Stannous-acetylacetonate was prepared efficiently and characterized by ^1H NMR and FT-IR. Its catalytic activity for poly（trimethylene terephthalate） （PTT） synthesis was investigated. By this catalyst, the degree ...Stannous-acetylacetonate was prepared efficiently and characterized by ^1H NMR and FT-IR. Its catalytic activity for poly（trimethylene terephthalate） （PTT） synthesis was investigated. By this catalyst, the degree of esterification of pure terephthalic acid was up to 91.7% after reaction at 260 ℃ for 2 h, while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PTT polymerized at 260 ℃, 60 Pa for 2 h was 0.8816 dL/g and 17 mol/t,respectively. Stannous-acetylacetonate was more active and promising than tetrabutyl titanate and stannous octoate for PTT synthesis.展开更多
Poly（trimethylene terephthalate） （PTT） is an excellent fiber material. Its thermal degradation and isothermal crystalline behaviors were in this study investigated using thermogravimetric analysis （TGA）, thermog...Poly（trimethylene terephthalate） （PTT） is an excellent fiber material. Its thermal degradation and isothermal crystalline behaviors were in this study investigated using thermogravimetric analysis （TGA）, thermogravimetric analysis-Fourier transform infrared spectroscopy （TGA-FTIR） analysis, differential scanning calorimetry （DSC） and X-ray diffraction （XRD）. The thermal degradation mechanism of PTT follows Mclafferty rearrangement principle. The PTTwithintrinsicviscosity（IV） of 0.74 dL/g has a maximum crystallinity of about 55% at 190 ℃, as demonstrated by DSC and XRD measurements consistently.展开更多
Lipase preparation from Aspergillus oryzae could act on ester bonds on the surface of poly （ethylene terephthalate） fibers and a possible hydrolytic product mono （2-hydroxyethyl） terephthalate was released. After ...Lipase preparation from Aspergillus oryzae could act on ester bonds on the surface of poly （ethylene terephthalate） fibers and a possible hydrolytic product mono （2-hydroxyethyl） terephthalate was released. After the iipase modification, there were more carboxyi groups on the treated poly （ethylene terephthalate） fabric surface that resulted in binding with more cationic dyes. Increased hydrophilicity and antistatic ability of poly （ethylene terephthalate） samples were found based on moisture regain, water contact angle and static half decay time.展开更多
Various morphologies of poly（trimethylene terephthalate） （PTT） solution-cast thin films at different crystallization temperatures were investigated by polarized light microscopy （PLM）,atomic force microscopy （...Various morphologies of poly（trimethylene terephthalate） （PTT） solution-cast thin films at different crystallization temperatures were investigated by polarized light microscopy （PLM）,atomic force microscopy （AFM） and transmitted electron microscopy （TEM）.In the range of 110-150 ℃,banded spherulite occurred and banding space gradually decreased along the radial direction from the primary nucleation site.Between 160 and 170 ℃,normal non-banded spherulite was found.Above 170 ℃,banded configuration occurred again.Lamellar growth direction of banded spherulite was determined to the crystal a-axis.展开更多
The non-isothermal crystallization kinetics of modified poly(ethylene terephthalate) (PET) with the function of ultraviolet (UV) protection was studied by means of differential scanning calorimetry. The kinetics of th...The non-isothermal crystallization kinetics of modified poly(ethylene terephthalate) (PET) with the function of ultraviolet (UV) protection was studied by means of differential scanning calorimetry. The kinetics of the modified polymer under non-isothermal crystallization was analyzed by Ozawa equation. The crystallization behavior of the modified polymer obeyed Ozawa theory. The additives in the polymer whose function was UV-resistant acted as crystal nucleus in the processing of crystallization, which resulted in the increase of Avrami index and the crystallization rate of the cooling system.展开更多
The spherulites of the short carbon fiber(SCF)/poly(trimethyleneterephthalate)(PTT)compositesformedin limited space at designed temperatures,and their melting behaviors were studied by the polarized optical microscopy...The spherulites of the short carbon fiber(SCF)/poly(trimethyleneterephthalate)(PTT)compositesformedin limited space at designed temperatures,and their melting behaviors were studied by the polarized optical microscopy,atomic force microscopy(AFM),and scanning electron microscopy(SEM),respectively.The results suggest that SCF content,isothermal crystallization temperatures,and the film thicknesses influence the crystal morphology of the composites.The dimension of the spherulites is decreased with increasing SCF content,but whether banded or nonbanded spherulites will form in the composites is not dependent on SCF content.However,the crystal morphology of the composites depends strongly on the temperature.When the isothermal crystallization temperatures increase from 180℃ to 230℃,the crystal morphology of SCF/PTT composites continuously changes in the following order:nonbanded→banded→nonbanded spherulites.Disconti-nuous circle lines form in the film when the film thickness increases from 30 to 60μm.Basing on the SEM observation,it is found that these circle lines are cracks formed due to the constriction difference of the different parts of the spherulites.These cracks are formed when the film is cooled from the isothermal crystallization temperature to the room tempera-ture at a slow cooling rate;while they will disappear gradually at different temperatures in the heating process.The crack will appear/disappear first around the center of the spherulite when the film was cooled/heated.The nontwisted or slightly twisted lamellas will reorganize to form highly twisted lamellas inducing apparent banded texture of the spherulites.展开更多
