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Polystyrene (PS) honeycomb patterned porous films filled with titanium dioxide (TiO2) nanoparticles were prepared by a modified breath figure method. The honeycomb patterned porous films filled with TiO2 nanoparticles were obtained by pouring titanium butoxide over partially dried PS solution during the fabrication of the PS films under humid conditions. TiO2 nanoparticles were obtained by the hydrolysis...
Localized shear flow was imposed by pulling glass fiber in polyethylene (PE) melt below and above its equilibrium melting point (141.6 °C). Immediately after the cessation of shear, the structure around the fiber was investigated with in-situ synchrotron radiation scanning X-ray microdiffraction (SR-μSXRD), which had spot area of 4.2 × 4.5 μm2 and step size of 6 μm. Results indicate that crystalline...
Hydrogels with good mechanical properties have received intense interests recently. Simplifying the method to prepare tough hydrogels and meantime incorporating additional properties such as anti-swelling, self-recovery, healing ability, facile processability, and recyclability will likely expand their applications significantly. Here we report a simple method to prepare tough hydrogels: dripping...
High lignin-containing cellulose nanocrystals (HLCNCs) were successfully isolated from hydrothermally treated aspen fibers and freeze-dried and compounded with poly (lactic acid) (PLA) by extrusion and injection molding. As a comparison, PLA composites containing commercial lignin-coated CNCs (BLCNCs) were also produced. HLCNCs showed higher crystallinity, larger surface area, lower degree of agglomeration,...
Cyclic polymers synthesized by ring-closure method from linear precursors contain some of linear contaminates. In this work, the origin of linear contaminates in cyclic polystyrenes (c-PS) is demonstrated by the coupling of liquid chromatography at the critical condition (LCCC) with matrix-assisted laser desorption/ionization time-of-flight mass spectra. The linear contaminates are revealed to be...
The properties of the dental resin composites have been studied extensively with several different methods including infrared and Raman spectroscopy, volume dilatometry, and mechanical analyses. Photo-calorimetry has also been used to measure the kinetics and extent of polymerization, but many of the variables associated with this technique remain to be fully defined and tested to enable quick and...
We adopt here a novel approach to identify the para- and meta-aramid fibers using the available free volume in them. Positron Annihilation Lifetime Spectroscopy (PALS) has been employed to characterize the free volume in these fibers. The free volume content in the para-variety (Kevlar) is less and the free volume distribution is narrow as compared to its meta-counterpart (Nomex). The results are...
Nitroxide-functionalized polymers are attractive macroinitiators for nitroxide mediated polymerization (NMP) and further modification of polymers. In this work, a facile reaction method to chemically bond nitroxide groups to polymer chains has been demonstrated with incorporation of 2,2,6,6-tetramethylpiperydinyl-1-oxyl (TEMPO) groups into poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) through the atom...
Alginate hydrogels have shown great promise for applications in wound dressings, drug delivery, and tissue engineering. This report details the fabrication and rheological properties of a multicomponent hydrogel consisting of alginate and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers, and the achievement of thick, castable gels with tunable, thermoreversible...
We investigate surface sealing behavior of polymer hollow particles with an open hole on their surfaces during thermal annealing. A series of processes involving synthesis of polystyrene (PS) solid particles, their swelling with the use of a swelling solvent, and freeze-drying enable us to make hollow particles with a controllable structure including outer/inner diameter and surface hole size. Based...
Composition-, temperature-, and polarization-dependent low-frequency Raman and terahertz (far-infrared; FIR) spectra were measured for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(HB-co-HV)) with PHB-type crystal structure and PHV-type crystal structure to investigate their intermolecular interactions. Band assignments were attempted by comparing the low-frequency Raman and terahertz (FIR) spectra...
Waste electrical and electronic equipment (WEEE) have attracted attention due to their high pollutant potential and increasing volume produced in recent years as function of the modernization and continuum substitution of the current equipment that quickly become obsolete. Among polymeric materials that make up the WEEE, acrylonitrile-butadiene-styrene (ABS) and high-impact polystyrene (HIPS) copolymers...
The utility of amorphization of drug molecules, such as enhanced solubility, dissolution rate and oral bioavailability, has been well exemplified in the literature. Yet, the application of this technique is often hindered by the crystallization liability of the drug. Amorphous solid dispersions (ASD), in which polymers are mixed with the amorphous drug, are often utilized to maintain the amorphous...
Crystals of precise acid- and ion-containing polyethylenes were prepared from solution. While large pendant groups on polyethylene backbones are typically excluded from the crystalline domain, the precisely-placed acid and ionic functional groups are accommodated into the solution-grown crystals. Polyethylene containing carboxylic acid pendant groups on every 21st carbon atom (p21AA) grows into rectangular...
Compared to polysulfone (PSF), the effects of chemical structure on gas separation performance of polyethersulfone (PES) are rarely in-depth studied. To explore the potential of various PES polymers as gas separation membranes, PES containing four different backbone structures have been synthesized. They are polyphenylsulfone (PPSU), poly trimethyl benzene ethersulfone (TPESU), polyethersulfone (PESU)...
We present a high-resolution study of the viscoelastic response of a thermoplastic alloy using a multifrequency method called intermodulation atomic force microscopy. We quantitatively characterize the response in terms of calibrated dynamic force quadrature curves, showing the conservative and dissipative forces at each image pixel as functions of the oscillation amplitude for industrial polymer...
Self-assembly induced increase of magnetic susceptibility for the tadpole-shaped block copolymer based on paramagnetic FeCl4 pyridinium was reported in this work. The tadpole-shaped block copolymer was prepared by sequential reversible addition-fragmentation chain transfer polymerization of styrene (St) and 4-vinylpyridine (4VP) at the presence of chain transfer agent-modified polyhedral oligomeric...
This paper develops an approach for predicting cohesive energy density and solubility parameter of thermoset polymers directly based on atomistic simulations. The cohesive energy density and solubility parameter are obtained from the intermolecular nonbond energy, after excluding the intramolecular nonbond energy from the total nonbond energy by computationally characterizing the detailed network...
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