Two CaCO3-based materials （limestone and clamshells） and steel slag were used as mineral admixtures in cement to produce ternary blends and their influences on hydration and portlandite formation were analyzed. Addi...Two CaCO3-based materials （limestone and clamshells） and steel slag were used as mineral admixtures in cement to produce ternary blends and their influences on hydration and portlandite formation were analyzed. Additionally, mechanical properties were determined. These properties were determined using X-ray diffraction and scanning electron microscopic/energy dispersive X-ray analytical techniques as well as applying methods specified by EN （European Standards） and ASTM （American Standards for Testing and Materials）. The portlandite （Ca（OH）E） content was considerably reduced from 36.9% of reference cement to between 13.79% and 15.5%. With the water demand and setting times of the cements containing up to 10%, admixtures did not change significantly. The mechanical tests results showed that ternary blends produced 2-day strengths higher than that specified by EN 197-1 and that blends containing up to 20% admixtures can be used to produce both Class 32.5N and 42.5N cements.展开更多
Inherent brittleness and low heat resistance are the two major obstacles that hinder the wide applications of poly（L-lactide）（PLLA）. In this study,we report a fully biobased,highly toughened and heat-resistant PLL...Inherent brittleness and low heat resistance are the two major obstacles that hinder the wide applications of poly（L-lactide）（PLLA）. In this study,we report a fully biobased,highly toughened and heat-resistant PLLA ternary blend,which was prepared by dynamic vulcanization of PLLA with poly（D-lactide）（PDLA） and an unsaturated bioelastomer（UBE）. The results indicated that during dynamic vulcanization PDLA cocrystallized with PLLA to form stereocomplex（SC） crystallites,which not only enhanced the molecular entanglement but also accelerated the crystallization rate of PLLA matrix. With increase in the content of PDLA,the matrix molecular entanglement increased while phase-separation was enhanced,which enabled the impact strength to increase first and then decrease. The ternary blends containing 10 wt.% PDLA showed the highest impact strength. The presence of SC crystallites makes it possible to achieve a fully sustainable PLLA/VUB/PDLA ternary blend with highly crystalline matrix under conventional injection molding,due to the high nucleation efficiency of SC towards crystallization of PLLA. The highly crystalline ternary blend showed excellent heat resistance and better impact toughness than high impact polystyrene.展开更多
文摘Two CaCO3-based materials （limestone and clamshells） and steel slag were used as mineral admixtures in cement to produce ternary blends and their influences on hydration and portlandite formation were analyzed. Additionally, mechanical properties were determined. These properties were determined using X-ray diffraction and scanning electron microscopic/energy dispersive X-ray analytical techniques as well as applying methods specified by EN （European Standards） and ASTM （American Standards for Testing and Materials）. The portlandite （Ca（OH）E） content was considerably reduced from 36.9% of reference cement to between 13.79% and 15.5%. With the water demand and setting times of the cements containing up to 10%, admixtures did not change significantly. The mechanical tests results showed that ternary blends produced 2-day strengths higher than that specified by EN 197-1 and that blends containing up to 20% admixtures can be used to produce both Class 32.5N and 42.5N cements.
基金supported by the National Science Foundation of China (51673158)the Opening Project of Key Laboratory of Polymer Processing Engineering (South China University of Technology),Ministry of Education (KFKT02)the Fundamental Research Funds for the Central Universities (XDJK2017A016 and XDJK2017C022)
文摘Inherent brittleness and low heat resistance are the two major obstacles that hinder the wide applications of poly（L-lactide）（PLLA）. In this study,we report a fully biobased,highly toughened and heat-resistant PLLA ternary blend,which was prepared by dynamic vulcanization of PLLA with poly（D-lactide）（PDLA） and an unsaturated bioelastomer（UBE）. The results indicated that during dynamic vulcanization PDLA cocrystallized with PLLA to form stereocomplex（SC） crystallites,which not only enhanced the molecular entanglement but also accelerated the crystallization rate of PLLA matrix. With increase in the content of PDLA,the matrix molecular entanglement increased while phase-separation was enhanced,which enabled the impact strength to increase first and then decrease. The ternary blends containing 10 wt.% PDLA showed the highest impact strength. The presence of SC crystallites makes it possible to achieve a fully sustainable PLLA/VUB/PDLA ternary blend with highly crystalline matrix under conventional injection molding,due to the high nucleation efficiency of SC towards crystallization of PLLA. The highly crystalline ternary blend showed excellent heat resistance and better impact toughness than high impact polystyrene.
