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 ZnO Reduction Car photo ZnO Reduction 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 toxin Exposure 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.

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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 Oil Acid 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 Palmitic acid Dihydroxystearic acid 0.3 to 0.5% Others 0.2 to 0.5%

Structure of Castor oil Mono-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 oil Vegetable oil offers Lubricity Other seed oils lack the HYDROXY Group Due to this Hydroxy group- 1. Reactive 2. Offers xtra stability 3. High viscosity

Metal Oxide Varying ratios COMPOUND ZnO MgO Ca(OH)2 1 2 3 4 5 6 7

Blank Preparation MATERIALS Parts by Weight Natural Rubber 100 Zinc Oxide 3 Stearic Acid 2 Sulphur 2.5 Acc (CBS) 1

RX formulation MATERIALS Parts by Weight Natural Rubber 100 Activator System 5 Sulphur 2.5 Acc (CBS) 1

1600C for 20mins

1600C for 20mins

1600C for 20mins INFERENCE : Both RX6 and RX7 haven’t cured, so we neglected both the samples.

Rheological Props (GUM cmpds) 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 RX7 0.47 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 INFERENCE : Hardness values found to decrease with COMPOUNDS HARDNESS (Shore A) RX 58 RX1 18 RX2 25 RX3 16 RX4 RX5 32 INFERENCE : Hardness values found to decrease with our Activator compounds

TENSILE STRENGTH INFERENCE : T.S is very much lower COMPOUNDS TENSILE STRENGTH MPa RX 22.65 RX1 1.44 RX2 4.65 RX3 2.99 RX4 2.83 RX5 4.5 INFERENCE : T.S is very much lower

MAX Strain % INFERENCE : profound increase in STRAIN % COMPOUNDS 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

MODULUS MODULUS = Resistance to extension or stiffness 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 = Resistance to extension or stiffness INFERENCE : Modulus was found to be low

Aging Properties Aging Condition- 700C for 7 days COMPOUND Tensile Strength MPa R 15.4 RX1 0.3 RX2 2.8 RX3 1.1 RX4 1.02 RX5 2.6

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 Formulation Benchmarked with usual mixture, ZnO - 3 phr MATERIALS Parts by Weight Nitrile Rubber, NBR 100 C-Black 50 Activator system 5 Sulphur 1.5 TMTD CBS Benchmarked with usual mixture, ZnO - 3 phr St Acid – 2 phr

Rheograph 1600C for 20mins

Rheograph 1600C for 20mins

Rheological Props INFERENCE : Scorch time is INCREASED, 1600C for 20mins COMPOUNDS 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

Tests for C-B filled cmpds Hardness Tensile Strength Tear Strength Swelling Index Compression Set Flex Cracking Resistance

Hardness INFERENCE : Not much change in Hardness COMPOUND HARDNESS (Shore A) P 76 PC1 72 PC2 70 PC3 68 PC4 71 PC5 69 INFERENCE : Not much change in Hardness

Tensile Strength (Before aging) MPa Aging Condition – 1000C for 22hr COMPOUND Tensile Strength (Before aging) MPa Tensile 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 INFERENCE : Tensile Strength is low But % retention of our activator cmpds is high

Tear Strength Aging Condition – 1000C for 22hr COMPOUND Tear Strength (Before aging) N/mm (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 INFERENCE : Tear Strength and % Retention is HIGH for our activator compounds

Swelling Index Swelling Index α 1 / Crosslink Density Immersed in toluene for 7 days COMPOUND SWELLING INDEX % P 69 PC1 87 PC2 80 PC3 76 PC4 PC5 77 SWELLING INDEX = (Ws – Wi)/Wi Swelling Index α 1 / Crosslink Density

Compression Set SET % = (t0 – tr) / (to - ts) × 100 COMPOUND 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 resistance SAMPLE 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

Summary With 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 as its 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.