In the present study,thermal behavior and crystal transition of pure poly(butylene adipate)(PBA)upon heating process were investigated by FTIR spectroscopy.To gain further insight into the thermal behavior alteration ...In the present study,thermal behavior and crystal transition of pure poly(butylene adipate)(PBA)upon heating process were investigated by FTIR spectroscopy.To gain further insight into the thermal behavior alteration and the phase transition of PBA,we performed two-dimensional(2D)correlation analysis.We found thatβ-form PBA crystal undergoes not only the melting process but also crystal transition upon the heating process.展开更多
Poly(glycolic acid)(PGA)is derived from glycolide obtained by fermenting pineapples or sugarcane,which has excellent gas barrier properties and a small carbon footprint.PGA is a potential substitute for the current al...Poly(glycolic acid)(PGA)is derived from glycolide obtained by fermenting pineapples or sugarcane,which has excellent gas barrier properties and a small carbon footprint.PGA is a potential substitute for the current aluminum-plastic composite films used in high barrier packaging applications.However,its poor ductility and narrow processing window limit its application in food packaging.Herein,poly(butylene succinate-co-butylene adipate)(PBSA)was used to fabricate PGA/PBSA blend films through an in situ fibrillation technique and blown film extrusion.Under the elongational flow field used during the extrusion process,a unique hierarchical structure based on the PBSA nanofibrils and interfacially oriented PGA crystals was obtained.This structure enhances the strength,ductility and gas barrier properties of the PGA/PBSA blend film.In addition,an epoxy chain extender(ADR4468)was used as a compatibilizer to further enhance the interfacial adhesion between PGA and PBSA.70PGA/0.7ADR exhibited a very low oxygen permeability(2.34×10^(-4)Barrer)with significantly high elongating at break(604.4%),tensile strength(47.4 MPa),and transparency,which were superior to those of petroleum-based polymers.Thus,the 70PGA/0.7ADR blown films could satisfy the requirements for most instant foods such as coffee,peanuts,and fresh meat.展开更多
The effects of crystallization temperature and blend ratio on the polymorphic crystal structures of poly(butylene adipate) (PBA) in poly(butylene succinate) (PBS)/poly(butylene adipate) (PBS/PBA) blends we...The effects of crystallization temperature and blend ratio on the polymorphic crystal structures of poly(butylene adipate) (PBA) in poly(butylene succinate) (PBS)/poly(butylene adipate) (PBS/PBA) blends were studied by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (XRD) and atomic force microscopy (AFM). It was revealed that the polymorphism of PBA can be regulated by the blend ratio even in a non-isothermal crystallization process. The results demonstrate that high temperature favors fiat-on α crystals, while low temperature contributes to edge-on β crystals. It was also found that the effect of blend ratio on the crystallization mechanism of PBA is well coincident with that of the crystallization temperature. The increment of PBS content in the PBS/PBA blend gives rise to more β-form crystals of PBA. For those PBS/PBA blends with low PBA content, the interlamellar phase segregation of PBA makes its molecular chains so difficult to diffuse from one isolated microdomain to another that high crystallization temperature and sufficiently long crystallization time will be required if the PBA α-type crystals are targeted.展开更多
Zinc phenylphosphonate (PPZn), a benign and biocompatible nucleating agent, was prepared and incorporated into the biodegradable poly(ethylene adipate) (PEA) to investigate its effect on the crystallization beha...Zinc phenylphosphonate (PPZn), a benign and biocompatible nucleating agent, was prepared and incorporated into the biodegradable poly(ethylene adipate) (PEA) to investigate its effect on the crystallization behavior, crystallization kinetics and spherulite morphology of PEA. Upon addition of PPZn, the crystallization temperature and crystallinity of PEA in the non-isothermal crystallization process increased significantly. Analysis of crystallization kinetics by Avrami equation suggests that the crystallization time shortened greatly and crystallization rate increased markedly after addition of PPZn. In the presence of PPZn, the spherulite size decreased and spherulite density increased significantly. It suggests that PPZn is an efficient nucleating agent for the crystallization of PEA. The accelerated crystallization in the presence of PPZn is mainly attributed to the epitaxial nucleation of PEA crystals on the surface of PPZn crystals, that is, a perfect lattice matching between PEA crystal and PPZn crystal occurs.展开更多
The crystallization behavior of poly(ethylene adipate) (PEA) on highly oriented high-density polyethylene (PE) substrate both from solution and isotropic melt was studied by means of optical microscopy, differen...The crystallization behavior of poly(ethylene adipate) (PEA) on highly oriented high-density polyethylene (PE) substrate both from solution and isotropic melt was studied by means of optical microscopy, differential scanning calorimetry, atomic force microscopy and electron diffraction. The results show that the PE influences the crystallization of PEA strongly, which results in an epitaxial growth of PEA with well ordered structure. At the boundary of the PE substrate, a transcrystalline PEA layer is observed. Fine structural observation illustrates that the PEA grows on the PE substrate in edge- on lamellae with fixed orientation. Electron diffraction demonstrates that the epitaxial organization of PEA on PE occurs with both polymer chains parallel, which leads to the (00l) PEA diffractions inclined ±23.5° to the chain direction of PE crystals. Combining the real space morphological observation and electron diffraction results, it is concluded that the epitaxial PEA edge-on lamellae are folded in the {00l} lattice planes.展开更多
