聚酯醚共聚物中PEG嵌段的储能行为

采用重均分子量为１０００－４０００的聚乙二醇、对苯二甲酸二甲酯和乙二醇为原料合成了聚醚含量在４０－６０％（重量）的聚对苯二甲酸乙二酯－聚乙二醇共聚物，采用差热分析和宽角×射线衍射的方法，研究了共 聚物中聚乙二醇嵌段的储能行为，探讨了采用取醚嵌段可结晶的聚酯醚为原料熔融纺丝研制具有蓄热调温功能纤维的可能性。     

多嵌段聚醚-酯共混物的微相结构与血液相容性研究

本工作合成了两种性质不同的聚醚-酯多嵌段共聚物,一种是以聚对苯二甲酸乙二酯为硬链段,聚乙二醇(PEGT)为软链段的亲水性多嵌段共聚物,另一种是以聚对苯二甲酸乙二酯为硬链段,聚四亚甲基醚二醇(PTMGT)为软链段的疏水性多嵌段共聚物。将两种共聚物以一定的比例共混,制备多嵌段聚醚-酯共混物。 改变共混物的组成,研究其微相结构与血液相容性的关系。采用动态力学谱(VES)、示差扫描量热(DSC)、透射电镜(TEM)和扫描电镜(SEM)等测定共混物的微观结构,采用微球柱法评价共混物的血液相容性。实验结果表明:材料的微观非均相结构及亲水平衡是决定血液相容性的重要因素。     

聚酯-聚醚多嵌段共聚物的共聚改性

高硬段含量和高软段分子量的聚酯-聚醚多嵌段共聚物有明显的组成不均一性,可分离出大量高熔点的氯仿不溶组份.通过和5mol%间苯二甲酸二甲酯(DMI)共聚,可改进其表观组成均一性,得到不含氯仿不溶物和力学性能优良的硬段含量为40wt%、软段分子量为4000的聚对苯二甲酸乙二酯-聚乙醇醚多嵌段共聚物(PET-PEG).另一合成途径是以间苯二甲酸(IPA)酸解 PET,再和端羟基聚乙二醇醚共缩聚,也可制得相应的改性 PET-PEG.降低聚醚分子量可以有效地改进其组成均一性.     

链段相容性对聚酯-聚醚多嵌段共聚物组成均一性的影响

<正> 由结晶型芳族聚酯为硬链段,无定型脂肪族聚醚为软链段的聚酯-聚醚多嵌段共聚物,是一类性能优良的热塑弹性体,本文研究链段相容性对这类聚合物组成均一性的影响,因此,合成了一系列不同链段结构的聚酯-聚醚多嵌段共聚物。 如硬链为聚对苯二甲酸乙二醇酯(PET)和丁二醇酯(PBT);软链段有聚乙二醇醚(PET)、聚丁二醇醚(PTMG)、聚二醇醚(PPG)和四氢呋喃同环氧丙烷的共聚醚二醇     

聚酯的生物改性

从四个方面综述了近年来聚对苯二甲酸乙二酯(PET)和聚对苯二甲酸丁二酯(PBT)生物改性的研究进展:(1)在聚酯合成中采用生物原料;(2)采用共聚技术制备可生物降解性共聚酯;(3)生物活性物质在聚酯中的引入改性,可提高其生物相容性和抗菌能力,在聚酯用于人造器官时,可使血管纤维原细胞的细胞增殖;(4)生物酶对聚酯进行水解改性,可减轻重量,并改善吸湿性、染色性等性能。     

酞侧基聚芳醚砜／对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物共混物的研究

酞侧基聚芳醚砜／对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物共混物的研究李刚，殷敬华，李滨耀（中国科学院长春应用化学研究所，长春，１３００２２）关键词酞侧基聚芳醚砜，热致性液晶高聚物，原位复合材料，对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物将热塑性树脂与热...     

生物可降解聚乙二醇-b-聚对苯二甲酸丁二醇酯共聚物载药微球的制备

嵌段共聚物;生物可降解性;左炔诺孕酮;载药性;生物可降解聚乙二醇-b-聚对苯二甲酸丁二醇酯共聚物载药微球的制备     

聚对苯二甲酸乙二酯(PET)/聚对乙酰氧基甲酸(PHB)共聚酯及同类共聚物序列分布表征的数学统计

由聚对苯二甲酸乙二酯(PET)和对-乙酰氧基苯甲酸制得的PET/PHB共聚酯代表了一类序列结构较一般二元共聚物复杂的共聚体系.在揭示了这类共聚物与序列分布有关的诸概率参数中只有一个是独立的之后,定义了参数B_q来描述此类共聚物的无规度.并指出,共聚物B_q=b时的序列分布,可以从一般二元共聚物无规度B=b时的序列结构加以推断.     

