PLLA/PCL共混纤维的力学性能研究

本文以二氯甲烷为溶剂,采用离心纺丝制备出聚乳酸-聚己内酯纤维,通过FT-IR、DSC、SEM、接触角、拉伸测试表征了所得产品,并考察了浓度、配比、转速等条件对纤维结构和形貌的影响。最终得到性能优异的聚乳酸-聚己内酯离心纺丝纤维。研究结果表明:PLLA/PCL共混物为不相容体系,并相互限制对方的结晶行为;在PLLA/PCL共混体系中,PCL可作为PLLA结晶过程的异相成核剂,并促使PLLA的熔融重结晶;离心纺丝最佳纺丝液浓度为12%、最佳组分比(PLLA:PCL)为7:3、最佳离心转速为10 000r/min;PLLA/PCL共混物的接触角处于单组份值之间,表现为疏水性;PLLA/PCL的共混离心纺丝样品力学强度得到显著的增加,韧性也有一定程度的改善。     

聚己内酯(PCL)/苯乙烯-丙烯腈共聚物(SAN)共混体系相容性研究进展

从聚己内酯(PCL)与苯乙烯 丙烯腈共聚物(SAN)共混物的相容性机理、PCL/SAN共混物的形态结构以及SAN组分的共聚组成及含量对共混物相容性和结晶行为的影响等方面,综述了近年来国内外有关PCL/SAN共混体系相容性的研究进展,指出了研究目前存在的问题,展望了PCL/SAN共混物今后的发展。     

PCL/PLLA共混物的制备及其形状记忆功能研究

以聚己内酯(PCL)与左旋聚乳酸(PLLA)为基体,采用共混改性的方法制备PCL/PLLA共混物,并获得具备形状记忆功能的共混物,以满足医学工程对可生物降解的形状记忆功能材料的特殊需求。由于两者的溶解度参数相差较大,采用无生理毒性的柠檬酸三丁酯(TBC)作为共混物增容剂。研究了PLLA含量、拉伸比、回复次数与共混物形状记忆功能之间的关系。结果表明,TBC可明显改善PCL与PLLA的相容性,用其制备的PCL/PLLA共混物在PLLA含量大于20%时,具备较好的热致形状记忆功能。     

PBS/PCL共混物的增容研究

采用1,4-丁二酸、1,4-丁二醇和己内酯为共聚单体,合成丁二酸丁二酯-己内酯共聚物[P(BS-coCL)],作为聚丁二酸丁二酯(PBS)/聚己内酯(PCL)共混物的增容剂。通过将m(PBS)∶m(PCL)为80∶20的PBS/PCL共混物与增容剂熔融共混,制备不同增容剂含量的PBS/PCL共混物。结果表明:随着增容剂P(BS-co-CL)的加入,PCL相的结晶能力增强,PBS相的结晶能力减弱;增容剂的加入未改变共混物中PBS及PCL相的晶体结构;当增容剂用量为5 phr时,共混物两相的界面相容性提高,共混物晶体生长受到抑制,晶体尺寸变小,共混物的拉伸形变显著增大。     

聚ε-己内酯及其在共混体系中结晶形态的研究

通过偏光显微镜(POM)研究了不同相对分子质量的聚ε-己内酯(PCL)均聚物的结晶形态及PCL在不同相容共混体系中的结晶形态.分别讨论了相对分子质量对PCL均聚物结晶形态的影响;共混物、共混组成及结晶温度对PCL在相容共混体系中结晶形态的影响.结果表明:PCL的相对分子质量越大,形成的球晶尺寸越小;第二组分的加入有利于...     

多壁碳纳米管对PCL结晶行为的影响

通过溶液法制备了聚己内酯(PCL)和PCL/多壁碳纳米管(MWCNT)薄膜,研究了不同结晶温度下PCL的结晶形态及MWCNT对PCL结晶的影响。利用扫描电子显微镜、原子力显微镜从微观层次研究了球晶环带形成的机理。结果表明,存20～50℃可通过溶液结晶得到PCL环带球晶,加入MWCNT使形成环带结构的温度向高温方向拓宽。     

PCL对PBAT薄膜气体透过率的影响

采用双螺杆挤出流延拉伸机组制备了聚己二酸-对苯二甲酸丁二酯/聚己内酯(PBAT/PCL)共混薄膜,并分别在不同环境温度和湿度下,研究了PBAT/PCL共混薄膜的气体透过率。结果表明:随着PCL用量的增加,PBAT/PCL共混薄膜出现较为明显的相分离,且晶体间的结晶会提高材料的阻隔性;PBAT/PCL共混薄膜的透氧系数最多降低了104%,透湿系数最多降低了38%;对于同一厚度的共混薄膜,随着温度和湿度的提高,其气体透过率增大。适宜用量的PCL可以提高共混薄膜晶体间的结晶度,降低其气体透过率,并且温度和湿度与气体透过率呈正相关。     