采用自主设计的熔体离心纺丝设备研究了聚己二酸对苯二甲酸丁二醇酯(PBAT)的可纺性,并分析纺丝参数对PBAT纤维形貌和性能的影响。结果表明:挤出机温度为220℃、喷丝器温度为200℃、电机转速为4000 r min、收集距离为18 cm时纤维形貌最佳...采用自主设计的熔体离心纺丝设备研究了聚己二酸对苯二甲酸丁二醇酯(PBAT)的可纺性,并分析纺丝参数对PBAT纤维形貌和性能的影响。结果表明:挤出机温度为220℃、喷丝器温度为200℃、电机转速为4000 r min、收集距离为18 cm时纤维形貌最佳;纺丝温度的提高可有效避免纤维卷曲以及纤维细化;随着纺丝温度的增加,聚合物熔体黏度下降,流动性变好,制备的纤维分布更加均匀,纤维结晶度得到提高,纤维膜的力学性能得到明显改善,其最大应力提高至15.3 MPa,最大应变为80%。展开更多
A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titana...A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titanate (TBT), dibutyltin oxide (Bu2SnO), and stannous octoate (SOC)). Their catalytic activity in the esterification process is monitored by measuring the amount of water generated, while intrinsic viscosity (IV) and content of terminal carboxyl groups (CTCG) are used as the index in the polycondensation process. Stannous oxalate shows higher activity than the other catalysts. Decrease in reaction time and improvements in PTT property are observed. The higher catalytic activity of stannous oxalate is attributed to its chelate molecular structure.展开更多
Double melting behavior of poly(trimethylene terephthalate) (PTT) was studied in detail by means of differential scanning calorimetry (DSC) and optical microscopy. The results indicate that the low-temperature melting...Double melting behavior of poly(trimethylene terephthalate) (PTT) was studied in detail by means of differential scanning calorimetry (DSC) and optical microscopy. The results indicate that the low-temperature melting peak of PTT at ca. 218℃ for the samples crystallized isothermally at 203℃ is associated with the melting of crystals produced by secondary crystallization, while the high-temperature melting peak of it at about 227℃ is related to the melting of the crystals produced by primary crystallization. The results further demonstrate that the PTT crystals growing non-isothermally during cooling process are thermodynamically unstable and can undergo structure reorganization during the DSC heating scan. The reorganized crystals melt at temperature higher than the crystals produced by secondary crystallization at 203 ℃. Consequently, for the non-fully crystallized samples, the crystals grown during cooling also exhibit contribution to the high-temperature melting peak.展开更多
The rheological,phase morphologic,thermal andmechanicalpropertiesofpoly(trimethyleneterephthalate)/metallocene polyethylene(PTT/mPE)blends in the presence of ethylene propylene diene monomer copolymer grafted with mal...The rheological,phase morphologic,thermal andmechanicalpropertiesofpoly(trimethyleneterephthalate)/metallocene polyethylene(PTT/mPE)blends in the presence of ethylene propylene diene monomer copolymer grafted with maleic anhydride(EPDM-g-MAH)as compatibilizer are studied by means of a capillary rheometer,scanning electron microscopy(SEM),differential scanning calorimetry(DSC)and thermogravimetric analyzer(TGA).Results suggest that the compatibility of PTT/mPE blends is improved greatly after the addition of a compatibilizer.The radius of the dispersed phase in the system decreases greatly when the compatibilizer is added into the blend.When the amount of compatibilizer exceeds 8 wt-%,the size of dispersed phase becomes larger again.This phenomena could be attributed to the higher viscosity of the EPDM-g-MAH phase,which is dispersed more difficulty in the PTT phase of lower viscosity,thus the mixing efficiency is apparently decreased during the melt blending process.Moreover,the melt viscosity of the blend reaches the maximal value in case of 4 wt-%compati-bilizer content,above which it would decrease again.This result is associated with the generation of more and bigger dispersed phase inside the bulk phase,thus the grafting efficiency at the interface is decreased,which could result in lower viscosity.The DSC results suggest that the mPE component shows a nucleating effect,and could increase the overall degree and rate of PTT crystallization,while the addition of a compatibilizer might slightly diminish these effects.In addition,the blend with 4 wt-%compatibilizer shows the best thermal stability.Furthermore,the Izod impact strength and the tensile strength at room temperature of the blend are also markedly improved by the addition of a 4–8 wt-%compatibilizer.展开更多
文摘Stannous-acetylacetonate was prepared efficiently and characterized by ^1H NMR and FT-IR. Its catalytic activity for poly（trimethylene terephthalate） （PTT） synthesis was investigated. By this catalyst, the degree of esterification of pure terephthalic acid was up to 91.7% after reaction at 260 ℃ for 2 h, while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PTT polymerized at 260 ℃, 60 Pa for 2 h was 0.8816 dL/g and 17 mol/t,respectively. Stannous-acetylacetonate was more active and promising than tetrabutyl titanate and stannous octoate for PTT synthesis.
