静电纺聚乳酸及其复合材料的研究及应用

聚乳酸及其复合材料作为绿色生物材料,由于其良好的生物相容性和可降解性,在组织工程支架、药物控释体系等领域得到了广泛的应用.静电纺丝技术制备的聚乳酸膜具有孔隙率高、比表面积大等特点.通过对聚乳酸的共聚物或与其他生物材料的共混物进行静电纺丝,改善了聚乳酸亲水性差、降解酸性和降解周期不易控制的缺点,进一步扩大了聚乳酸在药物缓释体系中的应用.本文简要介绍了静电纺丝技术的原理和发展,重点描述了聚乳酸及其复合材料的静电纺丝及其在药物缓释体系中的应用.     

静电纺聚乳酸及其复合材料的研究及应用

通过对聚乳酸的共聚物或与其他生物材料的共混物进行静电纺丝,改善了聚乳酸亲水性差,降解酸性和降解周期不易控制的缺点,进一步扩大了聚乳酸在药物缓释体系中的应用。介绍了静电纺丝技术的原理和发展,重点描述了聚乳酸及其复合材料的静电纺丝及其在药物缓释体系中的应用。     

静电纺聚乳酸及其复合材料的研究及应用

通过对聚乳酸的共聚物或与其他生物材料的共混物进行静电纺丝,改善了聚乳酸亲水性差,降解酸性和降解周期不易控制的缺点,进一步扩大了聚乳酸在药物缓释体系中的应用.介绍了静电纺丝技术的原理和发展,重点描述了聚乳酸及其复合材料的静电纺丝及其在药物缓释体系中的应用.     

聚乳酸电纺及其在生物医学领域的应用进展

聚乳酸作为可降解的绿色生物材料,在组织工程支架、药物控释系统等领域得到了广泛的应用.静电纺丝技术制备的聚乳酸膜具有孔隙率高、比表面积大等特点.对聚乳酸电纺过程相关的影响参数、共混电纺及PLA电纺纤维材料在生物学领域的应用及发展前景进行系统的阐述.     

高性能聚乳酸纤维的研究进展

介绍了高强度、可控降解周期的聚乳酸及其共聚物、共混物纤维的成型方法和纤维的应用情况;阐述了熔融纺丝、溶液纺丝、静电纺丝、超临界流体法、凝胶冻干等纤维成型方法的特点;评价了成型工艺对纤维形态结构和性能的影响、研究聚乳酸纤维的新方法、新成果以及高性能聚乳酸纤维在生物医学领域、日用工业等领域的应用前景。     

静电纺丝纤维的研究及应用进展

文章综述了静电纺丝纤维的形态及其影响因素,包括聚合物及其溶液性质,电压、电极间距、液体流速等纺丝条件,以及环境等因素。并介绍了静电纺丝纤维在增强复合材料、过滤分离、组织工程、药物传输、生物催化等领域的应用进展。     

壳聚糖基纳米复合材料在创伤修复的研究进展

综述了近年来通过静电纺丝、超声处理等方法制得的壳聚糖基纳米复合材料及其在创伤修复、抗菌领域中的应用新进展。分析了新颖的纳米生物材料对创面修复及保护伤口感染方面的潜在应用,还主要介绍了壳聚糖基纳米复合材料作为伤口敷料的应用研究现状并对其发展前景进行展望,为进一步的研究开发提供参考。     

基于海藻酸钠抗菌材料制备及应用的研究进展

概述了静电纺丝技术的原理及其在生物性纳米复合材料制备过程中的作用.该技术可将多种材料以不同的方式复合到同一根纤维中,使得纤维又增添了多种新的功能,因此其在多功能复合材料制备方面的应用广受关注.同时由于海藻酸钠纳米材料具有良好的理化性质、功能特性、生物相容性及特殊的纳米效应,利用静电纺丝技术将高效抗菌剂均匀分布到海藻酸钠材料中制备成抗菌复合薄膜,使其在食品包装、创伤敷料、药物载体及组织工程支架等方面体现出了重要的应用价值.此外,本文还在该技术的基础上,提出了关于静电纺丝制备海藻酸钠抗菌复合薄膜过程中改性剂的优化、抗菌剂的选择等方面的问题,并展望了基于静电纺丝技术的海藻酸钠抗菌复合薄膜的应用前景.     

