Natural rubber latex （NRL） and methyl methacrylate （MMA） grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The tens...Natural rubber latex （NRL） and methyl methacrylate （MMA） grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The tensile properties, swelling ratio and permanent set were measured. The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy. Modulus increases from 6.99 MPa to 9.87 MPa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose. Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends. The decreasing trend of permanent set is high up to 5 kGy absorbed dose, and beyond that dose, it becomes almost flat.展开更多
Under cyclic loading conditions,the breakdown of rubber products is mainly caused by the formation and spread of cracks.This study focuses on understanding how cracks initiate and grow during the fatigue failure of bl...Under cyclic loading conditions,the breakdown of rubber products is mainly caused by the formation and spread of cracks.This study focuses on understanding how cracks initiate and grow during the fatigue failure of blended rubber.We prepared composite materials by blending bio-mimetic rubber (BMR);butadiene rubber (BR) in different mass ratios and evaluated their resistance to crack initiation and propagation.Our results indicate a clear trend: as the BR content increases,crack initiation in blended rubber is inhibited,while crack propagation is enhanced.This shift leads to a change in the primary factor influencing fatigue fracture from crack initiation to crack propagation.Additionally,we observed that the fatigue life of the rubber blend initially increases and then decreases as the BMR content rises,indicating a critical threshold when the mass ratio of BMR to BR is comparable.By closely examining the materials using a scanning electron microscope (SEM);image analysis,we confirmed that before the threshold,crack initiation is the dominant factor in fatigue failure,while after the threshold,crack propagation takes over.This study provides valuable insights into the mechanisms behind fatigue failure in rubber blends,contributing to a better understanding of this important material behavior.展开更多
In terms of the classical theory in textbooks, the two components with phase separation in a binary polymer blend will, depending on their compatibility, have their respective Tg get closer or remain in their original...In terms of the classical theory in textbooks, the two components with phase separation in a binary polymer blend will, depending on their compatibility, have their respective Tg get closer or remain in their original values. According to the classical theory, the Tg of plastic component shall remain unchanged or move toward the lower Tg of rubber component in a rubber/plastic blend. However, ultra-fine full-vulcanized powdered rubber (UFPR) with a diameter of ca. 100 nm can simultaneously increase the toughness and the Tg of plastics, which is abnormal and is difficult to explain by classical theory. In this feature article, the abnormal behavior and its mechanism are discussed in detail.展开更多
文摘Natural rubber latex （NRL） and methyl methacrylate （MMA） grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The tensile properties, swelling ratio and permanent set were measured. The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy. Modulus increases from 6.99 MPa to 9.87 MPa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose. Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends. The decreasing trend of permanent set is high up to 5 kGy absorbed dose, and beyond that dose, it becomes almost flat.
基金supported by the National Key R&D Program of China (No.2022YFB3707303)the National Natural Science Foundation of China (No.52293471).
文摘Under cyclic loading conditions,the breakdown of rubber products is mainly caused by the formation and spread of cracks.This study focuses on understanding how cracks initiate and grow during the fatigue failure of blended rubber.We prepared composite materials by blending bio-mimetic rubber (BMR);butadiene rubber (BR) in different mass ratios and evaluated their resistance to crack initiation and propagation.Our results indicate a clear trend: as the BR content increases,crack initiation in blended rubber is inhibited,while crack propagation is enhanced.This shift leads to a change in the primary factor influencing fatigue fracture from crack initiation to crack propagation.Additionally,we observed that the fatigue life of the rubber blend initially increases and then decreases as the BMR content rises,indicating a critical threshold when the mass ratio of BMR to BR is comparable.By closely examining the materials using a scanning electron microscope (SEM);image analysis,we confirmed that before the threshold,crack initiation is the dominant factor in fatigue failure,while after the threshold,crack propagation takes over.This study provides valuable insights into the mechanisms behind fatigue failure in rubber blends,contributing to a better understanding of this important material behavior.
文摘In terms of the classical theory in textbooks, the two components with phase separation in a binary polymer blend will, depending on their compatibility, have their respective Tg get closer or remain in their original values. According to the classical theory, the Tg of plastic component shall remain unchanged or move toward the lower Tg of rubber component in a rubber/plastic blend. However, ultra-fine full-vulcanized powdered rubber (UFPR) with a diameter of ca. 100 nm can simultaneously increase the toughness and the Tg of plastics, which is abnormal and is difficult to explain by classical theory. In this feature article, the abnormal behavior and its mechanism are discussed in detail.
