The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C b...The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C bonds in mixed polyolefin plastics over non-noble metal catalysts under mild conditions. The nickelbased catalyst involving Ni_(2)Al_(3) phase enables the direct transformation of mixed polyolefin plastics into natural gas, and the gas carbon yield reaches up to 89.6%. Reaction pathway investigation reveals that natural gas comes from the stepwise catalytic cleavage of C–C bonds in polypropylene, and the catalyst prefers catalytic cleavage of terminal C–C bond in the side-chain with the low energy barrier.Additionally, our developed approach is evaluated by the technical economic analysis for an economically competitive production process.展开更多
Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and ...Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization.Herein,lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem-1000 polymer matrix to fabricate high performance MMHFMs.SEM,DLS,XRD and TGA were performed to characterize silane-modified MIL-53（S-MIL-53）and prepared MMHFMs.Moreover,the effect of MOFs loading was systematically investigated first;then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures.MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions.Compared to pure HFMs,CO2permeance of MMHFM loaded with 15%S-MIL-53 increased by 157%accompanying with 40%increase for CO2/N2selectivity,which outperformed the MMHFM filled with naked MIL-53.The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2plasticization.This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.展开更多
Comprehensive Summary:Recycling polyolefin and other plastic mixtures encounters significant obstacles due to the intricate nature and economic inefficiencies of physically separating vast streams of mixed waste.Incor...Comprehensive Summary:Recycling polyolefin and other plastic mixtures encounters significant obstacles due to the intricate nature and economic inefficiencies of physically separating vast streams of mixed waste.Incorporating compatibilizers emerges as a viable strategy to diminish interfacial energy and bolster compatibility,ultimately yielding homogeneous products.In this contribution,polar polyolefins featuring metal dynamic cross-linking networks were synthesized by tandem polymerizing ionic cluster type polar monomers and olefins.Subsequent treatment with HCl aqueous solution and esterification with polyester precursors yields high-performance grafted polar polyolefins for mixed polymer compatibilizing.For PP/PC melting blends,adding 5 wt%of graft-modified polyolefin results in tougher blends that surpass the performance of corresponding virgin iPP in elongation at break(εb).Polar polyolefins containing sodium carboxylate groups play a dual role in compatibilizing PET/HDPE blends,acting both as compatibilizers and nucleating agents.Moreover,this strategy enables the production of grafted polyolefins comprising ternary polymers,which can be employed in compatibilizing ternary blends.展开更多
基金supported by the National Natural Science Foundation of China (grant 22208339)the China Postdoctoral Science Foundation (2021M693132)+2 种基金the National Key R&D Program of China (2019YFC1905303)the Doctoral Scientific Research Foundation of Liaoning Province (2021-BS-006)the Youth Innovation Fund of Dalian Institute of Chemical Physics (DICP I202132)。
文摘The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C bonds in mixed polyolefin plastics over non-noble metal catalysts under mild conditions. The nickelbased catalyst involving Ni_(2)Al_(3) phase enables the direct transformation of mixed polyolefin plastics into natural gas, and the gas carbon yield reaches up to 89.6%. Reaction pathway investigation reveals that natural gas comes from the stepwise catalytic cleavage of C–C bonds in polypropylene, and the catalyst prefers catalytic cleavage of terminal C–C bond in the side-chain with the low energy barrier.Additionally, our developed approach is evaluated by the technical economic analysis for an economically competitive production process.
基金the financial support from the National Natural Science Foundation of China(No.21436009)
文摘Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization.Herein,lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem-1000 polymer matrix to fabricate high performance MMHFMs.SEM,DLS,XRD and TGA were performed to characterize silane-modified MIL-53（S-MIL-53）and prepared MMHFMs.Moreover,the effect of MOFs loading was systematically investigated first;then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures.MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions.Compared to pure HFMs,CO2permeance of MMHFM loaded with 15%S-MIL-53 increased by 157%accompanying with 40%increase for CO2/N2selectivity,which outperformed the MMHFM filled with naked MIL-53.The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2plasticization.This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.
基金supported by National Key R&D Program of China(No.2021YFA1501700)National Natural Science Foundation of China(No.52373002).
文摘Comprehensive Summary:Recycling polyolefin and other plastic mixtures encounters significant obstacles due to the intricate nature and economic inefficiencies of physically separating vast streams of mixed waste.Incorporating compatibilizers emerges as a viable strategy to diminish interfacial energy and bolster compatibility,ultimately yielding homogeneous products.In this contribution,polar polyolefins featuring metal dynamic cross-linking networks were synthesized by tandem polymerizing ionic cluster type polar monomers and olefins.Subsequent treatment with HCl aqueous solution and esterification with polyester precursors yields high-performance grafted polar polyolefins for mixed polymer compatibilizing.For PP/PC melting blends,adding 5 wt%of graft-modified polyolefin results in tougher blends that surpass the performance of corresponding virgin iPP in elongation at break(εb).Polar polyolefins containing sodium carboxylate groups play a dual role in compatibilizing PET/HDPE blends,acting both as compatibilizers and nucleating agents.Moreover,this strategy enables the production of grafted polyolefins comprising ternary polymers,which can be employed in compatibilizing ternary blends.