The miscibility, isothermal crystallization kinetics and morphology of the poly(vinylidene fluoride)(PVDF)/poly(ethylene adipate)(PEA) blends have been studied by differential scanning calorimetry(DSC), opti...The miscibility, isothermal crystallization kinetics and morphology of the poly(vinylidene fluoride)(PVDF)/poly(ethylene adipate)(PEA) blends have been studied by differential scanning calorimetry(DSC), optical microscopy(OM) and scanning electron microscopy(SEM). A depression of the equilibrium melting point of PVDF was observed. From the melting point data of PVDF, a negative but quite small value of the interaction parameter ?PVDF-PEA is derived using the Flory-Huggins equation, implying that PVDF shows miscibility with PEA to some extent. Nonisothermal and isothermal crystallization kinetics suggest that the crystallization rate of PVDF decreases with increasing the amount of PEA, and a contrary trend was found when PEA crystallizes with the increase of the amount of PVDF. It was further disclosed that the blend ratio and crystallization temperature affect the texture of PVDF spherulites greatly, which determines the subsequent crystallization of PEA. At high temperatures, e.g. 150 ℃, the band spacing of PVDF spherulites increases with the addition of PEA content and the spherulitic structure becomes more open. In this case, spherulitic crystallization of PEA is not observed for all blend compositions. At low temperatures, e.g. 130 ℃, for the PEA-rich blends, the interpenetrated structures are eventually formed by the penetration of the spherulites of PEA growing within the pre-existing PVDF spherulites.展开更多
Oriented and non-oriented Teflon films, which were found to have the same crystalline structure, but different surface morphologies, were used to sandwich poly(butylene adipate) (PBA) films during isothermal cryst...Oriented and non-oriented Teflon films, which were found to have the same crystalline structure, but different surface morphologies, were used to sandwich poly(butylene adipate) (PBA) films during isothermal crystallization. It was found that both the Teflon surface structure and the PBA polymorphic structure are the determining factors to induce epitaxial crystallization. The oriented Teflon film was able to induce epitaxial crystallization of PBA α crystal, while the non-oriented Teflon did not induce any epitaxial crystallization of PBA. Epitaxial crystallization did not occurred for PBA β crystals between neither the oriented nor the non-oriented Teflon films. The enzymatic degradation rate of PBA films was not determined by the epitaxial crystallization, in fact it was still dependent on the polymorphic crystal structure of PBA. The morphological changes of PBA films after enzymatic degradation confirmed again that the epitaxial crystallization only occurred for the PBA film with α crystal structure which was produced by being sandwiched between oriented Teflon films, and it happened only on the surface of PBA films.展开更多
The effects of PEA on the )γ-phase PVDF crystal structure and the crystallization of PEA within the pre-existing γ-phase PVDF spherulites have been investigated by optical microscopy (OM), infrared spectroscopy ...The effects of PEA on the )γ-phase PVDF crystal structure and the crystallization of PEA within the pre-existing γ-phase PVDF spherulites have been investigated by optical microscopy (OM), infrared spectroscopy (IR) and scanning electron microscopy (SEM). The results demonstrate that the γ-phase PVDF spherulites consist of the lamellae exhibiting a highly curved scroll-like morphology and develop preferentially in PEA-rich blend. With increasing PEA concentration, the scroll diameter increases and the scrolls are better separated from each other. PEA crystallizes first in the interspherulitic region and transcrystalline layer develops. Subsequently, the transcrystalline layer of PEA continues to grow within theγ-phase PVDF spherulites, e.g., in the region between the scrolls, until impinging on other PEA transcrystalline layers or spherulites. The crystallization kinetics results indicate that the growth rate of PEA crystals in the intraspherulitic region of γ-phase PVDF shows a positive correlation with content of PEA, but a negative one with the crystallization temperature of γ-phase PVDF.展开更多
We successfully use a co-precipitation method to prepare inclusion complex between poly(butylene adipate) (PBA) chains (guest component) and urea molecules (host component). The PBA/urea inclusion complex is c...We successfully use a co-precipitation method to prepare inclusion complex between poly(butylene adipate) (PBA) chains (guest component) and urea molecules (host component). The PBA/urea inclusion complex is confirmed to adopt a hexagonal crystal modification with lattice parameters ofa = 8.14 A and c = 10.92 A, and the interaction between PBA chains and urea is van der Waals force. The singly isolated PBA chains are suggested to take some gauche conformation, which is different from the all-trans conformation in r-form PBA. Furthermore, we employ the isolated PBA chains which are uniformly pre-established in a specific conformation in urea channels to regulate the crystal form of PBA for the first time. After removing the host urea molecules, the coalesced PBA chains are found to solely crystallize into a-form crystals at different coalescing temperatures. By comparing the FTIR spectra, it is found that PBA chains in inclusion complex plausibly contain some similar conformers as those in a-form crystal, which is suggested to be the intrinsic reason for the sole formation of a-form crystals. This research proves that inclusion complex can be used as a very effective method to regulate polymorphism of semi-crystalline polymers.展开更多
