聚乳酸-聚乙二醇嵌段共聚物及其交联聚氨酯弹性体的性能研究

通过改变聚乙二醇的用量,将丙交酯与聚乙二醇共聚制成嵌预聚体,用二苯基甲烷二异氰酸酯扩链后再用三羟甲基丙烷交联,制得系列聚氨酯型新颖性体。通过对其性能研究表明,随着ＰＥＧ含量的增加,共聚物的特性粘度降低,玻璃化转变温度降低,拉伸强度先升后降;聚氨酯弹性体的玻璃化转变温度降低,拉伸强度降低,而降解速度去加快。     

埃洛石纳米管对聚乳酸基材料的改性研究进展

埃洛石纳米管（HNTs）是一种天然的无机纳米管状材料,具有与高岭土相似的化学组成以及与碳纳米管类似的一维结构,因其来源广泛、价格低廉,并且具有较大的长径比、较大的比表面积以及高模量等特点,近年来受到广泛关注并被应用于高分子材料的改性之中。本文在HNTs的结构特点和现有的表面改性方法的基础上,梳理了近年来HNTs用于聚乳酸（PLA）基聚合物复合材料改性的相关研究工作,重点关注了HNTs对材料的热稳定性、相结构、结晶性能、降解性能、机械性能以及生物医学性能方面的影响,展望了HNTs改性PLA复合材料的研究和应用前景。     

CdTe/聚乳酸纳米杂化材料的制备及其荧光性能

以十二烷基胺(DDA)为表面修饰剂,将巯基水相法合成的CdTe纳米晶转移至有机溶剂三氯甲烷中,然后采用“物理共混法”实现了CdTe/聚乳酸(CdTe/PLA)纳米杂化材料及其透明荧光膜的制备.通过紫外-可见光谱仪(UV -vis)、荧光(PL)、紫外透射反射分析仪等表征方法考察相转移前后CdTe纳米晶的光学性能,并系统研究了CdTe/PLA纳米杂化材料的荧光性能.结果表明:相转移后CdTe纳米晶的粒径未发生明显变化,其量子产率却提高了;所制备的CdTe/PLA纳米杂化材料具有优越的荧光性能,CdTe纳米晶在聚合物中仍然保持良好的分散性和较好的量子尺寸效应.     

Melt rheology of poly (lactic acid) plasticized by epoxidized soybean oil

This study investigated that epoxidized soybean oil (ESO) was blended as plasticizer with poly (lactic acid) (PLA) and its effects on the melt rheological properties, such as melt flow index, apparent shear viscosity, and melt strength of the blends. PLA was blended by the twin-screw plastic extruder at five mass fractions: 3%, 6%, 9%, 12%, and 15% (based on PLA mass). Melt flow index (MFI) was examined with a melt flow indexer. The results indicate that the blends of PLA/ESO had higher MFI than pure PLA, except for MFI at 9% reaching to the lowest point, even lower than that of pure PLA. Melt rheological properties were studied by a capillary rheometer in a temperature range of 160–180 °C. The blends ends exhibited shear-thinning behavior and the apparent shear viscosity was well described by the power law in this shear rate region. The melt strength of PLA plasticized with 6% ESO reached the maximums. ESO was more effective in increasing the melt strength at the mass fractions less than 6%, which could toughen the blends to some extent. Therefore, the authors suggested the optimum addition level of 6%–9% ESO will get good melt rheological performance balance. Biography: XU Yuqiong (1974–), female, Ph.D., research direction: polymer composites.     

环氧化天然橡胶对聚乳酸性能的影响

通过溶液共混的方法制备了左旋聚乳酸（PLLA）/环氧化天然橡胶（ENR-50）共混物,研究了ENR-50对PLLA的热稳定性、结晶性、力学性能和降解性能的影响。结果表明,ENR-50因环氧基团的存在,其引入可以显著提高PLLA的热稳定性。同时,分子运动性较高的弹性体虽不利于PLLA的成核,但可以提高其晶体生长速率。脆断面扫描电镜（SEM）结果表明,ENR-50呈椭球状均匀分散于PLLA中,作为应力集中物,经退火处理一定时间后ENR-50可以显著提高PLLA的韧性。此外,10%（质量分数）以内ENR-50的引入并不影响PLLA的酶降解速率。     

聚乳酸-聚扁桃酸共聚物的合成与表征

合成乳酸OCA和扁桃酸OCA单体,用DMAP引发乳酸OCA和扁桃酸OCA开环共聚合成可生物降解的聚乳酸-聚扁桃酸共聚物,通过调节聚合共聚单体的比例,可得到分子量从3 620¹1 800 g/mol不等的共聚物,实现了分子量可控的目的.使用1H NMR、GPC、DSC、TEM、XRD等手段对共聚物进行了表征,所得共聚物的热力学性能、降解性能等均得到改善.并对轮状病毒进行负载制备成载药微球,对其降解行为进行研究,为药物控制释放提供一类新的载体材料.     