聚对苯二甲酸乙二酯(PET)/聚对乙酰氧基甲酸(PHB)共聚酯及同类共聚物序列分布表征的数学统计

 由聚对苯二甲酸乙二酯(PET)和对-乙酰氧基苯甲酸制得的PET/PHB共聚酯代表了一类序列结构较一般二元共聚物复杂的共聚体系.在揭示了这类共聚物与序列分布有关的诸概率参数中只有一个是独立的之后,定义了参数B_q来描述此类共聚物的无规度.并指出,共聚物B_q=b时的序列分布,可以从一般二元共聚物无规度B=b时的序列结构加以推断.     

侧链含炔丙基的PLGA-PEG-PLGA三嵌段共聚物的合成与表征

通过简单易行的技术路线合成了炔丙基化乙交酯单体,以1,4-二甲氨基吡啶为催化剂,亲水性和生物相容性良好的聚乙二醇为大分子引发剂,在较滥条件下引发炔丙基化乙交酯和丙交酯的开环共聚,制备了侧链含炔丙基的聚(乳酸-羟基乙酸)-聚乙二醇-聚(乳酸-羟基乙酸)(PLGA-PEG-PLGA)三嵌段共聚物,并对产物的组成与结构进行了表征.为生物孤犊触乳聚酯的分子修饰、生物相容性的提高探索一条简单而有效的途径     

Plasma-mediated grafting of poly(ethylene glycol) on polyamide and polyester surfaces and evaluation of antifouling ability of modified substrates

A simple cold plasma technique was developed to functionalize the surfaces of polyamide (PA) and polyester (PET) for the grafting of polyethylene glycol (PEG) with the aim of reducing biofilm formation. The surfaces of PA and PET were treated with silicon tetrachloride (SiCl4) plasma, and PEG was grafted onto plasma-functionalized substrates (PA-PEG, PET-PEG). Different molecular weights of PEG and grafting times were tested to obtain optimal surface coverage by PEG as monitored by electron spectroscopy for chemical analysis (ESCA). The presence of a predominant C-O peak on the PEG-modified substrates indicated that the grafting was successful. Data from hydroxyl group derivatization and water contact angle measurement also indicated the presence of PEG after grafting. The PEG-grafted PA and PET under optimal conditions had similar chemical composition and hydrophilicity; however, different morphology changes were observed after grafting. Both PA-PEG and PET-PEG surfaces developed under optimal plasma conditions showed about 96% reduction in biofilm formation by Listeria monocytogenes compared with that of the corresponding unmodified substrates. This plasma functionalization method provided an efficient way to graft PEG onto PA and PET surfaces. Because of the high reactivity of Si-Cl species, this method could potentially be applied to other polymeric materials.     

1,1,1-三羟基丙烷为核的三臂星型聚乙二醇合成及表征

以1,1,1-三羟甲基丙烷与过量癸二酸二乙酸酐反应,制得了端羧基的三官能度小分子核三癸二酸三羟甲基丙烷酯(TMP-SK3).在辛酸亚锡催化下,以二苯醚为共沸脱水剂,将三官能度小分子TMP-SK3作为偶联剂,进一步与不同分子量的端羟基聚乙二醇(PEG)和聚乙二醇单甲醚(PEGm)缩合,减压下共沸脱水,制备了以TMP-SK3为核,PEG或PEGm为臂的三臂星形大分子.通过1H-NMR,DSC,GPC,XRD等手段对所得聚合物进行了表征.DSC测试结果表明,与线型聚乙二醇相比,三臂星型聚乙二醇由于TMP-SK3核的存在,不仅影响聚乙二醇的结晶速度,同时也影响结晶的完善程度,导致其结晶温度和结晶熔融温度发生变化.     

Effect of Chain Length of Polyethylene Glycol and Crosslink Density (NCO/OH) on Properties of Castor Oil Based Polyurethane Elastomers

