The fracture toughness and fatigue crack propagation behaviour of annealed PET

The fracture toughness of poly(ethylene terephthalate) (PET) is correlated with various morphologies produced upon annealing. Annealing PET at a Hoffman regime III crystallization temperature (120°C) or inducing solid-state polymerization result in materials of high fracture toughness (K_c = 8.7 MPa m^1/2 and 9.5 MPa m^1/2, respectively); these high toughness values are related to multiple-crazing mechanisms produced by high tie-molecule densities. Annealing fully dried PET at 200°C transforms the material to a Hoffman regime I/II structure, and the fracture toughness decreases to 6.5 MPa m^1/2. Hydrolysis also reduces the fracture toughness (K_c < 3 MPa m^1/2). In these low toughness materials, multiple crazing is not observed. In addition, the fatigue crack propagation response of PET is found to be superior in samples annealed to produce high fracture toughness as compared with samples annealed to produce low fracture toughness values.     

Adhesion measurement of interfaces between gelatin and poly(ethylene terephthalate) using microscratch technique

A microscratch technique was used to evaluate the adhesion between interfaces of a gelatin coating and poly(ethylene terephthalate) (PET) film. The interface was reinforced by nitrogen plasma treatment on the PET surface and subsequently by heat treatment of each gelatin/PET sample to promote interactions at the interface. In the microscratch test, a normal load controlled conical stylus with 50‐μm radius tip was drawn over the gelatin coating surface under a continuously increasing normal load until failure occurred in the sample. Optical microscopy and depth profiling of the scratch track were used to detect failure and the failure mechanism. The critical normal load (F_c) was defined as when gelatin detached from the PET substrate or when a complete removal or plowing of the gelatin coating on the PET substrate occurred. With increasing plasma treatment time and heating treatment temperature, the F_c for both debonding and coating removal increased, which showed that both failure mechanisms are related to the adhesion. Different thicknesses of the gelatin coatings were also prepared under the same plasma and heat treatment conditions. It was found that the F_c increased with increasing coating thickness. The result demonstrated that both failure mechanisms depended on the plastic deformation of the coating and substrate. The F_c for coating detachment increased linearly with increasing coating thickness whereas the F_c for coating removal increased sharply with increasing thickness. Annealing temperatures ranging from 20 to 80°C exhibited a strong effect on the F_c, which increased with increasing annealing temperature. These results demonstrate that the microscratch technique can be used to access interfacial adhesion and that the F_c is a qualitative parameter for the evaluation of adhesion strengths. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1960–1974, 2006     

亲水性PET共混材料的制备及性能研究

以机械共混法制备亲水性聚对苯二甲酸乙二醇酯(PET)共混材料,并通过接触角测定仪、差示扫描量热仪(DSC)和电子万能材料试验机等对共混材料的亲水性能、热性能和力学性能等进行研究与分析。结果表明,亲水处理剂聚乙二醇(PEG)、聚丙烯酸钠(PAAS)、聚乙烯吡咯烷酮(PVP)均能改善PET的亲水性能,影响PET的结晶性能,但亲水处理剂对PET的力学性能影响较小,其中PET/PEG共混材料的亲水性最优;随着PEG含量的增加,PET/PEG共混材料的亲水性先逐渐增强,当PEG含量高于5%后,共混材料的亲水性变化很小;且PET的结晶度随着PEG的加入呈现先增大后减小的趋势。     

PC／RPET共混合金的研究

采用回收聚对苯二甲酸乙二酯增粘以及加入增韧剂的方法,通过一步法熔融共混挤出得到了具有良好力学性能的聚碳酸酯／回收ＰＥＴ（ＰＣ／ＲＰＥＴ）合金。通过适当地增粘ＲＰＥＴ以及合适地选择增韧剂,只需加入２．５％的增韧剂 以得到力学性能与纯ＰＣ工程塑料相当的ＰＣ／ＲＰＥＴ共混合金。同时成本比纯ＰＣ大幅度下降。     

