熔融／固相缩聚聚乳酸与聚乙二醇共聚物的合成与性能

以L-乳酸为原料,采用熔融缩聚/固相聚合的方法合成端羟基聚乳酸,再以异氰酸酯基团封端的柔性聚乙二醇链段扩链,合成内增韧的聚乳酸-聚乙二醇共聚物。结果表明:适当交联的共聚物具有良好性能;随着聚乙二醇用量的增加,共聚物拉伸强度降低,而冲击强度增加;相对分子质量高的聚乙二醇的增韧效果更为明显。SEM结果表明:聚乳酸与聚乙二醇的相容性良好,共聚物呈均相结构。     

含PLA-PEG-PLA三嵌段共聚物的PLA中空纤维的制备及其性能研究

合成制备了聚乳酸-聚乙二醇-聚乳酸三嵌段共聚物(PLA-PEG-PLA)三嵌段共聚物,并用NMR和GPC对其进行了表征。将PLA-PEG-PLA作为亲水性添加剂用于中空纤维的制备,并研究了PLA-PEG-PLA的加入对中空纤维性能的影响。结果发现:PLA-PEG-PLA和PLA有很好的相容性,而且PLA中空纤维的抗污性能明显得到改善。随着PLA-PEG-PLA用量的增加,中空纤维的透水量逐渐下降,牛血清白蛋白(BSA)阻止率逐渐增加。     

聚乙二醇改性聚乳酸的合成与表征

以乳酸为原料,聚乙二醇为改性剂,氯化亚锡为催化剂,采用熔融缩聚法合成了聚乙二醇-聚乳酸接枝共聚物(PLEG),讨论了反应温度、反应时间、催化剂用量和聚乙二醇用量对产物黏均摩尔质量的影响。研究表明,最佳反应条件为:反应温度155℃,反应时间8 h,催化剂质量分数0.8%,聚乙二醇质量分数2.5%。通过红外光谱对共聚物化学结构进行分析,并通过X射线衍射(XRD)研究共聚物的结晶性能。     

聚乙二醇改性聚乳酸及其在药物载体中的应用

综述了聚乙二醇改性聚乳酸及其端基化的制备方法,介绍了聚乙二醇-聚乳酸嵌段共聚物作为药物载体的研究进展,并对今后的研究进行了展望.     

生物可降解聚酯弹性体的制备及其改性PLA的研究

以聚对苯二甲酸-己二酸-丁二醇共聚物(PBAT)和聚对苯二甲酸-己二酸-乙二醇共聚物(PBAE)为原料,在高真空条件下,通过酯交换法合成一种生物可降解热塑性聚酯弹性体(PBATE)。利用这种弹性体对聚乳酸进行增韧。扫描电镜(SEM)结果显示生物可降解聚酯弹性体与聚乳酸具有良好的相容性。拉伸测试和冲击测试结果分别表明聚乳酸的断裂伸长率提高近70倍,冲击强度也能提高10倍以上。     

专利

乙烯-醋酸乙烯共聚物与聚乳酸接枝共聚物
　　及其制备方法和应用
　　公开号：CN103131016A
　　公开日：2013-06-05
　　申请人：宁波家塑生物材料科技有限公司
　　摘要：本发明公开了一种乙烯-醋酸乙烯共聚物与聚乳酸接枝共聚物的制备方法,包括以下步骤：将乙烯-醋酸乙烯共聚物和聚乳酸在催化剂的作用下反应,在90～180℃反应5～60 min,经分离、洗涤、干燥后得到乙烯-醋酸乙烯共聚物与聚乳酸接枝共聚物,催化剂为Ti(OPr)4、Ti(OPh)4、Ti(OBu)4中的一种或两种以上。本发明制备方法,能够顺利完成接枝,接枝率高。本发明方法制备过程简单,反应条件易于控制,能够实现连续化、规模化生产,具有广阔的应用前景。还公开了一种乙烯-醋酸乙烯共聚物与聚乳酸接枝共聚物,可用于制备聚乳酸/乙烯-醋酸乙烯共聚物复合材料,具有优异的力学性能。     

