Acid-base and surface energy characterization of grafted polyethylene using inverse gas chromatography

Preparation and Properties of Fluorinated Acrylate Resin Film with Resisting Fluid for Dairy Packaging

Nowadays there is a widespread phenomenon of dairy residue, which causes a great deal of waste. To solve this problem, the copolymer of fluorinated acrylate resin was synthesized and the resisting fluid film was prepared. The proprieties of the fluorinated acrylate resin coatings were characterized by scanning electron microscope (SEM), measuring the contact angle of the droplet liquid on the surface of the coating, the influence of acidic environment, the adhesion to substrate material, and analyzing thermogravimetry (TG) and Gas Chromatography (GC). It was found that the fluorinated acrylate resin film is a kind of resisting fluid film with excellent property and it is safe, nontoxic and readily biodegradable. So it was said a very potential dairy packaging material.

Surface characterization of poly(methyl methacrylate-co-n-butyl acrylate-co-cyclopentylstyryl-polyhedral oligomeric silsesquioxane) by inverse gas chromatography

The surface properties of poly(methyl methacrylate-co-n-butyl acrylate-co-cyclopentylstyryl polyhedral oligomeric silsesquioxane) (poly(MMA-co-BA-co-styryl-POSS)) were studied by means of inverse gas chromatography (IGC) using 10 non-polar and polar solvents as the probes. Thermodynamic parameters of adsorption, e.g., specific retention volume, the dispersive component of the surface free energy, the specific interaction contribution to the free energy of adsorption and the acid/base constants were obtained to investigate the interactions between the surfaces of the copolymers and different solvents. It was found that incorporation of styryl-POSS into polymer resulted in increasing interactions between polymers and solvents, dispersive component of surface free energy of polymer and acidity of the surfaces of the polymers. The more the styryl-POSS were embedded, the stronger the interaction between the polymer surface and solvent, the dispersive component of the surface free energy and the acidity of the polymer surface were.

Changes in surface properties by granulation and physicochemical stability of granulated amorphous cefditoren pivoxil with additives

The evaluation of the physicochemical stability of granules of amorphous cefditoren pivoxil (CDTR-PI), alone or with polymers, demonstrated that granulated amorphous CDTR-PI with hydroxypropyl methylcellulose was the most stable. We measured glass transition temperature by differential scanning calorimetry (DSC). The molecular mobility of the whole granules did not change, and it was not consistent with the results of the evaluation of physicochemical stability. Peak shifts were observed in IR spectra of amorphous CDTR-PI with polymers after granulation, and the shifts were similar to those observed for spray-dried samples. Furthermore, the shifts were not observed after the granules were ground. Acid-base parameters, which were also measured by inverse gas chromatography (IGC), changed after granulation. These results suggested that on the surface of the granules, CDTR-PI and the polymers would be mixed monomolecularly, as in the spray-dried samples. The changes in the molecular state of a drug when mixed monomolecularly with a polymer on the surface of granules were successfully confirmed by IGC and IR.

Surface free energies of silica fillers and their relation to the adsorption of poly(ethylene terephthalate)

The surface free energy of modified silica as well as of PET oligomers was evaluated through measurements of specific retention volumes of several probe molecules by use of the adsorption and adhesion principles in inverse gas chromatography. The nondispersive component of surface free energy of most silica fillers was larger than the dispersive component and the acidic component was much larger than the basic one, which indicated that the surfaces of most silica fillers were rather acidic. These methods were also applied to PET oligomer and it was found that the surface free energy of PET oligomer, regardless of preparation method, consisted of an almost dispersive component, suggesting that the surface of PET was neutral. The amount of PET oligomer adsorbed for the heat-treated silica fillers in acidic solvent increased linearly with increased acidic component of the surface free energy, which indicates that the acidic component of the surface free energy may be responsible for the adsorption. However, the adsorption amount on modified silica is much smaller than that for the heat-treated silica fillers because of steric hindrance caused by the attached organic chain, suggesting that the adsorption cannot be determined only by the surface free energy.

Influence of the microporosity and surface chemistry of polymeric resins on adsorptive properties toward phenol

In this work, the effects of the microporosity and chemical surface of polymeric adsorbents on adsorptive properties of phenol were investigated. Textural parameters of four kinds of polymeric resins, namely AB-8, D4006, NKA-II and D16 resin, were separately measured by ASAP 2010. The surface chemistry of these polymeric resins was determined by means of inverse gas chromatography (IGC) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Static equilibrium adsorption experiments were carried out to obtain the isotherms of phenol on the polymeric resins. It was shown that NKA-II and AB-8 resin possessed relatively high BET surface areas and micropore volumes, while D4006 and D16 resin possessed comparatively low BET surface areas and micropore volumes. The results of IGC experiments revealed that NKA-II resin had extraordinary high specific component of the free energy of adsorption both for polar acetone and benzene probe, and thus extraordinary strong surface polarity compared to the other polymeric resins. It was also found that the isotherm of phenol on NKA-II was much higher than that on the other polymeric resins due to its strongest surface polarity and largest micropore volume among four kinds of resins. These experimental observations indicated that adsorption of phenol on the polymeric resins depended greatly on their microporosity and surface chemistry. The well-developed microporosity and the strong surface polarity would improve the adsorption of phenol on the polymeric resins.