Blends of poly（lactic acid）（PLA） and thermoplastic acetylated starch（ATPS） were prepared by means of the melt mixing method. The results show that PLA and ATPS were partially miscible, which was confirmed with t...Blends of poly（lactic acid）（PLA） and thermoplastic acetylated starch（ATPS） were prepared by means of the melt mixing method. The results show that PLA and ATPS were partially miscible, which was confirmed with the measurement of Tg by dynamic mechanical analysis（DMA） and differrential scanning calorimetry（DSC）. The mechanical and thermal properties of the blends were improved. With increasing the ATPS content, the elongation at break and impact strength were increased. The elongation at break increased from 5% of neat PLA to 25% of the blend PLA/ATPS40. It was found that the cold crystallization behavior of PLA changed evidently by addition of ATPS. The cold crystallization temperature（Tcc） of each of PLA/ATPS blends was found to shift to a lower temperature and the width of exothermic peak became narrow compared with that of neat PLA. The thermogravimetry analysis（TGA） results showed that the peak of derivative weight for ATPS moved to higher temperature with increasing PLA content in PLA/ATPS blends. It can be concluded that PLA could increase the thermal stability of ATPS. The rheological measurement reveals the melt elasticity and viscosity of the blends decreased with the increased concentration of ATPS, which was favorable to the processing properties of PLA.展开更多
The interest in thermoplastic starch(TPS)as a substitute material to replace conventional thermoplastics continues especially due its biodegradability,availability,low cost and because it is obtained from renewable so...The interest in thermoplastic starch(TPS)as a substitute material to replace conventional thermoplastics continues especially due its biodegradability,availability,low cost and because it is obtained from renewable sources.However,its poor mechanical properties and its high sensitivity to humidity have limited its use in several applications.Here,the copolymer poly(ethylene-co-vinyl alcohol)(EVOH),with two different ethylene contents,27 and 44 mol%were blended with TPS by extrusion in order to overcome these limitations.The obtained blends were characterized by thermogravimetric analysis(TGA),differential scanning calorimetry(DSC),mechanical tensile testing,Scanning Electron Microscopy(SEM)and moisture absorption test.The addition of EVOH copolymer did not significantly changed the thermal stability of TPS,however it increased the tensile strength in 65%when compared to TPS.The morphology of the blends did not showed two distinct phases,an indication of miscibility or partial miscibility of the components.A decrease of moisture absorption was obtained by the addition of EVOH and is more pronounced for the EVOH with 44% of ethylene.展开更多
The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficien...The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficient biomechanical properties,blended films composed of silk fibroin( SF) and poly( ε-caprolactone)( PCL) were fabricated by electrospinning in this study. Scanning electron microscope( SEM), X-ray diffraction( XRD),thermal analysis,Fourier transform-infrared( FT-IR),Raman spectra,mechanical testing,and water solubility were used to characterize the morphological, structural and mechanical properties of the blended electrospinning films. Results showed that the diameter of the blended fiber was distributed between 600 and1000 nm,and the fiber diameter increased as the PCL content increased. There is no obvious phase separation due to the similarity and intermiscibility,as well as the interactions( mainly hydrogen bonds), between the two polymers. Meanwhile, the secondary structures of SF changed from random coils and Silk I to Silk II because of the interactions between SF and PCL. For this reason,the tensile strength and elongation at break of the electrospinning films improved significantly,and the water solubility decreased. In conclusion,the blended electrospinning films fabricated in this study showed satisfying mechanical properties and water insolubilities,and they may be promising biomaterials for applications in tissue engineering for blood vessels,nerve conduits,tendons,ligaments and other tissues.展开更多
In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction par...In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction parameter between the polymers is calculated from the melting point depression data. Using optical microscope, the shapes of the PCL spherulites in the blends are observed.展开更多
Polymer blends of cold water soluble starches (amylose or amylopectin soluble starch) with gelatin were prepared using solvent casting method. The solid state miscibility and polymer-polymer interactions between the c...Polymer blends of cold water soluble starches (amylose or amylopectin soluble starch) with gelatin were prepared using solvent casting method. The solid state miscibility and polymer-polymer interactions between the constituent polymers were studied by fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorirmetry (DSC), light optical microscopy (OP) and scanning electron microscopy (SEM), whereas the thermal stability of the blends was studied by thermogravimetric analysis (TGA). Furthermore, tensile and water vapor barrier properties of the blends were assessed. The obtained results exhibited that gelatin