不同分子量PCL增韧PLA的结构与性能

采用两种不同分子量的聚(ε-己内酯)(PCL)(粘均分子量60 000和3 000)与聚乳酸(PLA)在175℃下共混10 min制备PLA/PCL共混物。通过动态流变、扫描电子显微镜(SEM)和力学性能等研究了PLA/PCL共混物的结构和性能。动态流变显示,在PCL低含量(质量分数小于15%)时,PCL与PLA是相容的,质量分数为15%时PCL与PLA表现出明显的相分离行为。SEM显示,随着PCL含量的增加,PCL相的尺寸变大;低分子量PCL(L-PCL)的相尺寸明显大于高分子量PCL(H-PCL),而且相形态不是规则的球状。随着PCL含量的增加,共混物的拉伸强度下降,而断裂伸长率增加。当H-PCL质量分数为8.3%时,PLA/H-PCL共混物的断裂伸长率为137.32%。当H-PCL质量分数为15%时,其断裂伸长率高达232.76%。在添加相同含量PCL时,PLA/H-PCL共混物的拉伸强度高于PLA/L-PCL;而PCL质量分数8%时,共混物的断裂伸长率相差不多,当PCL质量分数大于8%时,PLA/H-PCL共混物的断裂伸长率明显比PLA/L-PCL共混物的高。     

PCL/PVP共混膜的制备及其性能研究

利用溶液浇铸法制备了聚ε-己内酯(PCL)/聚乙烯吡咯烷酮(PVP)共混膜,分析了PCL/PVP共混膜的结晶性能、相容性、力学性能、亲水性和生物降解性能。结果表明:PVP的加入对PCL的结晶晶型无影响,但产生了稀释作用,两者可以相容且在共混过程中未发生化学反应;一定含量的PVP有助于增强共混膜的力学性能,PVP的质量分数为20%时,PCL/PVP共混膜力学性能最佳;随着PVP含量的增加,共混膜与水的接触角减小,吸水率逐步增大,PCL的亲水性得到改善;PCL/PVP共混膜在磷酸盐缓冲液中的失重率随PVP含量的增加而增大,且共混膜的失重率逐渐由PCL主导过渡到PVP主导,加入脂肪酶可加速PCL/PVP共混膜的降解。     

PHBV/PCL共混纤维的结构与性能

采用熔融纺丝法制备聚羟基丁酸戊酸酯(PHBV)/聚ε-己内酯(PCL)生物可降解共混纤维。采用差示扫描量热仪、广角X射线衍射仪、热台偏光显微镜和傅立叶变换红外光谱仪对PHBV/PCL共混体系的相容性和结晶性能进行了表征。结果表明:PHBV和PCL是不相容的;PHBV/PCL共混体系中的PHBV影响了PCL的结晶机制和结晶速率,PCL的结晶形态没有改变;PCL不影响PHBV的结晶机制,降低了PHBV的结晶速率,改变了PHBV的结晶形态。     

Controlled drug release carriers based on PCL/PEO/PCL block copolymers

In order to create a new drug delivery system, the ibuprofen-loaded triblock copolymer PCL/PEO/PCL (PCEC) microspheres with a low PEO content (<2?wt%) were prepared by oil in water (o/w) solvent evaporation technique. The influence of PEO content, molecular weight of a polymer matrix and drug loading on the ibuprofen release profiles were evaluated. The interactions between polymer matrix and ibuprofen were detected by FTIR analysis. The presence of hydrophilic PEO segment in PCL chains caused the decrease in particle size, which further had a great impact on the drug release kinetics, i.e., initially faster release and significantly higher quantity of released drug compared to neat PCL. Ibuprofen release behavior from polymer matrix was governed by a diffusion process. In vitro cytotoxicity tests revealed that empty PCL and PCEC microspheres were not toxic at low concentrations, while ibuprofen-loaded microspheres exhibited cytotoxicity correlated with amounts of incorporated drug.     

