4.4.1.2PreparationThesecond generation:about1950about 5oC,a redox initiating system'cold rubbers':mostimportant
▪The second generation :about 1950 about 5oC , a redox initiating system ▪'cold rubbers' :most important 4.4.1.2 Preparation
4.4.1.3Generalproperties1.Properties:similar to natural rubber2.properties:different from natural rubber
4.4.1.3 General properties 1.Properties : similar to natural rubber 2. properties : different from natural rubber
4.4.1.3GeneralpropertiesAmajordifferencenaturalrubber:breakdown onmasticationSBR:does not breakdown on mastication
A major difference ▪natural rubber: break down on mastication ▪ SBR : does not break down on mastication. 4.4.1.3 General properties
4.4.1.3General propertiesOtherdifferencesslower Vulcanization-the lack of crystallinityLower tensile strengthgood abrasion resistance
Other differences ▪slower Vulcanization ▪the lack of crystallinity ▪Lower tensile strength ▪good abrasion resistance 4.4.1.3 General properties
4.4.1.3GeneralpropertiesOnageing■SBR:tends to cross-link on oxidation-NR:exhibit chain scission on oxidation
On ageing ▪ SBR : tends to cross-link on oxidation ▪NR : exhibit chain scission on oxidation 4.4.1.3 General properties