The main objective of this study is to investigate the effects of the nanoclay mixed with recycled polyester fiber on the mechanical behavior of soil as a new stabilizer material.To meet this objective,a series of dra...The main objective of this study is to investigate the effects of the nanoclay mixed with recycled polyester fiber on the mechanical behavior of soil as a new stabilizer material.To meet this objective,a series of drained direct shear and compaction tests were performed on unreinforced and reinforced soil specimens with three different combinations of the fiber-soil ratios ranging between 0.1%and 0.5%,as well as three different combinations of nanoclay soil ratios ranging between 0.5%and 1.5%of the soil dry weight.Results indicated that composition of the nanoclay recycled polyester fiber with the soil improved the friction angle(Φ)by 41%and cohesion(c)by 174%.The soil particles stick together through viscose gel produced by nanoclay.In addition,the rough and wavy surface of the fibers creates a bond and friction between the soil particles and prevents the movement of soil particles,and as a result,the soil strength is increased.展开更多
Polyesters,such as polylactide(PLA),are a class of biodegra-dable and biocompatible polymers that have received increasing attention in biomedicine,agriculture,and commodity thermoplastics[1-2].However,the lack of pen...Polyesters,such as polylactide(PLA),are a class of biodegra-dable and biocompatible polymers that have received increasing attention in biomedicine,agriculture,and commodity thermoplastics[1-2].However,the lack of pendant functionality of conventional polyesters makes it difficult to modify and modulate the physicochemical properties in subsequent applications[3-4].Since 2006[5],the ring-opening polymerization(ROP)of O-carbox-yanhydrides(OCAs),which can be readily synthesized from amino acid or hydroxyl acid precursors,has been recognized as a promising route to functionalized polyesters[3-4].However,due to the increased methine C-H acidity,significant racemization of the stereogenic center and decreased stereoregularity have been identified for most OCAs,for instance,ManOCA[6](OCA from mandelic acid)and SerOCA[7](OCA from serine),when using typical 4-(dimethylamino)pyridine(DMAP)as catalyst.To minimize epimerization,some classical metal-based catalysts of coordination polymerization have been introduced to mediate ROP of OCAs,furnishing isotactic polyesters[8].展开更多
Polyfunctional aziridine/polyester microcapsules as control-release waterborne cross-linker were synthesized by multiple emulsion-solvent evaporation method. The results show that,a lower surface free energy with shel...Polyfunctional aziridine/polyester microcapsules as control-release waterborne cross-linker were synthesized by multiple emulsion-solvent evaporation method. The results show that,a lower surface free energy with shell polyester is more favourable for the formation of microcapsules. Full encapsulating microcapsules are synthesized with the polyester with a surface free energy of 34.5 mJ/m2. Shell-to-core feeding mass ratio has a significant influence on the morphology and core content of the resulting microcapsules. Well defined spherical microcapsules with uniform shell thickness and core content at around 22% are produced at a shell-to-core mass ratio of 1:1. When 2.5% of colloid stabilizer is used,hollow spherical microcapsules are obtained. A high solvent evaporation rate results in wrinkling and porosity of the microcapsules,and an evaporation rate equivalent to solvent elimination in about 2 h provides a uniform rate of surface hardening. The characterization of the microcapsules by SEM and FTIR demonstrates that polyfunctional aziridine is encapsulated at the centre of the microcapsule. The microcapsules synthesized can be broken at a high shear rate.展开更多
文摘The main objective of this study is to investigate the effects of the nanoclay mixed with recycled polyester fiber on the mechanical behavior of soil as a new stabilizer material.To meet this objective,a series of drained direct shear and compaction tests were performed on unreinforced and reinforced soil specimens with three different combinations of the fiber-soil ratios ranging between 0.1%and 0.5%,as well as three different combinations of nanoclay soil ratios ranging between 0.5%and 1.5%of the soil dry weight.Results indicated that composition of the nanoclay recycled polyester fiber with the soil improved the friction angle(Φ)by 41%and cohesion(c)by 174%.The soil particles stick together through viscose gel produced by nanoclay.In addition,the rough and wavy surface of the fibers creates a bond and friction between the soil particles and prevents the movement of soil particles,and as a result,the soil strength is increased.
文摘Polyesters,such as polylactide(PLA),are a class of biodegra-dable and biocompatible polymers that have received increasing attention in biomedicine,agriculture,and commodity thermoplastics[1-2].However,the lack of pendant functionality of conventional polyesters makes it difficult to modify and modulate the physicochemical properties in subsequent applications[3-4].Since 2006[5],the ring-opening polymerization(ROP)of O-carbox-yanhydrides(OCAs),which can be readily synthesized from amino acid or hydroxyl acid precursors,has been recognized as a promising route to functionalized polyesters[3-4].However,due to the increased methine C-H acidity,significant racemization of the stereogenic center and decreased stereoregularity have been identified for most OCAs,for instance,ManOCA[6](OCA from mandelic acid)and SerOCA[7](OCA from serine),when using typical 4-(dimethylamino)pyridine(DMAP)as catalyst.To minimize epimerization,some classical metal-based catalysts of coordination polymerization have been introduced to mediate ROP of OCAs,furnishing isotactic polyesters[8].
基金Project(50903031) supported by the National Natural Science Foundation of ChinaProject(2009ZM0046) supported by the Fundamental Research Funds for the Central Universities in ChinaProject(N9100240) supported by the Foundation for Distinguished Young Talents in Higher Education of Guangdong Province, China
文摘Polyfunctional aziridine/polyester microcapsules as control-release waterborne cross-linker were synthesized by multiple emulsion-solvent evaporation method. The results show that,a lower surface free energy with shell polyester is more favourable for the formation of microcapsules. Full encapsulating microcapsules are synthesized with the polyester with a surface free energy of 34.5 mJ/m2. Shell-to-core feeding mass ratio has a significant influence on the morphology and core content of the resulting microcapsules. Well defined spherical microcapsules with uniform shell thickness and core content at around 22% are produced at a shell-to-core mass ratio of 1:1. When 2.5% of colloid stabilizer is used,hollow spherical microcapsules are obtained. A high solvent evaporation rate results in wrinkling and porosity of the microcapsules,and an evaporation rate equivalent to solvent elimination in about 2 h provides a uniform rate of surface hardening. The characterization of the microcapsules by SEM and FTIR demonstrates that polyfunctional aziridine is encapsulated at the centre of the microcapsule. The microcapsules synthesized can be broken at a high shear rate.