PET与PTT共聚酯的合成及其性能研究

采用直接酯化法合成了不同比例的PET与PTT共聚酯,研究了所得共聚酯的热性能、力学性能及染色性等与不同组成比之间关系。     

Melting,crystallization behaviors,and nonisothermal crystallization kinetics of PET/PTT/PBT ternary blends

The melting, crystallization behaviors, and nonisothermal crystallization kinetics of the ternary blends composed of poly(ethylene terephthalate), poly(trimethylene terephthalate) (PTT) and poly(buthylene terephthalate) (PBT) were studied with differential scanning calorimeter (DSC). PBT content in all ternary blends was settled invariably to be one‐third, which improved the melt‐crystallization temperature of the ternary blends. All of the blend compositions in amorphous state were miscible as evidenced by a single, composition‐dependent glass transition temperature (T_g) observed in DSC curves. DSC melting thermograms of different blends showed different multiple melting and crystallization peaks because of their various polymer contents. During melt‐crystallization process, three components in blends crystallized simultaneously to form mixed crystals or separated crystals depending upon their content ratio. The Avrami equation modified by Jeziorny and the Ozawa theory were employed to describe the nonisothermal crystallization process of two selected ternary blends. The results spoke that the Avrami equation was successful in describing the nonisothermal crystallization process of the ternary blends. The values of the t_1/2 and the parameters Z_c showed that the crystallization rate of the ternary blends with more poly(ethylene terephthalate) content was faster than that with the lesser one at a given cooling rate. The crystal morphology of the five ternary blends investigated by polarized optical microscopy (POM) showed different size and distortional Maltese crosses or light spots when the PTT or poly(ethylene terephthalate) component varied, suggesting that the more the PTT content, the larger crystallites formed in ternary blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

我国聚酯工业的发展现状及对策

综述了世界聚酯工业的发展的历史与现状,指出我国聚酯工业高速发展的同时存在的一些问题并对此进行了详细的论述。重点就现阶段我国聚酯工业如何更好发展,从产业链、工业结构、国产化、新技术、品牌战略、国际市场、研发等方面提出了相应对策。     

PET/PTT合金结晶形态的研究

采用XP-201热台偏光显微镜研究了对苯二甲酸乙二醇酯（PET）/对苯二甲酸丙二醇酯（PTT）合金等温结晶时的结晶形态及影响因素。研究结果表明：随着等温结晶温度的升高,PET/PTT(40/60)合金的结晶诱导期变长;在观察的时间范围内各样品的球晶尺寸随着时间的延长而增大;随着PTT含量的增加,样品球晶的线生长速率增大,球晶尺寸增大;对比不同温度下等温结晶的球晶形态,PET/PTT(100/0)样品在190℃结晶时球晶尺寸最大, PET/PTT(40/60)样品和PET/PTT(100/0)样品在180℃结晶时球晶尺寸最大; PET/PTT(0/100)样品等温结晶时呈现出了复杂的条带球晶。     

PET/PTT合金非等温结晶行为的研究

采用差示扫描量热仪对熔融共混制备的聚对苯二甲酸乙二醇酯（PET）/聚对苯二甲酸丙二醇酯（PTT）合金的非等温结晶行为进行研究。结果表明,在相同的降温速率时, 随着PTT含量的增加,PET/PTT合金结晶峰温度向低温方向移动,而且当合金中PET与PTT含量接近时,合金样品出现了双重结晶峰;在降温结晶的过程中,随着降温速率的增大,各合金样品结晶峰温度均降低,其结晶峰均宽化;采用Jeziorny法对上述非等温结晶过程进行了分析,分析结果表明,随着降温速率的增大,各合金样品非等温结晶速率常数增加,其Avrami指数在1~5之间,并且逐渐减小。     