Effect of PCL concentration on PCL/CaSiO3 porous composite scaffolds for bone engineering

Porous polycaprolactone (PCL)-coated calcium silicate (CaSiO₃) composite scaffolds were successfully prepared by 3D gel-printing (3DGP) and vacuum impregnation technology in this study. The effect of different PCL concentration on porous CaSiO₃ scaffolds prepared by 3DGP technology was studied. The composition and morphological characteristics of PCL/CaSiO₃ scaffolds were tested by using fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and energy dispersive spectrometer (EDS) analysis. PCL coating amount on the scaffolds surface was calculated by thermogravimetric analysis (TGA). Compressive strength was tested by a universal testing machine, and degradability was tested by immersing the scaffolds in a simulated body fluid (SBF). The results show that PCL coating thickness increased from 7.29 μm to 12.2 μm, and the compressive strength of the corresponding composite scaffolds increased from 17.15 MPa to 24.12 MPa following with PCL concentration increasing from 7.5% to 12.5%. When the porous composite scaffolds were immersed in SBF for 28 days, the degradation ratio was 1.06% (CaSiO₃), 1.63% (CaSiO₃-7.5PCL), 1.81% (CaSiO₃-10PCL) and 1.55% (CaSiO₃-12.5PCL), respectively. It is obviously that PCL/CaSiO₃ composite scaffolds, which are suitable for bone growth in bone repair engineering, are beneficial to improve the mechanical properties and biodegradability of pure CaSiO₃ scaffolds.     

Thermal properties and crystallinity of PCL/PBSA/cellulose nanocrystals grafted with PCL chains

Bionanocomposite films of poly(?‐caprolactone) (PCL) and poly(butilene succinate‐co ‐adipate) (PBSA) blends with cellulose nanocrystals (CNW) grafted with PCL chains (CNW‐g ‐PCL) were prepared by solution casting and their thermal properties and crystallinity were studied. The CNW surface was modified with PCL chains by grafting “from” approaches, in an effort to improve their compatibility with the polymer blends. The grafting efficiency was evidenced by FTIR and TGA analysis. The acicular morphology of CNW‐g ‐PCL was characterized by SEM. The TGA results showed an increase in the thermal stability of the CNW grafted with PCL chains. The PCL/PBSA blends showed higher thermal stability in comparison with the neat polymers and PCL/PBSA/CNW‐g ‐PCL bionanocomposites. DSC results showed the CNW‐g ‐PCL act as a nucleating agent in the bionanocomposites. Additionally, a better interaction of the CNW‐g ‐PCL in the blends of 30/70 composition in comparison with the blends of 50/50 composition was characterized. The results obtained for aforementioned films prepared by solution casting encourage the production of such bionanocomposites by melt compounding (extrusion), aiming the achievement of new bionanocomposites materials with improved thermal and mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44493.     

Synthesis and characterization of PCL/PEG/PCL triblock copolymers by using calcium catalyst

Triblock copolymer PCL-PEG-PCL was prepared by ring-opening polymerization of ε-caprolactone (CL) in the presence of poly(ethylene glycol) catalyzed by calcium ammoniate at 60 °C in xylene solution. The copolymer composition and triblock structure were confirmed by ¹H NMR and ¹³C NMR measurements. The differential scanning calorimetry and wide-angle X-ray diffraction analyses revealed the micro-domain structure in the copolymer. The melting temperature T_m and crystallization temperature T_c of the PEG domain were influenced by the relative length of the PCL blocks. This was caused by the strong covalent interconnection between the two domains. Aqueous micelles were prepared from the triblock copolymer. The critical micelle concentration was determined to be 0.4-1.2 mg/l by fluorescence technique using pyrene as probe, depending on the length of PCL blocks, and lower than that of corresponding PCL-PEG diblock copolymers. The ¹H NMR spectrum of the micelles in D₂O demonstrated only the -CH₂CH₂O- signal and thus confirmed the PCL-core/PEG-shell structure of the micelles.     

Effect of temperature and water on microphase separation of PCL–PEO–PCL triblock copolymers

Microphase separation of poly(ε-caprolactone-ethylene oxide-ε-caprolactone) (PCL–PEO–PCL), with block number-average molecular weights of 9,100–30,400–9,100 g/mol, was studied. Cylindrical morphology was observed in a solvent-cast sample. When the as-cast sample was heated above the melting points of both PEO and PCL blocks, a change in morphology was observed by Small Angle X-ray Scattering (SAXS). When this sample was cooled to room temperature in the ambient atmosphere, another morphology (lamellae) was observed with SAXS and Atomic Force Microscopy (AFM). This asymmetric change in morphology suggests a role of kinetics (microphase separation and crystallization) in determining the observed microstructures. Addition of water at room temperature also affected microphase separation of the block copolymer due to hydrophilicity of PEO. As the polymer concentration decreases from 100 to 60%, the morphology changes from cylinders to lamellae. Differential Scanning Calorimetry (DSC) data show that water addition decreases PEO crystallinity but PCL crystallinity remains.     

