Electrophysical Properties of a Poly(ethylene terephthalate) Film Modified in a Cyclohexane Plasma

The structure of a thin layer applied on a poly(ethylene terephthalate) (PET) film using ion-assisted chemical vapor deposition of cyclohexane was studied by electron spectroscopy for chemical analysis and IR spectroscopy. It was found that the film was composed of linear (–₂–)_n chains bearing six-membered cyclohexane rings, including those containing carbonyl groups as substituents, and carbon chains free of H atoms. The plasma-synthesized cyclohexane film was found to be semiconducting. The deposition of a film 10–120 nm in thickness on the surface of PET 30 m in thickness resulted in an increase in the bulk conductivity over the temperature range 20–200°C and in a considerable increase in the electric strength.     

The Degradation of Poly(ethylene terephthalate)

The penetration of new markets by polyester fibers has emphasized the need for increased stability of the polyester toward a variety of degradative reactions. Extensive studies of the nature of the thermal, hydrolytic, oxidative, and radiation-induced degradation reactions have been reported. The interpretation of kinetic investigations and the identification of the reaction products have been facilitated by using suitable esters as model compounds in place of the polymeric species.     

Low Pressure Radio Frequency Ammonia Plasma Surface Modification on Poly(ethylene terephthalate) Films and Fibers: Effect of the Polymer Forming Process

We investigated the effect of a polyethylene terephthalate (PET) forming process on radiofrequency ammonia plasma surface-treated PET flat films and fibres obtained by melt blowing. Ammonia plasma treatment allowed for the incorporation of amino functionalities on both the film and fibre surfaces, with higher values observed at very short treatment times. This plasma treatment also induced polymer chain scissions which were observed as the formation of hydrophilic nodules that coalesced together and were loosely bound to the underlying polymeric materials. These plasma-induced surface damages were notably more important on the melt-blown PET fibres. Consequently, maximisation of the surface amino groups with minimal polymer chain breaking was achieved using very short plasma treatment times (typically 1 s). We also demonstrated that the polymer forming process must be taken into account when plasma modifications are to be performed on PET, as it may already lead to polymer chain breakings subsequently added to those induced in the plasma environment.     

非晶聚对苯二甲酸乙二酯的制备与表征

采用引入U-polymer的路线制备了非晶聚对苯二甲酸乙二酯(APET).用DSC和DMA等手段研究了APET的性能.结果表明,经改性后得到的APET无结晶,透明性得到改善,玻璃化转变温度和储能模量都较PET有一定程度提高.     

Poly (ethylene terephthalate) thermo-mechanical and thermo-oxidative degradation mechanisms

¹H NMR and MALDI-TOF MS measurements were used to study the thermo-mechanical and thermo-oxidative degradation mechanisms of bottle-grade PET (btg-PET). In the thermo-oxidative degradation, the concentration of low molar mass compounds increased with time and the main products were cyclic and linear di-acid oligomers. In the thermo-mechanical degradation, the main-chain scission reactions affect the stability of the cyclic oligomers. One of the most important bottle-grade PET co-monomers is diethylene glycol (DEG), which is a “reactive site” in the thermal degradation of btg-PET. The DEG co-monomer was shown to be the precursor to colour changes in btg-PET, owing to the attack by molecular oxygen on the methylenic protons adjacent to the ether oxygen atoms of DEG. This behaviour was observed in the thermo-oxidative degradation process in which the degradation of DEG causes the release of hydroxyl radicals in the polymeric matrix, thereby producing mono- and di-hydroxyl substituted species. This was also observed in the thermo-mechanical degradation process.     

Kinetic Features of Initiation of Poly(ethylene terephthalate) Oxidative Degradation Processes in Oxygen Plasma

The results of measurements of time dependences for the formation rates of gaseous products and oxygen uptake rate in oxygen plasma treatment of a poly(ethylene terephthalate) film at discharge currents of 20–80 mA and a pressure ranging within 50–200 Pa are reported. The obtained data allow the authors to speculate on the mechanism of initiation of plasma-induced oxidative degradation of the material.     

Mechanical Properties of the Nanometer Scale Precrystalline Order of a Poly(ethylene terephthalate)/Poly(ethylene naphthalate) Blend

Summary: Nanometer scale morphological order of macroscopically amorphous polyesters, obtained from the melt at moderate cooling rates, was observed in the past. The effect of such order on mechanical properties of a PET/PEN blend, evaluated by AFM nanoindentations, is reported in this study. Results show that nanoindentations conducted at relatively high load, with penetration depths of the order of 100 nm, confirm the information obtained from mechanical tests at micrometer scale, i.e., microhardness. On the other hand, true nanometer scale indentations (<40 nm) are seen to discriminate between the mechanical properties of the nanophases formed during solidification.

Statistical distribution of elastic moduli observed after 60 nanoindentations performed at 1 µN on each sample solidified at the cooling rates reported in the legend.     

