三嵌段共聚物PS-b-PEG-b-PS与聚苯乙烯共混薄膜的表面形貌与性能研究

使用原子转移自由基聚合(ATRP)制备三嵌段共聚物PS-b-PEG-b-PS.通过红外光谱、核磁共振氢谱(1H-NMR)和凝胶渗透色谱(GPC)对嵌段共聚物结构及分子量进行表征.将嵌段共聚物与聚苯乙烯溶液共混成膜,使用原子力显微镜(AFM)和接触角测试仪(CA)对不同含量嵌段共聚物共混膜的表面形貌和性能进行了分析表征.PEG链段与PS链段在共混膜中发生了微相分离,由于PEG链段对PS链段的热力学排斥作用以及PS的硬链段特性,PS不能在PEG微区上方形成覆盖,因而在薄膜表面形成大量孔洞,PEG微相区位于孔洞底部.随嵌段共聚物含量增加,孔洞(PEG微区)尺寸增大.当嵌段共聚物含量增加10％以后,孔洞内出现PS微相区,导致形成“胞状”结构.嵌段共聚物含量增加使得共混薄膜的亲水性和表面张力增大.     

聚酯—聚醚系列嵌段共聚物动态力学性质的研究

本文研究了聚酯-聚醚(PET-PEG)系列嵌段共聚物的动态力学性质及其组成与特性粘度的关系,并对分子链中软、硬段序列长度进行了估算。研究表明,PETPEG系列嵌段共聚物存在两个分别对应于硬、软段的玻璃化转变温度Tg_((H))、Tg_((S)),其模量及Tg皆比PET的低,并随PEG含量的增大而下降,随PEG分子量的增大而提高。动态力学的实验结果与理论估算相吻合。本研究为制备该共聚物弹性纤维而选择合适的组分提供了理论依据。     

脂肪族聚丁二酸丁二醇-聚乙二醇嵌段共聚物的制备及性能研究

采用熔融缩聚法以钛酸四丁酯为催化剂,使单体发生酯交换反应,成功制备了一系列以聚乙二醇(PEG)为亲水软段,以聚丁二酸丁二醇酯(PBS)为硬段的嵌段共聚物,采用1H-NMR确定了共聚物的结构组成;采用DSC、吸水性测试及水解降解试验对嵌段共聚物性能表征,结果表明共聚物中两种链段的含量与原料投料比一致,具有可调控性。由于PEG的引入,使共聚物结晶性下降,亲水性和降解性得到显著改善。     

聚醚酰胺嵌段共聚物的合成及表征

采用熔融缩聚法合成了聚酰胺(PA)6/聚四氢呋喃(PTEMG)嵌段共聚物,研究了PA6、PTEMG链段的相对分子质量、含量对嵌段共聚物热性能的影响,通过傅立叶变换红外光谱、核磁共振、差示扫描量热、热重测试等对产物进行分析.结果表明,嵌段共聚物以羧基封端,当PA6、PTEMG链段相对分子质量分别为2 000、1 000时,共聚物的分子序列长度最长,相对分子质量最大;PTEMG链段相对分子质量越小,共聚物的熔点越低;PTEMG链段相对分子质量相同时,随PA6链段相对分子质量的增加,熔点升高;嵌段共聚物中PA6组分的熔融温度范围随着PTEMG含量的增加而逐步变宽;共聚物具有较高的热分解活化能.     

一步法合成聚醚酰胺嵌段共聚物及其抗静电性能研究

采用一步法合成了由聚乙二醇(PEG)链段和聚酰胺6(PA6)链段组成的聚醚酰胺嵌段共聚物,用红外光谱和核磁共振波谱等手段确证了它的化学结构。随着合成配方中己内酰胺用量的减少,聚醚酰胺嵌段共聚物相对分子质量下降,PA6链段变短。合成的聚醚酰胺嵌段共聚物具有微相分离结构,表面电阻率随着其中PEG链段含量的增加而下降。将合成的聚醚酰胺嵌段共聚物以10%的质量分数添加到ABS塑料中,其表面电阻率由1014Ω量级下降到1011Ω量级,拉伸强度变化不大,断裂伸长率有所下降。     

