含氟两亲接枝共聚物的制备及其与牛血清蛋白作用的研究

用端基反应法合成了对乙烯基苄基的聚乙二醇大分子单体,将该大分子单体与甲基丙烯酸六氟丁酯共聚,合成了一种含氟两亲接枝共聚物.利用1H-NMR1、9F-NMR、GPC对大分子单体和两亲接枝共聚物进行了表征.表面张力法测定了两亲接枝共聚物的临界胶束浓度,发现随着共聚物中含氟链段含量的增加,其临界胶束浓度降低.采用荧光光谱研究了含氟两亲接枝共聚物与牛血清蛋白(BSA)的相互作用,结果表明由于含氟链段疏水力的作用,含氟两亲接枝共聚物能与牛血清蛋白发生相互作用使其荧光增强,随着含氟两亲接枝共聚物浓度和共聚物中含氟链段含量的增加,荧光增强幅度加大.通过透射电子显微镜(TEM)和激光光散射粒度仪(PCS)测试发现,当BSA加入到含氟两亲接枝共聚物的胶束溶液后,所得胶束的粒径和粒径分布变大,共聚物胶束由规整的实心核壳结构变为囊泡状核壳结构.     

聚对二氧环己酮/聚乙二醇多嵌段共聚物的合成与表征

首先合成双端羟基的聚对二氧环己酮预聚物(PPDO)和双端羧基的聚乙二醇预聚物(PEG),然后以丁二酸酐/二环己基碳二亚胺(DCC)将PPDO与PEG偶联共聚,得到PPDO/PEG多嵌段共聚物.通过1H-NMR和GPC表征了聚合物的结构和分子量.采用差示扫描量热法(DSC)和热重分析(TGA)研究了共聚物的结晶性能和热稳定性.用透析法制备了共聚物纳米粒子,并用动态光散射(DLS)表征了共聚物纳米粒子的粒径及分散度,结果表明,随着共聚物亲水链段PEG含量的增加,其纳米粒子更易形成,粒子粒径随共聚物分子量增大而增大.     

新型微球载体材料——PACA-co-PEG的性能

聚氰基丙烯酸烷基酯;药物载体;生物降解性     

Metal-flee synthesis of amphiphilic functional polycarhonates

Amphiphilic block copolymers of poly（5-benzyloxy trimethylene carbonate） （PBTMC） and poly（ethylene glycol） （PEG） were synthesized through enzymatic polymerization using immobilized porcine pancreas lipase （IPPL）. The obtained copolymers with different compositions were characterized by GPC and IH NMR. The copolymer composition was in agreement with the feed ratio. The molecular weight of the copolymers showed an increasing trend with the decrease of PEG contents. MiceUes of the copolymers were formed by dialysis procedure, and characterized by transmission electron microscopy （TEM）.     

Synthesis and characterization of H-type amphiphilic liquid crystalline block copolymers by ATRP

H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization （ATRP）. Macroinitiators prepared by the esterification between poly（ethylene oxide） （PEG） and 2,2-dichloroacetyl chloride were utilized to initiate the polymerization of 6-[4-（4-ethoxyphenylazo）phenoxy]hexyl rnethacrylate （M6C）. The resulting macroinitiators and block copolymers were characterized by ^1H NMR, gel permeation chromatography （GPC）. Polarizing optical microscopy （POM） and differential scanning calorimetry （DSC） preliminarily revealed the liquid crystalline property of these block copolymers. This series of liquid crystalline block copolymers are promising in some areas, such as optical data storage, optical switch, and molecular devices.     

PLGA-(L-Asp-alt-diol)(x)-PLGAs with different contents of pendant amino groups: synthesis and characterization

A series of novel biodegradable multi-block copolymers PLGA-(L-Asp-alt-diol)(x)-PLGA with pendant amino groups was synthesized by ring-opening polymerization of D,L-lactide/glycolide(D,L-LA/GA) (75/25) using poly(N-Cbz-L-Asp-alt-diol)s as macroinitiator and stannous octoate as catalyst, in which the N-Cbz-L-Asp represents N-carbobenzyloxy-L-aspartic acid and diols are ethylene glycol, triethylene glycol, PEG200, and PEG600, respectively. Their structures and properties were characterized by FTIR, (1)H NMR, DSC, GPC, and elemental analysis (EA). The contents of the L-Asp unit in the copolymers were increased from 12.9 to 79.3 mmol.g(-1) with decreasing the chain length of the diol, while the glass transition temperatures of the copolymers were decreased from 27.1 to 11.7 degrees C with increasing the chain length of the diol. Thus, the results in this study provide a way to prepare biomaterials with different L-Asp unit densities or different number of bioactive sites as well as different properties through adjusting the chain length of the diol. Synthesis of PLGA-(N-Cbz-L-Asp-alt-diol)(x)-PLGA copolymers.     