was more miscible with amylose soluble starch than with amylopectin soluble starch. Moreover, enhancing mechanical and water barrier properties of amylose soluble starch/gelatin blends were more pronounced than those of amylopectin soluble starch/gelatin blends. Generally, tensile strength (TS) and Elongation percentage (E) of the blend films were found to be gradually increased with increasing the proportion of gelatin. Nevertheless, increasing starch proportion was in favor of decreasing water vapor permeability (WVP). At equal proportions of starch and gelatin (1:1), TS was raised up to 8.69 MPa for amylose soluble starch/gelatin blend films while it raised up to 4.96 MPa for amylopectin soluble starch/gelatin blend films, and so on E was increased to its maximum by ~179.6% for soluble amylose starch/gelatin blends while it was increased to ~114.5% for amylopectin soluble starch/gelatin blends. On the other hand, WVP was significantly decreased to be 6.46 and 12.09 g·mm/m2·day·kPa for blends of amylose and amylopectin soluble?starches, respectively.展开更多
Chitosan starch blend films were prepared, and their structure and properties were studied by FT IR, X ray diffraction, SEM and measurement of tensile strength. IR spectra and SEM analysis showed that the two polys...Chitosan starch blend films were prepared, and their structure and properties were studied by FT IR, X ray diffraction, SEM and measurement of tensile strength. IR spectra and SEM analysis showed that the two polysaccharides were compatible, when the starch was less than 30% by weight. From X ray diffraction patterns of blend fllms,it was observed that crystallization of starch was inhibited, and recrystallization of chitosan was also affected by starch. Crystal form Ⅰ, one of the main two crystal forms of chitosan,drastically increased in 30% starch content films. These results indicated that the interactions between chitosan and starch molecules exist in the blend films. The tensile strength of the film were improved when chitosan and starch were blended by weight ratios of 8∶2 and 7∶3, in which the highest tensile strength (781 kg/cm 2) was achieved.展开更多
The EVA-150 and starch were extruded by extruding press and the bio-degra- dation composite material was prepared to use as the controlled-release matrix of imazethapyr.The compatibility and crystallinity of EVA-150/s...The EVA-150 and starch were extruded by extruding press and the bio-degra- dation composite material was prepared to use as the controlled-release matrix of imazethapyr.The compatibility and crystallinity of EVA-150/starch blending were analyzed by SEM and DSC,and the controlled-released performance of imazethapyr in the carriers was also investigated by UV analysis.The results show that EVA-150/starch composite matrix has the obvious controlled-released function and the release rates of imazethapyr all exceed 50% in the environment of pH4,pH7,or pH9 after nine days.展开更多
基金Supported by the Chinese Academy of Sciences Direction Project(No.KTCX-YW-208)
文摘Blends of poly（lactic acid）（PLA） and thermoplastic acetylated starch（ATPS） were prepared by means of the melt mixing method. The results show that PLA and ATPS were partially miscible, which was confirmed with the measurement of Tg by dynamic mechanical analysis（DMA） and differrential scanning calorimetry（DSC）. The mechanical and thermal properties of the blends were improved. With increasing the ATPS content, the elongation at break and impact strength were increased. The elongation at break increased from 5% of neat PLA to 25% of the blend PLA/ATPS40. It was found that the cold crystallization behavior of PLA changed evidently by addition of ATPS. The cold crystallization temperature（Tcc） of each of PLA/ATPS blends was found to shift to a lower temperature and the width of exothermic peak became narrow compared with that of neat PLA. The thermogravimetry analysis（TGA） results showed that the peak of derivative weight for ATPS moved to higher temperature with increasing PLA content in PLA/ATPS blends. It can be concluded that PLA could increase the thermal stability of ATPS. The rheological measurement reveals the melt elasticity and viscosity of the blends decreased with the increased concentration of ATPS, which was favorable to the processing properties of PLA.
文摘The interest in thermoplastic starch(TPS)as a substitute material to replace conventional thermoplastics continues especially due its biodegradability,availability,low cost and because it is obtained from renewable sources.However,its poor mechanical properties and its high sensitivity to humidity have limited its use in several applications.Here,the copolymer poly(ethylene-co-vinyl alcohol)(EVOH),with two different ethylene contents,27 and 44 mol%were blended with TPS by extrusion in order to overcome these limitations.The obtained blends were characterized by thermogravimetric analysis(TGA),differential scanning calorimetry(DSC),mechanical tensile testing,Scanning Electron Microscopy(SEM)and moisture absorption test.The addition of EVOH copolymer did not significantly changed the thermal stability of TPS,however it increased the tensile strength in 65%when compared to TPS.The morphology of the blends did not showed two distinct phases,an indication of miscibility or partial miscibility of the components.A decrease of moisture absorption was obtained by the addition of EVOH and is more pronounced for the EVOH with 44% of ethylene.