基金the China High-Tech Development 863 Program(No.2007AA03Z217)Guangdong Province Sci,& Tech.Bureau(No.2006B 12401006,06300332,2007A090302040)+1 种基金Guangzhou Sci.& Tech.Bureau(No.2005U13D2031,2007Z2-D2031)Foshan Sci.& Tech.Bureau for financial support of this work.
文摘Poly（trimethylene terephthalate） （PTT） is an excellent fiber material. Its thermal degradation and isothermal crystalline behaviors were in this study investigated using thermogravimetric analysis （TGA）, thermogravimetric analysis-Fourier transform infrared spectroscopy （TGA-FTIR） analysis, differential scanning calorimetry （DSC） and X-ray diffraction （XRD）. The thermal degradation mechanism of PTT follows Mclafferty rearrangement principle. The PTTwithintrinsicviscosity（IV） of 0.74 dL/g has a maximum crystallinity of about 55% at 190 ℃, as demonstrated by DSC and XRD measurements consistently.
基金Program for Changjiang Scholars and Inno■tive Research Team in University (IRT 0526)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘Lipase preparation from Aspergillus oryzae could act on ester bonds on the surface of poly （ethylene terephthalate） fibers and a possible hydrolytic product mono （2-hydroxyethyl） terephthalate was released. After the iipase modification, there were more carboxyi groups on the treated poly （ethylene terephthalate） fabric surface that resulted in binding with more cationic dyes. Increased hydrophilicity and antistatic ability of poly （ethylene terephthalate） samples were found based on moisture regain, water contact angle and static half decay time.
基金Funded by the National Natural Science Foundation of China( No.20234020)
文摘Various morphologies of poly（trimethylene terephthalate） （PTT） solution-cast thin films at different crystallization temperatures were investigated by polarized light microscopy （PLM）,atomic force microscopy （AFM） and transmitted electron microscopy （TEM）.In the range of 110-150 ℃,banded spherulite occurred and banding space gradually decreased along the radial direction from the primary nucleation site.Between 160 and 170 ℃,normal non-banded spherulite was found.Above 170 ℃,banded configuration occurred again.Lamellar growth direction of banded spherulite was determined to the crystal a-axis.
文摘The non-isothermal crystallization kinetics of modified poly(ethylene terephthalate) (PET) with the function of ultraviolet (UV) protection was studied by means of differential scanning calorimetry. The kinetics of the modified polymer under non-isothermal crystallization was analyzed by Ozawa equation. The crystallization behavior of the modified polymer obeyed Ozawa theory. The additives in the polymer whose function was UV-resistant acted as crystal nucleus in the processing of crystallization, which resulted in the increase of Avrami index and the crystallization rate of the cooling system.
基金The work was supported by the financial support from the Natural Science Foundation of Hebei Province(B2007000148)Hebei University(Y2006065),China.
文摘The spherulites of the short carbon fiber(SCF)/poly(trimethyleneterephthalate)(PTT)compositesformedin limited space at designed temperatures,and their melting behaviors were studied by the polarized optical microscopy,atomic force microscopy(AFM),and scanning electron microscopy(SEM),respectively.The results suggest that SCF content,isothermal crystallization temperatures,and the film thicknesses influence the crystal morphology of the composites.The dimension of the spherulites is decreased with increasing SCF content,but whether banded or nonbanded spherulites will form in the composites is not dependent on SCF content.However,the crystal morphology of the composites depends strongly on the temperature.When the isothermal crystallization temperatures increase from 180℃ to 230℃,the crystal morphology of SCF/PTT composites continuously changes in the following order:nonbanded→banded→nonbanded spherulites.Disconti-nuous circle lines form in the film when the film thickness increases from 30 to 60μm.Basing on the SEM observation,it is found that these circle lines are cracks formed due to the constriction difference of the different parts of the spherulites.These cracks are formed when the film is cooled from the isothermal crystallization temperature to the room tempera-ture at a slow cooling rate;while they will disappear gradually at different temperatures in the heating process.The crack will appear/disappear first around the center of the spherulite when the film was cooled/heated.The nontwisted or slightly twisted lamellas will reorganize to form highly twisted lamellas inducing apparent banded texture of the spherulites.