The equilibrium swelling study of polyurethanes (PU) was carried out in various solvents in order to calculate their solubility parameter. The kinetics of swelling and sorption have also been studied in 1,4‐dioxane at 30°C. The PU was synthesized by reacting a novel polyol (castor oil derivative and epoxy based resin, EpxR) and one of the polyethylene glycols (PEG 200, PEG 400, PEG 600) with different weight compositions, with a toluene diisocyanate (TDI) adduct (derived from toluene diisocyanate and R60 polyol). Different NCO/OH ratio viz. 1, 1.3 and 1.7 were employed in the study. The results were found to vary with the weight composition of polyol components, as well as the crosslink density of the samples. The sorption behavior is also found to vary with the molecular weight of polyethylene glycol employed in the preparations of the polyurethanes. Kinetic studies of swelling revealed that the sorption is anomalous in nature. The diffusion coefficient (D) increased with an increase in the NCO/OH ratio and decreased with an increase in chain length of polyethylene glycol. The sorption coefficient (S) decreased with an increase in crosslink density (NCO/OH) and increased with increasing polyethylene glycol (i.e., PEG 200, PEG 400, and PEG 600) moieties in the polyurethanes. The molecular weight between two crosslink points was calculated using the Flory Rehner equation (24), and hence, the number of chains per unit volume (N) and degree of crosslinking (ν) in all the samples were determined.     

纳米TiO2光催化降解聚乙二醇反应

纳米TiO2光催化降解聚乙二醇反应;纳米二氧化钛; 光催化; 聚乙二醇     

含柔性间隔基的扩链脲增韧环氧树脂性能研究——环氧树脂／扩链脲／双氰双胺体系性能研究

合成了含不同分子量柔性间隔基的扩链脲（Ｕｉ），并对其与双氰双胺共同固化环氧树脂体系的反应活性、抗冲击性能、动态力学性能、形态结构及贮存性能进行了考察。结果表明：含分子量为４００的聚乙二醇柔性链的扩链脲／双氰双胺／环氧树脂固化体系的抗冲击强度较单纯双氰双胺／环氧树脂固化体系提高了７倍左右，其冲击试样断面电镜照片呈韧性断裂的特征。扩链脲的反应活性基本不受分子中聚乙二醇链段分子量的影响。环氧树脂／扩链脲／双氰双胺体系在５０℃下贮存期可达１～２天。     

Nanofibers of silk fibroin controlled by the crystallization of polyethylene glycol in frozen solution

The conformation of silk fibroin(SF) frozen with polyethylene glycol(PEG) at a molecular weight from 2kDa to 20kDa and a mass ratio of PEG:SF from 1:5 to 10:1 was studied by spectral and microscopic methods. It is found that the conformation transition of SF from random coil to b-sheet could be induced by the stress resulting from PEG crystallization at-20 °C, and greatly depended on the cooling rate, PEG:SF mass ratio and PEG molecular weight. These findings provide a new method for the preparation of desired SF nanofibers.     

Photosensitized degradation of polyethylene glycols in aqueous solutions. I. Viscosimetric measurements

Investigations were performed on acetone and benzene-sensitized degradation of triethylene glycol (TEG), polyethylene glycol 400 (PEG 400), and polyethylene glycol 4000 (PEG 4000) in aqueous solutions exposed to irradiation at λ = 254 nm and λ ～ 313 nm. The systems investigated were exposed at 20°C (±1°C) in both deaerated and undeaerated solutions. The course of the photosensitized degradation was examined viscosimetrically. The determined quantum yield (?) of chain scission decreases distinctly as the molecular weight of the polymer rises, irrespective of the wavelength of the light absorbed and deaeration of system exposed.     

Sol–gel silica antireflective coating with enhanced abrasion-resistance using polypropylene glycol as porogen

Silica antireflective (AR) coatings with high transmittance and enhanced abrasion-resistance were synthesized by sol–gel process using polypropylene glycol (PPG) as porogen. The effects of molecular weight of PPG and weight ratio of PPG to SiO₂ on the refractive index and abrasion-resistance of the coating were systematically studied and compared with those of polyethylene glycol (PEG). Experimental data showed that the refractive index decreased with increasing the weight ratio to SiO₂ and molecular weight of both PEG and PPG, but PPG was much more effective than PEG. In the case of same molecular weight, PPG modified coating has the higher porosity than PEG modified one. When the weight ratio of PPG to SiO₂ is in a low level, the PPG-containing silica AR coatings exhibit the good abrasion-resistance. PPG is liquid at room temperature and the better solubility than PEG. These effective and economic AR coatings with enhanced abrasion-resistance have potential value in the field of solar thermal collectors.     

凝胶色谱与多角激光光散射联用研究聚氧化乙烯的扩展效应和链构象

采用凝胶色谱与多角激光光散射联用的方法,测定了一系列不同分子量的聚乙二醇(PEG)和聚氧化乙烯(PEO)在色谱柱中的扩展效应.扩展因子随PEG/PEO分子量的增加而增大,经扩展效应改正后得到了样品的准确分子量和分子量分布.同时建立了PEO的Z均回转半径Rgz与重均分子量Mw之间的单分散标度关系:Rgz=0.0272 Mw0.56,结果表明,长链PEO在水溶液中由于排除体积效应采取溶胀的无规线团构象.