PLA-PEG纤维膜的制备及性能研究

以丙交酯和聚乙二醇(分子量400)为原料,辛酸亚锡为催化剂,通过溶液聚合法制备了聚乳酸-聚乙二醇共聚物(PLA-PEG)。以三氯甲烷为溶剂,通过静电纺丝法制备了PLA-PEG纤维膜。采用傅里叶变换红外吸收光谱(FT-IR)、核磁共振氢谱(~1H-NMR)对制备的共聚物结构进行了表征,采用场发射扫描电镜(FE-SEM)、热重分析仪(TGA)、光学接触角测量仪分别对纤维膜的表面形貌、直径分布、热稳定性及亲水性进行测试,最后通过浸泡法测试了纤维膜的平衡吸水率。结果表明:成功合成了PLA-PEG共聚物;PLA-PEG纤维膜形貌规整,分布均匀,直径为500~1 500 nm;PLA-PEG降低了PLA的热分解温度,提高了材料的亲水性,当共聚物中PLA:PEG从100:0变化到91:9时,纤维膜的接触角从135.21°降至55.41°,材料的平衡吸水率提高到551.09%。     

聚乳酸-聚乙二醇热致复合水凝胶的制备及性能

将疏水性不同的共聚物混合制备可注射水凝胶。通过先核后臂法分别制备出线型聚乳酸-聚乙二醇(PLLAPEG)共聚物和星型聚乳酸-聚乙二醇单甲醚(PLLA-mPEG)共聚物,将两者水溶液进行混合,采用试管翻转法测定混合溶液热致相转变行为。结果表明:线型PLLA-PEG_(600)溶液相转变范围15—42℃,星型PLLA-mPEG750溶液相转变范围52—68℃,当星型PLLA-mPEG750溶液与线型PLLA-PEG_(600)溶液混合,形成了以疏水性较强的线型共聚物为核,疏水性较差的星型共聚物为壳的核壳结构复合物,其相转变温度介于2种共聚物相转变温度之间,可作为注射水凝胶。体外药物释放结果表明:复合水凝胶对所包载的盐酸乌拉地尔具有良好的缓释作用,动力学释放符合一级动力学方程。     

聚乳酸/支化聚酯共混物的韧性和渗出性

文章通过缩聚反应制备聚丙二醇-柠檬酸共聚物(PPGCA),通过密炼制备其和聚乳酸(PLA)的共混物,对比了其和聚乙二醇-柠檬酸共聚物(PEGCA)对PLA的增韧效果和共混物的渗出性。实验表明:PEGCA和PPGCA对PLA都有明显的增韧效果,且效果接近。然而,PLA/PPGCA在高温下,以及在水、乙醇水溶液、异辛烷浸泡下的渗出率明显低于PLA/PEGCA,同纯PLA接近,符合食品包装材料的卫生要求。     

侧链可降解聚硅氧烷

甘肃农业职业技术学院的冯武将烯丙基缩水甘油醚与自制的聚乳酸-聚乙二醇共聚物在锌粉催化下反应，得到4-（3-烯丙氧-2-羟基）丙氧基封端的聚乳酸-聚乙二醇共聚物；再与含氢硅油进行硅氢加成反应，制得带可降解侧链的亲水性聚硅氧烷；并测定了其相对密度、折射率、数均摩尔质量、重均摩尔质量及其分布指数，胶膜的水接触角。     

Kinetics of water absorption and thermal properties of poly(lactic acid)/organomontmorillonite/poly(ethylene glycol) nanocomposites

Poly(lactic acid) (PLA)/organomontmorillonite (OMMT) nanocomposites were prepared by a melt intercalation technique. The effects of OMMT and poly(ethylene glycol) (PEG) on the thermal properties and water absorption behavior of PLA were investigated. The melting temperature and degree of crystallinity were comparable for the PLA and its nanocomposites. The glass transition temperature and crystallization temperature of PLA were decreased by the addition of PEG. X‐ray diffraction results revealed the formation of PLA nanocomposites, as the OMMT was partly intercalated and partly exfoliated. The maximum moisture absorption of PLA was increased in the presence of PEG and the diffusivity of the PLA nanocomposites decreased with increasing concentrations of PEG. However, the activation energy of the nanocomposites increased as the loading of PEG increased. These results indicated that the incorporation of OMMT and PEG enhanced the water‐barrier properties of the PLA. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

Coarse-grained modelling of self-assembling poly(ethylene glycol)/poly(lactic acid) diblock copolymers

