With the help of differential scanning calorimetry, cone-plate and capillary rheometry andscanning electron microscopy, a research has been conducted on rheological behavior,crystallization and morphology of poly (but...With the help of differential scanning calorimetry, cone-plate and capillary rheometry andscanning electron microscopy, a research has been conducted on rheological behavior,crystallization and morphology of poly (butylene terephthalate) (PBT) blends containing athermotropic LCP. The blend has zero entrance pressure loss, although the LCP has rather largeone. The viscosity curve of the blend lies between those of the LCP and PBT. The crystallizationof PBT is not affected by the presence of the LCP together with no indication oftransesterification between the two ingredients. LCP spheres and ellipsoids with the size of 0. 5--1. 5 μm disperse in PBT matrix uniformly, which is related to the viscosity ratio of the two components.展开更多
The fluorescent complex Eu(TTA)2(Phen)(MA) (HTTA=2-Thenoyltrifluoroacetone, Phen=1,10-phenanthroline, MA=Maleic an- hydrider) was synthesized and characterized with elemental analysis, infrared spectrum (IR)...The fluorescent complex Eu(TTA)2(Phen)(MA) (HTTA=2-Thenoyltrifluoroacetone, Phen=1,10-phenanthroline, MA=Maleic an- hydrider) was synthesized and characterized with elemental analysis, infrared spectrum (IR), scanning electron microscope (SEM), X-ray Diffraction(XRD), differential scanning calorimetry(DSC), and fluorescent measurement. To explore the effect of different physical dispersion state of Eu-complex on the fluorescent property of the Eu-complex/silicon rubber composites, various quantifies of Eu(TTA)2(phen) (MA) were mixed with silicon rubber (SIR) and peroxide to form uncured composites. These composites were vulcanized to obtain cured Eu-complex/SiR composites at 250 ℃, which was higher than the melting-point of Eu-complex. The SEM, XRD, DSC, and the fluorescent measurement of these composites showed that both the complex molecules dispersed in the silicon rubber during the melting process and the parent Eu-complex particles had positive effects on fluorescent property, whereas the re-crystallized Eu-complex particles and the aggregating complexes formed during the melting-process had negative effects on fluorescent property. For the uncured composites, their fluorescent intensities almost did not change with the increasing amount of Eu-complex. Furthermore, for the composites with small content of Eu-complex, their fluorescent intensities decreased significantly after curing, and this difference in fluorescent intensity became smaller as the content of Eu-complex increases.展开更多
Polyphenylene sulfides(PPS) and low-melting temperature glasses(LMTG) were used to prepare a PPS/LMTG organicinorganic hybrid material by melt blending.The etched surfaces of the hybrids were observed by scanning ...Polyphenylene sulfides(PPS) and low-melting temperature glasses(LMTG) were used to prepare a PPS/LMTG organicinorganic hybrid material by melt blending.The etched surfaces of the hybrids were observed by scanning electron microscope (SEM) and the images showed different dispersed phase morphologies compared to traditional filled composites,which maybe induced by shear.Advanced rheometric expanded system(ARES) was used to investigate the rheological behaviors of the hybrids and the results showed that the strain y dependence of dynamic storage modulus G' for the hybrids with high contents of LMTG did not appear Payne effect.展开更多
Fused deposition modelling(FDM)is a commonly used 3D printing technology.The development of FDM materials was essential for the product quality of FDM.In this work,a series of polycaprolactone(PCL)-based composites fo...Fused deposition modelling(FDM)is a commonly used 3D printing technology.The development of FDM materials was essential for the product quality of FDM.In this work,a series of polycaprolactone(PCL)-based composites for low-temperature FDM were developed.By melt blending technique,different ratios of starch were added into PCL to improve the performances of FDM,and the printability,tensile strength,rheological properties,crystallization behaviors and biological performances of the composites were studied.The PCL/starch composite had the best performance in FDM process with the starch ratio of 9 ph at 80–90°C.The melting strength and solidification rate of PCL/starch composites were improved.The starch also increased the crystallization temperature,degree of crystallinity and crystallization rate of PCL/starch composites,while had no negative effects on the tensile strength of PCL.Due to the low printing temperature,various kinds of bioactive components were added into PCL/starch composites for preparation of antibacterial and biocompatible materials for FDM.The present work provides a new method to develop novel low-temperature FDM materials with various functions.展开更多
基金Supported by the National Natural Science Foundation of China
文摘With the help of differential scanning calorimetry, cone-plate and capillary rheometry andscanning electron microscopy, a research has been conducted on rheological behavior,crystallization and morphology of poly (butylene terephthalate) (PBT) blends containing athermotropic LCP. The blend has zero entrance pressure loss, although the LCP has rather largeone. The viscosity curve of the blend lies between those of the LCP and PBT. The crystallizationof PBT is not affected by the presence of the LCP together with no indication oftransesterification between the two ingredients. LCP spheres and ellipsoids with the size of 0. 5--1. 5 μm disperse in PBT matrix uniformly, which is related to the viscosity ratio of the two components.