Phthalates and adipate ester in water have been extracted with n-hexane and analyzed by gas chromatography-mass spectrometry(GC-MS).The mean recoveries ranged from 69% to 109% with their RSD range of 1.96%-10.2%.The r...Phthalates and adipate ester in water have been extracted with n-hexane and analyzed by gas chromatography-mass spectrometry(GC-MS).The mean recoveries ranged from 69% to 109% with their RSD range of 1.96%-10.2%.The research results also showed that the method presented simplicity-operating,excellent linearity and reproducibility.展开更多
An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in th...An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in the presence of a catalyst, p-toluene sulfonic acid. The biodegradation of these polyesters were studied in the laboratory by enzyme attack and outdoor soil burial. The results show that these polyesters have good biodegradability and the copolyester PHAS, even displayed a better biodegradability than the polyester PHA. In the presence of Penicillium chrysogenum the weight loss reached 18.3% for the PHAS (film thickness 1.0 mm) and 9.1% for the PHA (film thickness 1.0 mm) after 28 days. Outdoor soil burial tests indicate that these polyesters also have good biodegradability in natural conditions. The weight loss reached 14.2% for PHAS (film thickness 0.1 mm) and 6.7% for PHA (film thickness 0.1 mm) after burying in soil for 36 days.展开更多
The enzyme-mediated highly enantioselective hydrolysis of aliphatic dicarboxylic acid diesters has been developed. The racemic diesters were easily prepared by the coupling of racemic alcohols with dicarboxylic anhydr...The enzyme-mediated highly enantioselective hydrolysis of aliphatic dicarboxylic acid diesters has been developed. The racemic diesters were easily prepared by the coupling of racemic alcohols with dicarboxylic anhydrides followed by esterification or with dicarboxylic acids. In the cases of bis(1-phenylethyl) glutarate and bis(1-phenylethyl) adipate, the diesters which contained the dl- and meso-form diastereomers, were enantioselectively hydrolyzed by lipase from Candida antarctica (Novozym 435) in buffer at 30°C to afford the almost optically pure (R)-1-phenylethanol. On the other hand, the following chemical hydrolysis of the remaining (S, S)-diesters and (S)-monoesters gave the (S)-alcohol. Finally, both enantiomers were stoichiometrically obtained in about 100% isolated yield based on the racemic diesters. The enzymatic reaction was also applicable for the preparation of several optically active alcohols. In some cases, both the reactivities and enantioselectivities were quite different from those in the case of the corresponding simple acetates.展开更多
The adipic acid is an important intermediate in the production of nylon,polyurethane and polye ster resin s.The industrial approach for preparing adipic acid is through the liquid catalytic oxidation of KA oil with ni...The adipic acid is an important intermediate in the production of nylon,polyurethane and polye ster resin s.The industrial approach for preparing adipic acid is through the liquid catalytic oxidation of KA oil with nitric acid.In this work,a comprehensive model is developed for this reaction based on the kinetic study conducted in a continuous flow tubular reactor.The kinetic model fits well with the experimental results across the experimental conditions,and the average relative error between the calculated and experimental values is 5.7%.Results show that there was an induction period at the early stage of reaction.Moreover,it is found that at temperature range of 328-358 K,the formation rate of adipic acid strongly dependents on the temperature and nitric acid concentration.The developed model is used to predict the yield of adipic acid at 359-368 K.The work in this study could provide much knowledge for industrial tubular reactor design.展开更多
Adipic acid is a dicarboxylic acid of great industrial importance,mainly used in the production of nylon-6,6 and polyurethane.The use of nitric acid as an oxidant in the industrial production of adipic acid poses sign...Adipic acid is a dicarboxylic acid of great industrial importance,mainly used in the production of nylon-6,6 and polyurethane.The use of nitric acid as an oxidant in the industrial production of adipic acid poses significant carbon footprint to the environment.Clean adipic acid synthesis methods using a heterogeneous catalyst with H2O2 as oxidant and water as solvent have potential advantages of low catalyst cost,easy synthesis and recovery,cleanness and environmental protection.In this work,hexagonal mesoporous silicate materials were synthesized by a sol–gel method and evaluated for cyclohexanol/cyclohexanone oxidation to adipic acid.The physical and chemical properties of Fe-HMS were characterized by XRD,HR-TEM,BET and UV–Vis.The experimental results showed that Fe-HMS materials show pore sizes ranging from 2–3 nm.W-and Mo-based polyoxometalates were also evaluated and compared to the Fe-based HMS catalysts.To improve the adipic acid yield,the influence of the transition metal as well as the effect of metal loading,reaction temperature and catalyst amount on the catalytic performances of Fe-HMS have been investigated in details.When Si/Fe atomic ratio=100,Fe-HMS catalyst shows the highest activity,with a cyclohexanone conversion of 92.3%and adipic acid selectivity of 29.4%.The reaction pathway of cyclohexanone oxidation was further proposed based on experimental data.展开更多