PET／沸石分子筛复合材料制备及结晶行为与热性能研究

通过熔融共混方法制备了聚对苯二甲酸乙二醇酯(PET)/沸石分子筛复合材料,考察了沸石分子筛在PET中的分散状态;从定性和定量两个方面研究了其结晶行为和结晶动力学;分析了其热稳定性。结果表明,沸石分子筛在PET中分散良好;沸石分子筛对PET具有很好的成核效果和加速PET结晶的作用,平均结晶速率是纯PET的2～3倍;热稳定性也比纯PET有较大幅度提高。     

PTT／PET共混体系结晶行为和形态研究

利用差示扫描量热仪、正交偏光显微镜研究了聚对苯二甲酸丙二醇酯(PTT)、聚对苯二甲酸乙二醇酯(PET)及PTT/PET共混体系(质量比为25∶75)的结晶行为、形态和等温结晶动力学。结果表明,PTT/PET共混物中,少量的PTT部分地起到了成核作用,但在一定程度上阻碍了PET链段规则地进入晶格,影响了结晶速率。偏光显微镜观察到PET、PTT和PTT/PET共混物在120℃下1、20min的溶液滴膜有较清晰的球晶。     

PET/PLA共混物相容性和结晶性能的研究

研究了相容剂钛酸四丁酯[Ti(OBu)4]含量、聚乳酸(PLA)含量对聚对苯二甲酸乙二醇酯(PET)/PLA共混物相容性的影响,探讨了共混物的熔融和结晶行为,并对其结晶形貌进行了观察。结果表明,Ti(OBu)4含量为PLA的4%(质量分数,下同)时,PET/PLA共混物的相容性良好,但当PLA含量超过30%时,共混物出现相分离;PLA的加入使PET的结晶峰变窄,结晶速率增加,且结晶峰温度向高温方向移动;PLA的加入使PET的晶粒尺寸大幅减小,晶粒数目大幅增加,结晶更加完善。     

Improved adhesion property and electromagnetic interference shielding effectiveness of electroless Cu‐plated layer on poly(ethylene terephthalate) by plasma treatment

To develop high‐quality electromagnetic interference (EMI) shielding materials, the effect of plasma pretreatment with various gases prior to Cu plating was investigated. Plasma treatment increased the surface roughness in the decreasing order of Ar > O₂ > NH₃, but adhesion of the Cu layer on poly(ethylene terephthalate) (PET) film increased in the following order of O₂ < Ar < NH₃, indicating that the appropriate surface roughness and introduction of an affinitive functional group to Pd on the surface of the PET film were key factors for improving adhesion of the Cu layer. As investigated by XPS analysis, plasma treatment with NH₃ produced N atoms on the PET film, which enhances the chemisorption of Pd²⁺ on PET film, resulting in improved adhesion and shielding effectiveness of the Cu layer deposited on the Pd‐catalyzed surface, because of the high affinity of Pd²⁺ for nitrogen. Comparatively, O₂ plasma treatment allowed the chemisorption of more Sn²⁺ than of Pd²⁺ due to a lack in the affinity of Pd²⁺ for oxygen, resulting in the lowest Pd_3d/Sn_3d ratio; thereby, the lowest EMI–shielding effectiveness (SE) value was obtained. In addition, fairly low adhesion was obtained with Ar plasma‐treated PET, even though the PET surface was significantly etched with Ar plasma, due to introduced oxygen groups on the PET surface. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1369–1379, 2002; DOI 10.1002/app.10272     

湿度对单轴取向PET纤维结晶过程的影响

采用DSC研究了不同拉伸比的单轴取向PET纤维在不同湿度下的冷结晶过程。发现湿度可以诱导纤维双重结晶峰的出现。从DSC图可以看出,随着湿度的提高,结晶峰向低温移动,且分化成两个较小的结晶峰,结晶可在玻璃化转变温度之下发生。DSC数据处理结果表明,所得Avrami指数呈规律变化,由于湿度的影响,单轴取向PET纤维在低温时的结晶机理发生变化。     

Characterisation of shrinkage in oriented PET films and containers by thermomechanical analysis (TMA)

