Changfa Xiao

Investigation on the thermal behaviors and mechanical properties of ultrahigh molecular weight polyethylene (UHMW‐PE) fibers

Fibers of ultrahigh molecular weight polyethylene (UHMW-PE) were prepared with the gel fiber drawing method, and the solvent and extraction solvent used were a general kerosene and gasoline, respectively. The thermal behaviors and mechanical properties of the fiber were studied using thermal analysis, a wide-angle X-ray diffractiometer, density, the sound orientation factor, as well as mechanical property measurement. The results showed that the morphology of macromolecular chains was changed from the folded state to an extendedcain structure with increasing of the drawing ratio. In addition, the crystal form of the fiber also changed. These changes were more evident while the drawing ratio exceeded 20. The tensile strength, similar to the modulus of the fibers, increases with an increasing draw ratio in the range that we researched, whereas the sonic velocity orientation factor and the degree of crystallinity increase slowly when the draw ratio is over 30.

Diffusion and Swelling Behavior in Treatment of Oil Spill to Semi-Interpenetrating Polymer Network from Oil-Absorptive Fiber

In this article, diffusion and swelling behaviors in the absorption process are investigated. The absorption about crude oil diluted with toluene floating on water shows the affinity to oil. The diffusion mode is determined by diffusion exponent n, and the values suggest that the diffusion process deviates slightly from normal Fickian behavior but not completely non-Fickian in short immersion time. The data indicate that the adsorption process of fiber onto the toluene is fit for the second-order kinetic model. Absorbency has been promoted with the increasing temperature because molecular motions are accelerated and ester-containing polymer has the high efficiency. Furthermore, Langmuir and Freundlich isotherms are adopted to describe the adsorption process. The parameters show respectively monolayer adsorption, and multilayer adsorption even heterogeneous adsorption is concomitant.

Characterization of membranes prepared from PVDF/PAN blends and their modification with hydrolysis

In this study, the melt-spinning and stretching processes were used to prepare polyvinylidene fluoride (PVDF)/polyacrylonitrile (PAN) blend hollow-fiber membranes. These blend membranes have a higher tensile strength than those prepared via the wet phase inversion method. The influence of stretching temperature and draw ratios on the membrane microstructure, pure water flux, and porosity of the membranes was studied. The draw ratio and the stretching temperature can greatly affect the morphology and the permeation performance of the membranes. The Fourier transform infrared spectra demonstrate the differences in the PVDF/PAN blend membranes before and after hydrolysis. The water flux of the hydrolyzed PVDF/PAN blend membranes is sensitive to pH value and salt ionic strength. The effects of different salt ions on the permeability of the hydrolyzed membranes were also investigated.

Thermal Behavior of Polyarylate/Polyester Blend Fibers

The thermal behavior of polyarylate/polyester (PHET) blend fibers is investigated by means of DSC thermal analysis. The results show that the crystallization behaviors of the two components in the PHET fibers, poly(4-hydroxybenzoic acid/6-hydroxyl-2-naphthonic acid) [P(HBA/HNA)] and poly(ethylene terephthalate) (PET), are independent of each other during annealing, in contrast to their crystal melting behaviors. The degree of three- dimensional order of P(HBA/HNA) is not as good as that of PET. and the structural regularity of P(HBA/HNA) has been improved to a certain extent in the PHET blend fibers.The thermal behavior of polyarylate/polyester (PHET) blend fibers is investigated by means of DSC thermal analysis. The results show that the crystallization behaviors of the two components in the PHET fibers, poly(4-hydroxybenzoic acid/6-hydroxyl-2-naphthonic acid) [P(HBA/HNA)] and poly(ethylene terephthalate) (PET), are independent of each other during annealing, in contrast to their crystal melting behaviors. The degree of three- dimensional order of P(HBA/HNA) is not as good as that of PET. and the structural regularity of P(HBA/HNA) has been improved to a certain extent in the PHET blend fibers.

Synthesis and Property of Butyl Methacrylate-Butyl Acrylate-Acrylic Acid Terpolymer With Absorptive Capacity

Butyl methacrylate-butyl acrylate-acrylic acid terpolymer was synthesized by suspension polymerization with benzoyl peroxide as an initiator and poly(vinyl alcohol) as a dispersing agent to absorb organic liquids, and then the terpolymer was modified to absorb distilled water, NaCl aqueous solution, and toxic metal ions by swelling in isopropyl alcohol and hydrolysis in sodium hydroxide aqueous solution. The morphology changes during the liquid absorption process were observed via a polarizing light microscope. The thermostabilities of the original and modified terpolymers were tested in a thermogravimetric analyzer. The test results indicated that the unmodified terpolymer could absorb a certain amount of toluene, trichloroethylene or tetrachloroethylene to become a swollen system, and its remaining (residual) ratio was more than 75% after absorbing the organic liquids for 24 h. The modified terpolymer not only had a marked capacity to absorb distilled water and NaCl aqueous solution, but also showed a significant absorption of toxic metal ions; e.g., its saturated absorbency of Cu2+ could reach 421.0 mg/g. The morphology changes demonstrated that the modified terpolymer could be swollen in distilled water, forming a gel-like structure. The results obtained from thermogravimetric analysis revealed that the thermal stability of the modified terpolymer was better than that of the unmodified terpolymer.

Highly Hydrophobic Conductive Polyester Fabric Based on Homogeneous Coating Surface Treatment

ABSTRACT A highly hydrophobic conductive polyester (PET-HE) fabric was prepared by a simple two-steps method. Firstly, homogeneous coating (the mixture of PET and carbon black (CB)) was uniformly coated on the PET fabric, which through curing in water coagulation bath and electrically conductive (PET-E) fabric was prepared. Then the solvent-induced crystallization process was adopted to PET-E fabric to endow the hydrophobic property. Investigations showed that PET-HE treated fabrics exhibited better hydrophobic and conductivity when the content of PET is 9wt% and the content of CB is the range of 8wt%-10wt%. The prepared polyester fabric proved to have such features as WCA was about 145°and surface resistance was about 300 Ω.GRAPHICAL ABSTRACT Graphical Abstract

Fabrication and Characterization of Functional Fiber Based on Polymethacrylate/Polypropylene Alloy via in situ Compatibilization

A poly(butyl methacrylate) (PBMA)/polypropylene (PP) blended fiber was prepared via reactive extrusion and melt spinning based upon the mechanism of in situ compatibilization, and its capacity to absorb organic liquid, gel fraction and remaining ratio were investigated. In addition, the miscibility between PBMA and PP, crystallization behavior and morphology of the blended fiber were characterized. The results indicate the blended fiber can absorb a certain amount of liquid, such as toluene, chloroform, and trichloroethylene, etc., and its absorption capacity gradually weakens and even disappears with increasing the mass fraction of PP in the mixture of PBMA and PP. The results obtained by thermogravimetric (TG) analysis show the miscibility between PBMA and PP becomes better due to an increase of the interactions between two phases under the effect of in situ compatibilization reaction, and the blended fiber has relatively better thermal stability with an increase in the mass fraction of PP. X-ray diffraction (XRD) results demonstrate the additional amount of PP has a significant impact on its crystallization capacity for the blended fiber, along with in situ compatibilization reaction. The results observed via field emission scanning electron microscope (FESEM) reveal that PP can efficiently improve the spinnability of PBMA, and endow the blended fiber with a near-optimal morphology. However, in situ compatibilization reaction also has a marked influence on the surface and cross-section morphology of the blended fiber.