利用重组大肠杆菌生产聚-3-羟基丁酸的研究

利用携带能合成聚-3-羟基丁酸的基因的大肠杆菌E. coli XL1-Blue,优化培养基和培养条件后,进行了补料分批培养.结果表明,重组大肠杆菌E. coli XL1-Blue(pKSS105)的最适培养基为R培养基.在最佳条件下,以葡萄糖为唯一碳源培养工程菌60h后,发酵液中菌体干重达183g/ L,P(3HB)的产量为133.8g/ L,P(3HB)含量为73.1%.实验结果为P(3HB)实际应用提供了可能性的基础.     

可生物降解的新型阻垢缓蚀剂聚天门冬氨酸

聚天门冬氨酸是新一代可生物降解的绿色阻垢缓蚀剂。本文对聚天门冬氨酸的合成、性能及发展前景进行了较详细的介绍 ,认为 :间接生产工艺已较成熟 ,直接生产工艺有待发展。     

聚乳酸膜表面氨等离子体改性

为研究氨等离子体对聚乳酸膜表面进行改性以及改性时发生的化学变化，采用接触角和XPS来表征．实验结果表明，氨等离子体能对聚乳酸膜表面进行改性，氨主要以-NH-CO-或C-N和-NH3^ 基团形式接枝在聚乳酸膜表面的链段上，并且随着等离子体处理时间从5min延长到20min，聚乳酸膜表面N元素的含量也从3.2％增加至5.2％(P=80W，而接触角则随聚乳酸膜表面接枝上亲水性极强的-NH3基团含量而变化．     

Study of Synthesis of Copoly （lactic acid／glycolic acid） by Direct Melt Polycondensation

A two steps direct copolymerisation process was developed. The first step is to produce oligomer and then the oligomer of lactic acid/glycolic acid (90/10) is polymerized with binary catalyst tin chloride dihydrate/ptoluenesulfonic acid. In this way, the direct synthesis of copoly (lactic acid/glycolic acid) without any organic solvent was investigated. The properties and structures of products were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray diffraction and so on. The results show that comparatively high molecular weight copolymer of lactic acid and glycolic acid can be prepared by direct processing under appropriate technological conditions.     

Influence of Mica Particles on the Rheological Properties and Thermal Stability of Poly（ lactic acid）

The influence of mica particles on the rheological and thermal properties of poly（ lactic acid）（ PLA） / mica composites were investigated by capillary rheometer and thermogravimetric（ TG）analysis. The results show that the PLA / mica blends are nonNewtonian pseudoplastic and display shear-thinning. The value of non-Newtonian index of the blends melt decreased obviously with the addition of mica particles but somehow even increased when shear rate exceeded 4 500 s- 1. In this work,it could be indicated that appropriate amount of mica particles could somehow enhance the resistance of PLA melt under high shear rate to deviate from Newtonian fluid. TG analysis shows that the thermal stability of PLA decreases a little after the incorporation of the mica particles.As mica particles decompose in a completely different way in contrast to PLA,this abnormal decrease of thermal stability of PLA / mica composite may be attributed to moisture stored between mica layers released at high temperature.     

聚丙交脂-乙交酯纤维的温压成形

通过溶液沉析纺丝法制备聚丙交酯-乙交酯(PLGA)纤维,观察纤维的形貌并对其进行XRD和SEM表征.采用纤维温压成形法控制压力和温度得到条形的PLGA材料结合试样断口分析,研究成型压力与温度对PLGA材料的力学性能的影响.研究结果表明:非晶多孔结构的PLGA纤维可通过溶液沉析纺丝的方法获得,其孔径为0.1～ 1.0 μm;压制压力和压制温度对材料的力学性能影响较大,材料的抗弯强度、剪切强度和抗弯模量均随着温度和压力的增大而先增大后降低;在压制压力为105 MPa,压制温度为160 ℃时,试样的力学性能比较理想,此时,其抗弯强度可达到187.3 MPa,剪切强度达到100.1 MPa,抗弯模量达到2.5 GPa,可望作为非承重部位骨折愈合内固定材料.     

木质素接枝右旋聚乳酸的结晶行为及对左旋聚乳酸的结晶促进作用

木质素（lignin）作为仅次于纤维素的第二大可再生生物质资源,近年来受到广泛关注并已被应用于高分子材料的改性。本文在对碱木质素烷基化修饰的基础上,利用其丰富的羟基对右旋丙交酯进行开环聚合,制备了一系列不同分子量的烷基化木质素接枝右旋聚乳酸（LGPD）。通过对LGPD自身结晶行为的研究表明,木质素的存在能够促进右旋聚乳酸（PDLA）的结晶,提高其吸收紫外线的能力。相对于4臂右旋聚乳酸（4a-PDLA）,将LGPD作为添加剂加入到左旋聚乳酸（PLLA）后更有利于立构复合晶的形成,从而进一步提高了共混材料的结晶能力。     

