Surface characterization of polyester fibers

Fibers made from poly(ethylene terephthalate) (PET) are characterized by a hydrophobic surface with low reactivity. Modifications of the PET surface to render a higher degree of hydrophilicity and reactivity are therefore common. The modification often involves a surface layer of only a few nanometers thickness. The relatively low fraction of the modified surface layer and the fact that it is generally an organic modification on a thin curved organic substrate presents difficulties in surface analyses. Surface characterization is, however, of high importance in the evaluation of the degree and durability of a given surface modification. The paper will discuss the possibilities and the limits of using wettability studies according to the Wilhelmy method to evaluate the degree of surface modification and its permanence. Comparison between internal and external reflection Fourier-transform infrared spectroscopy will be made. The use of electron spectroscopy for chemical analysis, secondary ion mass spectrometry, laser microprobe mass analysis, and microprobe molecular optics laser examiner will be illustrated. Data will be presented from studies of model yarns and films coated with D-417 dip.     

Synthesis and characterization of brominated polyester composites

Two unsaturated polyesters containing a halogen (bromine) in the backbone of the polymer chain were synthesized and compared with a halogen‐free polyester. The bromine content was measured by elemental analysis. The chemical structures of the polyesters were characterized by means of IR and ¹H‐NMR spectroscopies. Feldspar was used as the filler to form the polyester composites. The effects of the halogen substituents, filler concentration, and crosslinking monomers and comonomers on the electrical and mechanical properties of the polyester composites were studied. The flammability was also investigated. The styrenated polyesters and their composites achieved fire resistance and good mechanical and electrical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1356–1365, 2006     

聚富马酸对苯二甲酸二环氧丁烷马来酸酯的制备与表征

目前可功能化的生物活性材料在生物医学领域有着不可替代的作用,本文利用酸诱导环氧开环聚合反应制备新型功能化聚酯材料,聚富马酸对苯二甲酸二环氧丁烷马来酸酯(PTFB-M)。通过~1H-NMR谱图和红外谱图对PTFB-M进行结构表征,并利用TGA和DSC研究PTFB-M的热学性能,实验结果表明该聚合物有着稳定的热学性能,通过水相接触角测试,说明该聚合物为亲水性材料。该聚合物含有大量的羟基,为反应位点,可进一步进行功能化修饰。     

脂肪酶催化法功能聚酯的合成与表征

以脂肪酶(Novozyme-435)为催化剂,L-苹果酸、己二酸和1,8-辛二醇为单体,直接缩聚得到主链带羟基的线型功能性聚酯.对聚合物的结构和结晶性能进行了表征.L-苹果酸的反应活性小于己二酸,随L-苹果酸用量的增加,所得聚合物分子质量下降;引入L-苹果酸单元后,聚合物的结晶性能下降.     

齐聚物对聚酯纺丝及拉膜的影响研究

选择了不同齐聚物含量的聚酯进行了拉膜和纺丝实验,研究齐聚物对聚酯后加工性能的影响。发现在拉膜过程中齐聚物的存在会导致高破膜率,影响薄膜产量和质量,在纺丝过程中齐聚物的存在容易导致组件压力上升、喷丝板堵塞、断头飞丝等情况,可纺性受到影响。     

Synthesis and characterization of polyazomethine conducting polymers and oligomers

Conjugated polyazomethine polymers were prepared from the polycondensation of terephthalaldehyde with 4,4′-thiodianiline, and 4,4-thiodibenzaldehyde with 4,4′-thiodianiline, 4,4′-phenylenediamine and benzidine. The polymers showed good stability in air and were soluble in many organic solvents. The electrical conductivities of the undoped and doped (H₂SO₄ and I₂) polymers were studied. Doping the polymers markedly increased their conductivities from 10^?8 ? 10^?11 S cm^?1 (dielectric region) to 10^?3 ? 10^?5 S cm^?1 (semiconducting region). The polymers were characterized by IR spectroscopy, elemental analyses, viscosity measurements and X-ray diffraction. Furthermore, polyazomethine oligomers were prepared and a comparative study of the physical properties of the oligomers and their corresponding polymers was performed. The electrical behavior of the oligomers was studied. It was found that oligomers with a minimum of eight aromatic (Ar) rings gave almost the same electrical conductivities as long-chain polymers.     

酸性染料可染聚酯添加剂的合成及表征

己二酸二甲酯与三胺按等量比在反应釜中进行聚合,在酯交换温度180~220℃,缩聚温度240~270℃,压力40~50Pa条件下即可获得酸性染料可染添加剂。红外分析结果显示,在1 639 cm-1处,存在明显的酰胺键的特征峰,说明反应产物的分子结构中存在酰胺结构,为一种聚酰胺。DSC图谱中,出现明显的熔点及玻璃化温度,证实产物为一种结晶性聚合物。     

GPC and HPLC characterization of unsaturated polyester resins

This article is concerned with the characterization of unsaturated polyester (UP) resins by conventional gel permeation chromatography (GPC), GPC connected with multiangle laser light scattering detector (GPC-MALLS), and reversed-phase high performance liquid chromatography (HPLC). The ability of particular methods to analyze UP resins is demonstrated in several examples. © 1994 John Wiley & Sons, Inc.     