两亲性嵌段共聚物的合成及其在离子液体中的自组装行为

采用阴离子开环聚合法合成了嵌段共聚物PCL—PEG—PCL（聚己内醋-聚乙二醇-聚己内酯）。用1HNMR和GPC等对产物的分子量和组成进行表征,将其在离子液体中配成胶束,通过透射电镜（TEM）观察胶束的微观结构。研究结果表明,当疏水链段长度固定时,胶束的自组装形状主要依赖于亲水链的长度。     

PLA/PBAu嵌段共聚物合成工艺优化及降解性能

以端羟基聚乳酸（PLA）、聚己二酸-丁二醇-尿素（PBAu）为预聚物,六亚甲基二异氰酸酯（HDI）为扩链剂,制备出一种新型PLA/PBAu嵌段共聚物。研究了扩链剂用量、扩链温度以及催化剂用量对PLA/PBAu嵌段共聚物分子量的影响,确定了合成PLA/PBAu嵌段共聚物的最佳工艺条件。采用核磁共振、凝胶渗透色谱、差示扫描量热仪、扫描电镜等对共聚物薄膜结构及性能进行表征。结果表明：成功合成了PLA/PBAu嵌段共聚物,分子量可达10×10⁴,玻璃化转变温度约为41℃;并且随着PBAu含量的增加,共聚物的结晶度逐渐增加。以NaOH溶液为模拟液进行加速降解实验发现,当PBAu含量为30%时,可以显著提高嵌段共聚物的降解速率,并且通过调节PLA、PBAu预聚物的含量,可以控制嵌段共聚物的降解速率。     

聚醚氨酯结构与微相分离的研究

以聚四氢呋喃二醇(PTMEG)为软段，以4，4’-二苯基甲烷二异氰酸酯(MDI)和间苯二胺为硬段，合成了一系列聚醚氨酯嵌段共聚物。利用傅立叶红外光谱(FTIR)、差热分析(DSC)和小角X光散射(SAXS)对聚醚氨酯嵌段共聚物的微相分离进行了研究，发现在聚醚氨酯嵌段共聚物中存在两相结构，其微相分离程度随硬段含量的增加而降低。     

聚对苯二甲酸乙二酯—聚四亚甲基醚嵌段共聚物的玻璃化转变

<正> 对于[A—B]_n型多嵌段共聚物的结构形态和性能的研究,近年来引起了广泛的兴趣。这里“A”表示硬链段即芳族结晶性聚酯或能形成氢键的氨酯键;“B”表示软链段的脂族聚醚或聚酯。由于两链段在热力学上不相容性,而呈现出两相分离,这种不相容性特征是与两嵌段的化学结构、链段长度、链段有否形成氢键或结晶和制备方法密切相关。聚酯-聚醚多嵌段共聚物鉴于两嵌     

含苯并咪唑的芳香族聚酰胺共聚物的合成与表征

采用低温溶液缩聚法,在N-甲基吡咯烷酮(NMP)-氯化锂(LiCl)溶剂体系中加入2-(4-氨基苯基)-5-氨基苯并咪唑(DAPBI)作为第三单体,与对苯二胺(PPD)和对苯二甲酰氯(TPC)共聚得到改性对苯二甲酰对苯二胺(PPTA)共聚物。控制共聚单体投料顺序,设计合成出一系列序列结构不同的杂环段与PPTA硬段相间的嵌段聚合物。研究了序列结构和DAPBI含量对共聚物比浓对数黏度的影响,采用红外光谱、X射线衍射、热重分析仪等对共聚物结构和性能进行表征。试验结果表明:DAPBI成功引入到了PPTA分子链中,改性PPTA树脂为非晶结构,所得有规嵌段共聚物比无规共聚物拥有更好的有序性和结晶性能,共聚物能保持良好的耐热性能,溶解性能和力学性能得到了提升。     

PET-PEG嵌段共聚物纤维和PET/PET-PEG共混纤维的吸湿性和抗静电性能研究

本文对PET-PEG嵌段共聚物的可纺性、PET-PEG纤维和PET/PET-PEG共混纤维的吸湿性和抗静电性能进行了研究,探讨了共混纤维的抗静电机理。发现随PEG含量的增加,PET-PEG嵌段共聚物的可纺性变差,但纤维的吸湿性和抗静电性能提高,抗静电耐久性变差。PEG在PET-PEG纤维和PET/PET-PEG共混纤维中的导电机理为质子导电。PEG含量为30wt％(占 TPA)的PET-PEG嵌段共聚物与PET的共混纤维具有工业化前途。     

