Effect Of Mixing Technology On Properties Of Eucommia Ulmoides Gum/Natural Rubber Blends

The eucommia ulmoides gum(EUG)is a natural polymer material with the same chemical composition-(C5H8)n-as natural rubber(NR),but they are isomers of each other,and its main component is trans-1,4-polyisoprene.The excellent physical and mechanical properties of the blend of EUG and NR are due to the double bonds contained in the blend,which can be easily vulcanized during blending.The phase structure of EUG/NR blends was analyzed.The atomic force microscope(AFM)was used to analyze the morphology and structure of the blend.Differential scanning calorimetry(DSC)was used to characterize the crystals in the system,scanning electron microscope(SEM)was used to observe the stretched section of the vulcanizate.The results show that when the mixing temperature is low,the two-phase structure of eucommia and natural rubber is a single-phase continuous structure.As the mixing temperature gradually rises,the two-phase structure gradually changes to a two-phase continuous structure,and the more uniform the sulfur diffusion,the lower the crystallinity of the vulcanizate,the softer its hardness,With the decrease of the mixing temperature,the elongation at break and tensile strength gradually become smaller,the 100% elongation stress and the 300% elongation stress gradually increase.The effects of different mixing temperatures on the properties of the blended rubber were studied.The carbon black dispersion in the system was analyzed by a rubber processing analyzer(RPA),differential scanning calorimetry(DSC)was used to characterize the crystals in the system,the tensile cross section of the vulcanizate was observed by means of a scanning electron microscope(SEM).The results show that as the mixing temperature increases,the crystallinity of the compound rubber and vulcanizate gradually decreases,the carbon black is more uniformly dispersed,and the hardness of the compound rubber is higher,when the mixing temperature is in the range of 25°C ? 50°C,as the mixing temperature decreases,the elongation at break and tensile strength become smaller,the 100% elongation stress and the 300% elongation stress become larger.The analysis suggests that the occurrence of these phenomena is related to the morphological structure of EUG and NR with the change of mixing temperature.The effects of different process technologies on the vulcanization characteristics,dynamic mechanical properties,crystallization ability,and physical and mechanical properties of the EUG/NR blended rubber were studied,and the micro two-phase structure of the vulcanized rubber was characterized.The results show that compared with other technologies,the Mooney viscosity of the first technology is higher and the hardness of the compound rubber is greater.The fourth technology has the best overall performance.The fifth technology has the highest elongation at break.The analysis suggests that these changes are related to the microcrystals of the rubber,the two-phase structure of the rubber,and the dispersion of the compounding agent.The properties of extruded EUG/NR blends were analyzed.Characterize the mechanical properties of the blended rubber through the Akron abrasion test,flexural fatigue test,and tensile test,analyze its dynamic performance through the compression heat build up test with constant load,the corrosion resistance was analyzed by salt spray aging test.The results show that the blended rubber has lower compressive deformation rate,lower heat build-up,better wear resistance and flex resistance,and has good resistance to salt spray corrosion.