Electrosynthesis and characterization of o‐phenylenediamine oligomers

The contribution of electrochemical methods to the development of conducting polymers has been most relevant, although the electropolymerization mechanism has not yet been totally elucidated. The formation of a high‐density oligomeric region in the electrode–solution interface has been clearly established as formed by oligomers with different chain lengths. It has been confirmed that, depending on the variables governing the process (applied potential, electrolysis time, concentration, etc), it is possible to control to some extent the oligomer to be generated. In this present work, the electrosynthesis of oligomers of o‐phenylenediamine is proposed. A saturated solution of the monomer was electrolysed at 0.95 V versus SCE over 1 min, using stainless steel as the working electrode material. Under these conditions, a mixture of the dimer and tetramer, relatively easy to separate by thin layer chromatography, was deposited. The products were characterized by mass spectrometry, UV–vis spectroscopy, elemental analysis and ¹H NMR spectroscopy. This approach allows the synthesis of oligomers in a fast and simple way. In addition, the product is directly obtained on the electrode surface, hence making its separation and purification very straightforward. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of some polyazomethine conducting polymers and oligomers

Polyazomethine polymers were prepared from the polycondensation of terephthaldehyde with different diamines, namely, benzidine, 2,3-diaminopyridine, 1,4-diaminoanthraquinone and 3,5-diamino-1,2,4-triazole. The electrical conductivities of the polymers were studied with doping with H₂SO₄ and 5% I₂ together with the undoped polymers. The crystallinity and morphology of the polymers were studied using XRD and scanning electron microscopy. A comparative study of the electrical conductivities of oligomers of polyazomethines and those of their corresponding polymers was performed. Received: 8 January 1997/Accepted: 10 May 1997     

Hydrolytic stability and protective properties of polyurethane oligomers based on polyester/ether/polyols

The present study deals with effect of the type and chemical character of incorporated polyester/polyether blocks on the hydrolytic stability of crosslinked polyurethane oligomers. Diffusion parameters of the investigated polyurethane oligomers, giving information concerning chemical changes taking place in neutral, basic and acidic aqueous environments, have also been determined.     

Effect of fillers on curing of wood surfaces with polyester oligomers by ultraviolet radiation

A set of formulations was prepared with polyester acrylate (oligoester M‐9050) oligomers in combination with reactive diluents of different functionalities such as ethylhexyl acrylate, tripropylene glycol diacrylate , and trimethylol propane triacrylate (TMPTA). The thin films were prepared with these formulated solutions under UV radiation on a glass plate, and their physical properties such as pendulum hardness and gel content were studied. The formulation containing TMPTA showed the greatest pendulum hardness and gel content. The polished wood surfaces were cured with these formulated solutions. Physical properties such as pendulum hardness gloss at 20° and 60° angles, adhesion, abrasion resistance, and scratch hardness of UV‐cured surfaces of the wood were characterized. The formulation containing TMPTA had the best physical properties. Two types of filler, sand and talc, were used in the base coat to obtain these better properties. Both fillers improved the properties; however, the 1% sand– and 4% talc–containing formulations performed better. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3826–3834, 2003     

Synthesis and characterization of di‐polyester diamides

A series of di‐polyester diamides was synthesized via a nucleophilic ring opening polymerization process. FTIR investigations revealed the spectral characteristics evidencing the newly formed chemical bonds as well as the changes in the relative intensity of the characteristic peaks, due to the increasing side‐block lengths of the different members of the series. ¹H‐NMR analysis of the described materials confirmed the chemical structures seen by FTIR analysis. The side segment length of the different di‐polyester diamides was calculated from the integration ratios in the NMR spectra. The molecular weight results exhibited relatively small deviations from the stoichiometrically calculated values. All the members of the triblock series, with side blocks of up to 120 lactoyl units, were essentially amorphous and glassy at room temperature. The presence of two separate glass transitions indicated a segmented and microphase separated morphology. It was deducted that the amorphous nature of the relatively long poly(lactic acid) side blocks occurs due to the dominance of the hydrogen‐bonded central segment. Synthesis of a di‐polyester diamide containing a reduced number of hydrogen‐bond‐forming groups in the central segment yielded a partial side‐block crystallization. The di‐polyester diamide with 120 lactoyl unit‐long side blocks was eventually able to crystallize in solid state, following thermal treatment during thermal analysis. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of novel citric acid-based polyester elastomers

In this paper we report successful simple synthesis of unique elastic polyesters by carrying out catalyst-free polyesterification of multifunctional non-toxic monomers: 1,8-octanediol (OD), citric acid (CA) and sebacic acid (SA). The chemical, physical, and surface chemical properties of the resulting copolyester polyoctanediol citrate/sebacate [p(OCS)] have been investigated. This new material was characterized by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-ToF-MS), nuclear magnetic resonance spectroscopy (NMR), thermal analysis (TA), mechanical tests, photo-acoustic Fourier-transform infrared spectroscopy (PA-FTIR), X-ray photoelectron spectroscopy (XPS) and swelling experiments. We demonstrate that the chemical structure, morphology, physical integrity and surface chemistry of the synthesized co-polymer can be controlled by simply varying the initial acid concentration (CA/SA) in the pre-polymer. This novel p(OCS) polymer exhibits versatility in mechanical properties, hydration and hydrolytic degradation as determined by the chemical structure of the polyester elastomer.     