基金the National Natural Science Foundation of China,the China Energy Conservation Investment Corporation (50173004 and 50503002)the Beijing New Star Project (2003A11)+2 种基金the National High-Tech. Research Developing Foundation (863,2003AA324030)Beijing Municipal Commission of Education (JD100100403)National Key Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Technology of China (2006BAE03B)
文摘The fluorescent complex Eu(TTA)2(Phen)(MA) (HTTA=2-Thenoyltrifluoroacetone, Phen=1,10-phenanthroline, MA=Maleic an- hydrider) was synthesized and characterized with elemental analysis, infrared spectrum (IR), scanning electron microscope (SEM), X-ray Diffraction(XRD), differential scanning calorimetry(DSC), and fluorescent measurement. To explore the effect of different physical dispersion state of Eu-complex on the fluorescent property of the Eu-complex/silicon rubber composites, various quantifies of Eu(TTA)2(phen) (MA) were mixed with silicon rubber (SIR) and peroxide to form uncured composites. These composites were vulcanized to obtain cured Eu-complex/SiR composites at 250 ℃, which was higher than the melting-point of Eu-complex. The SEM, XRD, DSC, and the fluorescent measurement of these composites showed that both the complex molecules dispersed in the silicon rubber during the melting process and the parent Eu-complex particles had positive effects on fluorescent property, whereas the re-crystallized Eu-complex particles and the aggregating complexes formed during the melting-process had negative effects on fluorescent property. For the uncured composites, their fluorescent intensities almost did not change with the increasing amount of Eu-complex. Furthermore, for the composites with small content of Eu-complex, their fluorescent intensities decreased significantly after curing, and this difference in fluorescent intensity became smaller as the content of Eu-complex increases.
基金supported by the National Natural Science Funds of China(No.51073137)
文摘Polyphenylene sulfides(PPS) and low-melting temperature glasses(LMTG) were used to prepare a PPS/LMTG organicinorganic hybrid material by melt blending.The etched surfaces of the hybrids were observed by scanning electron microscope (SEM) and the images showed different dispersed phase morphologies compared to traditional filled composites,which maybe induced by shear.Advanced rheometric expanded system(ARES) was used to investigate the rheological behaviors of the hybrids and the results showed that the strain y dependence of dynamic storage modulus G' for the hybrids with high contents of LMTG did not appear Payne effect.
基金supported by National Natural Science Foundation of China(Grant No.51873012)National Key Research and Development Program of China(Grant No.2016YFC1100404)+2 种基金Beijing Municipal Natural Science Foundation(Grant No.7161001)Fundamental Research Funds for the Central Universities(Grant No.XK1802-2)Research Projects on Biomedical Transformation of China-Japan Friendship Hospital(Grant No.PYBZ1832).
文摘Fused deposition modelling(FDM)is a commonly used 3D printing technology.The development of FDM materials was essential for the product quality of FDM.In this work,a series of polycaprolactone(PCL)-based composites for low-temperature FDM were developed.By melt blending technique,different ratios of starch were added into PCL to improve the performances of FDM,and the printability,tensile strength,rheological properties,crystallization behaviors and biological performances of the composites were studied.The PCL/starch composite had the best performance in FDM process with the starch ratio of 9 ph at 80–90°C.The melting strength and solidification rate of PCL/starch composites were improved.The starch also increased the crystallization temperature,degree of crystallinity and crystallization rate of PCL/starch composites,while had no negative effects on the tensile strength of PCL.Due to the low printing temperature,various kinds of bioactive components were added into PCL/starch composites for preparation of antibacterial and biocompatible materials for FDM.The present work provides a new method to develop novel low-temperature FDM materials with various functions.