聚对二氧环己酮/聚乙二醇两亲性聚合物共网络的合成与表征

以辛酸亚锡为催化剂,季戊四醇(PTOL)为引发剂,引发对二氧环己酮(PDO)单体开环聚合,合成了以PTOL为核的四臂聚对二氧环己酮(4s-PPDO).通过直接将4s-PPDO预聚物和聚乙二醇(PEG)于熔点以上、惰性气体保护下与偶联剂甲苯二异氰酸酯(TDI)交联共聚得到聚对二氧环己酮/聚乙二醇(PPDO-b-PEG)两亲性共网络聚合物(PPDO-PEG APCNs).研究了两亲性聚合物共网络结构、配比组成、溶剂种类等对聚合物溶胀率的影响,结果表明APCNs在不同类型的溶剂中表现出不同的溶胀行为,可以通过调节偶联剂的用量及PPDO/PEG的投料比来满足不同的实际需求.通过示差扫描量热分析(DSC)详细研究APCNs的结晶性能,证实交联反应降低APCNs的结晶度和结晶尺寸.     

含氟两亲接枝共聚物的制备及其结晶行为

采用大分子单体技术合成了一系列以聚乙二醇为支链、甲基丙烯酸六氟丁酯为主链的含氟两亲接枝共聚物(PHFMA-g-PSPEG)。用1HNMR和凝胶色谱(GPC)对制备的大分子单体和两亲接枝共聚物的结构进行了表征。利用示差扫描量热法(DSC)、X射线衍射(XRD)和偏光显微镜(POM)测试技术对含氟两亲接枝共聚物的结晶行为进行了研究。DSC和XRD结果表明,随着共聚物中含氟链段质量分数的增加,其结晶温度(Tc)和结晶度(Xc)均降低,而结晶熔融温度(Tm)先减小后增加。POM发现,随着共聚物中含氟链段质量分数的增加,其结晶速度减慢,共聚物形成清晰球晶的能力减弱,当共聚物中含氟链段质量分数为57%时,含氟两亲接枝共聚物已不能形成清晰的球晶。     

新型聚乙烯接枝共聚物的制备与表征

以聚氧乙烯和全氟辛基聚氧乙烯醚(FPEOE)为起始原料, 合成了一系列的特种氟表面活性剂及其丙烯酸酯, 用FTIR和1H NMR对其结构进行了表征, 用最大气泡法测定了其表面张力. 以其作为接枝单体, 利用反应挤出接枝的方法制备了系列功能化聚乙烯, 用FTIR确定了接枝共聚物的结构和接枝率; 用DSC、接触角测量仪和XPS对接枝共聚物的热性能、结晶行为和表面性能进行了测试分析. 结果表明, 随着聚氧乙烯分子量的增加, 氟表面活性剂的表面活性降低; 聚乙烯接枝共聚物的结晶温度高于线形低密度聚乙烯, 且具有较好的亲水性.     

磷酸钙骨水泥/聚肽共聚物生物复合材料力学性能及微观结构

磷酸钙骨水(Calcium Phosphate Cement,CPC)是一种新型的人工骨材料,可用于人体骨缺损的修复,具有良好的生物相容性、骨传导性和骨替代性．然而,磷酸钙骨水泥的抗压强度较低,脆性较大,限制了其应用,因而提高抗压强度和减小其脆性成为CPC研究领域的一个重要课题．目前,普遍采用添加纤维的方法来提高CPC材料的抗压强度和韧性．然而大多数的纤维是非降解性的．     

Amphiphilic Seven-arm Star Triblock Copolymers with Diverse Morphologies in Aqueous Solution Induced by Crystallization and pH

Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly(ε-caprolactone)(PCL) blocks, hydrophobic non-crystalline poly(tert-butyl acrylate)(PtBA) blocks and hydrophilic poly(ethylene glycol)(PEG) blocks were precisely synthesized by a combination of ring-opening polymerization(ROP), atom transfer radical polymerization(ATRP) and “click” reaction. Such star copolymers could self-assemble into “core-shell-corona” micelles and “multi-layer” vesicles depending on the fraction of each block. Meanwhile, the selective hydrolysis of middle PtBA blocks into the poly(acrylic acid)(PAA) blocks allowed the star block copolymers to further change their morphologies of aqueous aggregates in response to pH values.     