In vitro study of poly(ethylene carbonate) as a drug-eluting stent coating

An in vitro feasibility study of the use of poly(ethylene carbonate) (PEC) as a biodegradable coating material for drug-eluting stents is reported, and the performance of PEC is compared with that of poly(lactic-co-glycolic acid) (PLGA). Scanning electron microscopy (SEM) images of PEC and PLGA discs after treatment with an alkaline KO2 solution as a superoxide source showed that the PEC maintained its integrity whereas holes and small particles appeared during the treatment of PLGA. Sirolimus and paclitaxel were loaded into PEC and PLGA in order to study drug release performance. Attenuated total reflectance–infrared (ATR– FTIR) spectroscopy of sirolimus, PEC and the sirolimus-loaded PEC coating showed that no chemical reaction occurred between sirolimus and PEC. The results of atomic force microscopy (AFM) revealed that the mean roughness (Ra) values of the bare metal stent (BMS) and the drugeluting stent (DES) were 2.3 nm and 1.0 nm, respectively. After balloon expansion experiments, no delamination or destruction of the PEC coating was observed. The drug release profile of sirolimus was different from that of paclitaxel when PEC was employed as the drug carrier, and the release curves of sirolimus were different when PEC and PLGA were used as drug carriers. All the experimental results demonstrated that PEC was one of the best potential stent-coating materials.     

双金属离子水热催化转化葡萄糖制备乳酸

选择不同的双金属阳离子作为催化剂,在碱性条件下用于水热转化葡萄糖制备乳酸,发现Sn2+和Cu2+具有一定的协同作用.研究了反应温度、时间、碱加入量和金属离子比例对乳酸产率的影响,获得最优工艺条件如下:0.025 g葡萄糖,2 mmol NaOH,n(Sn2+)∶n(Cu2+)=0.25∶0.75(共1mmol),20 ...     

Protein adsorption on the poly（L-lactic acid） surface modified by chitosan and its derivatives

Surface modification of biomaterials has been adopted over the years to improve their biocompatibility. In this study, aiming to promote hydrophilicity and to introduce natural recognition sites onto poly（L-lactic acid） （PLLA） films, chitosan and its derivatives, carboxymethyl chitosan（CMC） and N-methylene phosphonic chitosan （NPC）, were used to modify the surface of PLLA films by an entrapment method. Radiolabeled （^125I） proteins were used to measure the amount of protein adsorbed to PLLA surfaces. Fibronectin （Fn） was used to study the protein adsorption on the modified PLLA surfaces, including isotherm adsorption and adsorption kinetics of single protein, competitive adsorption of binary proteins system and serum multi-proteins and the desorption behavior in serum solution. The results showed that in the isotherm adsorption, Fn had a larger adsorption capacity on the CS-modified surface at lower concentrations, but had a high adsorption capacity at CMC-modified surface at higher concentrations. In the study of absorption kinetics, Fn had a fastest adsorption equilibrium and a highest equilibrium adsorption capacity at the CS-modified surface, while it was opposite at the PCS-modified surface. When BSA and serum were added, it had the greatest effect on the adsorption of Fn on the PCS-modified surface. After 6 hours soaking in the desorpUon study, Fn had reached desorption equilibrium on all the modified surfaces, which had different effects on the desorption rate and the remaining percentage of Fn.     

微波法合成低分子量聚L-乳酸研究

在微波辐射条件下，以L-乳酸为原料抽真空直接合成低分子量聚乳酸。根据微波辐射的特点制作了两口长颈反应釜，考察单体纯度、催化剂种类和用量、聚合时间、聚合温度等因素对聚卜乳酸粘均分子量的影响，确定了最佳工艺；并采用IR、^1HNMR和^13CNMR等测试手段对聚合产物进行了结构表征。     

Preparation and characterization of poly(vinylidene fluoride) composite membranes blended with nano-crystalline cellulose

Poly(vinylidene fluoride) (PVDF) composite membranes blended with nano-crystalline cellulose (NCC) for ultrafiltration were prepared by a Loeb-Sourirajan (L-S) phase inversion process.The effects of NC...     

Flexible free-standing polyaniline/poly(vinyl alcohol) composite electrode with good capacitance performance and shape memory behavior

The increasing demand for portable and flexible energy storage devices drives the development of flexible electrodes and electrolytes. The aim of this work is to fabricate the flexible free-standing polyaniline/poly(vinyl alcohol)(PANI/PVA) composite electrode with good capacitance performance and shape memory behavior. The electrodes were fabricated by chemical oxidation polymerization of aniline in porous PVA(P-PVA) films. The morphology, electrochemical and mechanical properties of PANI/P-PVA...     

骨组织工程聚左旋乳酸多孔框架快速成形研究

为制备用于骨组织工程的细胞载体框架结构 ,对快速成形技术制备聚左旋乳酸多孔框架结构的若干基础问题进行了研究。提出了聚左旋乳酸快速成形的精密挤出成形工艺 ,研究了此工艺制备多孔框架结构的设备与工艺过程 ,分析了制备的多孔框架结构应用于组织工程人工骨的可行性。制备的多孔框架结构具有合适的分子量、孔隙结构、孔隙率、机械强度和生物降解性能 ,可以用作骨组织工程的组织再生框架结构