An implicit-solvent coarse-grained model for poly(ethylene glycol)/poly(lactic acid) (PEG/PLA) diblock copolymer is derived using the iterative Boltzmann inversion technique. The model is shown to be effective in reproducing the micellar core-shell structure of PEG/PLA diblock copolymer recently reported in experiments. Influence of block architecture on the aggregate morphology is investigated. Upon increasing the length of PLA block, the model predicts a morphological change from conventional spherical to anisotropic (e.g., lamellar or cylindrical) structure, in agreement with experimental findings. The current model is also noted to provide very rapid aggregation of the block copolymers, allowing observation of copolymer micelles in their equilibrium structures in a short simulation time.     

Water Absorption of Poly(lactic acid) Nanocomposites: Effects of Nanofillers and Maleated Rubbers

Injection-molded poly(lactic acid)/organo-montmorillonite (PLA/OMMT) and poly(lactic acid)/ nano-precipitated calcium carbonate (PLA/NPCC) were exposed to a water absorption test at 30°C for 70 days. The analysis was focused on the water diffusion kinetics and impact strength changes induced by the hydrolysis. The diffusion exponent (n) values of all the PLA samples are less than 0.5, indicating the Fickian diffusion model (case I) is obeyed. Adding nanofillers and maleated rubbers (SEBS-g-MAH or EPR-g-MAH) increased equilibrium moisture content but decreased diffusion coefficient values of PLA. The recoverability and retention-ability of the maleated rubbers toughened PLA/OMMT and PLA/NPCC after water absorption are excellent.     

Preparation and drug‐release behavior of 5‐fluorouracil‐loaded poly(lactic acid–4‐hydroxyproline–polyethylene glycol) amphipathic copolymer nanoparticles

Poly(lactic acid–4‐hydroxyproline–polyethylene glycol) (PLA–Hpr–PEG) was synthesized via melt copolymerization with stannous chloride as a catalyst activated by a proton acid. Copolymers with different poly(ethylene glycol) (PEG) concentrations (0.1, 0.5, 1, and 5 wt %) were synthesized and exhibited moderate molecular weights (weight‐average molecular weight = 9705–13,600 g/mol) and reasonable molecular weight distributions (weight‐average molecular weight/number‐average molecular weight = 1.35– 1.66). The structure of the polymers was verified with infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The nanoparticles were made by the nanoprecipitation method with PLA–Hpr–PEG. The size and size distribution of the nanoparticles were investigated with laser light scattering, and the surface morphology of the nanoparticles was investigated with transmission electron microscopy. The drug encapsulation efficiency and drug loading content were measured with ultraviolet absorption spectroscopy. The effects of various formulation parameters were evaluated. The prepared nanoparticles were spherical and greater than 100 nm in size. The drug loading content and encapsulation efficiency were greatly influenced by the amount of the copolymer and the volume of the solvent. The PEG content in the polymer could affect the release of drugs from the PLA–Hpr–PEG nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2654–2659, 2007     

Characterization and emulsifying properties of block copolymers prepared from lactic acid and poly(ethylene glycol)

Block copolymers were prepared by the direct polycondensation of an aqueous lactic acid solution on monomethoxy or dihydroxyl poly(ethylene glycol) (PEG) in the absence of a catalyst. The resulting poly(lactic acid) (PLA)–PEG diblock and PLA–PEG–PLA triblock copolymers were characterized by various analytical techniques, including matrix‐assisted laser desorption/ionization time of flight mass spectrometry (MALDI‐TOF MS), gel permeation chromatography, and ¹H‐NMR. The molecular structure between PLA–PEG and PLA–PEG–PLA could be distinguished after the calculation of the repeat unit masses and end‐group masses through the MALDI‐TOF MS spectra. Interestingly, both copolymers could serve as a hydrophilic emulsifier to stabilize the squalene/water interfaces and yield narrowly distributed oil‐in‐water nanoparticles. In contrast, the prepolymer PEG failed to stabilize the squalene/water interface under the same homogenization conditions. These features are of great interest for applications as bioactive agent delivery, especially for candidate vaccine antigens and lipophilic anticancer drugs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of cholic acid‐containing biodegradable hydrogels by photoinduced copolymerization

