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将熔喷法制备的聚乙交酯(PGA)纤维膜置于生理盐水中进行体外降解试验。采用pH计、傅里叶红外光谱仪、扫描电子显微镜、差示扫描量热仪、X射线衍射仪、万能材料试验机等研究PGA纤维膜降解前后的结构和性能。结果表明:在整个降解过程中,降解液的p H值逐渐降低,纤维膜的质量损失率逐渐增大;纤维表面逐渐出现纵向裂纹直至断裂;熔点逐渐降低,晶体结构基本不变,但结晶度呈先升高后降低的趋势;纤维膜的平均拉伸强度呈现先缓后快的下降趋势,14 d平均拉伸强度保持率为21.3%,因此,该纤维膜在降解14 d后仍然保持一定的力学性能。 相似文献
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聚乙交酯纤维纺丝工艺研究 总被引:2,自引:0,他引:2
采用改变纺丝速度、拉伸工艺以及测试纤维内应力、声速值、强度值等方法对聚乙交酯(PGA)的纺丝加工工艺及纤维的力学性能进行了分析研究。结果表明:纺丝速度对PGA初生纤维的取向度几乎没有影响,后拉伸能有效提高纤维的取向度及强度。低速纺丝得到的初生纤维内应力较小,可以进行高倍后拉伸,而高速纺丝得到的初生纤维内应力较大,只能进行低倍后拉伸。适当的加温以及低速拉伸有利于得到较高强度的PGA纤维。总体来说,要得到具有较好力学性能的PGA纤维,必须采用低速纺丝、高倍后拉伸、低速拉伸相加的工艺路线。 相似文献
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采用金属化合物催化剂/羟基引发剂体系引发乙交酯开环聚合,制备了高相对分子质量聚乙交酯(PGA),研究了反应温度、反应时间、催化剂用量、单体与催化剂纯度、PGA的特性黏度,以及不同金属中心(如Sn,Al,Zn,Zr)和配体结构(如烷氧基、羧基、乙酰丙酮基和卤素)的催化剂对PGA热稳定性的影响规律。结果表明:在催化剂用量低于100μg/g的情况下,严格控制单体和催化剂纯度可使PGA的特性黏度显著提高,热降解温度提高了20.0~50.0℃;采用Sn基催化剂制备的PGA的热降解温度最低,采用Zn基和Al基催化剂制备的PGA的热降解温度最高可达318.6℃;金属化合物催化剂是控制PGA热稳定性的关键因素。 相似文献
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使用热重分析仪(TG)对聚乙丙交酯(PGLA)与聚乙交酯(PGA)的热降解性能进行测试,并通过Kissinger、Flynn-wan-ozawa和Friedman 3种方法计算其降解过程中的活化能Ea。结果表明,PGLA的热稳定性较PGA更好,3种方法均能较好的分析其降解过程,当使用Flynn-wan-ozawa法拟合时,其线性相关性较好。 相似文献
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K.T. Shalumon J. Anjana Ullas Mony R. Jayakumar Jyh-Ping Chen 《Journal of Polymer Research》2018,25(3):82
This study describes the preparation of electrospun poly(caprolactone) (PCL) and poly(lactic acid) (PLA) fibrous scaffolds with and without nano-hydroxyapatite (nHAp) having nanoscale, microscale and combined micro/nano (multiscale) architecture. Processing parameters such as polymer concentration, voltage, flow rate and solvent compositions were varied in wide range to display the effect of each one in determining the diameter and morphology of fibers. The effect of each regulating parameter on fiber morphology and diameter was evaluated and characterized using scanning electron microscope (SEM). Degradability of the selected fibrous scaffolds was verified by phosphate buffered saline immersion and its morphology was analyzed through SEM, after 5 and 12 months. Quantitative measurement in degradation was further evaluated through pH analysis of the medium. Both studies revealed that PLA had faster degradation compared to PCL irrespective of the size scale nature of fibers. Structural stability evaluation of the degraded fibers in comparison with pristine fibers by thermogravimetric analysis further confirmed faster degradability of PLA compared to PCL fibers. The results indicate that PLA showed faster degradation than PCL irrespective of the size-scale nature of fibrous scaffolds, and therefore, could be applied in a variety of biomedical applications including tissue engineering. 相似文献
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聚乳酸是目前已开发的生物降解高分子中最具潜力的一种。尽管它具有众多优异的性能,但是,仍存在一些如脆性大、成型稳定性差等缺点。因此,对聚乳酸进行复合改性是目前重要的研究趋势。文章综述了近年来聚乳酸基生物质复合材料的研究进程。以聚乳酸为基体,以麻纤维、木纤维、竹纤维或其它植物纤维为生物质填料,采用热压、挤出等方法生产不同种类的聚乳酸基生物质复合材料,介绍了植物纤维的改性方法,如碱处理、化学改性、微生物改性等,并对这些生物质复合材料的力学性能、热稳定性能、结晶性能、尺寸稳定性能等进行了简要阐述,同时,对聚乳酸基生物质复合材料的应用领域及开发前景进行了展望。 相似文献
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聚乳酸及其纤维的发展概况和应用前景 总被引:5,自引:0,他引:5
介绍了聚乳酸及其纤维的发展现状,纺丝成型及纤维的性能和主要应用领域。由于聚乳酸纤维采用了天然可再生的植物资源,使用后可自然降解,所以在纺织、医学、农业等领域都有广阔的发展前景。 相似文献
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Mukhamed A. Khavpachev Elena S. Trofimchuk Nina I. Nikonorova Elisaveta S. Garina Marina A. Moskvina Alexander V. Efimov Varvara A. Demina Artem V. Bakirov Nikita G. Sedush Vladislav V. Potseleev Tatiana A. Cherdyntseva Sergei N. Chvalun 《大分子材料与工程》2020,305(7)
Bioactive suture materials made of biodegradable polymers containing biologically active substances are increasingly demanded in contemporary surgical practice. Herein, the functional fibrous materials are produced by structural modification of polylactide (PLA) fibers according to the crazing mechanism in water–ethanol solutions. The threshold of ethanol concentration, at which the breaking elongation of the polymer substantially increases (up to 600–700%), is found to be 30 wt%. The crazing mechanism is employed to fill the porous structure of PLA fibers by different antiseptic substances (brilliant green, iodine, and fuchsin). PLA loaded by 0.8 wt% of brilliant green exhibits antimicrobial activity on Escherichia coli and Candida guilliermondii. The additive is released stepwise for a prolongated time period (2.5 months). The addition of 1–6 wt% iodine dramatically accelerates the polymer degradation in sodium‐phosphate buffer solution at 37 °C. The obtained filled fibers may possess great interest for producing suture materials with prolonged action of functional components and variable degradation times. 相似文献
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Guillaume Derombise Laëtitia Vouyovitch Van Schoors Marie‐Fleur Messou Peter Davies 《应用聚合物科学杂志》2010,117(2):888-898