文摘采用自主设计的熔体离心纺丝设备研究了聚己二酸对苯二甲酸丁二醇酯(PBAT)的可纺性,并分析纺丝参数对PBAT纤维形貌和性能的影响。结果表明:挤出机温度为220℃、喷丝器温度为200℃、电机转速为4000 r min、收集距离为18 cm时纤维形貌最佳;纺丝温度的提高可有效避免纤维卷曲以及纤维细化;随着纺丝温度的增加,聚合物熔体黏度下降,流动性变好,制备的纤维分布更加均匀,纤维结晶度得到提高,纤维膜的力学性能得到明显改善,其最大应力提高至15.3 MPa,最大应变为80%。
基金Supported by the National High Technology Research and Development Program of China 863 Plan (Grant No. 2003AA321010) the Innovation Research Fund of Graduate University, Chinese Academy of Sciences (2006)
文摘A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titanate (TBT), dibutyltin oxide (Bu2SnO), and stannous octoate (SOC)). Their catalytic activity in the esterification process is monitored by measuring the amount of water generated, while intrinsic viscosity (IV) and content of terminal carboxyl groups (CTCG) are used as the index in the polycondensation process. Stannous oxalate shows higher activity than the other catalysts. Decrease in reaction time and improvements in PTT property are observed. The higher catalytic activity of stannous oxalate is attributed to its chelate molecular structure.
基金Supported by the Outstanding Youth Fund of China (Grant No. 20425414)National Natural Science Foundation of China (Grant Nos. 50521302, 20574079, 20634050, and 50773088)
文摘Double melting behavior of poly(trimethylene terephthalate) (PTT) was studied in detail by means of differential scanning calorimetry (DSC) and optical microscopy. The results indicate that the low-temperature melting peak of PTT at ca. 218℃ for the samples crystallized isothermally at 203℃ is associated with the melting of crystals produced by secondary crystallization, while the high-temperature melting peak of it at about 227℃ is related to the melting of the crystals produced by primary crystallization. The results further demonstrate that the PTT crystals growing non-isothermally during cooling process are thermodynamically unstable and can undergo structure reorganization during the DSC heating scan. The reorganized crystals melt at temperature higher than the crystals produced by secondary crystallization at 203 ℃. Consequently, for the non-fully crystallized samples, the crystals grown during cooling also exhibit contribution to the high-temperature melting peak.
基金supported by the Natural Science Foundation of Hebei Province(Grant No.B2007000148)Hebei University(Grant No.Y2006065),China.
文摘The rheological,phase morphologic,thermal andmechanicalpropertiesofpoly(trimethyleneterephthalate)/metallocene polyethylene(PTT/mPE)blends in the presence of ethylene propylene diene monomer copolymer grafted with maleic anhydride(EPDM-g-MAH)as compatibilizer are studied by means of a capillary rheometer,scanning electron microscopy(SEM),differential scanning calorimetry(DSC)and thermogravimetric analyzer(TGA).Results suggest that the compatibility of PTT/mPE blends is improved greatly after the addition of a compatibilizer.The radius of the dispersed phase in the system decreases greatly when the compatibilizer is added into the blend.When the amount of compatibilizer exceeds 8 wt-%,the size of dispersed phase becomes larger again.This phenomena could be attributed to the higher viscosity of the EPDM-g-MAH phase,which is dispersed more difficulty in the PTT phase of lower viscosity,thus the mixing efficiency is apparently decreased during the melt blending process.Moreover,the melt viscosity of the blend reaches the maximal value in case of 4 wt-%compati-bilizer content,above which it would decrease again.This result is associated with the generation of more and bigger dispersed phase inside the bulk phase,thus the grafting efficiency at the interface is decreased,which could result in lower viscosity.The DSC results suggest that the mPE component shows a nucleating effect,and could increase the overall degree and rate of PTT crystallization,while the addition of a compatibilizer might slightly diminish these effects.In addition,the blend with 4 wt-%compatibilizer shows the best thermal stability.Furthermore,the Izod impact strength and the tensile strength at room temperature of the blend are also markedly improved by the addition of a 4–8 wt-%compatibilizer.