缓释药物纤维的发展

综述了药物纤维的发展现状,简述了缓释药物纤维的特点、重点介绍了缓释药物纤维的开发技术及其应用价值;指出了缓释药物纤维今后研究的方向为准确控制缓释药物纤维药量、高温纺丝过程中有效保护药物性能,纤维降解时避免药物突释等。     

静电纺丝纳米纤维在吸波材料中的应用

随着电子设备的迅速普及，电磁干扰和电磁污染问题随之而来，因此，高性能电磁波吸收材料的设计迫在眉睫。静电纺丝纳米纤维复合材料具有质量轻、柔性大、易加工、兼容性强等优势，有望实现吸波材料“薄、轻、宽、强”的技术要求。该文首先介绍了电磁波吸收材料的吸波原理，之后综述了静电纺丝技术在吸波材料中的研究进展，包括静电纺丝纳米纤维与金属及其氧化物、碳纳米材料与导电聚合物、过渡金属碳化物的复合以及在多层吸波材料中的应用，总结了不同种类复合材料的优缺点。最后，展望了静电纺丝纳米纤维在吸波领域的发展趋势以及应该关注的问题。     

聚乳酸/聚丙烯/淀粉复合材料的制备及性能研究

采用模压成型制备了聚乳酸(PLA)/聚丙烯(PP)和PLA/PP/淀粉两种复合材料.主要研究了复合材料的热性能、力学性能和降解性能.结果表明:对于PLA/PP复合材料而言,复合材料的熔融温度先增加后降低,结晶度随PLA的含量增加而变大,而且出现了结晶双峰.力学性能相较与纯PLA,断裂伸长率明显提高,拉伸强度有所下降,最...     

Degradation of wheat straw/polylactic acid composites with and without sodium alginate in natural soil and the effects on soil microorganisms

In order to improve the degradability of polylactic acid (PLA) composites and screen PLA degradation microorganisms. Sodium alginate was added into the wheat straw/PLA composites, and both composites (with/without sodium alginate) were buried in natural soil for 100 consecutive days subsequently. Weight loss and characterization of the PLA composites, carbon and nitrogen content in soil and microbial community composition were detected after degradation, with the result that the degradability of the PLA composites was greatly improved after the addition of sodium alginate. The weight loss of PLA composites with sodium alginate was 8.5%, which was 1.81 times that of PLA composites without sodium alginate. Sodium alginate and/or wheat straw in the PLA composites took the lead in the beginning course of the degradation. The added sodium alginate serves the purpose of making it easier to degrade the crystallization zone of the PLA composites. Bionectriaceae in the soil shoots up in the number after degradation, signifying its potential to be part of the microorganism family serving to degrade PLA composites. The results would help reveal the degradation mechanism of PLA composites and provide support for the screening of PLA composites degradation microorganisms.     

In vitro degradation behavior of biodegradable 4-star micelles

Drug delivery vectors for sustained release include a variety of polymeric constituents, both natural and synthetic. Among synthetic polymers several linear block copolymer systems have been explored for use as drug delivery vectors. Release of the pharmaceutical agent is affected by the degradation characteristics and/or by the swelling of the polymer. The goal of this study is to evaluate the degradation behavior of branched polyethylene oxide polylactide polyether ester as a drug delivery vector. Three samples of a star polyethylene oxide/polylactide copolymer with differing polylactide chain lengths were evaluated by characterizing the thermal properties of the neat polymer and in vitro degradation behavior.The thermal and morphological properties were examined by DSC, TGA and XRD. The in vitro polymeric micelle samples were observed over time by UV-vis, TEM and fluorescence. The four star PEO-PLA polymers have exceptional amphiphilic characteristics, which enable their use for a variety of applications. The polymers are thermally stable at biological conditions. In addition, the star polymers have shorter degradation times as compared to previously reported linear PLA and PEG-PLA copolymers, suggesting use as a short-term drug release agent. The four star PEO/PLA copolymer may be an excellent candidate for drug delivery applications.     