生物相容性聚酯共聚物PBS-b-PEG的合成与性能

以1,4-丁二酸、1,4-丁二醇和聚乙二醇(PEG)为主要原料进行熔融缩聚,制备了不同PEG含量的PEG-聚丁二酸丁二酯(PBS)嵌段共聚物(PBS-b-PEG).核磁共振和凝胶渗透色谱分析表明:合成的PBS-b-PEG结构明确.透过差示扫描量热仪、广角X射线衍射仪、偏光显微镜、原子力显微镜和接触角分析仪研究了共聚物的...     

Synthesis,characterization, and hydrolytic degradation of biodegradable poly(ether ester)‐urethane copolymers based on ε‐caprolactone and poly(ethylene glycol)

In this article, a new kind of biodegradable poly(ε‐caprolactone)‐poly(ethylene glycol)‐poly(ε‐caprolactone)‐based polyurethane (PCEC‐U) copolymers were successfully synthesized by melt‐polycondensation method from ε‐caprolactone (ε‐CL), poly(ethylene glycol) (PEG), 1,4‐butanediol (BD), and isophorone diisocyanate (IPDI). The obtained copolymers were characterized by ¹H‐nuclear magnetic resonance (¹H‐NMR), FTIR, and gel permeation chromatography (GPC). Thermal properties of PCEC‐U copolymers were studied by DSC and TGA/DTG under nitrogen atmosphere. Water absorption and hydrolytic degradation behavior of these copolymers were also investigated. Hydrolytic degradation behavior was studied by weight loss method. ¹H‐NMR and GPC were also used to characterize the hydrolytic degradation behavior of PCEC‐U copolymers. The molecular weight of PCL block and PEG block in soft segment and the content of hard segment strongly affected the water absorption and hydrolytic degradation behavior of PCEC‐U copolymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of poly(ϵ‐caprolactone)‐b‐poly(ethylene glycol) block copolymers prepared by a salicylaldimine‐aluminum complex

A series of poly(?‐caprolactone)‐b‐poly(ethylene glycol) (PCL‐b‐PEG) block copolymers with different molecular weights were synthesized with a salicylaldimine‐aluminum complex in the presence of monomethoxy poly(ethylene glycol). The block copolymers were characterized by ¹H NMR, GPC, WAXD, and DSC. The ¹H NMR and GPC results verify the block structure and narrow molecular weight distribution of the block copolymers. WAXD and DSC results show that crystallization behavior of the block copolymers varies with the composition. When the PCL block is extremely short, only the PEG block is crystallizable. With further increase in the length of the PCL block, both blocks can crystallize. The PCL crystallizes prior to the PEG block and has a stronger suppression effect on crystallization of the PEG block, while the PEG block only exerts a relatively weak adverse effect on crystallization of the PCL block. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and hydrophilicity of poly(butylene 2,6‐naphthalate)/poly(ethylene glycol) copolymers

Poly(butylene 2,6‐naphthalate) (PBN)/poly(ethylene glycol) (PEG) copolymers were synthesized by the two‐step melt copolymerization process of dimethyl‐2,6‐naphthalenedicarboxylate (2,6‐NDC) with 1,4‐butanediol (BD) and PEG. The copolymers produced had different PEG molecular weights and contents. The structures, thermal properties, and hydrophilicities of these copolymers were studied by ¹H NMR, DSC, TGA, and by contact angle and moisture content measurements. In particular, the intrinsic viscosities of PBN/PEG copolymers increased with increasing PEG molecular weights, but the melting temperatures (T_m)_, the cold crystallization temperatures (T_cc)_, and the heat of fusion (ΔH_f) values of PBN/PEG copolymers decreased on increasing PEG contents or molecular weights. The thermal stabilities of the copolymers were unaffected by PEG content or molecular weight. Hydrophilicities as determined by contact angle and moisture content measurements were found to be significantly increased on increasing PEG contents and molecular weights. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2677–2683, 2006     

Synthesis, characterization and properties of chitosan modified with poly(ethylene glycol)-polydimethylsiloxane amphiphilic block copolymers