In this paper, we report from an extensive series of tests in which the thermal shrinkage behaviour of poly(ethylene terephthalate) (PET) homopolymer and copolymer films and containers has been studied by thermomechanical analysis (TMA). Several independent variables have been investigated, and the accuracy of dynamic TMA scans of temperature-dependent shrinkage has been verified by parallel measurements made isothermally. Typical shrinkage levels of biaxially oriented films, of draw ratios between 2.7 and 4.1, are of the order of 5% at 100°C. The magnitude of shrinkage increases with draw ratio, and any evidence to suggest that PET copolymer is marginally more prone to shrinkage is thought to arise from differences in strain-induced crystallinity induced by elongational deformations during processing. Correlations between measurements made on films and commercial containers are good enough to suggest that the simulation technique used is sufficiently valid for further experimentation on processing behaviour.     

Dye–fiber interactions in PET fibers: Hydrogen bonding studied by IR‐spectroscopy

Dye–fiber interactions are studied in poly (ethylene terephthalate) fibers by FT‐IR spectroscopy. It is shown for the first time that DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) serves as an easy applicable and accurate technique for the study of fibrous structures. This article focuses on the possible hydrogen bond interactions in the dye–fiber system, where the PET fibers are dyed with anthraquinone‐based disperse dyes. The dyes and related anthraquinone structures are studied in both the dilute solution state, the solid state, and as present in the PET fibers. It is proven that 1‐amino anthraquinones show strong “chelate‐type” intramolecular hydrogen bonding in all three states. In the fibers an important supplementary intermolecular hydrogen bonding with the C?O groups in the PET fiber is observed. The extend of hydrogen bonding seems to be prone to dye concentration variations. Further analysis by modulated differential scanning calorimetry links the hydrogen bonding to an intrinsic plasticizing effect of the dyes affecting the dye diffusion process. This thus offers a tool for the fundamental understanding of the dyeing process and possible observed differences in dyeing behavior in dye–fiber systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Preparation and properties of PET/PA6 copolymer/montmorillonite hybrid nanocomposite

From in situ polycondensation, a poly(ethylene terephthalate)/Polyamide 6 copolymer/montmorillonite nanocomposite was prepared, after the treatment of montmorillonite (MMT) with a water soluble polymer. The resulting nanocomposites were characterized by X‐ray diffraction (XRD), differential scanning calorimeter (DSC), nuclear magnetic resonance (NMR), dynamic mechanical analysis (DMA), and transmission electron microscopy (TEM). The results of DSC, ¹H NMR, and DMA proved that the nanocomposite synthesized was PET/PA6 copolymer/MMT nanocomposite, not the PET/PA6 blend/MMT nanocomposite. The results of XRD and TEM proved that the dispersion of MMT was improved observably after the introduction of PA6 molecular chain into PET. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2512–2517, 2006     

Improvement of adhesion of PET fibers to rubber by argon-oxygen plasma treatment

Polyethylene terephthalate fibers cords were modified with argon, oxygen, and successive argon/oxygen cold plasmas as a function of treatment time. Plasma treated cords were coated with resorcinol formaldehyde latex, then tested as rubber reinforcing materials. The peel strength was discussed with respect to the polar component of the surface energy and the etching of the fibers. An increased adhesion of ∼ 280% was obtained with 30 min argon plasma followed by 30 min oxygen plasma, at 75 W power and 40 Pa pressure without altering the traction strength of the fibers cords. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2321–2330, 1998     

PET／PTT共混体系在无定形区的相容性

计算了不同温度下PET/PTT、共混体系的混合自由能，预测了其在热力学上的相容性。通过对不同组分共混物DSC图谱的分析和对玻璃化转变温度的Fox方程及Gordon-Taylor方程的拟合以及冷结晶峰温随组分的变化，表明其为在无定形区相容的体系。针对组成接近的共混体系的玻璃化转变温度范围变宽的现象，使用扫描电镜观察共混物，未发现相分离现象，从而提供了PET／PTT体系相容性在形态方面的证据。