USE OF COCONUT SHELL CHARCOAL OUST AS A FILLER IN THE RUBBER INDUSTRY A DISSERTATION PRESENTED TO L I B R A i r ^ ^ ^ U W V f M I T Y or M O R A ftnwA. i m i i f l mqkatuwa ^ ^ THE POLYMER TECHNOLOGY DIVISION UNIVERSITY OF MORATUWA SRI LANKA IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE DEGREE MASTER OF SCIENCE IN POLYMER TECHNOLOGY ^ « 6 1 & 0 4 S - N.J.W. GAM AGE APRIL 1987. University of Morai 78519 78519 MM Thesis 18511 ACKNOWLEDGEMENT THIS study has been made possible through the generous help and co-operation extended to me by many individuals and institutions, to all of whom I am most grateful. I regret that lack of space does not permit me to mention every name. Especially, I would like to express my gratitude to my supervisor Dr. (Mrs.) I.Sivagurunathan, E e a d , Polymer Technology Division, University of Moratuwa for the advice-, . suggestions, assistance and co-operation she extended to me, to make this industry oriented research project a success. I acknowledge with thanks, the advice and guidance given by D r . K.P. Fernando, lecturer of the same Department. I am deeply indebted to my Employer THE STATE TIMBER CORPORATION for sanctioning me leave and providing facilities and finance to follow the course and undertake this research project. I am thankful to HAYCARB LTD., for the generous supply of coconut shell charcoal dust which was used in this investigation. My special thanks are due to Miss Y . Karunarathna, who kindly undertook and accomplished the most difficult task of typing this dissertation at short notice. i SYNOPSIS COCONUT SHELL CHARCOAL DUST (CSCD) is a waste product in the production of activated carbon. The main objective of this research project is to determine the suitability of this waste product as a reinforcing filler in the rubber industry. With this objective in mind, firstly the characteristic properties of CSCD which can have an influence on reinforcement were determined. These determinations show that CSCD resembles HA? (N 3 3 0 ) , PEP (N 550), SRP (N 770) blacks and lamp black in certain respects. The effect of CSCD as a filler in two non-polar rubber compounds namely NR (RSS-2) and SBR (1500); and a polar rubber compound NBR (medium) has been investigated by measuring the tensile properties, dead load hardness, vertical rebound resilience and volume abrasion loss of the vulcanisates. Finally, the HAF (N 330) in car tyre tread formulation was partially and wholly replaced by CSCD and results of physical testing of these vulcanisates compared with the vulcanisates of the control compound containing 50 pphr of HAF. A comparision was also made with the requirements for car tyre treads as specified by Sri Lanka Tyre Corporation. These results show that CSCD can be used as a reinforcing filler in rubber industry. However, it was not possible to carry out any ageing test due to limited time. ii LIST OP CONTENTS Page ACKNOWLEDGEMENT i'. SYNOPSIS - ii CHAPTER ONE 1.0 INTRODUCTION 1 1.1 USE OP CARBON BLACK IN RUBBER INDUSTRY 1 1.2 APPLICATION AREAS OP CARBON BLACK 1 1.3 SUBSTITUENTS POR CARBON BLACK 1 CHAPTER TWO 2.0 INFLUENCE OP FILLER ON ELASTOMER REINFORCEMENT 5 2.1 INTRODUCTION 5 ' 2.2 FACTORS INFLUENCING ELASTOMER REINFORCEMENT 5 2.3 MORPHOLOGY OP CARBON BLACK 6 2.4 TYPICAL FILLER CHARACTERISTICS 8 2.4.1 THE EXTENSITY FACTOR 8 2.4'.2 TEE INTENSITY FACTOR 8 2.4.3 GEOMETRICAL FACTOR 8 2.5 THE REINFORCEMENT MECHANISM 10 2.5.1 MOLECULAR SLIPPAGE MODEL 10 CHAPTER THREE 3.0 DETERMINATION OP SOME PROPERTIES OP COCONUT SHELL CHARCOAL DUST 13 3.1 INTRODUCTION 13 3.2 DEGREE OF CRYSTALLINITY OF CSCD 14 3.3 IODINE ADSORPTION NUMBER OF CSCD 21 3.4 DIBUTYLPHTHALATE ABSORPTION NUMBER OF CSCD 23 3.5 TINT STRENGTH OF CSCD 24 3.6 pH VALUE OP CSCD 26 3.7 PERCENTAGE HEATING LOSS OP CSCD 27 3.8 PERCENTAGE ASH CONTENT OP CSCD 28 3.9 POUR DENSITY OP CSCD " 29 3.10 PERCENTAGE SIEVE RESIDUE 30 3.11 SUMMARY OP PROPERTIES 31 3.12 SECTION OP REPERENCE BLACKS 34 CHAPTER POUR 4.0 COMPOUND FORMULATION AND PREPARATION OP TEST SPECIMENS 35 4.1 INTRODUCTION 35 4.2 TEST RECIPES 35 4.3 WEIGHING PROCEDURE 39 4.4 MIXING PROCEDURE 39 4.4.1 MIXING CYCLE 40 4.5 DETERMINATION OP CURE CHARACTERISTICS B Y ODR 42 4.5.1 CURE TIME 42 4.6 PREPERATION OP TEST SPECIMENS 48 4.6.1 DIMENSIONS OP TEST SPECIMENS 48 4.6.2 MOULDING OP TEST SPECIMENS 49 CHAPTER PIVE 5.0 AN OUTLINE OP TEST METHODS 50 5.1 INTRODUCTION 50 5.2 TENSILE TESTING 51 5.3 PERCENTAGE COMPRESSION SET UNDER CONSTANT STRAIN IN AIR 54 5.4 ABRASION LOSS 5.5 HARDNESS TESTING 5.6 REBOUND RESILIENCE CHAPTER SIX 6.0 TABULATION AND ANALYSIS OP RESULTS 6.1 INTRODUCTION 6.2 LIST OP TABLES AND FIGURES 6.3 ANALYSIS OP RESULTS 6.3.1 TENSILE STRENGTH 6.3.2 MODULUS AT 300% ELONGATION 6.3.3 PERCENTAGE ELONGATION AT BREAK 6.3.4 DEAD LOAD HARDNESS 6.3.5 VERTICAL REBOUND RESILIENCE 6.3.6 VOLUME ABRASION LOSS 6.3.7 PERCENTAGE COMPRESSION SET CHAPTER SEVEN 7.0 USE OP CSCD IN TYRE TREAD FORMULATIONS 7.1 INTRODUCTION 7.2 MIXING PROCEDURE 7.2.1 MIXING CYCLE 7.3 PREPARATION OP TEST SPECIMENS 7.4 CURE CHARACTERISTICS 7.5 TESTING OF TYRE TREAD COMPOUNDS 7.6 ANALYSIS OF RESULTS 7.7 INFERENCE CHAPTER EIGHT 8.0 CONCLUSIONS AND SUGGESTIONS FOR FURTHER WORK 117 8.1 INTRODUCTION 117 8.2 CONCLUSIONS ~ 117 8.3 SUGGESTIONS FOR FURTHER WORK 119 4 LIST OF REFERENCES 120 APPENDIX X - R A Y DIFFRACTOGRAM ANALYSIS REPORT a 1