Many properties of polyester filaments such as heat shrinkage, tenacity, elongation at break and etc. are greatly influenced by drawing, so post-drawing is important in downstream processing. As more and more profile ...Many properties of polyester filaments such as heat shrinkage, tenacity, elongation at break and etc. are greatly influenced by drawing, so post-drawing is important in downstream processing. As more and more profile fibers and multi-variance fibers used in textile industry, the properties of above two kinds of differential polyester filaments after drawing in different heat conditions were studied. Finally following conclusions were obtained: Firstly, the tenacity and elongation at break decreases with the rise of Tp. Secondly, the tenacity rises but the elongation at break decreases with the increase of Tb. Then, when the Tb is low, both the shrinkage in boiling water and hi hot air decreases with the rise of Tp, while, when the Tb is high, both the shrinkage rises with the rise of Tp. The last, both the shrinkage decreases with the rise of Tb.展开更多
The effects of curing temperature on the expansive effectiveness, strength, hydration degree, and microstructure of shrinkagecompensated binder were studied. The results showed that under the standard curing temperatu...The effects of curing temperature on the expansive effectiveness, strength, hydration degree, and microstructure of shrinkagecompensated binder were studied. The results showed that under the standard curing temperature (20℃), most crystalline ettringite grows in pores, which makes less contribution to the expansion of paste than gelatinous ettringite blended with C-S-H gel. An elevated curing temperature (40℃) promotes the hydration rate of expansive agent and cement. However, quickly developing strength of paste limits its expansion. The pore structure of hardened paste under moderate curing condition is the densest one among all the pastes cured at different temperatures due to the filling effect of crystalline and gelatinous ettringite. Under a high curing temperature (60℃), the formation of massive stick-like ettringite leads to excessive expansion at early hydration age. Some ettringite decomposes at sustainable high temperature, which decreases the restricted expansion rate of paste at a late age. Appropriate volume expansion is benefit to the improvement of pore structure of hardened paste by reducing large pores.展开更多
基金supported by Leading Academic Discipline Project of SHNU(No.DZL803)Innovation Project of Shanghai Education Committee(No.12YZ081)+3 种基金General Scientific Research Project of SHNU(No. SK201121)Mathematical Tianyuan Foundation of China(No.10926078)National Natural Science Foundation of China(No.11001046)Fundamental Research Foundation for the Central Universities(No.11D10904)
文摘Many properties of polyester filaments such as heat shrinkage, tenacity, elongation at break and etc. are greatly influenced by drawing, so post-drawing is important in downstream processing. As more and more profile fibers and multi-variance fibers used in textile industry, the properties of above two kinds of differential polyester filaments after drawing in different heat conditions were studied. Finally following conclusions were obtained: Firstly, the tenacity and elongation at break decreases with the rise of Tp. Secondly, the tenacity rises but the elongation at break decreases with the increase of Tb. Then, when the Tb is low, both the shrinkage in boiling water and hi hot air decreases with the rise of Tp, while, when the Tb is high, both the shrinkage rises with the rise of Tp. The last, both the shrinkage decreases with the rise of Tb.
基金supported by the National Basic Research Program of China ("973"Project) (Grant No. 2009CB623106)
文摘The effects of curing temperature on the expansive effectiveness, strength, hydration degree, and microstructure of shrinkagecompensated binder were studied. The results showed that under the standard curing temperature (20℃), most crystalline ettringite grows in pores, which makes less contribution to the expansion of paste than gelatinous ettringite blended with C-S-H gel. An elevated curing temperature (40℃) promotes the hydration rate of expansive agent and cement. However, quickly developing strength of paste limits its expansion. The pore structure of hardened paste under moderate curing condition is the densest one among all the pastes cured at different temperatures due to the filling effect of crystalline and gelatinous ettringite. Under a high curing temperature (60℃), the formation of massive stick-like ettringite leads to excessive expansion at early hydration age. Some ettringite decomposes at sustainable high temperature, which decreases the restricted expansion rate of paste at a late age. Appropriate volume expansion is benefit to the improvement of pore structure of hardened paste by reducing large pores.
