亲水性PET共混材料的制备及性能研究

以机械共混法制备亲水性聚对苯二甲酸乙二醇酯（PET）共混材料,并通过接触角测定仪、差示扫描量热仪(DSC)和电子万能材料试验机等对共混材料的亲水性能、热性能和力学性能等进行研究与分析。结果表明,亲水处理剂聚乙二醇（PEG）、聚丙烯酸钠（PAAS）、聚乙烯吡咯烷酮（PVP）均能改善PET的亲水性能,影响PET的结晶性能,但亲水处理剂对PET的力学性能影响较小,其中PET/PEG共混材料的亲水性最优;随着PEG含量的增加,PET/PEG共混材料的亲水性先逐渐增强,当PEG含量高于5 %后,共混材料的亲水性变化很小;且PET的结晶度随着PEG的加入呈现先增大后减小的趋势。     

聚己内酯/聚乙烯吡咯烷酮共混物的亲水性和生物降解性

用X-射线衍射、傅里叶变换红外光谱和扫描电镜方法对聚己内酯(PCL)/聚乙烯吡咯烷酮(PVP)共混物进行表征,并对共混物进行接触角测试和体外降解试验。结果表明:PVP的加入对PCL的晶型无影响,两者在共混过程中并未发生化学反应;随着PVP质量分数的增加,共混物与水的接触角减小,黏附功和浸湿功同步增大,3种参数都在PVP质量分数为15%处发生转折;PCL/PVP共混物降解质量损失率随PVP质量分数的增加而逐渐增大,且共混物的总质量损失逐渐由以PCL为主过渡到以PVP为主,脂肪酶加速了PCL/PVP共混物的降解速率。     

PBT/ε-PCL共混物的性能

实验通过熔融共混制备聚对苯二甲酸丁二醇酯(PBT)/聚己内酯(PCL)共混物,共混物中PCL的质量百分比从10%变化到90%,间隔为10%.实验研究PCL树脂质量百分比对共混物相容性、热性能、力学性能、相形态、熔融及结晶行为的影响.DMA和DSC热分析结果表明:PBT和PCL是部分相容体系,相容性随PCL含量的增加而增加,PCL的加入降低了PBT/PCL共混物中PBT相的熔点,改善了PBT的结晶能力.通过SEM对PBT/PCL共混物的相形态研究表明:PBT/PCL共混物具有两相结构,PCL质量含量为50%时发生相反转.力学性能分析结果表明:PCL能够增韧PBT,但效果不明显.     

环保增塑剂TBC的合成以及其对环保体系PLA/PCL影响

本文以柠檬酸和正丁醇为原料,对甲苯磺酸为催化剂,制备出环保增塑剂柠檬酸三丁酯(TBC),而后用核磁共振氢谱(1H-NMR)和红外光谱(FI-IR)对产物结构进行表征。随后将TBC与PLA/PCL共混,制得可生物降解共混物。采用差示热量扫描对共混物热学性能进行研究,表明TBC能显著提高PLA/PCL体系的结晶能力;采用拉伸试验对共混物进行力学性能测试,结果显示TBC增大了PLA/PCL体系的断裂伸长率;以去离子水和无水乙醇为溶剂,测试共混物的耐抽出性能,结果表明TBC会被溶剂抽出,共混体系在去离子水中5周失重率为0.64%,无水乙醇中5周失重率为1.91%。     

PCL/PLA/凹凸棒土复合材料的制备及性能

采用熔融共混法制得了PLA/PCL/凹凸棒土复合材料,考察了PCL、凹凸棒土对复合材料力学性能、热稳定性和降解性能的影响。结果表明,PCL含量为15%、凹凸棒土含量为5%,复合材料的力学性能较好,拉伸强度达到37.62MPa;随着PCL添加量的增加,复合材料的热稳定性增强;复合材料的降解率随着凹凸棒土添加量的增大而增大,但降解率较低,最大降解率为2.56%。     

