 72

PC2 70

PC3 68

PC4 71

PC5 69

INFERENCE : Not much change in Hardness

Tensile StrengthCOMPOUND Tensile Strength

(Before aging) MPaTensile Strength (After aging) MPa

P 25.57 19.61

PC1 22.45 18.20

PC2 20.72 16.97

PC3 15.37 9.57

PC4 17.25 11.23

PC5 19.50 12.60

Aging Condition – 1000C for 22hr

INFERENCE : Tensile Strength is low But % retention of our activator cmpds is high

Tear StrengthCOMPOUND Tear Strength

(Before aging) N/mmTear Strength

(After aging) N/mm

P 7.07 3.61

PC1 15.78 9.11

PC2 18.83 15.62

PC3 9.48 4.54

PC4 11.25 8.05

PC5 14.14 10.15

Aging Condition – 1000C for 22hr

INFERENCE : Tear Strength and % Retention is HIGH for our activator compounds

Swelling IndexCOMPOUND SWELLING INDEX %

P 69

PC1 87

PC2 80

PC3 76

PC4 80

PC5 77

Swelling Index α 1 / Crosslink Density

Immersed in toluene for 7 days

SWELLING INDEX = (Ws – Wi)/Wi

Compression SetCOMPOUND Compression Set %

P 32

PC1 58

PC2 49

PC3 43

PC4 51

PC5 46

SET % = (t0 – tr) / (to - ts) × 100

INFERENCE : Set found to be lower as cross-link density is less

Flex Cracking resistanceSAMPLE No of cycles for Pin-Prick to

appear

P 1777

PC1 >1,00,000

PC2 15,796

PC3 2481

PC4 7596

PC5 5319

INFERENCE : profound increase in Flex-Cracking resistance

SummaryWith reduced viscosity, thereby reducing mix duration

with less mech generation of heat & energy consumption reqd to breakdown rubber.

Ease of handling as processing aids is in the form of pellets.

With increased scorch time(Ts2), better Processing safety.

With shorter curing cycles, we get faster productivity.The physical props of C-B filled cmpds was similar to the

control, but this was not the case in GUM cmpds.

Coupling action of Veg. oil

Interacts with Rubber molecules

Interacts with C-Black asits surface contains Phenol,Carboxyl, Quinone & Lactones

Why MgO & Ca(OH)2

These were the acid acceptors playing a dual role :

1. Neutralization of acid-byproducts of vulcanization and;

2. Act as cross-linking agents forming weak ionic bonds.