嵌段共聚酯的合成研究

采用直接酯化法合成了一系列含间苯二甲酸的PEIT－PEG嵌段共聚酯,研究了聚合时间,聚合效率及聚酯的特性粘度与产物中间苯二甲酸含量及共聚酯分子量的关系,得出适于纺丝工艺及工业化生产的共聚酯分子量和间苯二甲酸的含量。     

聚丙烯／聚对苯二甲酸乙二酯共混自增强材料的研究

聚丙烯／聚对苯二甲酸乙二酯共混自增强材料的研究陈鸣才，黄玉惠，赵树录，廖兵，林果，丛广民（中国科学院广州化学研究所广州５１０６５０）关键词聚丙烯，聚对苯二甲酸乙二酯，高分子共混物，自增强材料聚对苯二甲酸乙二酯（ＰＥＴ）具有良好的成纤性和透明性，但收缩...     

Low-Frequency Glow Discharge Treatment of Poly(ethylene terephthalate) Films

The alteration of surface characteristics of the PET-E poly(ethylene terephthalate) film by treatment in the cathode fall of an ac (50 Hz) glow-discharge plasma was studied. The plasma-assisted modification leads to surface hydrophilization which is retained for a long period of time. It was found that the discharge treatment induced a negative charge in the polymer surface layer. The charge density created under different treatment conditions was correlated with the contact angle. The thermally stimulated relaxation and depolarization measurements on the original and the modified film showed that charge buildup in the film during the discharge treatment was due to trapping of injected electrons. From the experimental data, it was inferred that the charge states emerged play the determining role in enhancing the surface energy of modified PET films.     

High-energy ion implantation of polymers: Poly(ethylene terephthalate)

The effect of high-energy ion implantation of oxygen into a thin film of poly(ethylene terephthalate) (PET) was studied by Fourier transform infrared spectroscopy and differential scanning calorimetry (DSC). Mylar samples 13 μm thick were implanted with 6-MeV oxygen ions at fluences ranging from 5 × 10¹² to 2 × 10¹⁴ ions/cm². The DSC data showed a substantial loss of crystallinity, even at the lowest fluence, which extended deeper into the polymer film than the predicted range for oxygen deceleration in PET. Solubility measurements indicated the presence of cross-linking, especially at the highest fluence, but bands due to cross-linking could not be detected in the infrared. The trans/gauche ratio for the glycol group conformation was measured by a pair of conformationally sensitive infrared bands. Surprisingly, the conformation of the glycol segments did not change appreciably with increasing fluence, although crystallinity decreased and degree of cross-linking increased. The implications these results have on possible mechanisms of chemical and physical alterations of the polymer structure by ion implantation are discussed.     

Poly(amido‐amine)s Carrying Primary Amino Groups as Side Substituents

Poly(amido‐amine)s carrying primary amino groups as side substituents have been obtained by polyaddition of N‐triphenylmethyl‐monosubstituted 1,2‐diaminoethane (TPHMAE) to 2,2‐bisacrylamido acetic acid or 1,4‐bisacryloylpiperazine and subsequent removal of the protecting triphenylmethyl group by treating the resultant polymers with aqueous hydrochloric acid. Soluble polymers can be also obtained directly by the polyaddition of monoprotonated 1,2‐diaminoethane to 2,2‐bisacrylamido acetic acid in the presence of a limited amount of added acetic or hydrochloric acid. The resultant polymers are of a higher molecular weight than the corresponding ones prepared from TPHMAE. By adding a limited amount of N‐triphenylmethyl‐monosubstituted 1,2‐diaminoethane to the monomer mixtures leading to poly(amido‐amine)s with a recognised potential as nonviral vectors, such as ISA 23 and ISA 1, a controlled number of pendant primary amino groups have been introduced. By this procedure, ISA 23 and ISA 1 become suitable as polymer carriers for carboxylated drugs as well as amenable to the labelling techniques by fluorescent probes commonly employed for proteins.

Formation of monoprotected primary diamines.     

Recovery of Uniaxially Stretched Amorphous Poly(ethylene terephthalate) Film

Thedeformationandrecoveryofamorphouspolymerwerestudiedinrecentyears'-'.SomeresearcherssuggestedthatthepostyieldingdeformationofamorphouspolymerwasmadeupoftwocomponentsfromDSC--volumeanddimensionrecoveryexperiments'-'.Butunderstandingaboutthisprocesswasincomplete,especiallyaboutthemotionofthechain.Theaimofthisarticlewastoinvestigate,onamacroscopicscale,thedifferentcomponentsoflargescaletensiledeformationbyobservingtherecoveryofuniaxiallystretcheda-PETfilmasafunctionoftime,temperatureanddrawra…     

Poly(p‐phenylene) with Poly(ethylene glycol) Chains and Amino Groups as a Functional Platform for Controlled Drug Release and Radiotherapy

Conventional cancer treatments such as chemotherapy, radiotherapy, or combination of these two result in side effects, which lower the quality of life of the patients. To overcome problems with these methods, altering the drug properties by conjugating them to carrier polymers has emerged. Such polymeric carriers also hold the potential to make tumor cells more sensitive to radiation therapy. Herein, poly(p‐phenylene) (PPP) polymer with poly(ethylene glycol) (PEG) chains and primary amino groups (PPP‐NH₂‐g‐PEG) is synthesized and conjugated with anticancer drug Doxorubicin (DOX). pH dependent drug release experiments are performed at pH 5.3 and pH 7.4, respectively. Cell viability studies on human cervix adenocarcinoma cells show that lower doses of DOX inhibit cell proliferation when conjugated with nontoxic doses of PPP‐NH₂‐g‐PEG polymer. Additionally, PPP‐NH₂‐g‐PEG/Cys/DOX bioconjugate significantly increases radiosensitive properties of DOX. It is possible to use lower doses of DOX when conjugated to PPP‐NH₂‐g‐PEG in combination with radiotherapy.