Aramid fibers are high‐performance materials which have been used in ropes and protective clothing for many years. They are also now being proposed in geotextiles for ground reinforcement. The influence of the surface finish composition and content has been studied in the field of cables and textiles, but there is no published data concerning the effect of a finish treatment on the hydrolytic degradation. Aramid fibers with different finish contents have been aged in an alkaline environment. The degradation has been identified by FTIR, viscosimetry, TGA, SEM, and tensile tests. For Technora fibers, the presence of finish appears to limit the tensile strength loss of aramid fibers at pH 11 by limiting abrasion, as well as bulk and surface degradation. For Twaron fibers, higher finish content only has a slight influence on the fibers durability at pH 11 and pH 9, by limiting abrasion and bulk degradation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Biodegradable polymer composites based on poly(ɛ‐caprolactone) (PCL) and poly(lactic acid) (PLA) fibers were prepared by melt compounding. The effects of PLA fibers on the crystallization, mechanical properties, and enzymatic degradation of PCL composites were investigated. The addition of PLA fibers enhanced the crystallization of PCL due to the heterogeneous nucleation effect of fibers. However, the final crystallinity of the PCL in the composites was little changed in the presence of PLA fibers. With the addition of PLA fibers, significant improvement in storage modulus (E′) of PCL in the composites was achieved. A significant increase in E′ was 173% for the composites as compared to that of the neat PCL at 20°C. With the increase in PLA fibers content, the PCL composites showed decreased elongation and strength at break; however, the tensile yield strength and modulus were increased significantly, indicating that PCL was obviously reinforced by adding PLA fibers. Although the PLA fibers retarded the enzymatic degradation of PCL, it was possible to be completely degraded without much degradation time for PCL blending with suitable amounts of PLA fibers. POLYM. COMPOS., 34:1745–1752, 2013. © 2013 Society of Plastics Engineers 相似文献
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Poly(lactic acid) (PLA) was synthesized using l ‐lactic acid by condensation polymerization. Polystyrene (PS) and surface modified montmorillonite (OMMT) was used for the preparation of PS:PLA composites and PS:PLA:OMMT nanocomposites. The composite materials prepared had varying amount of PLA (10–30%) and OMMT (0.5–5 phr). These composites were subjected to degradation in minimal medium using the fungi Aspergillus niger (A. niger) under controlled conditions. Scanning electron microscopy (SEM) showed the growth of microorganism on the polymer surface and fracture within the polymer matrix as a result of degradation. Fourier transform infra red spectroscopy (FTIR) was further used to determine the mechanism leading to biodegradation. It was found that the biodegradation of both PS:PLA and PS:PLA:OMMT took place mainly via break down and utilization of ester group, as can be seen from disappearance of absorption peak of ester group and simultaneous appearance of a typical IR absorption of microbial mass at 1450 cm−1. The thermal stability of PS:PLA:OMMT nanocomposites was found to increase with increasing concentration of OMMT, as observed from thermo gravimetric analysis (TGA), while mechanical property was found to be decreased after degradation at 30% of PLA and 5 wt% of OMMT content. Change in extracellular protein content, biomass production and % degradation with respect to time (up to 28 days) were studied and correlated to evaluate the effectiveness of A. niger in biodegradation of the composites. POLYM. COMPOS., 35:263–272, 2014. © 2013 Society of Plastics Engineers 相似文献
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Sasan Khalaj Amnieh Peiman Mosaddegh Mohammad Mashayekhi Mahshid Kharaziha 《应用聚合物科学杂志》2021,138(19):50389
In this study, an experimental investigation is conducted on mechanical characteristics of poly(lactic acid) (PLA), before, and during degradation for stent application. A bioreactor is designed and fabricated to mimic in-vivo environment of the body for studying degradation behavior of PLA fibers manufactured by melt spinning method. Beside PLA fibers, the degradation of PLA braided stents is investigated as control samples. To measure stress–strain and stress relaxation properties of PLA fibers, tensile, and relaxation tests are conducted. The decreasing trend of Young's modulus, variations in residual stress value after relaxation and pattern of stress relaxation are found during degradation. The influence of effective parameters, that is, temperature and stress, on PLA degradation is also studied. Moreover, the PLA degradation is analyzed by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA) and microscopic images. GPC results indicate the molecular weight decreases from 196,000 to 80,000 due to degradation while DSC analysis confirmed that the degradation promote an increase in PLA degree of crystallinity (from 43.3% to 59.8%). In addition, TGA results show that the PLA thermal stability decreases during degradation. This study provides useful information on PLA properties during degradation to assess the material in context of degradable stents. 相似文献