Adipic acid is an important petrochemical product,and its production process emits a high concentration of greenhouse gas N_2 O.This paper aims to provide quantitative references for relevant authorities to formulate ...Adipic acid is an important petrochemical product,and its production process emits a high concentration of greenhouse gas N_2 O.This paper aims to provide quantitative references for relevant authorities to formulate greenhouse gas control roadmaps.The forecasting method of this paper is consistent with the published national inventory in terms of caliber.Based on the N_2 O abatement technical parameters of adipic acid and the production trend,this paper combines the scenario analysis and provides a measurement of comprehensive N_2 O abatement effect of the entire industry in China.Four future scenarios are assumed.The baseline scenario(BAUS) is a frozen scenario.Three emission abatement scenarios(ANAS,SNAS,and ENAS) are assumed under different strength of abatement driving parameters.The results show that China's adipic acid production process can achieve increasingly significant N_2 O emission abatement effects.Compared to the baseline scenario,by 2030,the N_2 O emission abatements of the three emission abatement scenarios can reach 207-399 kt and the emission abatement ratios can reach 32.5%-62.6%.By 2050,the N_2 O emission abatements for the three emission abatement scenarios can reach 387-540 kt and the emission abatement ratios can reach 71.4%-99.6%.展开更多
The ring-opening copolymerization of adipic anhydride with propylene oxide was carried out with yttrium triflates as a catalyst. Poly(propylene adipate) could be synthesized by controlling the copolymerization condi...The ring-opening copolymerization of adipic anhydride with propylene oxide was carried out with yttrium triflates as a catalyst. Poly(propylene adipate) could be synthesized by controlling the copolymerization conditions. The copolymerization procedure was tracked by ^1H NMR analyses.展开更多
A novel binucleus complex [Cd2(phen)4(adip)(NO3)2] (phen = phenanthroline, H2adip = adipic acid) has been synthesized by the reaction of phen and H2adip with cadmium(Ⅱ) salt. Elemental analysis, IR spectra ...A novel binucleus complex [Cd2(phen)4(adip)(NO3)2] (phen = phenanthroline, H2adip = adipic acid) has been synthesized by the reaction of phen and H2adip with cadmium(Ⅱ) salt. Elemental analysis, IR spectra and X-ray crystal structure analysis were carried out to determine the crystal structure of the title complex. The crystal belongs to triclinic, space group P1^- with a = 9.638(7), b = 10.315(7), c = 13.109(10) A, α = 88.305(11), β = 69.011(11), γ = 75.818(11)°, C27H20N5O5Cd, Mr = 606.88, Z = 2, V = 1177.2(14)A^3, Dc = 1.712 g/cm^3,μ= 0.979 mm^-1, -8≤h ≤11, -12≤k≤ 12, -10≤l≤ 15, F(000) = 610, Rint = 0.0314, R = 0.0739 and wR = 0.1922 (Ⅰ〉 2σ(Ⅰ). The cadmium atom is seven-coordinated in a distorted pentagonal bipyramidal configuration. The complex forms a 2-D supramolecular framework by C-H…O weak interactions and π-π stacking of neighbouring phen ligands.展开更多
The goal of this work was to measure the heat transfer rates from thermofluid, Therminol 66, to two phase change materials, D-mannitol and adipic acid. It concerns the determination of heat transfer coefficients for t...The goal of this work was to measure the heat transfer rates from thermofluid, Therminol 66, to two phase change materials, D-mannitol and adipic acid. It concerns the determination of heat transfer coefficients for the design of a concentrated solar energy plant requiring PCM thermal energy storage and is part of a wider set of experiments, where several PCMs were tested. An experimental installation was used with a cylindrical vessel with three tubes disposed almost horizontally (5°inclination), containing the phase change material, around which the thermal fluid flowed almost perpendicular to the tubes. The experimental installation allowed to recreate heating and cooling cycles. In order to evaluate the influence of the flow on the rate at which the heating and cooling processes took place, tests were performed at different thermofluid mass flow rates, concluding that there is no great influence, since the thermal resistance inside the tubes is much higher than on the outside. D-mannitol and adipic acid, present different phase change temperatures, 164°C for D-mannitol and 152°C for adipic acid. The average heat transfer coefficient, during the phase change process, was of 340 W/(m<sup>2</sup>K) for D-mannitol and 1320 W/(m<sup>2</sup>K) for adipic acid.展开更多
The coordination polymer,[Mn3(L) 2(adip) 3]·2H2O(L = 2-(4-fluorophenyl) -1H-imidazo[4,5-f] [1,10]phenanthroline and H2adip = adipic acid) ,has been synthesized under hydro-thermal conditions and character...The coordination polymer,[Mn3(L) 2(adip) 3]·2H2O(L = 2-(4-fluorophenyl) -1H-imidazo[4,5-f] [1,10]phenanthroline and H2adip = adipic acid) ,has been synthesized under hydro-thermal conditions and characterized by elemental analysis,IR and single-crystal X-ray diffraction. It crystallizes in triclinic,space group P1^- with a = 8.4085(11) ,b = 11.1273(14) ,c = 14.5758(18) ,α = 78.528(2) ,β = 75.425(2) ,γ = 78.143(2) °,V = 1276.0(3) A^3,Z = 1,C56H50F2Mn3N8O14,Mr = 1261.86,Dc = 1.642 g/cm^3,F(000) = 647,μ(MoKa) = 0.819 mm^-1,R = 0.0446 and wR = 0.1008. The backbones of the two types of adip dianions link the neighboring trinuclear Mn(Ⅱ) clusters to yield a two-dimensional layer structure. The large conjugated L ligands are located on both sides of the two-dimensional layers. Additionally,the O-H···O,O-H···N and N-H···O hydrogen bonds further stabilize the structure.展开更多
文摘In the present study,thermal behavior and crystal transition of pure poly(butylene adipate)(PBA)upon heating process were investigated by FTIR spectroscopy.To gain further insight into the thermal behavior alteration and the phase transition of PBA,we performed two-dimensional(2D)correlation analysis.We found thatβ-form PBA crystal undergoes not only the melting process but also crystal transition upon the heating process.
