Zinc oxide (ZnO) nanoparticles were successfully prepared by a one-step precipitation reaction in an aqueous solution of zinc acetate and sodium hydroxide with stearic acid (SA) as the modifying agent. Hydrophilic composites of poly(ethylene terephthalate) (PET), poly(ethylene glycol), and ZnO nanoparticles were prepared further by in situ polymerization. The surface modification of ZnO and the microstructure and properties of prepared nanoparticles were investigated by relative contact angle measurements (CA), Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, and thermogravimetric analysis (TGA). Measurements of CA and XRD indicated that the surface-treated ZnO was hydrophobic and had a significant improvement in crystallinity with SA. Compared with the nanocomposites filled with the pure ZnO, the modified ZnO exhibits a better dispersion in PET–PEG matrix. TGA results showed that the presence of modified ZnO nanoparticles can improve the thermal stability of PET–PEG matrix. CA and low field nuclear magnetic resonance methods were used to investigate the hydrophilic behavior of nanocomposites. The results revealed that modified nanoparticles had a positive effect on the bound water absorption. A simple model for the interactions between ZnO, SA, and PET–PEG matrix was proposed. POLYM. COMPOS., 37:1830–1838, 2016. © 2015 Society of Plastics Engineers

Poly(ethylene terephthalate)/polyethylene glycol (PETG) copolymers with molecular weight of PEG varied from 800 to 20,000 g/mol were synthesized by melt macromolecular interesterification method. The results of contact angle and water adsorption capacity reveal that the molecular weight of PEG has a positive effect on the hydrophilic behavior of PETG copolymers. The interaction between water molecule and PETG copolymer was investigated through each relaxation time component by the Carr–Purcell–Meiboom–Gill sequence of low-field nuclear magnetic resonance. The analysis of T₂ component with different states shows that with the increase of molecular weight of PEG, the water adsorption capacity increases due to the microphase separation behavior of PETG copolymers. This result was also supported by the endothermic behavior of H₂O/PETG mixtures measured by differential scanning calorimetry (DSC). Water molecule was tightly bound with PEG flexible chains at first stage, and then water molecules could swell the PETG copolymers, additional water permeating into the swelling copolymers. POLYM. ENG. SCI., 55:2195–2204, 2015. © 2015 Society of Plastics Engineers

It is widely accepted that the melt processibility of polytetrafluoroethylene (PTFE) is poor. In this article, a high-molecular-weight PTFE was extruded smoothly with a modified die; and critical shear rate could be raised to 4 s⁻¹, using a die with L/D (length to diameter) ratio of 200. Meanwhile, we compared the current PTFE fiber spinning method with melt spinning to investigate the effects of high-temperature treatment on the drawability of PTFE and found that the processing sequence could play a key role. The deformation imposed before or after the high-temperature treatment could determine whether the fibrillation can be achieved continuously and effectively. Based on the experiment phenomenon, together with the results of differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy characterization, we proposed a model to describe the submicron structural change of PTFE during extension. From this model, the fundamental mechanism for the poor melt processibility of PTFE was elucidated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A new class of polyether amide thermoplastic elastomers (TPAE) was synthesized via a three-step polymerization route. In the first step a binary carboxyl terminated polyamide-6 (PA6) with relatively low number-average molecular weight was prepared via a caprolactam hydrolytic ring-opening process. 4,4′-Diphenylmethane diisocyanate (MDI) was reacted with the PA6 to produce PA6–MDI hard segments in the second step. Chain extension of the hard segments with poly(tetramethylene glycol) was the last step to furnish a series of new TPAEs. Structural characterization, physical properties and the effects of reaction conditions on the properties of the copolymer were investigated by infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy and other analytical techniques. Possible side reactions and phase separation are reported. Copyright © 2011 Society of Chemical Industry