聚乳酸/聚己内酯共混材料的性能研究

采用熔融共混的方法制备了聚乳酸(PLA)/聚己内酯(PCL)共混材料,研究了PLA/PCL共混材料的动态力学性能、力学性能、热性能和微观形貌。结果表明,制备的PLA/PCL共混材料为部分相容体系;材料拉伸强度随PCL含量的增加先增加后降低,当PCL质量分数为30%时,材料的拉伸强度为55.9 MPa,比纯PLA提高了8%;冲击强度随PCL含量的增加而增大,当PCL质量分数为50%时,材料的冲击强度为14.7 kJ/m2,比纯PLA提高了2.5倍。     

PEG含量对PVDF/PEG共混膜性能的影响

以聚乙二醇(PEG)为添加剂,利用非溶剂致相分离法制备了聚偏氟乙烯(PVDF)/PEG共混膜,使用傅里叶变换红外光谱、X射线衍射、扫描电子显微镜、接触角测量等表征测试方法,研究了PEG含量对PVDF/PEG共混膜性能的影响。结果发现,PEG的加入使PVDF的结晶性能下降,同时也使其结构发生了变化。但是由于PEG的亲水性,当PEG的质量分数小于5%时,PVDF/PEG共混膜的亲水性随着PEG含量的增大而逐渐得到改善。     

热塑性淀粉/聚己内酯复合材料制备与性能

以柠檬酸为增容剂,采用熔融共混的方法制备了不同聚己内酯(PCL)含量的热塑性淀粉/聚己内酯复合材料(TPS/PCL),对复合材料结构、冲击强度、力学性能进行了表征。结果表明:FTIR结果证实PCL的加入对整个体系并未产生明显影响;样品的拉伸强度,断裂伸长率及抗冲击强度随PCL含量大于30份时增加而增大;随着淀粉含量的增加,复合材料的吸水率增加。     

聚己内酯对聚乳酸熔融结晶的影响

聚合物共混材料的结晶行为对材料性能有重要的影响,结晶行为是共混材料研究的主要问题。选用聚乳酸(PLA)和聚己内酯(PCL)共混材料,采用偏光显微镜和差示扫描量热仪,对PLA/PCL共混材料的结晶行为进行研究。通过等温结晶动力学,分析PCL对PLA在100和120℃时等温结晶的影响。结果表明,PCL相作为异相成核剂加入PLA相,使得PCL/PLA共混物中异相结晶成核效率提高,晶体直径减小,半结晶时间减小,提高PCL/PLA共混物的结晶能力。随着PCL相的占比增大,PCL/PLA(40/60)试样中出现"海-岛结构",异相成核效率增大,半结晶时间较小,结晶直径减小,结晶度减小。     

竹纤维质量分数对PCL/PLA/竹纤维复合材料性能的影响

将竹纤维(BF)与聚己内酯(PCL)、聚乳酸(PLA)熔融共混,通过模压工艺制备了PCL/PLA/BF增强复合材料。研究了BF质量分数对该复合材料力学性能、热稳定性以及熔融结晶行为的影响。结果表明:随着BF质量分数的增加,PCL/PLA/BF复合材料的冲击强度、拉伸强度和断裂伸长率均先增大后减小,并均在BF质量分数为40%时达到最大值,分别为11.26 k J/m2、12.68 MPa和5.2%;BF质量分数对PCL/PLA/BF复合材料的热稳定性无明显影响;BF的加入使得复合材料中PCL、PLA共混物的玻璃化转变温度降低,但不同BF质量分数的复合材料玻璃化转变温度变化不大;BF的加入使得复合材料结晶温度小幅提升,但结晶峰强度随着BF质量分数的增加而逐渐减弱。     

Effect of Poly(vinyl pyrrolidone) on Antifouling Properties of Asymmetric Poly(ethylene‐co‐vinyl alcohol) Membranes

Poly(ethylene‐co‐vinyl alcohol)/poly(vinyl pyrrolidone) (EVAL/PVP) blend membranes with antifouling properties were prepared by nonsolvent induced phase separation. Residual PVP in the sample was calculated by infrared spectroscopic data and confirmed by thermogravimetric analysis. The effect of residual PVP on hydrophilicity and permeation characteristics of the membranes was evaluated. Porosity and equilibrium water content of the membranes were influenced by the addition of PVP. The effect of protein fouling on flux using bovine serum albumin as a model system was studied in detail. The residual PVP content could enhance the antifouling property of the membrane. All membranes proved to have sufficient mechanical strength to withstand pressure‐driven filtrations.     