基金the National Key Research and Development Program of China(No.2022YFB3704900)the National Natural Science Foundation of China(No.52073004)China National Tobacco Corporation Guizhou Company(No.2023XM24)。
文摘Poly(glycolic acid)(PGA)is derived from glycolide obtained by fermenting pineapples or sugarcane,which has excellent gas barrier properties and a small carbon footprint.PGA is a potential substitute for the current aluminum-plastic composite films used in high barrier packaging applications.However,its poor ductility and narrow processing window limit its application in food packaging.Herein,poly(butylene succinate-co-butylene adipate)(PBSA)was used to fabricate PGA/PBSA blend films through an in situ fibrillation technique and blown film extrusion.Under the elongational flow field used during the extrusion process,a unique hierarchical structure based on the PBSA nanofibrils and interfacially oriented PGA crystals was obtained.This structure enhances the strength,ductility and gas barrier properties of the PGA/PBSA blend film.In addition,an epoxy chain extender(ADR4468)was used as a compatibilizer to further enhance the interfacial adhesion between PGA and PBSA.70PGA/0.7ADR exhibited a very low oxygen permeability(2.34×10^(-4)Barrer)with significantly high elongating at break(604.4%),tensile strength(47.4 MPa),and transparency,which were superior to those of petroleum-based polymers.Thus,the 70PGA/0.7ADR blown films could satisfy the requirements for most instant foods such as coffee,peanuts,and fresh meat.
基金financially supported by the National Natural Science Foundation of China(Nos.21204045 and 21276151)Natural Science Basic Research Plan in Shaanxi Province of China(No.2011JQ2004)Key Scientific Research Group of Shaanxi Province(No.2013KCT-08)
文摘The effects of crystallization temperature and blend ratio on the polymorphic crystal structures of poly(butylene adipate) (PBA) in poly(butylene succinate) (PBS)/poly(butylene adipate) (PBS/PBA) blends were studied by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (XRD) and atomic force microscopy (AFM). It was revealed that the polymorphism of PBA can be regulated by the blend ratio even in a non-isothermal crystallization process. The results demonstrate that high temperature favors fiat-on α crystals, while low temperature contributes to edge-on β crystals. It was also found that the effect of blend ratio on the crystallization mechanism of PBA is well coincident with that of the crystallization temperature. The increment of PBS content in the PBS/PBA blend gives rise to more β-form crystals of PBA. For those PBS/PBA blends with low PBA content, the interlamellar phase segregation of PBA makes its molecular chains so difficult to diffuse from one isolated microdomain to another that high crystallization temperature and sufficiently long crystallization time will be required if the PBA α-type crystals are targeted.
基金financially supported by the National Natural Science Foundation of China(No.21304070)Natural Science Foundation of Tianjin City(No.15JCYBJC47300)+1 种基金Major Program of National Natural Science Foundation of China(No.11432016)the Municipal Key Program of Natural Science Foundation of Tianjin(No.14JCZDJC40700)
文摘Zinc phenylphosphonate (PPZn), a benign and biocompatible nucleating agent, was prepared and incorporated into the biodegradable poly(ethylene adipate) (PEA) to investigate its effect on the crystallization behavior, crystallization kinetics and spherulite morphology of PEA. Upon addition of PPZn, the crystallization temperature and crystallinity of PEA in the non-isothermal crystallization process increased significantly. Analysis of crystallization kinetics by Avrami equation suggests that the crystallization time shortened greatly and crystallization rate increased markedly after addition of PPZn. In the presence of PPZn, the spherulite size decreased and spherulite density increased significantly. It suggests that PPZn is an efficient nucleating agent for the crystallization of PEA. The accelerated crystallization in the presence of PPZn is mainly attributed to the epitaxial nucleation of PEA crystals on the surface of PPZn crystals, that is, a perfect lattice matching between PEA crystal and PPZn crystal occurs.
基金financially supported by the National Natural Science Foundation of China(Nos.50833006,21274009,21204018,51221002and50973008)
文摘The crystallization behavior of poly(ethylene adipate) (PEA) on highly oriented high-density polyethylene (PE) substrate both from solution and isotropic melt was studied by means of optical microscopy, differential scanning calorimetry, atomic force microscopy and electron diffraction. The results show that the PE influences the crystallization of PEA strongly, which results in an epitaxial growth of PEA with well ordered structure. At the boundary of the PE substrate, a transcrystalline PEA layer is observed. Fine structural observation illustrates that the PEA grows on the PE substrate in edge- on lamellae with fixed orientation. Electron diffraction demonstrates that the epitaxial organization of PEA on PE occurs with both polymer chains parallel, which leads to the (00l) PEA diffractions inclined ±23.5° to the chain direction of PE crystals. Combining the real space morphological observation and electron diffraction results, it is concluded that the epitaxial PEA edge-on lamellae are folded in the {00l} lattice planes.