Synthesis and characterization of unsaturated polyester/carborundum composites

Two unsaturated polyesters, one based on phthalic anhydride PE_P and the other based on isophthalic acid PE_I, were synthesized. The chemical structure of the two polyesters was characterized by IR and ¹H and ¹³C NMR spectroscopy. The effect of styrene concentration on the curing of polyesters was also studied. It has been found that the percent of polyester/styrene (70/30 wt %) gave the highest percent of curing. Different concentrations of carborundum (0–70 wt %) were used to prepare polyester composites. A comparative study was done on the properties of the two prepared polyesters PE_P and PE_I and their composites in term of their thermal, mechanical, electrical, and physical properties. The results indicate that the polyester based on isophthalic acid (PE_I) and its composites gave higher compressive strength values and lower water absorption than those based on phthalic anhydride (PE_P). The presence of carborundum improved the thermal stability than the cured polyesters and electrical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Separation and characterization of ɛ-caprolactone oligomers by gel permeation chromatography

Summary It is shown that the combined use of gel permeation chromatography and the isocyanate method of determination of hydroxyl end groups extends the possibilities for studying complex oligomer mixtures of -caprolactone. Oligomer mixtures of -caprolactone obtained by (C₆H₅)₃CSbCl₆ and by (C₆H₅)₃CK are investigated. At initiation by both the initiators — the cationic and the anionic one — a covalent bond between the initiator and the polymer chain is formed. In the case of the initiation by (C₆H₅)₃CK intramolecular transesterification proceeds which results in cyclic oligomers. At initiation by (C₆H₅)₃CSbCl₆ linear oligomers are formed. It is assumed that the -caprolactone polymerization by (C₆H₅)₃CSbCl₆ proceeds by alkyl-oxygen bond scission.     

Synthesis and characterization of natural rubber-based telechelic oligomers via olefin metathesis

Metathesis degradation and functionalization of natural rubber (NR) were conducted with 1-hexene, 1-octene, 1-decene, 1-dodecene, trans-stilbene, and 4,4′-dibromo-trans-stilbene as chain transfer agents (CTAs) in presence of Grubbs 2nd generation catalyst to generate NR-based telechelic oligomers that had been a long-lasting challenge due to the structure and compositions of NR with various impurities. Orthogonal experiments were applied and the effects of the CTA type, CTA concentration, catalyst concentration, reaction time, and reaction temperature on the formation of telechelic oligomers were studied, indicating that the catalyst concentration was the major factor influencing the number average molecular weights (M_n) and polymer dispersity index (PDI) of telechelic oligomers. The structures of the oligomers were characterized using ¹H NMR, ¹³C NMR, and MALDI-TOF-MS, which confirmed the formation of the designed terminal groups. The results showed that well-defined telechelic oligomers with a M_n of a few thousand and a PDI around 1.6 were obtained, with potential applications in binder, lubricant and many other fields.     

Electrochemical characterization of arylene vinylene oligomers containing triphenylamine and carbazole units

Cyclic voltammetry (CV) has been used to investigate the electrochemical behavior of three arylene vinylene oligomers containing triphenylamine and carbazole units at the ends. The synthesis of oligomers was performed using Wittig reaction conditions, between 4-formyltriphenylamine or 3-formyl-N-hexyl-carbazole and two diphosphonium salts. The cyclic voltammograms, recorded in anodic range of potentials, revealed that the oligomers undergo quasi-reversible or irreversible redox processes. Polymer films were deposited on Pt electrode by CV and CPE (Controlled Potential Electrolysis) methods. The polymer films obtained by electrochemical polymerization methods show no solubility in all organic solvents and present similar FT-IR data with those polymers synthesized by chemical oxidative polymerization. Characterizations of the oligomers were made by ¹H-NMR spectroscopy, UV–Vis and fluorescence spectroscopy. Due to the lack of their solubility, the polymers obtained by electrochemical methods were characterized only by FT-IR spectroscopy.     

聚酯弹性体热熔胶的制备及其性能研究

以以聚酯弹性体、聚烯烃共聚物和增粘树脂共混制备了聚酯弹性体热熔胶,研究了聚烯烃共聚物和增粘树脂的含量对热熔胶粘接性能的影响,考查了热熔胶的耐水性能。结果表明,聚酯弹性体热熔胶适用于极性聚合物与金属材料的粘接复合,具有粘接强度高、耐水性能好的优点。