Biodegradable membrane based on polycaprolactone/polybutylene succinate: Characterization and performance evaluation in wastewater treatment

Biodegradable membranes with different compositions of polycaprolactone (PCL) and polybutylene succinate (PBS) are prepared via immersion precipitation. The morphology, hydrophilicity, chemical structure, crystalline structure, mechanical properties, and biodegradability of the membranes are studied to assess the effect of PBS concentration in the polymer blend on membrane properties. Furthermore, the performance of the obtained membranes is assessed through the treatment of wastewater sampled from the chips and snacks factory. Also, membranes' antifouling properties are assessed by filtration of a model foulant. The investigations revealed that the addition of PBS to PCL increases the membrane hydrophilicity and biodegradability. Regarding the results, the PCL membrane blended with 30 wt% PBS has 106%, 26%, and 37% higher pure water flux, flux recovery ratio, and permeate flux, in addition to the higher rejection of pollution indices, in comparison with the PCL membrane.     

Fabrication and characterization of hydrophilic poly(ε‐caprolactone)/pluronic P123 electrospun fibers

Poly(ε‐caprolactone) (PCL) has been widely investigated for tissue engineering applications because of its good biocompatibility, biodegradability, and mechanical properties; however hydrophobic nature of PCL has been a colossal obstacle toward achieving scaffolds which offer satisfactory cell attachment and proliferation. To produce highly hydrophilic electrospun fibers, PCL was blended with pluronic P123 (P123) and the resulted electrospun scaffolds physiochemical characteristics such as fiber morphology, thermal behavior, crystalline structure, mechanical properties, and wettability were investigated. Moreover molecular dynamic (MD) simulation was assigned to evaluate the blended and neat PCL/water interactions. Presence of P123 at the surface of electrospun blended fibers was detected using ATR‐FTIR analysis. P123 effectiveness in improving the hydrophilicity of the scaffolds was demonstrated by water contact angel which experienced a sharp decrease from 132° corresponding to the neat PCL to almost 0° for all blended samples. Also a steady increase in water uptake ratio was observed for blended fibers as P123 content increased. The 90/10 blend ratio had the maximum tensile strength, elongation at break and crystallinity percentage. Therefore 90/10 blend ratio of PCL/P123 can balance the mechanical properties and bulk hydrophilicity of the resulted electrospun scaffold and would be a promising candidate for tissue engineering application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43345.     

Preparation and characterization of electrospun poly(ε‐caprolactone)/poly(vinyl pyrrolidone) nanofiber composites containing silver particles

A nanofiber membrane composed of poly(ε‐caprolactone) (PCL), poly(vinyl pyrrolidone) (PVP), and silver nanoparticles was prepared via electrospinning technique. The morphology and structure of the PCL/PVP/Ag nanofibers composite were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS). The SEM images showed that various composites of PCL/PVP/Ag could be electrospun to yield continuous and uniform nanofibers. FTIR spectra indicated that the molecular interactions between PCL and PVP are weak. The hydrophilicity, mechanical property, and swelling behavior of the as‐spun composites can be manipulated by altering the blend ratio of PCL/PVP. XRD patterns and XPS spectra showed that the Ag nanoparticles were dispersed in the PCL/PVP nanofiber composites; and the Ag nanoparticles endowed the PCL/PVP/Ag composite with antibacterial activities. The obtained PCL/PVP/Ag nanofiber composites with the morphology similar to that of native extracellular matrix have the potential to create a moist environment and to kill bacteria, which make it possible to be used for wound dressing application. POLYM. COMPOS., 37:2847–2854, 2016. © 2015 Society of Plastics Engineers     

