Since the introduction of＂green tyres＂ in the early 90＇s, the use of silica as a reinforcing filler, along with a silane coupling agent, has spread and grown worldwide. The greatest advantage of using silica over c...Since the introduction of＂green tyres＂ in the early 90＇s, the use of silica as a reinforcing filler, along with a silane coupling agent, has spread and grown worldwide. The greatest advantage of using silica over carbon black as reinforcing filler in a tyre tread compound is that a lower rolling resistance is achieved, while maintaining good wet traction. However, a previous study has shown that the wear resistance of a silica filled ENR （epoxidised natural rubber） compound was not as high as those of conventional OESBR （oil extended styrene butadiene rubber） and NR/BR compounds used in passenger car and truck tyre treads. In this work, with the aim of improving abrasion resistance, the effect of blending BR （butadiene rubber） into a silica filled ENR compound was studied. Blends with 0 to 30 phr BR were prepared in a Polylab Haake internal mixer. The rheological properties of the compounds were measured using a Mooney viscometer and oscillating-disc rheometer. The hardness, tensile strength and DIN abrasion resistance were also measured. The results showed that the ENR/silica compound properties such as tensile strength and hardness were as good as those of the conventional compounds. However, the most important finding was that abrasion resistance increased significantly with BR content, exceeding that of the conventional compound at BR： ENR ratios of greater than 20：80.展开更多
Alloying and nanocompositing are two most effective techniques by which isotactic polypropylene(iPP), one of the most promising polymers of the 21 st century, can be endowed with high performance for ever-demanding hi...Alloying and nanocompositing are two most effective techniques by which isotactic polypropylene(iPP), one of the most promising polymers of the 21 st century, can be endowed with high performance for ever-demanding high-end applications. Thanks to the continuous advancement of catalyst technology, the technological trend for iPP alloy and nanocomposite fabrication has been projected to be in-reactor synthesis, the performance and economic advantages of which are beyond doubt. In this paper, we review two recent key developments in the iPP in-reactor alloy and in-reactor nanocomposite technology in our laboratory that will have profound influence on the continuing development of the prestigious iPP modification art. The first is the simultaneous EPR(ethylene-propylene random copolymer) cross-linking chemistry for controlling its physical growth pattern during in-reactor alloying, which helps to remove the compositional cap on EPR that so far greatly limits the iPP in-reactor alloying technique. The second is the nanofiller support fabrication strategy for simultaneously controlling both the phase morphology of the nanofiller dispersion and the polymer particle granule morphology of synthesized nanocomposites, which resolves the critical scale-up issue surrounding the iPP in-reactor nanocompositing technique. Based on these new developments, new advancements of iPP materials are envisaged.展开更多
文摘Since the introduction of＂green tyres＂ in the early 90＇s, the use of silica as a reinforcing filler, along with a silane coupling agent, has spread and grown worldwide. The greatest advantage of using silica over carbon black as reinforcing filler in a tyre tread compound is that a lower rolling resistance is achieved, while maintaining good wet traction. However, a previous study has shown that the wear resistance of a silica filled ENR （epoxidised natural rubber） compound was not as high as those of conventional OESBR （oil extended styrene butadiene rubber） and NR/BR compounds used in passenger car and truck tyre treads. In this work, with the aim of improving abrasion resistance, the effect of blending BR （butadiene rubber） into a silica filled ENR compound was studied. Blends with 0 to 30 phr BR were prepared in a Polylab Haake internal mixer. The rheological properties of the compounds were measured using a Mooney viscometer and oscillating-disc rheometer. The hardness, tensile strength and DIN abrasion resistance were also measured. The results showed that the ENR/silica compound properties such as tensile strength and hardness were as good as those of the conventional compounds. However, the most important finding was that abrasion resistance increased significantly with BR content, exceeding that of the conventional compound at BR： ENR ratios of greater than 20：80.
基金supported by the National Natural Science Foundation of China(21574143,51373178)
文摘Alloying and nanocompositing are two most effective techniques by which isotactic polypropylene(iPP), one of the most promising polymers of the 21 st century, can be endowed with high performance for ever-demanding high-end applications. Thanks to the continuous advancement of catalyst technology, the technological trend for iPP alloy and nanocomposite fabrication has been projected to be in-reactor synthesis, the performance and economic advantages of which are beyond doubt. In this paper, we review two recent key developments in the iPP in-reactor alloy and in-reactor nanocomposite technology in our laboratory that will have profound influence on the continuing development of the prestigious iPP modification art. The first is the simultaneous EPR(ethylene-propylene random copolymer) cross-linking chemistry for controlling its physical growth pattern during in-reactor alloying, which helps to remove the compositional cap on EPR that so far greatly limits the iPP in-reactor alloying technique. The second is the nanofiller support fabrication strategy for simultaneously controlling both the phase morphology of the nanofiller dispersion and the polymer particle granule morphology of synthesized nanocomposites, which resolves the critical scale-up issue surrounding the iPP in-reactor nanocompositing technique. Based on these new developments, new advancements of iPP materials are envisaged.