化学酶法合成五嵌段聚合物及其自组装行为的研究

用酶促开环聚合与ATRP方法相结合,制备了聚甲基丙烯酸六氟丁酯-聚己内酯-聚乙二醇-聚己内酯-聚甲基丙烯酸六氟丁酯(PHFMA-b-PCL-b-PEG-b-PCL-b-PHFMA)五嵌段聚合物.首先用Novozym e 435作为催化剂合成了聚己内酯-聚乙二醇-聚己内酯三嵌段聚合物,然后通过端基官能化法合成了大分子引发剂,并用其引发甲基丙烯酸六氟丁酯(HFMA)的ATRP反应,合成了五嵌段聚合物.通过核磁和GPC证明了大分子引发剂和五嵌段共聚物的结构,五嵌段共聚物的GPC分析表明这种合成方法的可行.共聚物胶束的直径和大小通过动态光散射方法和原子力显微镜测试,五嵌段共聚物在水中的的自组装行为也被研究.结果证明胶束是球形,其平均直径为77 nm.聚合物在四氢呋喃中的浓度对聚合物的聚集形貌有很大的影响.     

PEG链段对聚乙二醇接枝聚苯胺结构与性能的影响

将苯胺(An)与甲氧基聚乙二醇邻氨基苯基醚氧化共聚,制备了梳状接枝共聚物PAn-g-PEG.研究了梳状接枝共聚物的UV-Vis、微观结构、热稳定性和溶解成膜性等随侧链聚乙二醇(PEG)链段的变化规律.结果表明随PAn-g-PEG中PEG链段长度和含量的提高,共聚物的溶解性和成膜性能显著提高,电子导电率缓慢降低,热稳定性变差.共聚物具有微相分离结构,其形态随PEG链段的改变分别为“海-岛相”和“双连续相”;提高PEG链段长度和含量,PAn-g-PEG能形成稳定的水溶性分散体系,并能浇注成柔韧平整的导电高分子自支撑膜.     

二维核磁共振法研究线型聚乙二醇与树枝状聚苄醚形成的三嵌段共聚物

嵌段共聚物是由几个不同的高分子链段通过化学键相连所构成的 .在合成方法上一般是通过几类不同的活性聚合 ,调控单体的加料次序或者通过不同的大分子链段末端的反应活性点偶联而成[1～ 3 ] .所形成的化学键将嵌段共聚物中不相溶的几段相连 ,于是在特定的条件下就产生了微相分离的现象 ,继而可以在 1 0～ 1 0 0nm尺度范围内形成各种各样的微区结构[4,5] .在过去的几十年里 ,研究的重点是认定嵌段共聚物的微区结构和研究微相分离的动力学 ,已发表了大量重要的结果 ,至今仍然是高分子科学中的热门课题 .非常重要的一点是 ,正是由于不同的高分…     

含聚氧化乙烯嵌段的三元多嵌段共聚物的合成和性能

用聚乙二醇、聚丙二醇、遥爪羟基聚苯乙烯和二氯甲烷在氢氧化钾存在下合成了氧亚甲基连接的聚氧化乙烯－聚氧化丙烯－聚苯乙烯多嵌段聚合物；并研究其乳化性能和相转移催化性能。     

Synthesis, characterization and protein adsorption behaviors of PLGA/PEG di-block co-polymer blend films

A series of poly(D,L-lactic-co-glycolic acid) (PLGA)/poly(ethyleneglycol) (PEG) di-block copolymers were synthesized by ring-opening polymerization of D,L-lactide and glycolide with different molecular weights of monomethoxy polyethyleneglycol (mPEG) 750, 2000 and 5000 as an initiator. The bulk properties of these co-polymers were characterized by using 1H NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry (DSC). Electron spectroscopy for chemical analysis (ESCA) results, in which the blend films with the di-block copolymers showed increasing surface oxygen atomic percentage with increasing PEG chain length, indicate that PEG chain segment in the di-block copolymers is surface oriented and enriched onto the surface of the blend films. The extent of protein adsorption onto the surface of these blend films was studied, using iodine radio-labeled human serum albumin, gamma globulin and human growth hormone. The protein adsorption amount was reduced for the blend films prepared with PLGA/PEG 750 and 2000 di-block copolymers, but increased to a great extent for PLGA/PEG 5000 di-block copolymer. This is due to the increased water uptake capacity of the blend film, which absorbed more protein molecules into a swollen polymer matrix in addition to surface adsorption.     