Effect of liquid plasticizers on crystallization of PCL in soft PVC/PCL/plasticizer blends

In this work, poly(ε-caprolactone) (PCL) and liquid plasticizer were combined used to plasticize poly(vinyl chloride) (PVC), and the possibility of using PVC/PCL/plasticizer blends to fabricate soft PVC with enhanced migration resistance was investigated. Through partial replacement of liquid plasticizers in soft PVC by equal quantity of PCL, flexibility was maintained while extraction loss of plasticizer by organic solvent was reduced significantly. Furthermore, crystallization of PCL in PVC/PCL/plasticizer blends with low PCL content was observed, and crystallization rate of PCL was found to be influenced by plasticizer contents and structures. For instance, crystallization rate of PCL in PVC/PCL/diisononyl phthalate (DINP) (100/40/100) was 3.7 times faster than in PVC/PCL/DINP (100/40/80), while crystallization rate of PCL in PVC/PCL/dioctyl adipate(DOA)(100/40/100) was 8.3 times faster than in PVC/PCL/diisononyl cyclohexane-1,2-dicarboxylate (DINCH) (100/40/100). Low-field ¹H NMR test manifested that different crystallization rate of PCL in PVC/PCL/plasticizer blends with different plasticizer structures was triggered by difference in plasticizers' compatibility with PVC, that is, the number of interaction point between PVC and plasticizers. It is concluded that PCL crystallization favored by liquid plasticizers in PVC/PCL/plasticizer blends was induced by interaction competition between PVC/plasticizer and PVC/PCL. As plasticizer content increases or its compatibility with PVC decreases, interaction competition becomes more intense and consequently faster crystallization of PCL occurs. Thus, to obtain soft PVC products with improve migration resistance while avoiding PCL crystallization, the total content of plasticizer (including both liquid plasticizer and PCL) should be lower than 66 phr (40 wt %). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48803.     

聚己内酯改性研究进展

介绍了聚己内酯(PCL)的改性目的,综述了PCL的改性方法,包括将PCL与聚合物共混或共聚、在PCL中填充无机粒子或纤维,以及PCL的成纤改性和表面改性等,并指出了PCL改性的发展方向。     

辐照改性对聚己内酯的影响

研究了不同填料对聚己内酯(PCL)力学性能的影响,以及在不同气氛下,射线辐照剂量对其分子量大小、交联密度,高温模量以及生物降解性的影响。结果表明,可溶性淀粉是PCL较为理想的填充剂,它的加入对PCL力学性能的影响较小;经Co60-γ射线辐照后,可提高PCL的分子量、交联密度、高温模量,降低生物降解性。30~90kGy的辐照剂量即可赋予材料满意的加工性和较好的生物降解性。     

PCL/CNTs复合材料的性能

以聚己内酯(PCL)和碳纳米管(CNTs)为主要材料,采用熔融共混制备PCL/CNTs复合材料。随着CNTs含量增加,以直径为10 nm的CNTs(简称CNTs10)制备的PCL/CNTs10复合材料的拉伸强度先增加后降低,以直径为5 nm的CNTs(简称CNTs5)制备的PCL/CNTs5复合材料的拉伸强度先减小后增大,断裂伸长率先降低后增加,体积电阻率逐步降低。CNTs含量相同时,PCL/CNTs5复合材料的体积电阻率小于PCL/CNTs10;CNTs5含量分别为12%和14%时,复合材料的体积电阻率分别为0.92Ω·cm和0.52Ω·cm。扫描电子显微镜分析发现,随着CNTs含量增加,复合材料表面暴露的CNTs5数量逐渐增多,当CNTs10含量≥12%和CNTs5含量≥10%时出现一定的团聚。CNTs5含量为12%的复合材料综合性能最佳,其体积电阻率为0.92Ω·cm、拉伸强度为26.4 MPa、断裂伸长率为267.7%、撕裂强度为46.0 N/cm;在3.7 V直流电压下通电12 min,可从28℃上升到36℃,20 min后达到38℃,随后温度缓慢上升,该复合材料在热敷保健和医疗器械领域具有良好的应用前景。     

淀粉/PCL共混物的研究进展

介绍了淀粉／PCK的共混目的及该体系在增容方法方面的研究进展。