Effect of electrospun ethylene vinyl alcohol copolymer (EVOH) fibres on the structure,morphology, and properties of poly(lactic acid) (PLA)

The effect of ethylene content and of the concentration of the solution used for electrospinning on the morphology of electrospun poly ethylene vinyl alcohol (EVOH) fibre was studied. Also, poly(lactic acid) (PLA) filled with electrospun EVOH fibres was investigated. Good interfacial adhesion between PLA and EVOH fibres was obtained with smaller diameter fibres. The effect of electrospun fibres resulted in disrupted lamellar morphology and also decreased the degree of crystallinity related to the semicrystalline framework. Surface roughness was calculated using atomic force microscopy (AFM). Surface roughness increased with the increase in fibre diameters. The rheology experiments revealed that electrospun EVOH fibres enhance the storage modulus of PLA composites while having low crystallinity. EVOH fibres showed the capacity of tuning the degradation behaviour. The good interfacial morphology between PLA and smaller diameter fibres slowed down the degradation rate, whereas composites with larger diameter fibres, due to poor interfacial adhesion showed faster degradation rate than the other compositions, because large EVOH fibres afford channels by which NaOH solution can easily penetrate throughout the composite material. The incorporation of EVOH fibres into PLA matrix allowed obtaining materials with increased storage modulus and also showed viability to tune the degradation behaviour of PLA based products.     

In vitro degradation behavior of carbon fiber-reinforced PLA composites and influence of interfacial adhesion strength

In the present study, carbon fiber-reinforced polylactide (C/PLA) composites with different interfacial conditions were prepared to determine the influence of interfacial adhesion strength (IAS) on in vitro degradation behavior of the C/PLA composites. Pure PLA and untreated and treated C/PLA composite samples were immersed in phosphate buffered saline (PBS; pH 7.4, 37 ± 0.5^°C) for predetermined time periods. These samples were removed at each degradation time, measured to analyze molecular weight loss, weighed to assess water uptake and mass loss, and mechanically tested to obtain bending strength, modulus, and IAS. The matrixes in the C/PLA composites showed higher water uptake and lower mass loss in comparison with the pure PLA. Further, the PLA matrix in the treated composite absorbed less water and lost less mass and molecular weight than its counterpart in the untreated composite. Mechanical tests confirmed that the treated C/PLA composite exhibited a slower rate of decrease in bending strength, modulus, and IAS than the untreated one. The differences in degradation behavior between two composites can only be attributed to the difference in interfacial conditions because all other parameters were kept constant. The loss of bending strength and modulus was mainly caused by the interface degradation of the C/PLA composites. It can be concluded from our in vitro observations that the IAS had an obvious influence on the degradation characteristics of the C/PLA composites. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 150–158, 2001     

十二烷基硫酸钠/聚乳酸复合材料性能研究

主要研究了聚乳酸（PLA）与十二烷基硫酸钠（SDS）复合材料的制备,以及SDS/PLA复合材料亲水性和降解过程当中pH值的改变程度。采用溶解成膜法制备SDS/PLA复合材料。主要考察了在PLA中加入SDS后形成复合材料后对其亲水性的影响,结果表明,当加入适量的SDS能比较明显地改变其亲水性,让复合材料亲水性提高。对SDS/PLA复合材料进行了降解测试,通过对三种降解体系比较,结果表明,添加了SDS之后的复合材料能够较好地保持聚乳酸原有的力学性能,添加了适量的SDS能够较好地中和聚乳酸降解过程所产生的乳酸,从而使降解体系的pH值保持相对稳定。     

Enhancing the durability of poly(lactic acid) composites by nucleated modification

Biodegradable poly(lactic acid) (PLA) composites were prepared using an innovative combination of wood fiber (WF) and 1,3,2,4‐bis(3,4‐dimethylobenzylideno)sorbitol (DMDBS). DMDBS acted as an effective nucleating agent, which improved the mechanical properties and slowed down the degradation of the WF/PLA composites. The enzymatic degradation of the composites was examined by immersing in proteinase K or cellulase buffer. The presence of DMDBS resulted in a 26.7% increase of the crystallinity compared to the WF/PLA composites. The increase in crystallinity enhanced the thermal stability and tensile strength of the WF/DMDBS/PLA composites by 8.5%. The durability of the WF/DMDBS/PLA composites after nucleated modification was enhanced after enzymolysis. After nucleated modification, the surface of the WF/PLA composites showed clear cracks due to degradation, while these appeared about 2 weeks later in the case of the WF/DMDBS/PLA composites. The results revealed that the introduction of cellulase degraded WF in the composites, which increased hydrolysis or enzymolysis sites. The combination of nucleated modification and enzyme buffer gave an expanded downstream application of WF/PLA composites in packaging and agricultural materials. © 2019 Society of Chemical Industry     