A cholic acid (CA)‐containing biodegradable hydrogel (PLA‐PEG‐PLA‐co‐MACAH) was synthesized from the photoinduced copolymerization of a CA‐modified methacrylate monomer (MACAH), bearing a spacer of hexane‐1,6‐diol spacer between the methacryloyl and the cholanoate moieties, and a macromonomer (PLA‐PEG‐PLA‐DA), bearing two acryloyl end groups derived from a poly(lactic acid)‐b‐poly(ethylene glycol)‐b‐poly(lactic acid) triblock copolymer. The structure of MACAH was confirmed by FTIR, ¹H‐NMR, and MS. The hydrogel PLA‐PEG‐PLA‐co‐MACAH was characterized by scanning electron microscopy and X‐ray diffraction. The experiment results showed that the swelling ratios of the hydrogels decreased with the increase of the CA fraction. The investigation on the in vitro degradation of the hydrogel showed that the CA‐containing hydrogels degraded much slower than the hydrogels without CA component. The bioactivity of the synthesized hydrogels was assessed by the simulated body fluid method. The observed formation of hydroxyapatite on the scaffold of the hydrogels indicated that the hydrogels possess good bioactivity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Phase separation to create hydrophilic yet non‐water soluble PLA/PLA‐b‐PEG fibers via electrospinning

In moisture wicking fabrics, fibers with hydrophilic surfaces that are also non‐water soluble are desirable. In poly(lactic acid), PLA, fibers it is expected that the addition of poly(ethylene glycol), PEG, will monotonically increase their wicking rates. In this paper, phase separation was used to create biocompatible, biodegradable, hydrophilic yet non‐water soluble fibers by electrospinning PLA with PEG and PLA‐b‐PEG copolymers. By tuning the thermoelectric parameters of the apparatus, and the chemical properties of the dopes, the amount of PEG in the fibers was improved over prior work; concentration increased by 60% (by weight, wt %) to 16 wt % in the PLA fiber. Instead of the expected increasing wicking rates with PEG concentration, there is a peak at 12 wt %; at greater concentrations, wicking decreases due to PEG crystallization within the PLA (verified via DSC). At 12 wt % PEG from copolymers, the nanofabric's wettability increases to 1300% its original weight. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41030.     

原位熔融接枝淀粉/PLA生物可降解材料性能研究

研究了聚乙二醇(PEG)用量对淀粉-聚乳酸(PLA)原位熔融接枝反应的影响以及淀粉/PLA可降解材料的力学性能和耐水性能.结果表明:PEG能有效地提高淀粉接枝率.PEG的加入,改善了淀粉与PLA的界面相容性和黏结效果,同时提高了淀粉/PLA材料的拉伸强度和耐水性能.     

Plasticizing effect of poly(ethylene glycol)s with different molecular weights in poly(lactic acid)/starch blends

Binary and ternary blends composed of poly(lactic acid) (PLA), starch, and poly(ethylene glycols) (PEGs) with different molecular weights (weight‐average molecular weights = 300, 2000, 4000, 6000, and 10, 000 g/mol) were prepared, and the plasticizing effect and miscibility of PEGs in poly(lactic acid)/starch (PTPS) or PLA were intensively studied. The results indicate that the PEGs were effective plasticizers for the PTPS blends. The small‐molecule plasticizers of PEG300 (i.e., the M_w of PEG was 300g/mol) and glycerol presented better plasticizing effects, whereas its migration and limited miscibility resulted in significant decreases in the water resistance and elongation at break. PEG2000, with a moderate molecular weight, was partially miscible in sample PTPS3; this led to better performance in water resistance and mechanical properties. For higher molecular weight PEG, its plasticization for both starch and PLA was depressed, and visible phase separation also occurred, especially for PTPS6. It was also found that the presence of PEG significantly decreased the glass‐transition temperature and accelerated the crystallization of the PLA matrix, depending on the PEG molecular weight and concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41808.     

PEG、PPG改性PLA材料的性能研究

采用熔融共混法用聚乙二醇(PEG)对生物可降解材料聚乳酸(PLA)进行改性,研究了PEG的相对分子质量对共混体系热性能和力学性能的影响,对比了相同相对分子质量的PEG和聚丙二醇(PPG)由分子结构差异对共混体系性能的影响。结果表明,PEG的相对分子质量为2 000时,改性效果最好;相同相对分子质量的PEG改性效果优于PPG。