Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and the...Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and theories of the binder at room temperature were proposed according to the interactions between various compositions. Thus, the reasons for the binder to have excellent combination properties and unique adhesive bonding and self-curing characteristics were explained by these theories successfully. And the theories are of great directive importance to design and development of composite binder for green sand mould/core.展开更多
Hygroscopicity-resistance of an α-starch based composite binder for dry sand molds (cores) has been studiedexperimentally and theoretically. Focus is placed on the relationship between the hardening structure andhumi...Hygroscopicity-resistance of an α-starch based composite binder for dry sand molds (cores) has been studiedexperimentally and theoretically. Focus is placed on the relationship between the hardening structure andhumidity-resistance of the composite binder. The results show that the α-starch composite binder has goodhumidity-resistance due to its special complex structure. SEM observations illustrate that the composite binder consists ofreticular matrix and a ball- or lump-shaped reinforcement phase, and the specific property of the binding membrane withheterogeneous structure is affected by humidity to a small extent. Based on the analyses on the interplays of differentingredients in the binder at hardening, the structure model and hygroscopicity-resistant mechanisms of the hardeningcomposite binder were further proposed. Moreover, the reasons for good humidity-resistance of the composite binderbonded sand are well explained by the humidity-resistant mechanisms.展开更多
The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a n...The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a novel CL-20 based explosive ink formulation have been developed successfully for MEMS initiation systems via DIW technology.We designed PVA/GAP into an oil-in-water(O/W)emulsion,in the way that the aqueous solution of PVA as water phase,the ethyl acetate solution of GAP as oil phase,the combination of Tween 80 and SDS as emulsifier,BPS as a curing agent of GAP.The ideal formulation with good shear-thinning rheology properties and clear gel point was prepared using only 10 wt%emulsion.The dual-cured network formed during the curing process made the printed sample have good mechanical properties.The printed samples had satisfactory molding effect without cracks or fractures,the crystal form of CL-20 not changed and the thermal stability have improved.Deposition of explosive inks via DIW in micro-scale grooves had excellent detonation performances,which critical detonation size was 1×0.045 mm,detonation velocity was 7129 m/s and when the corner reaching 150°can still detonated stably.This study may open new avenues for developing binder systems in explosive ink formulations.展开更多
基金This work was supported by the China Postdoctoral Science Foundation(China Fund[1998]6)that was entitled“Synthesis of Modified Starch Binder and Its Application in Foundry”.Authors would like to thank academician Jinzong YANG and lecturer Hua ZHANG for the kind analyses and discussions.
文摘Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and theories of the binder at room temperature were proposed according to the interactions between various compositions. Thus, the reasons for the binder to have excellent combination properties and unique adhesive bonding and self-curing characteristics were explained by these theories successfully. And the theories are of great directive importance to design and development of composite binder for green sand mould/core.
文摘Hygroscopicity-resistance of an α-starch based composite binder for dry sand molds (cores) has been studiedexperimentally and theoretically. Focus is placed on the relationship between the hardening structure andhumidity-resistance of the composite binder. The results show that the α-starch composite binder has goodhumidity-resistance due to its special complex structure. SEM observations illustrate that the composite binder consists ofreticular matrix and a ball- or lump-shaped reinforcement phase, and the specific property of the binding membrane withheterogeneous structure is affected by humidity to a small extent. Based on the analyses on the interplays of differentingredients in the binder at hardening, the structure model and hygroscopicity-resistant mechanisms of the hardeningcomposite binder were further proposed. Moreover, the reasons for good humidity-resistance of the composite binderbonded sand are well explained by the humidity-resistant mechanisms.
基金This work was supported by the Graduate Education Innovation Project of Shanxi Province(2020SY401)No.55 Research Institute of China North Industries Group Corporation Open Innovation Fund(WDZC2020JJ017).
文摘The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a novel CL-20 based explosive ink formulation have been developed successfully for MEMS initiation systems via DIW technology.We designed PVA/GAP into an oil-in-water(O/W)emulsion,in the way that the aqueous solution of PVA as water phase,the ethyl acetate solution of GAP as oil phase,the combination of Tween 80 and SDS as emulsifier,BPS as a curing agent of GAP.The ideal formulation with good shear-thinning rheology properties and clear gel point was prepared using only 10 wt%emulsion.The dual-cured network formed during the curing process made the printed sample have good mechanical properties.The printed samples had satisfactory molding effect without cracks or fractures,the crystal form of CL-20 not changed and the thermal stability have improved.Deposition of explosive inks via DIW in micro-scale grooves had excellent detonation performances,which critical detonation size was 1×0.045 mm,detonation velocity was 7129 m/s and when the corner reaching 150°can still detonated stably.This study may open new avenues for developing binder systems in explosive ink formulations.