Polyvinyl alcohol and acidity-regulating KH2PO4 synergistically accelerated degradation of PBAT/PLA composites

Poly(butylene adipate-co-terephthalate) (PBAT)/polylactic acid (PLA) composites were prepared by water-soluble polyvinyl alcohol (PVA) and degradation-promoting agent (DPA) which were made from acidity-regulating KH₂PO₄ and halloysite by a physical layer-by-layer coating method. The effect of PVA and DPA on the biodegradation of PBAT/PLA composites in the cross-sectional morphology, thermal properties, molecular structure, due to degradation was evaluated using a host of characterization methods. The results showed that PVA had a good solubilizing effect on the composite system and improved the overall compatibility. DPA had little effect on the compatibility, crystallinity, and thermal stability of the composite system, but greatly accelerated the degradation. The interior of composite material containing DPA (Com-DPA) was shown to be severely damaged after 29 weeks of degradation, which was attributed to preferential degradation of amorphous regions of the composite by ester hydrolysis. Our results demonstrated the PVA and DPA worked synergistically to promote swelling and diffusivity of degradation products, and provided an acid environment for enhancing ester hydrolysis. This technology may have good prospects for accelerated degradation of materials in agricultural applications.     

Thermal and biodegradation properties of poly(lactic acid)/fertilizer/oil palm fibers blends biocomposites

Poly(lactic acid) (PLA) and NPK fertilizer with empty fruit bunch (EFB) fibers were blends to produced bioplastic fertlizer (BpF) composites for slow release fertilizer. Thermal properties of BpF composites were investigated by thermogavimteric analysis (TGA), differential scanning calorimetry (DSC), and morphological and degradation properties were anlayzed by scanning electron microscopy (SEM), soil burial test, respectively. TGA themogram display that neat PLA, PLA/NPK, and BpF composites degradate at different temperatures. DSC curves of PLA and other composites exhibited same glass transition temperature (T_g) value indicating that both major blend components are miscible. The T_g, crystallization temperature (T_c), melting temperature (T_m) values also decreased with increased amount of fertilizer and fibers. The T_m of BpF composites did not change with an increase in fertilizer content because thermal stability of PLA and PLA/NPK composites was not affected. Soil burial and fungal degradation test of PLA, PLA/NPK, and BpF composites were also carried out. Soil burial studies indicated that BpF composites display better biodegradation as compared with neat NPK. Fungal degradation study indicated that fungi exposure times of BpF composites show higher value of degradation as compared with PLA/NPK. We attribute that developed BpF composites will help oil palm plantation industry to use it as slow release fertilizer. POLYM. COMPOS. 36:576–583, 2015. © 2014 Society of Plastics Engineers     

Development and characterization of photopolymerizable biodegradable materials from PEG-PLA-PEG block macromonomers

As tissue engineering and drug delivery applications increase in both number and complexity, the demand for new synthetic biocompatible polymers with precisely tailored properties grows accordingly. Block copolymers are a particularly promising biomaterial as the physical and physiological properties of these polymers can be closely controlled through manipulation of the type and organization of the blocks in the polymer's backbone. In this work, poly(ethylene glycol) (PEG) and poly(lactic acid) (PLA) were incorporated into PEG-PLA-PEG block macromonomers with (meth)acrylate functionality to form photopolymerizable, highly cross-linked polymers for potential use in a variety of biomedical applications. Simply by directing the PLA:PEG ratio in these macromonomers, the hydrophobicity, physical behavior, degradation, and biocompatibility of the resulting polymer were controlled. Specifically, it was found that by increasing the PLA:PEG ratio, the degree of water uptake and the mechanical strength of the material is significantly decreased, while the glass transition temperature and degradation of the PEG-PLA polymers are delayed. Additionally, the biocompatibility of the PEG-PLA polymers is significantly influenced by the chemical composition of the material as increased PLA generally yields greater cell compatibility. By demonstrating the versatility of the photopolymerizable PEG-PLA polymers, the results of this study indicate that these materials have the potential to serve as a synthetic biomaterial platform, in which the properties of the polymer can be tailored to a variety of tissue engineering or drug delivery applications.