基金financially supported by the National Natural Science Foundation of China(Nos.21204045,21276151)Key Scientific Research Group of Shanxi Province(No.2013KCT-08)Scientific Research Group of Shanxi University of Science and Technology(No.TD12-04)
文摘The miscibility, isothermal crystallization kinetics and morphology of the poly(vinylidene fluoride)(PVDF)/poly(ethylene adipate)(PEA) blends have been studied by differential scanning calorimetry(DSC), optical microscopy(OM) and scanning electron microscopy(SEM). A depression of the equilibrium melting point of PVDF was observed. From the melting point data of PVDF, a negative but quite small value of the interaction parameter ?PVDF-PEA is derived using the Flory-Huggins equation, implying that PVDF shows miscibility with PEA to some extent. Nonisothermal and isothermal crystallization kinetics suggest that the crystallization rate of PVDF decreases with increasing the amount of PEA, and a contrary trend was found when PEA crystallizes with the increase of the amount of PVDF. It was further disclosed that the blend ratio and crystallization temperature affect the texture of PVDF spherulites greatly, which determines the subsequent crystallization of PEA. At high temperatures, e.g. 150 ℃, the band spacing of PVDF spherulites increases with the addition of PEA content and the spherulitic structure becomes more open. In this case, spherulitic crystallization of PEA is not observed for all blend compositions. At low temperatures, e.g. 130 ℃, for the PEA-rich blends, the interpenetrated structures are eventually formed by the penetration of the spherulites of PEA growing within the pre-existing PVDF spherulites.
基金financially supported by the National Natural Science Foundation of China(No.51025314)the Oticon Foundation in Denmark
文摘Oriented and non-oriented Teflon films, which were found to have the same crystalline structure, but different surface morphologies, were used to sandwich poly(butylene adipate) (PBA) films during isothermal crystallization. It was found that both the Teflon surface structure and the PBA polymorphic structure are the determining factors to induce epitaxial crystallization. The oriented Teflon film was able to induce epitaxial crystallization of PBA α crystal, while the non-oriented Teflon did not induce any epitaxial crystallization of PBA. Epitaxial crystallization did not occurred for PBA β crystals between neither the oriented nor the non-oriented Teflon films. The enzymatic degradation rate of PBA films was not determined by the epitaxial crystallization, in fact it was still dependent on the polymorphic crystal structure of PBA. The morphological changes of PBA films after enzymatic degradation confirmed again that the epitaxial crystallization only occurred for the PBA film with α crystal structure which was produced by being sandwiched between oriented Teflon films, and it happened only on the surface of PBA films.
基金financially supported by the National Natural Science Foundation of China(Nos.21204045 and 21276151)Key Scientific Research Group of Shanxi Province(No.2013KCT-08)Scientific Research Group of Shanxi University of Science and Technology(No.TD12-04)
文摘The effects of PEA on the )γ-phase PVDF crystal structure and the crystallization of PEA within the pre-existing γ-phase PVDF spherulites have been investigated by optical microscopy (OM), infrared spectroscopy (IR) and scanning electron microscopy (SEM). The results demonstrate that the γ-phase PVDF spherulites consist of the lamellae exhibiting a highly curved scroll-like morphology and develop preferentially in PEA-rich blend. With increasing PEA concentration, the scroll diameter increases and the scrolls are better separated from each other. PEA crystallizes first in the interspherulitic region and transcrystalline layer develops. Subsequently, the transcrystalline layer of PEA continues to grow within theγ-phase PVDF spherulites, e.g., in the region between the scrolls, until impinging on other PEA transcrystalline layers or spherulites. The crystallization kinetics results indicate that the growth rate of PEA crystals in the intraspherulitic region of γ-phase PVDF shows a positive correlation with content of PEA, but a negative one with the crystallization temperature of γ-phase PVDF.
基金financially supported by the National Natural Science Foundation of China(No.21674128)China University of Petroleum(Beijing)
文摘We successfully use a co-precipitation method to prepare inclusion complex between poly(butylene adipate) (PBA) chains (guest component) and urea molecules (host component). The PBA/urea inclusion complex is confirmed to adopt a hexagonal crystal modification with lattice parameters ofa = 8.14 A and c = 10.92 A, and the interaction between PBA chains and urea is van der Waals force. The singly isolated PBA chains are suggested to take some gauche conformation, which is different from the all-trans conformation in r-form PBA. Furthermore, we employ the isolated PBA chains which are uniformly pre-established in a specific conformation in urea channels to regulate the crystal form of PBA for the first time. After removing the host urea molecules, the coalesced PBA chains are found to solely crystallize into a-form crystals at different coalescing temperatures. By comparing the FTIR spectra, it is found that PBA chains in inclusion complex plausibly contain some similar conformers as those in a-form crystal, which is suggested to be the intrinsic reason for the sole formation of a-form crystals. This research proves that inclusion complex can be used as a very effective method to regulate polymorphism of semi-crystalline polymers.
