Polymer Tech

D Damping :   The quality of an elastomer to absorb forced Vibrationsl energy. Date Code : In hose identification , Any combination of numbers, letters, symbols or other methods used by manufacturer to identify the time of manufacture of a product. Deburr : To remove ragged edges from the inside diameter of a hose end; an important fabrication step for assembling hose of fluropolymer in order to insure a good seal. Deflashing : Any of various processes used to remove the waste edge from a moulded rubber part. Dielectric properties : The ability if a material to resist puncture due to electric stress. DeMattia Flex Test  – This laboratory test to determine the flexible life of a material. It measures the rate of formation of cracks in a standard molded test bar. Diffusion :The mixing of two or more substances due to the intermingling motion of their individual molecules. Durometer : An instrument for measuring the hardness if a rubbe...

INTRODUCTION Butyl rubber is a copolymer of Isobutylene with a small percentage of isoprene to provide curing sites for curing. Isobutylene was the first alkene to be polymerized.IIR has Unusually low resilience at room temperature for an elastomer with such a low Tg(-70°C) The rubber has excellent aging stability, and another excellent feature is impermeable to gases. Butyl rubber does not breakdown easily in milling.Thus in presence of a promotor like p- dinitroso benzene this rubber interacts with carbon black at Banbury mixer about 180°C and get better reinforcement this is called heat treatment of IIR.

INTRODUCTION Carbon black is the most important filler for rubbers.The reinforcing ability of carbon black was discovered decades back.Today around 50 types of black are produced. Carbon black is made by either incomplete combustion of hydrocarbon by thermal decomposition of the hydrocarbons. The different forms of production Furnace process: Most of the carbon black are produced by this method.In this partial combustion is done in horizontal furnaces.The raw material is liquid or gaseous aromatic hydrocarbons.A yellow flame is produced due to limited supply of air, this leads to partial combustion which causes soot to form,this carbon black which is present along with Co2 and water vapour in the gas produced.This is cooled by water spray and passed through a series of cyclone separators from which the carbon black is collected.This particle size is small and these particles have to be pelletized for easy handling. Thermal Black: It accounts for about 5% of the c...