Hydrogen bonding is considered to have significant effect on the interaction between polymeric chains and on the viscoelasticity of the polymeric materials. In this paper, we attempt to discuss the relationship betwee...Hydrogen bonding is considered to have significant effect on the interaction between polymeric chains and on the viscoelasticity of the polymeric materials. In this paper, we attempt to discuss the relationship between hydrogen bonding density and damping behavior and mechanical properties of polyethylene-based polymeric materials. For this reason, a series of pendant chain hydrogen bonding polymers （PCHBP） with different hydrogen bonding density （HBD） were prepared by quantitatively changing the content of pendent hydroxyl groups on the main chain of polyethylene. It was found that PCItBP with low HBD showed similar properties to polyethylene, indicating that the property of the materials was dependent mainly on the structure of the main chain. However, PCHBP with high HBD exhibited two tandpeaks and a platform of loss modulus as well as a high storage modulus （about 400 MPa） at the second tand peak temperature, demonstrating that a polymeric material with high strength and damping properties was obtained. More importantly, the maximum of loss modulus showed a linear increase with the HBD, indicating that a higher HBD greatly improved the damping properties of the polymeric materials.展开更多
New ambient sound absorption material,lightweight isocyanate-based polyimide foam(IBPIF),was fabricated by operable combination between different distinctive acoustic IBPIF.Cellular structure of IBPIF was facilely and...New ambient sound absorption material,lightweight isocyanate-based polyimide foam(IBPIF),was fabricated by operable combination between different distinctive acoustic IBPIF.Cellular structure of IBPIF was facilely and obviously adjusted by increased slurry temperature corresponding to change in distinctive acoustic properties.Moreover,density of all IBPIF kept at only 12-17 kg/m3.With increasing slurry temperature from 0℃to 40℃,cell size and window opening rate gradually increased from 553μm to 791μm and from 6.85%to 58.46%,respectively.In this study,IBPIF generated by slurries at 0℃(marked as PIF-2)and 40℃(marked as PIF-6)showed best and distinctive acoustic behavior in 315-800 Hz and 800-6300 Hz regions,respectively.After acoustic behavior study of combined IBPIF prepared by stitching combination between two distinctive acoustic IBPIFs,results showed that only when PIF-6 sheet used as sound receiving surface even though with thickness of only 10 mm could the combined IBPIF possess the best acoustic level in 800-6300 Hz region as PIF-6.Furtherly,acoustic behavior in 315-800 Hz region could be significantly enhanced by increasing thickness of PIF-2 and could reach or close to the best acoustic level.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51003018 and 21374009)Program of International S&T Cooperation Special Project(No.2011DFR50770)the Fundamental Research Funds of the Central University(No.HEUCFJ161003)
文摘Hydrogen bonding is considered to have significant effect on the interaction between polymeric chains and on the viscoelasticity of the polymeric materials. In this paper, we attempt to discuss the relationship between hydrogen bonding density and damping behavior and mechanical properties of polyethylene-based polymeric materials. For this reason, a series of pendant chain hydrogen bonding polymers （PCHBP） with different hydrogen bonding density （HBD） were prepared by quantitatively changing the content of pendent hydroxyl groups on the main chain of polyethylene. It was found that PCItBP with low HBD showed similar properties to polyethylene, indicating that the property of the materials was dependent mainly on the structure of the main chain. However, PCHBP with high HBD exhibited two tandpeaks and a platform of loss modulus as well as a high storage modulus （about 400 MPa） at the second tand peak temperature, demonstrating that a polymeric material with high strength and damping properties was obtained. More importantly, the maximum of loss modulus showed a linear increase with the HBD, indicating that a higher HBD greatly improved the damping properties of the polymeric materials.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.3072020CF1019)Heilongjiang Provincial Postdoctoral Science Foundation(No.LBH-Z19137)Natural Science Foundation of Heilongjiang Province(No.LH2019E038)。
文摘New ambient sound absorption material,lightweight isocyanate-based polyimide foam(IBPIF),was fabricated by operable combination between different distinctive acoustic IBPIF.Cellular structure of IBPIF was facilely and obviously adjusted by increased slurry temperature corresponding to change in distinctive acoustic properties.Moreover,density of all IBPIF kept at only 12-17 kg/m3.With increasing slurry temperature from 0℃to 40℃,cell size and window opening rate gradually increased from 553μm to 791μm and from 6.85%to 58.46%,respectively.In this study,IBPIF generated by slurries at 0℃(marked as PIF-2)and 40℃(marked as PIF-6)showed best and distinctive acoustic behavior in 315-800 Hz and 800-6300 Hz regions,respectively.After acoustic behavior study of combined IBPIF prepared by stitching combination between two distinctive acoustic IBPIFs,results showed that only when PIF-6 sheet used as sound receiving surface even though with thickness of only 10 mm could the combined IBPIF possess the best acoustic level in 800-6300 Hz region as PIF-6.Furtherly,acoustic behavior in 315-800 Hz region could be significantly enhanced by increasing thickness of PIF-2 and could reach or close to the best acoustic level.