Improvement of filtration performance of polyvinyl chloride/cellulose acetate blend membrane via acid hydrolysis

Based on the hydrophilicity and biodegradability of cellulose acetate (CA), polyvinyl chloride (PVC)/CA blend membrane was prepared by solution comixing and phase transformation method. Then the CA in the blend membrane was partially hydrolyzed under acidic conditions to improve the hydrophilicity of the blend membrane, so as to improve the filtration performance of the PVC/CA blend membrane. The properties of the membranes were systematically characterized by Fourier transform infrared spectroscopy, differential scanning calorimeter, and scanning electron microscopy (SEM). The porosity, water contact angle, pure water flux (PWF), protein retention rate, and mechanical properties of the membrane were measured, and the effect of hydrolysis on the filtration performance of the blend membrane was analyzed. The results showed that the hydrophilicity and porosity of the blend membrane increased, the PWF and protein rejection rate enhanced after acid catalyzed hydrolysis, while the mechanical properties of PVC membrane were maintained. This simple preparation method endows PVC/CA blend membrane with desirable filtration performance, and also helps to overcome the disadvantages of poor hydrophilicity and easy pollution of pure PVC membrane.     

Crystallization behavior and hydrophilicity of poly(vinylidene fluoride)/poly(methyl methacrylate)/poly(vinyl pyrrolidone) ternary blends

Ternary blends composed of matrix polymer poly(vinylidene fluoride) (PVDF) with different proportions of poly(methyl methacrylate) (PMMA)/poly(vinyl pyrrolidone) (PVP) blends were prepared by melt mixing. The miscibility, crystallization behavior, mechanical properties and hydrophilicity of the ternary blends have been investigated. The high compatibility of PVDF/PMMA/PVP ternary blends is induced by strong interactions between the carbonyl groups of the PMMA/PVP blend and the CF₂ or CH₂ group of PVDF. According to the Fourier transform infrared and wide‐angle X‐ray difffraction analyses, the introduction of PMMA does not change the crystalline state (i.e. α phase) of PVDF. By contrast, the addition of PVP in the blends favors the transformation of the crystalline state of PVDF from non‐polar α to polar β phase. Moreover, the crystallinity of the PVDF/PMMA/PVP ternary blends also decreases compared with neat PVDF. Through mechanical analysis, the elongation at break of the blends significantly increases to more than six times that of neat PVDF. This confirms that the addition of the PMMA/PVP blend enhances the toughness of PVDF. Besides, the hydrophilicity of PVDF is remarkably improved by blending with PMMA/PVP; in particular when the content of PVP reaches 30 wt%, the water contact angle displays its lowest value which decreased from 91.4° to 51.0°. Copyright © 2011 Society of Chemical Industry     

Investigating the effect of PGA on physical and mechanical properties of electrospun PCL/PGA blend nanofibers

In the field of tissue engineering there is always a need for new engineered polymeric biomaterials which have ideal properties and functional customization. Unfortunately the demands for many biomedical applications need a set of properties that no polymers can fulfill. One method to satisfy these demands and providing desirable new biomaterials is by mixing two or more polymers. In this work, random nanofibrous blends of poly (ε‐caprolactone) (PCL) and polyglycolic acid (PGA) with various PCL/PGA compositions (100/0, 80/20, 65/35, 50/50, and 0/100) were fabricated by electrospinning method and characterized for soft‐tissue engineering applications. Physical, chemical, thermal, and mechanical properties of PCL/PGA blend nanofibers were measured by scanning electron microscopy (SEM), porosimetry, contact angle measurement, water uptake, attenuated total reflectance Fourier transform‐infrared spectroscopy (ATR‐FT‐IR), X‐ray diffraction (XRD), differential scanning calorimetric (DSC), dynamic mechanical thermal analysis (DMTA), and tensile measurements. Morphological characterization showed that the addition of PGA to PCL results in an increase in the average diameter of the nanofibers. According to these results, when the amount of PGA in the blend solution increased, the hydrophilicity and water uptake of the nanofibrous scaffolds increased concurrently, approaching those of PGA nanofibers. Differential scanning calorimetric studies showed that the PCL and PGA were miscible in the nanofibrous structure and the mechanical characterization under dry conditions showed that increasing PGA content results in a tremendous increase in the mechanical properties. In conclusion, the random nanofibrous PCL/PGA scaffold used in this study constitutes a promising material for soft‐tissue engineering. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polycaprolactone-blended gelatin microspheres and their morphological study