     

Kinetics of Structural and Chemical Changes in Poly(ethylene terephthalate) Films Treated in Oxygen and Nitrogen Plasmas

The results of measurements of the kinetics of formation of various functional groups in the surface layer of poly(ethylene terephthalate) under the action of a dc-discharge plasma in oxygen and nitrogen are reported. Based on these data, the mechanisms of polymer modification and degradation are hypothesized.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 5, 2005, pp. 392–395.Original Russian Text Copyright © 2005 by Kuvaldina, Rybkin, Titov, Shutov.     

乙烯吡咯烷酮对PET薄膜的表面接枝改性

利用低温等离子体和UV诱导技术,制备具有较高生物相容性和亲水性的聚对苯二甲酸乙二醇酯(PET)-聚乙烯吡咯烷酮(PNVP)复合膜。利用衰减全反射傅里叶红外光谱(ATR-FTIR)、X射线光电子能谱(XPS)、原子力显微镜(AFM)对PET-PNVP复合膜表面的结构形态进行了系统表征,对影响接枝度的因素如引发剂浓度、UV辐射时间、单体浓度也做了系统分析。润湿性分析结果表明,接枝PNVP的PET膜表面亲水性得到了有效改善。体外血液相容性实验表明PET-PNVP复合膜具有较好的血液相容性。噻唑蓝比色法(MTT法)细胞毒性实验表明,PETPNVP复合膜没有细胞毒性。     

Evaluation of the Distribution Depth of Charge Injected by Direct-Current Discharge Plasma into Thin Polyimide and Poly(ethylene terephthalate) Films

The dynamic capacitor method was proposed for determining the distribution depth of negative charge induced in the surface layers of thin polymer films under exposure to a dc discharge as a result of trapping plasma-injected electrons, and equations for calculation were obtained. Charge distribution in thin poly(pyromellitimide) and poly(ethylene terephthalate) films with different thickness (1–6 m) was experimentally studied, and the negative charge due to the injection of electrons from plasma was found penetrate to a depth greater than 0.5 m.     

Poly(ethylene terephthalate) synthesis catalysed by chelated Sn,Zn and Mg complexes

A series of four C,N‐chelated diorganotin(IV) compounds, namely (L^CN)₂Sn(OCH₂CH₂O) ( 1 ), [L^CNBuSn(OCH₂CH₂O)]₂ ( 2 ), (L^CN)₂Sn(1,2‐(O)₂‐3,5‐tBu₂C₆H₂) ( 3 ) and [L^CNBuSn(1,2‐(O)₂‐3,5‐tBu₂C₆H₂)]₂ ( 4 ) (L^CN = 2‐(Me₂NCH₂)C₆H₄), one zinc species, namely L^NOZnEt ( 5 ) (L^NO = [2‐(MeO)C₆H₄]NC(Me)?C(H)C(Me)?O), and one magnesium complex, namely [L^NNMg]₆ ( 6 ), (L^NN = [2‐(Me₂NCH₂)C₆H₄]N), were used as catalysts for the synthesis of poly(ethylene terephthalate) (PET) from dimethyl terephthalate and ethylene glycol. Prepared PET samples were primarily characterized using the size exclusion chromatography technique. The highest number‐average molar mass of prepared PET samples reached 10.7 kg mol^?1. Novel dimeric compound 2 was structurally characterized using both multinuclear NMR spectroscopy and X‐ray diffraction analysis. In addition, an alternative synthesis of 1 is described. Copyright © 2015 John Wiley & Sons, Ltd.     

Modeling of Semibatch Esterification Process for Poly(ethylene terephthalate) Synthesis

The esterification kinetics of terephthalic acid (TPA) and ethylene glycol (EG) in poly(ethylene terephthalate) (PET) synthesis were studied using a semibatch reactor. Rate constants were optimized by data fitting with the oligomeric chain length, the fraction of carboxyl groups in the terminal groups (α) and the water generation curve for different EG/TPA feed ratios. The influence of the TPA particle size distribution on the solid‐liquid mass transfer rate and on acid conversion (ε) was investigated. It was observed that conversion became more sensitive towards TPA particle size as the EG/TPA feed ratio was lowered. It is advantageous to use the model based on TPA particle size for mass transfer limited esterification reactors. The effect of the monomer feed ratio on conversion, chain length and system heterogeneity can be predicted with this model.