Synthesis of poly(ethylene glycol)-polydimethylsiloxane amphiphilic block copolymers is discussed herein. Siloxane prepolymer was first prepared via acid-catalyzed ring-opening polymerization of octamethylcyclotetrasiloxane (D₄) to form polydimethylsiloxane (PDMS) prepolymers. It was subsequently functionalized with hydroxy functional groups at both terminals. The hydroxy-terminated PDMS can readily react with acid-terminated poly(ethylene glycol) (PEG diacid) to give PEG-PDMS block copolymers without using any solvent. The PEG diacid was prepared from hydroxy-terminated PEG through the ring-opening reaction of succinic anhydride. Their chemical structures and molecular weights were characterized using ¹H NMR, FTIR and GPC, and thermal properties were determined by DSC. The PEG-PDMS copolymer was incorporated into chitosan in order that PDMS provided surface modification and PEG provided good water swelling properties to chitosan. Critical surface energy and swelling behavior of the modified chitosan as a function of the copolymer compositions and contents were investigated.     

PET与PEG嵌段共聚物合成及应用的研究

将聚酯(PET)和聚乙二醇(PEG)进行嵌段共聚,制得PET-PEG 嵌段共聚物,以PEG 加入比例为25% 的共聚物作改性剂,与CDP共混纺丝,所制纤维的抗静电性、染色性和吸湿性均得到改善     

Paclitaxel-incorporated nanoparticles using block copolymers composed of poly(ethylene glycol)/poly(3-hydroxyoctanoate)

Block copolymers composed of poly(3-hydroxyoctanoate) (PHO) and methoxy poly(ethylene glycol) (PEG) were synthesized to prepare paclitaxel-incorporated nanoparticle for antitumor drug delivery. In a ¹H-NMR study, chemical structures of PHO/PEG block copolymers were confirmed and their molecular weight (M.W.) was analyzed with gel permeation chromatography (GPC). Paclitaxel as a model anticancer drug was incorporated into the nanoparticles of PHO/PEG block copolymer. They have spherical shapes and their particle sizes were less than 100 nm. In a ¹H-NMR study in D₂O, specific peaks of PEG solely appeared while peaks of PHO disappeared, indicating that nanoparticles have core-shell structures. The higher M.W. of PEG decreased loading efficiency and particle size. The higher drug feeding increased drug contents and average size of nanoparticles. In the drug release study, the higher M.W. of PEG block induced the acceleration of drug release rate. The increase in drug contents induced the slow release rate of drug. In an antitumor activity study in vitro, paclitaxel nanoparticles have practically similar anti-proliferation activity against HCT116 human colon carcinoma cells. In an in vivo animal study using HCT116 colon carcinoma cell-bearing mice, paclitaxel nanoparticles have enhanced antitumor activity compared to paclitaxel itself. Therefore, paclitaxel-incorporated nanoparticles of PHO/PEG block copolymer are a promising vehicle for antitumor drug delivery.     

Synthesis and Characterization of GAP-PEG Copolymers

ABSTRACT

A series of glycidylazide–poly(ethylene glycol) (GAP-PEG) copolymers were synthesized by cationic ring-opening polymerization of epichlorohydrin (ECH) in the presence of poly(ethylene glycol) (PEG) using borontrifluoride etherate (BF₃-etherate) as catalyst, followed by the conversion of the CH₂Cl groups of poly(epichlorohydrin) (PECH) to CH₂N₃ groups. The formation of PECH-b-PEG-b-PECH triblock copolymers was confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy. The corresponding GAP-b-PEG-b-GAP triblock copolymers were characterized by UV, IR, ¹H NMR, and ¹³C NMR spectroscopy. The copolymers have shown an increment in their molecular weights as the higher analogue molecular weight PEGs were used in the polymerizations. The thermogravimetry-differential thermogravimetry (TG-DTG) and differential scanning calorimetry (DSC) studies of the GAP triblock copolymers indicate an increase in the decomposition temperature of the azide groups of GAP block in the copolymers caused by the introduction of higher molecular weight PEG blocks. GAP-PEG copolymers have shown lower glass transition temperatures than the homo glycidylazide polymer. The nitrogen content of the GAP-PEG copolymers was estimated by various methods and the value was in good agreement with the estimated values.