Polycaprolactone (PCL)-blended gelatin microspheres were prepared in the size ranges of 5–20 μm as well as 70–340 μm and modified through different compositions of PCL to gelatin in the oil-in-water emulsion solvent evaporation method. The formation of the polymer particles and particle morphology, stability, crystallinity, and thermal behavior of the polymer blends were studied. The changes in physiochemical properties of the blends were also studied with the addition of very less amount of polyvinylpyrrolidone (PVP), as it enhances the particle size distribution of microspheres as well as the surface morphology. Differential scanning calorimetry analysis shows the shifting of exothermic peak in the PCL/gelatin blend, and the PCL/gelatin blend stabilized by PVP results in the decrease in crystallinity. PCL-blended gelatin microspheres were smooth with definite shape and fine dispersibility with the increased concentration of gelatin to the polymer while lower concentration of the gelatin caused agglomeration. Optimization of the gelatin and PVP ratio to the polymer matrix results in large-size spherical stable microparticles. The stabilizing ability of microsphere decreases with the increased concentration of PCL during the solvent evaporation method. The addition of PVP to the PCL/gelatin blend enhanced the particle size distribution of microspheres as well as the surface morphology.     

Performances of poly(vinylidene fluoride‐co‐hexafluoropropylene) ultrafiltration membranes modified with poly(vinyl pyrrolidone)

The structure and performance of modified poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐co‐HFP) ultra‐filtration membranes prepared from casting solutions with different concentrations of poly(vinyl pyrrolidone) (PVP) were investigated in this study. Membrane properties were studied in terms of membrane compaction, pure water flux (PWF), water content (WC), membrane hydraulic resistance ( R _m), protein rejection, molecular weight cut‐off (MWCO), average pore size, and porosity. PWF, WC, and thermal stability of the blend membranes increased whereas the crystalline nature and mechanical strength of the blend membranes decreased when PVP additive concentration was increased. The contact angle (CA) decreased as the PVP concentration increased in the casting solution, which indicates that the hydro‐philicity of the surface increased upon addition of PVP. The average pore size and porosity of the PVdF‐co‐HFP membrane increased to 42.82 Å and 25.12%, respectively, when 7.5 wt% PVP was blended in the casting solution. The MWCO increased from 20 to 45 kDa with an increase in PVP concentration from 0 to 7.5 wt%. The protein separation study revealed that the rejection increased as the protein molecular weight increased. The PVdF‐co‐HFP/PVP blended membrane prepared from a 7.5 wt% PVP solution had a maximum flux recovery ratio of 74.3%, which explains its better antifouling properties as compared to the neat PVdF‐co‐HFP membrane. POLYM. ENG. SCI., 55:2482–2492, 2015. © 2015 Society of Plastics Engineers     

乙酰化淀粉/聚己内酯共混物的制备和性能研究

分别采用淀粉(TPS)、乙酰化淀粉(TPAS)与聚己内酯(PCL)进行熔融共混，制备了可生物降解的塑料，探讨了淀粉乙酰化改性后对共混物力学性能、耐水性、熔融流动性、相容性及生物降解性的影响。共混物的拉伸强度均随PCL用量的增加而增大，TPAS／PCL体系的拉伸强度低于TPS／PCL体系，而断裂伸长率高于TPS／PCL体系。PCL可以明显改善淀粉基材料的耐水性，淀粉乙酰化后共混体系的相容性及熔体流动性得到一定的改善，生物降解性略微下降。