文摘Phthalates and adipate ester in water have been extracted with n-hexane and analyzed by gas chromatography-mass spectrometry(GC-MS).The mean recoveries ranged from 69% to 109% with their RSD range of 1.96%-10.2%.The research results also showed that the method presented simplicity-operating,excellent linearity and reproducibility.
文摘An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in the presence of a catalyst, p-toluene sulfonic acid. The biodegradation of these polyesters were studied in the laboratory by enzyme attack and outdoor soil burial. The results show that these polyesters have good biodegradability and the copolyester PHAS, even displayed a better biodegradability than the polyester PHA. In the presence of Penicillium chrysogenum the weight loss reached 18.3% for the PHAS (film thickness 1.0 mm) and 9.1% for the PHA (film thickness 1.0 mm) after 28 days. Outdoor soil burial tests indicate that these polyesters also have good biodegradability in natural conditions. The weight loss reached 14.2% for PHAS (film thickness 0.1 mm) and 6.7% for PHA (film thickness 0.1 mm) after burying in soil for 36 days.
文摘The enzyme-mediated highly enantioselective hydrolysis of aliphatic dicarboxylic acid diesters has been developed. The racemic diesters were easily prepared by the coupling of racemic alcohols with dicarboxylic anhydrides followed by esterification or with dicarboxylic acids. In the cases of bis(1-phenylethyl) glutarate and bis(1-phenylethyl) adipate, the diesters which contained the dl- and meso-form diastereomers, were enantioselectively hydrolyzed by lipase from Candida antarctica (Novozym 435) in buffer at 30°C to afford the almost optically pure (R)-1-phenylethanol. On the other hand, the following chemical hydrolysis of the remaining (S, S)-diesters and (S)-monoesters gave the (S)-alcohol. Finally, both enantiomers were stoichiometrically obtained in about 100% isolated yield based on the racemic diesters. The enzymatic reaction was also applicable for the preparation of several optically active alcohols. In some cases, both the reactivities and enantioselectivities were quite different from those in the case of the corresponding simple acetates.
基金the Ningbo Science and Technology Plan Project (2018B10013)the Program of Shanghai Subject Chief Scientist (18XD1402000)。
文摘The adipic acid is an important intermediate in the production of nylon,polyurethane and polye ster resin s.The industrial approach for preparing adipic acid is through the liquid catalytic oxidation of KA oil with nitric acid.In this work,a comprehensive model is developed for this reaction based on the kinetic study conducted in a continuous flow tubular reactor.The kinetic model fits well with the experimental results across the experimental conditions,and the average relative error between the calculated and experimental values is 5.7%.Results show that there was an induction period at the early stage of reaction.Moreover,it is found that at temperature range of 328-358 K,the formation rate of adipic acid strongly dependents on the temperature and nitric acid concentration.The developed model is used to predict the yield of adipic acid at 359-368 K.The work in this study could provide much knowledge for industrial tubular reactor design.
基金supported by the National Natural Science Foundation(21706290)Natural Science Foundation of Shandong Province(ZR2017MB004,ZR2017BB007)+5 种基金Postdoctoral Research Funding of Shandong Province(201703016)Fundamental Research Funding of Qingdao(17-1-1-67-jch,17-1-1-80-jch)Qingdao Postdoctoral Research Funding(BY20170210)“the Fundamental Research Funds for the Central Universities”(18CX02145A,17CX02017A)new faculty start-up funding from China University of Petroleum(YJ201601058)China Postdoctoral Science Foundation(2017M612374)。
文摘Adipic acid is a dicarboxylic acid of great industrial importance,mainly used in the production of nylon-6,6 and polyurethane.The use of nitric acid as an oxidant in the industrial production of adipic acid poses significant carbon footprint to the environment.Clean adipic acid synthesis methods using a heterogeneous catalyst with H2O2 as oxidant and water as solvent have potential advantages of low catalyst cost,easy synthesis and recovery,cleanness and environmental protection.In this work,hexagonal mesoporous silicate materials were synthesized by a sol–gel method and evaluated for cyclohexanol/cyclohexanone oxidation to adipic acid.The physical and chemical properties of Fe-HMS were characterized by XRD,HR-TEM,BET and UV–Vis.The experimental results showed that Fe-HMS materials show pore sizes ranging from 2–3 nm.W-and Mo-based polyoxometalates were also evaluated and compared to the Fe-based HMS catalysts.To improve the adipic acid yield,the influence of the transition metal as well as the effect of metal loading,reaction temperature and catalyst amount on the catalytic performances of Fe-HMS have been investigated in details.When Si/Fe atomic ratio=100,Fe-HMS catalyst shows the highest activity,with a cyclohexanone conversion of 92.3%and adipic acid selectivity of 29.4%.The reaction pathway of cyclohexanone oxidation was further proposed based on experimental data.