基金National Natural Science Foundations of China(No.30970714,No.51103092)Natural Science Foundation of Jiangsu Province,China(No.BK2012634)+1 种基金College Natural Science Research Project of Jiangsu Province,China(No.12KJA430003)Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficient biomechanical properties,blended films composed of silk fibroin( SF) and poly( ε-caprolactone)( PCL) were fabricated by electrospinning in this study. Scanning electron microscope( SEM), X-ray diffraction( XRD),thermal analysis,Fourier transform-infrared( FT-IR),Raman spectra,mechanical testing,and water solubility were used to characterize the morphological, structural and mechanical properties of the blended electrospinning films. Results showed that the diameter of the blended fiber was distributed between 600 and1000 nm,and the fiber diameter increased as the PCL content increased. There is no obvious phase separation due to the similarity and intermiscibility,as well as the interactions( mainly hydrogen bonds), between the two polymers. Meanwhile, the secondary structures of SF changed from random coils and Silk I to Silk II because of the interactions between SF and PCL. For this reason,the tensile strength and elongation at break of the electrospinning films improved significantly,and the water solubility decreased. In conclusion,the blended electrospinning films fabricated in this study showed satisfying mechanical properties and water insolubilities,and they may be promising biomaterials for applications in tissue engineering for blood vessels,nerve conduits,tendons,ligaments and other tissues.
基金The subject supported by National Natural Science Foundation of China
文摘In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction parameter between the polymers is calculated from the melting point depression data. Using optical microscope, the shapes of the PCL spherulites in the blends are observed.
文摘Polymer blends of cold water soluble starches (amylose or amylopectin soluble starch) with gelatin were prepared using solvent casting method. The solid state miscibility and polymer-polymer interactions between the constituent polymers were studied by fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorirmetry (DSC), light optical microscopy (OP) and scanning electron microscopy (SEM), whereas the thermal stability of the blends was studied by thermogravimetric analysis (TGA). Furthermore, tensile and water vapor barrier properties of the blends were assessed. The obtained results exhibited that gelatin was more miscible with amylose soluble starch than with amylopectin soluble starch. Moreover, enhancing mechanical and water barrier properties of amylose soluble starch/gelatin blends were more pronounced than those of amylopectin soluble starch/gelatin blends. Generally, tensile strength (TS) and Elongation percentage (E) of the blend films were found to be gradually increased with increasing the proportion of gelatin. Nevertheless, increasing starch proportion was in favor of decreasing water vapor permeability (WVP). At equal proportions of starch and gelatin (1:1), TS was raised up to 8.69 MPa for amylose soluble starch/gelatin blend films while it raised up to 4.96 MPa for amylopectin soluble starch/gelatin blend films, and so on E was increased to its maximum by ~179.6% for soluble amylose starch/gelatin blends while it was increased to ~114.5% for amylopectin soluble starch/gelatin blends. On the other hand, WVP was significantly decreased to be 6.46 and 12.09 g·mm/m2·day·kPa for blends of amylose and amylopectin soluble?starches, respectively.
文摘Chitosan starch blend films were prepared, and their structure and properties were studied by FT IR, X ray diffraction, SEM and measurement of tensile strength. IR spectra and SEM analysis showed that the two polysaccharides were compatible, when the starch was less than 30% by weight. From X ray diffraction patterns of blend fllms,it was observed that crystallization of starch was inhibited, and recrystallization of chitosan was also affected by starch. Crystal form Ⅰ, one of the main two crystal forms of chitosan,drastically increased in 30% starch content films. These results indicated that the interactions between chitosan and starch molecules exist in the blend films. The tensile strength of the film were improved when chitosan and starch were blended by weight ratios of 8∶2 and 7∶3, in which the highest tensile strength (781 kg/cm 2) was achieved.
基金the Enterprise Postdoctoral Fund of Liaoning Province(BSH2005921077)
文摘The EVA-150 and starch were extruded by extruding press and the bio-degra- dation composite material was prepared to use as the controlled-release matrix of imazethapyr.The compatibility and crystallinity of EVA-150/starch blending were analyzed by SEM and DSC,and the controlled-released performance of imazethapyr in the carriers was also investigated by UV analysis.The results show that EVA-150/starch composite matrix has the obvious controlled-released function and the release rates of imazethapyr all exceed 50% in the environment of pH4,pH7,or pH9 after nine days.
