Various of modifiers were used to modify the surface activity of white carbon black. The oil absorption, viscosity, hydrophobic rate and burning loss of white carbon black and the mechanical propertiess of silicone ru...Various of modifiers were used to modify the surface activity of white carbon black. The oil absorption, viscosity, hydrophobic rate and burning loss of white carbon black and the mechanical propertiess of silicone rubber were measured. The influences of the modifiers on the properties of white carbon black and the mechanical properties of silicone rubber were discussed.展开更多
Carbon black-based conductive rubber composites have important impacts on electromagnetic interference(EMI)shielding applications.However,an excessive amount of carbon black in the recipes of these conductive rubbers ...Carbon black-based conductive rubber composites have important impacts on electromagnetic interference(EMI)shielding applications.However,an excessive amount of carbon black in the recipes of these conductive rubbers has caused their weak elasticity.Herein,hollow carbon black(HCB)particles were used to tune the elasticity of conductive rubber composites.Unique hollow morphology produced a better compression recovery of HCB than other solid carbon black,such as acetylene black.When the coupling agent was bonded to HCB,their conductive silicone rubber composites were featured by high stretching resilience,a fast compression recovery and excellent conductivity to satisfy the electromagnetic interference shielding requirements.Importantly,the rubber composites with coupling HCB had extremely low variations of mechanical property,conductivity and EMI shielding effectiveness after thermal accelerated aging tests.It is therefore revealed that the elasticity of HCB and its interfacial chemical coupling with rubber chains both play crucial roles in adjusting the elasticity of conductive rubber to sever long-term EMI protection.展开更多
The viscoelastic properties of synthetic polyisoprenes （PI） reinforced by white carbon black （WCB） have been investigated and compared with WCB reinforced natural rubber （NR）, including cure characteristics, phy...The viscoelastic properties of synthetic polyisoprenes （PI） reinforced by white carbon black （WCB） have been investigated and compared with WCB reinforced natural rubber （NR）, including cure characteristics, physio-mechanical and dynamic mechanical properties. Compared with NR, PI loaded with the same amount of WCB （PI/WCB） exhibited shorter scorch time and optimal cure time, indicating that WCB fillers are comparatively easier to conjugate with PI. The tensile strength and elongation at break decreased with WCB filling in both PI and NR vulcanizates. The hardness of the rubber vulcanizates increased with the WCB filling in the rubber matrix. PI/WCB blends exhibited smaller hardness data, lower tensile strength, as well as lower elongation at break and tensile stress. Increasing the amount of WCB in rubber matrix induced the Payne effect. However, the Payne effect is much more obvious for the PI/WCB system, and PI/WCB also displayed higher storage modulus whereas lower loss modulus and loss tangent than NR/WCB, which could all be attributed to the poor dispersibilities of WCB in the PI matrix.展开更多
Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H2O2) and distilled...Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H2O2) and distilled water(H2O). The functional groups on the surface of CNTs, changes in nanotube structure and morphology were characterized by Fourier transform infrared spectroscopy(FT-IR), Raman Spectroscopy, and transmission electron microscopy(TEM). It shows that hydroxyl(OH·) is successfully introduced. The surface defects of modified CNTs were obviously higher than those of original CNTs, and the degree of agglomeration was greatly reduced. Thermal conductivity of the composites was tested by protection heat flow meter method. Compared with unmodified CNTs/CB filling system, the thermal conductivity of hybrid composites is improved by an average of 5.8% with 1.5 phr(phr is parts per hundred rubber) of hydroxyl CNTs and 40 phr of CB filled. A three-dimensional heat conduction network composed of hydroxyl CNTs and CB, as observed by TEM, contributes to the good properties. Thermal conductivity of the hybrid composites increases as temperature rises. The mechanical properties of hybrid composites are also good with hydroxyl CNTs filled nanocomposites;the tensile strength, 100% and 300% tensile stress are improved by 10.1%, 22.4% and 26.2% respectively.展开更多
文摘Various of modifiers were used to modify the surface activity of white carbon black. The oil absorption, viscosity, hydrophobic rate and burning loss of white carbon black and the mechanical propertiess of silicone rubber were measured. The influences of the modifiers on the properties of white carbon black and the mechanical properties of silicone rubber were discussed.
文摘Carbon black-based conductive rubber composites have important impacts on electromagnetic interference(EMI)shielding applications.However,an excessive amount of carbon black in the recipes of these conductive rubbers has caused their weak elasticity.Herein,hollow carbon black(HCB)particles were used to tune the elasticity of conductive rubber composites.Unique hollow morphology produced a better compression recovery of HCB than other solid carbon black,such as acetylene black.When the coupling agent was bonded to HCB,their conductive silicone rubber composites were featured by high stretching resilience,a fast compression recovery and excellent conductivity to satisfy the electromagnetic interference shielding requirements.Importantly,the rubber composites with coupling HCB had extremely low variations of mechanical property,conductivity and EMI shielding effectiveness after thermal accelerated aging tests.It is therefore revealed that the elasticity of HCB and its interfacial chemical coupling with rubber chains both play crucial roles in adjusting the elasticity of conductive rubber to sever long-term EMI protection.
基金financially supported by the National Basic Research Program of China(No.2010CB934700)
文摘The viscoelastic properties of synthetic polyisoprenes （PI） reinforced by white carbon black （WCB） have been investigated and compared with WCB reinforced natural rubber （NR）, including cure characteristics, physio-mechanical and dynamic mechanical properties. Compared with NR, PI loaded with the same amount of WCB （PI/WCB） exhibited shorter scorch time and optimal cure time, indicating that WCB fillers are comparatively easier to conjugate with PI. The tensile strength and elongation at break decreased with WCB filling in both PI and NR vulcanizates. The hardness of the rubber vulcanizates increased with the WCB filling in the rubber matrix. PI/WCB blends exhibited smaller hardness data, lower tensile strength, as well as lower elongation at break and tensile stress. Increasing the amount of WCB in rubber matrix induced the Payne effect. However, the Payne effect is much more obvious for the PI/WCB system, and PI/WCB also displayed higher storage modulus whereas lower loss modulus and loss tangent than NR/WCB, which could all be attributed to the poor dispersibilities of WCB in the PI matrix.
基金Supported by the National Natural Science Foundation of China(51606107,51576102)the Collaborative Innovation Project of Green Tire and Rubber(0200501436)
文摘Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H2O2) and distilled water(H2O). The functional groups on the surface of CNTs, changes in nanotube structure and morphology were characterized by Fourier transform infrared spectroscopy(FT-IR), Raman Spectroscopy, and transmission electron microscopy(TEM). It shows that hydroxyl(OH·) is successfully introduced. The surface defects of modified CNTs were obviously higher than those of original CNTs, and the degree of agglomeration was greatly reduced. Thermal conductivity of the composites was tested by protection heat flow meter method. Compared with unmodified CNTs/CB filling system, the thermal conductivity of hybrid composites is improved by an average of 5.8% with 1.5 phr(phr is parts per hundred rubber) of hydroxyl CNTs and 40 phr of CB filled. A three-dimensional heat conduction network composed of hydroxyl CNTs and CB, as observed by TEM, contributes to the good properties. Thermal conductivity of the hybrid composites increases as temperature rises. The mechanical properties of hybrid composites are also good with hydroxyl CNTs filled nanocomposites;the tensile strength, 100% and 300% tensile stress are improved by 10.1%, 22.4% and 26.2% respectively.