基金financial support by the Ministry of Science and Technology of China (Grant No.2018YFC1509006)the National Natural Science Foundation of China (Grant No.71874096)+1 种基金the Macao SAR Government Higher Education Fundthe Macao University of Science and Technology (Grant No.FRG-19-008-MSB)。
文摘Adipic acid is an important petrochemical product,and its production process emits a high concentration of greenhouse gas N_2 O.This paper aims to provide quantitative references for relevant authorities to formulate greenhouse gas control roadmaps.The forecasting method of this paper is consistent with the published national inventory in terms of caliber.Based on the N_2 O abatement technical parameters of adipic acid and the production trend,this paper combines the scenario analysis and provides a measurement of comprehensive N_2 O abatement effect of the entire industry in China.Four future scenarios are assumed.The baseline scenario(BAUS) is a frozen scenario.Three emission abatement scenarios(ANAS,SNAS,and ENAS) are assumed under different strength of abatement driving parameters.The results show that China's adipic acid production process can achieve increasingly significant N_2 O emission abatement effects.Compared to the baseline scenario,by 2030,the N_2 O emission abatements of the three emission abatement scenarios can reach 207-399 kt and the emission abatement ratios can reach 32.5%-62.6%.By 2050,the N_2 O emission abatements for the three emission abatement scenarios can reach 387-540 kt and the emission abatement ratios can reach 71.4%-99.6%.
基金Supported by the National Natural Science Foundation of China(Nos.20704036, Key Program 20434020)the State Basic Research Projects of China(No.2005CB623802)
文摘The ring-opening copolymerization of adipic anhydride with propylene oxide was carried out with yttrium triflates as a catalyst. Poly(propylene adipate) could be synthesized by controlling the copolymerization conditions. The copolymerization procedure was tracked by ^1H NMR analyses.
基金This work was supported by the Foundation of Education Committee of Liaoning Province (No. 2004c021) and Foundation of Excellent Personal of Shenyang Institute of Chemical Technology
文摘A novel binucleus complex [Cd2(phen)4(adip)(NO3)2] (phen = phenanthroline, H2adip = adipic acid) has been synthesized by the reaction of phen and H2adip with cadmium(Ⅱ) salt. Elemental analysis, IR spectra and X-ray crystal structure analysis were carried out to determine the crystal structure of the title complex. The crystal belongs to triclinic, space group P1^- with a = 9.638(7), b = 10.315(7), c = 13.109(10) A, α = 88.305(11), β = 69.011(11), γ = 75.818(11)°, C27H20N5O5Cd, Mr = 606.88, Z = 2, V = 1177.2(14)A^3, Dc = 1.712 g/cm^3,μ= 0.979 mm^-1, -8≤h ≤11, -12≤k≤ 12, -10≤l≤ 15, F(000) = 610, Rint = 0.0314, R = 0.0739 and wR = 0.1922 (Ⅰ〉 2σ(Ⅰ). The cadmium atom is seven-coordinated in a distorted pentagonal bipyramidal configuration. The complex forms a 2-D supramolecular framework by C-H…O weak interactions and π-π stacking of neighbouring phen ligands.
文摘The goal of this work was to measure the heat transfer rates from thermofluid, Therminol 66, to two phase change materials, D-mannitol and adipic acid. It concerns the determination of heat transfer coefficients for the design of a concentrated solar energy plant requiring PCM thermal energy storage and is part of a wider set of experiments, where several PCMs were tested. An experimental installation was used with a cylindrical vessel with three tubes disposed almost horizontally (5°inclination), containing the phase change material, around which the thermal fluid flowed almost perpendicular to the tubes. The experimental installation allowed to recreate heating and cooling cycles. In order to evaluate the influence of the flow on the rate at which the heating and cooling processes took place, tests were performed at different thermofluid mass flow rates, concluding that there is no great influence, since the thermal resistance inside the tubes is much higher than on the outside. D-mannitol and adipic acid, present different phase change temperatures, 164°C for D-mannitol and 152°C for adipic acid. The average heat transfer coefficient, during the phase change process, was of 340 W/(m<sup>2</sup>K) for D-mannitol and 1320 W/(m<sup>2</sup>K) for adipic acid.
基金Supported by the Institute Foundation of Siping City (No.2009011)
文摘The coordination polymer,[Mn3(L) 2(adip) 3]·2H2O(L = 2-(4-fluorophenyl) -1H-imidazo[4,5-f] [1,10]phenanthroline and H2adip = adipic acid) ,has been synthesized under hydro-thermal conditions and characterized by elemental analysis,IR and single-crystal X-ray diffraction. It crystallizes in triclinic,space group P1^- with a = 8.4085(11) ,b = 11.1273(14) ,c = 14.5758(18) ,α = 78.528(2) ,β = 75.425(2) ,γ = 78.143(2) °,V = 1276.0(3) A^3,Z = 1,C56H50F2Mn3N8O14,Mr = 1261.86,Dc = 1.642 g/cm^3,F(000) = 647,μ(MoKa) = 0.819 mm^-1,R = 0.0446 and wR = 0.1008. The backbones of the two types of adip dianions link the neighboring trinuclear Mn(Ⅱ) clusters to yield a two-dimensional layer structure. The large conjugated L ligands are located on both sides of the two-dimensional layers. Additionally,the O-H···O,O-H···N and N-H···O hydrogen bonds further stabilize the structure.