Crystallization behavior, thermal property and biodegradation of poly(3-hydroxybutyrate)/poly(ethylene glycol) grafting copolymer

The poly(3-hydroxybutyrate)(PHB)/poly(ethylene glycol)(PEG) grafting copolymer was successfully prepared by PHB and acrylate groups ended PEGM using AIBN as initiator. The crystallization behavior, thermal stability and environmental biodegradability of PHB/PEG grafting copolymers were investigated with differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and Biodegradation test in vitro. In the results, all the grafting copolymers were found to show the X-ray diffraction arising from the PHB crystal lattice, while none of the PEG crystallized peaks could be found even though the graft percent reached 20%. This result indicated that PEG molecules were randomly grafted onto PHB chain. The thermal properties measured by DSC showed that the melting temperature(T_m) and glass transition temperature (T_g) were both shifted to lower temperature with the graft percent increasing, and this broadened the narrow processability window of PHB. According to TGA results, the thermal stability of the grafting copolymers is not changed compared to pure PHB. From the biodegradation test, it could be concluded that degradation occurred gradually from the surface to the inside and that the degradation rate could be adjusted by the PEG grafting ratio. In another words, the biodegradation profiles of PHB/PEG grafting copolymer can be controlled. These properties make PHB/PEG grafting copolymer have promising potential applications especially in agriculture fields.     

环氧丙烷聚醚三元醇/聚乳酸嵌段共聚物的合成与性能

以低不饱和度环氧丙烷聚醚三元醇与L型及DL型丙交酯为原料, 合成了不同单体物质的量比的聚醚与聚乳酸嵌段共聚物. 采用FTIR, 1H NMR, GPC对共聚物的结构进行了表征; 用DSC, DTA对共聚物的玻璃化转变温度、熔点及热分解温度进行了研究. 结果表明, 丙交酯在聚醚多元醇端羟基的引发下发生开环反应, 得到聚环氧丙烷L型乳酸(POLLA)或聚环氧丙烷DL型乳酸(PODLA)二嵌段共聚物. POLLA二嵌段共聚物具有结晶能力, 且随着L型聚乳酸链段的增长而增强. PODLA二嵌段共聚物为非晶态聚合物. 两种共聚物的玻璃化转变温度与共聚物的组成有关, 其值介于聚醚和聚乳酸玻璃化转变温度之间. 与聚醚三元醇相比, 二嵌段共聚物的耐热性得到提高, 其热分解温度提高了30～60 ℃, 约为235～262 ℃. 共聚物的结构和组成对材料的热降解机制有很大影响. PODLA在高温区发生热氧化降解.     

Aggregation and thermoresponsive properties of new star block copolymers with a cholic acid core

Poly(allyl glycidyl ether) (PAGE) and poly(ethylene glycol) (PEG) blocks were sequentially grown via anionic polymerization to form four block copolymer arms on a cholic acid (CA) core, yielding star block copolymers (CA(AGE(8)-b-EG(n))(4)) with low polydispersities (ca. 1.05). The introduction of PAGE segments into CA(PEG)(4) significantly reduced their crystallinity. The polymers can aggregate in water at room temperature above their critical aggregation concentration. The copolymers are thermoresponsive; their behavior in aqueous solutions was studied by the use of UV-visible spectroscopy, dynamic light scattering, and transmission electron microscopy. Their cloud points vary from 13 to 55 °C with increasing length of the PEG segments. Double thermoresponsive behavior was observed with short PEG segments because of a two-step transition process: small micelles are formed upon heating and then further aggregate into micellar clusters through the association of PEG chains.     

Effect of block lengths on the association behavior of poly(l-lactic acid)/poly(ethylene glycol) (PLA–PEG–PLA) micelles in aqueous solution

A series of poly(l-lactic acid)/poly(ethylene glycol) triblock copolymers with a PLA–PEG–PLA architecture were synthesized by a ring-opening polymerization (ROP) process. The copolymers were characterized by ¹H NMR and GPC. The total number average molecular weights were in the range of 4,700–50,000, whereas the degrees of polymerization of the PLA and PEG blocks varied from 15 to 359 and from 68 to 136, respectively. The self-association of these copolymers in aqueous environment was studied by emission fluorescence spectroscopy of anilinonaphthalene probe and the critical association concentration (CAC) of the copolymers was measured. It was found that the micellization process of these copolymers was mainly determined by the length of the hydrophobic LA block, while the length of the hydrophilic PEG block had little effect. Furthermore, the low CAC values of the copolymers suggest that the copolymers form stable supramolecular structures in aqueous solutions.